Aces High Bulletin Board
General Forums => Aircraft and Vehicles => Topic started by: Ardy123 on June 06, 2010, 12:39:17 AM
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I should conduct more tests but often in the MA it feels like brewsters dive a bit too well and hold their e much longer than I would expect (compared to the I-16). Sadly all I have is anicdotal information, "pilot A says a f4f could out dive a brewster", etc..
main question...
Unlike the P51 or Me 109s or many of the more 'famous' planes of WW2, there doesn't appear to be much information on the filght characteristics of the finish version of the arplane. furthermore, there are almost no finish Buffalows in exsistance today. What sources have people found?
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Brewster sure does seem to beat the heck out of even FM2 in turn rate & radius, acceleration seems quite a bit better, too. Verdict: Clown Wagon :banana:
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Unlike the P51 or Me 109s or many of the more 'famous' planes of WW2, there doesn't appear to be much information on the filght characteristics of the finish version of the arplane. furthermore, there are almost no finish Buffalows in exsistance today. What sources have people found?
IIRC much of the info for modeling the Brewster came from actual, real-life Finns who play AH2.
:rock
wrongway
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...in the MA it feels like brewsters dive a bit too well and hold their e much longer than I would expect (compared to the I-16).
And you know this basis what analysis?
"It is a capital mistake to theorize before one has data. Insensibly one begins to twist facts to suit the theories, instead of theories to suit facts." (Sherlock Holmes)
Looking for some real Brewster data and not pilot anecdotes? For starters here's some. Go knock yourself out ;).
7 NACA Reports:
Power-on wind tunnel test F2A 1/8-scale model
Power-on longitudinal-stability and control tests F2A 1/8-scale model
Power-off wind tunnel test F2A 1/8-scale model
Additional power-on wind-tunnel test F2A 1/8-scale model
F2A-2 compressibility flight test data
F2A-2 lateral control flight test data
Calculated and measured turning peformance of F2A-3 including flaps
Here is the NTRS search results for the above:
http://ntrs.nasa.gov/search.jsp?N=0&Ntk=all&Ntx=mode%20matchall&Ntt=f2a
Additionally:
NACA F2A-2 flight tests with various flap configs:
http://hdl.handle.net/2060/19930092639
NACA Drag Analysis which includes tests and data on the XF2A-1:
http://hdl.handle.net/2060/19930092657
http://hdl.handle.net/2060/19760019077
Tango
412th FS Braunco Mustangs
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Midway commander realises they're under attack.
CO: What have we got?
XO: We can put up half a dozen F4Fs and 15 Brewsters.
CO: Damned relics!
:D
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Nice find there dtango, problem is those wind tunnel tests showed the Brewster to be better than it turned out to be in combat. They also don't show that the "export" model B-239 sold to Finland were F2A-1s stripped of all extraneous equipment including armor, which lightened them up considerably compared to thier U.S. Navy/Marines counterparts and they weren't tested under combat conditions until the Finns got them. The overall combat service record for the Buffalo was bad, especially against the Japanese Ki-43 and A6M, against antique Russian aircraft it turned out much better.
Ardy, if you want a close appoximation of the B-239 performance, just look up the F2A-1 with the Wright Cyclone R-1820-34 (940hp) or R-1820-G5 (950hp), I've found both mentioned. Oddly, some references claim the Finnish Buffalo produced 1000hp with the R-1820-G5 engine. Finnish ingenuity?
There is some interesting information (for what it's worth) here:
http://www.warbirdforum.com/buff.htm (http://www.warbirdforum.com/buff.htm)
Good luck.
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Nice find there dtango, problem is those wind tunnel tests showed the Brewster to be better than it turned out to be in combat.
*Sigh*. And you know this how? ;)
Tango
412th FS Braunco Mustangs
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*Sigh*. And you know this how? ;)
Tango
412th FS Braunco Mustangs
Well, ok that was my assessment after lots of hairy eyeball reading because I object to having the Finnish B-239 substituted for F2A-1/2s in PTO special event setups. Specifically the 1941 1/8 scale tests didn't account for weight differences and modifications in post production aircraft...armor plate, self sealing fuel tanks, radio equipment, added weapons/ammo, propeller types, etc...
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Fact is the Brewster is easy mode in the MA, greats guns, holds E , turns great, and dives well......eny should be alot lower(close to the hurri 2c)
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Fact is the Brewster is easy mode in the MA, greats guns, holds E , turns great, and dives well......eny should be alot lower(close to the hurri 2c)
...slow. Can't get out of it's own way....
Sure it turns about like a Zero or Hurricane but you are hard pressed to land anything you don't kill right over your own base because you get run down by almost, if not all, other aircraft in the arena.
All a smart pilot has to do to kill a Brew is extend, climb, reverse, repeat. Don't try and fight to it's strength's, round and round, and it's an easy kill.
wrongway
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Well, ok that was my assessment after lots of hairy eyeball reading because I object to having the Finnish B-239 substituted for F2A-1/2s in PTO special event setups. Specifically the 1941 1/8 scale tests didn't account for weight differences and modifications in post production aircraft...armor plate, self sealing fuel tanks, radio equipment, added weapons/ammo, propeller types, etc...
This.
Giving the Allies the B-239 in Pac scenarios isn't very fair to the Japanese as it gives the Allies a fighter that can turn with the A6M when there shouldn't be an Allied fighter there that can turn with the A6M.
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...slow. Can't get out of it's own way....
Sure it turns about like a Zero or Hurricane but you are hard pressed to land anything you don't kill right over your own base because you get run down by almost, if not all, other aircraft in the arena.
All a smart pilot has to do to kill a Brew is extend, climb, reverse, repeat. Don't try and fight to it's strength's, round and round, and it's an easy kill.
wrongway
Yea extending is easy, but if someone brings one to a bnz fight it can do just that....better then F4Us....
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If you lose to a zeke in an brew its on you. The later model zeke will Easily handle the brewster in an E fight and the early one has the edge in angles and is marginally double superior. The big issue here is that very few folks who fly the zeke are used to being put in a position where they have to fly an E attack vs an angles attack. The reality is that the Brewster and the Hawk75 were both excellent planes for their time. At Midway they were outnumbered, tactically at a disadvantage and facing very seasoned pilots. Floyd Parks put his best pilots in the few F4F's he had, The records I've seen credit the F2A-3's with 5 kills and 2 probables spread over 4 pilots, 3 of which were USMC. Overall VMF-221 went into action with 11 pilots USMC and 14 officially rostered as USMCR. My inference is that the unit was simply the best available and not truly combat capable in the sense that it was not fully "up to speed". This mirrors the issues with the P-39s that literally had to be assembled in Australia by there crews and then flown into combat in Port Moresby. Compare the results the French and Finns got with the Hawk75/Brewster and the Russians with the P-39 and you get a feel for what effect training, familiarization and pilot selection play in air combat results...nothing at all wrong with the Brew IMO....exactly what it should be...
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Granted Humble the A6M2 shouldn't have much trouble with the B-239 but something about the way it's modeled in AH, if that is how the thing performed in real life, they should have sent the Finns to the PTO against the Japs. The kill/loss record for the F2A-3s at Midway was 17 went up and 5 returned. The kills credited were mostly bombers with a couple of possible Zekes. If the B-239 in AH had the same flight characteristics as the F2A-3 nobody would be complaining about it in special event setups since it was the heaviest and least maneuverable of the Buffaloes. Flight tests and pilot testimony show the F2A-2 was the most maneuverable version the U.S. flew but was considered slow for its time, and even it only had a 950hp engine. My understanding is the B-239 in AH is the F2A-1, lightened up by a couple of hundred pounds and equipped with a 1000hp engine. The U.S. Navy F2A-1 only had a 940hp engine.
There is just something hinky about it. If the A6M2 and early 109s have faster level speeds and can climb faster there should be no reason a Brewster should be able to stay on either one that is climbing out, but they do it often.
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Fact is the Brewster is easy mode in the MA, greats guns, holds E , turns great, and dives well......eny should be alot lower(close to the hurri 2c)
Gee...it seems like every plane in the planeset is "easy mode" for you. Hubris?
ack-ack
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Lots of different issues being tossed in here. The title of the thread and ardy's OP deals specifically with 1) B239 dive performance, 2) B239 energy retention. Ardy (and probably others) has questioned how the B239 performs relative to other aircraft in these areas in AH. The question about the performance is stated in a way as if it's known objective fact. There are opinions and then there are facts. If it's indeed a fact then people need to present the data and the analysis to demonstrate the fact.
I've purposely tossed data out there to ardy and for anyone else to examine to help them analyze the data to see if their theory is indeed fact or not.
Why is some of the data I pointed out relevant? There's a scattering of F2A variants listed in the reports none of them specifically say B239 so none of them are useful right? It would be foolish to dismiss them in this manner. I'm tempted to be obtuse about it all and stop there because in my old age I have neither the time nor energy anymore to explain why it's relevant :). I'll at least toss some bones out there!
1) Are you curious about the dive performance of the F2A? Well the "Compressibility Phenomena" report has dive time history data for an F2A-2 at ~5500 lbs going from 0 to max dive limit. If you don't think a 5500 lbs F2A-2 is similar enough to a B239 then just apply the aerodynamics & adjust for whatever differences you think the extra horsepower might mean on the dive performance.
2) Want to know the energy retention / sustained level turn performance of the F2A? Look at the "Calculated & Measured Turn Performance of a F2A-3" report which gives you performance of a F2A-3 at 6500 lbs from clean to full flaps. Apply the aero adjusts and calculate to see what the effect might be by lightening the the load and reducing the horsepower to match that of a B239.
By the way gyrene- just a point of reference, the B239's engine is rated at 1000 hp military at sea level. The F2A-2/3 is rated at 1200 hp military at sea level.
Tango
412th FS Braunco Mustangs
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By the way gyrene- just a point of reference, the B239's engine is rated at 1000 hp military at sea level. The F2A-2/3 is rated at 1200 hp military at sea level.
R-1820-40 not the R-1820-22 or 34...I've been looking at the wrong engines, and there is ~100hp discrepancy between references. :huh
Thanks for pointing it out dtango... :aok
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Well, ok that was my assessment after lots of hairy eyeball reading because I object to having the Finnish B-239 substituted for F2A-1/2s in PTO special event setups.
Actually, it's not substituting for F2A-1/2s in PTO special events setups at all. It's substituting for:
F2A-3 (USMC)
B-339 (Dutch)
B-339E (British/Commonwealth)
From what I gather, the 339 used by the Dutch wasn't TOO far off the 239 we actually have. I think I read the British overloaded the 339E even worse than what the F2A-3 was.
The best option is to add the F2A-3 as a separate aircraft from the 239. That would cover the widest variety of aircraft, as the F2A-1/2 were already out of combat by the beginning of the war. This would give the F2A-3 for the Americans and 339E, with the 239/339 for the Finns/Dutch.
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R-1820-40 not the R-1820-22 or 34...I've been looking at the wrong engines, and there is ~100hp discrepancy between references. :huh
Thanks for pointing it out dtango... :aok
You bet. Dean lists in AHT the B239 using a R-1820-G5. Graham White says the G series Wright R-1820's achieved improved performance due to inclusion of additional cooling fin area and a redesigned two-piece crankcase.
Tango
412th FS Braunco Mustangs
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The kill/loss record for the F2A-3s at Midway was 17 went up and 5 returned. The kills credited were mostly bombers with a couple of possible Zekes.
Context?
On the morning of June 4, Admiral Nagumo launched his first strike with 108 aircraft, 36 Nakajima B5N2 Kate torpedo bombers, 36 Aichi D3A1 Val dive bombers and 36 Mitsubishi A6M2 Zero
So, 17 Buffaloes and 7 Wildcats, with unseasoned pilots, attacked 108 Japanese veteran pilots....
It had to be the planes....
wrongway
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B-239s may have had one engine, but that engine wasn't necessarily what the Finns put into it. Remember they were scrambling for anything they could, similar to the AVG. I think they put the engines from a DC-3 in them, or some other transport?
Saxman, the 339 was an export version of the F2A3.
239s would have less horsepower and less efficient props than the F2A2s.
Also, the Brewster was supposed to be somewhat unstable, and yet in-game is probably one of the better gun platforms. Before being shipped to Finland, the pilot armor, the self-sealing fuel tanks, and the tail hook were removed. Note that the Finns themselves restored the pilot armor once they received them.
Overall the weight of a tail hook and self-sealing fuel tanks isn't that much, yet somehow we've been given a Brew in AH that performs like a zeke. Something that never happened in real life. We're talking 100kg and change between the dry weights of the B-239 and the F2A2 here. That's not going to make a total pig that suffers in all theaters suddenly become a wunder-plane.
Overall it's like Karnak says, unfair to use it in any PTO setup.
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The Brewster B-239 is NOT the crappy Buffalo. the Buffalo was the American Brewster F2A2 and the F2A3 that was weighed down substantially with too much armor. The B-239 is a lighter and more maneuverable Brewster. If you want them in PTO scenarios we need them to be the F2A2s and F2A3s. The 239 was the Swedish version which outflew the I-16s and had approximately a 60 to 1 K/D versus the EW Russian aircraft. Many Swedish aces scored more than 20 victories without being shot down. One ace scored over 60 kills against the Russians. The Dutch in the PTO had the 339 which was almost like the 239 in maneuverability but could not stand against the A6M2s that the japanese used. Almost no Dutch Brewsters killed any Japanese.
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B-239s may have had one engine, but that engine wasn't necessarily what the Finns put into it. Remember they were scrambling for anything they could, similar to the AVG. I think they put the engines from a DC-3 in them, or some other transport?
Saxman, the 339 was an export version of the F2A3.
239s would have less horsepower and less efficient props than the F2A2s.
Also, the Brewster was supposed to be somewhat unstable, and yet in-game is probably one of the better gun platforms. Before being shipped to Finland, the pilot armor, the self-sealing fuel tanks, and the tail hook were removed. Note that the Finns themselves restored the pilot armor once they received them.
Overall the weight of a tail hook and self-sealing fuel tanks isn't that much, yet somehow we've been given a Brew in AH that performs like a zeke. Something that never happened in real life. We're talking 100kg and change between the dry weights of the B-239 and the F2A2 here. That's not going to make a total pig that suffers in all theaters suddenly become a wunder-plane.
Overall it's like Karnak says, unfair to use it in any PTO setup.
all negative information about the Brewsters were about the American Buffalo versions. The 239 was a somewhat ok aircraft for the Early War and the 339 was up there with it. but both could not out fly any Japanese aircraft. By the way Karnak, 100kg (250lbs) weight difference on a plane as big as my thumb is a MASSIVE difference in weight change.
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Actually, it's not substituting for F2A-1/2s in PTO special events setups at all. It's substituting for:
F2A-3 (USMC)
B-339 (Dutch)
B-339E (British/Commonwealth)
From what I gather, the 339 used by the Dutch wasn't TOO far off the 239 we actually have. I think I read the British overloaded the 339E even worse than what the F2A-3 was.
The best option is to add the F2A-3 as a separate aircraft from the 239. That would cover the widest variety of aircraft, as the F2A-1/2 were already out of combat by the beginning of the war. This would give the F2A-3 for the Americans and 339E, with the 239/339 for the Finns/Dutch.
the F2A-2 and F2A-3 American Buffaloes and the B-339E British Brewster were all weighed down too much by armor. the B-339 and the B-239 models were lighter and more maneuverable. the difference between the scenarios of the Swedes and the Dutch are what they flew against as i stated above
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the F2A-2 and F2A-3 American Buffaloes and the B-339E British Brewster were all weighed down too much by armor. the B-339 and the B-239 models were lighter and more maneuverable. the difference between the scenarios of the Swedes and the Dutch are what they flew against as i stated above
Actually, no, only the F2A-3 was. Boyington himself spoke highly about the F2A-2. It wasn't until the -3 that they really got overloaded. However NO "designated" F2A-2s saw combat during the war. All American Buffaloes at Midway were F2A-3s. The B-339C and D used by the Dutch was much closer to the F2A-2.
And Krusty,
From everything I've ever seen the 339C and D used by the Dutch was an ENTIRELY different animal from the F2A-3. She was actually much closer to the US F2A-2 (because the 339 was derived FROM the -2, NOT the -3) in weight and performance. The Dutch birds acquitted themselves fairly well against the Zero and Oscar, it was overwhelming numbers that really did them in.
The 239 we have is "close enough" to work for the 339C and D. Add the F2A-3 and that gives us the US and British/Commonwealth version.
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Digressing from Ardy's OP...
The issue of weight...here are the variants being discussed in question and weights (per Dean's AHT):
Var. Empty Wt Gross Wt No.A/C
F2A-1 3785 lbs 5055 lbs 11
B239 3744 lbs 5276 lbs* 44
F2A-2 4150 lbs 5419 lbs 43
339B 4020 lbs 5437 lbs 40
339E 4268 lbs 6112 lbs 170
339D 4282 lbs 6095 lbs 72
F2A-3 4765 lbs 6519 lbs 108
* 4 gun load out / 110 gal-fuel
Any which way you cut it, the weight difference between the B239 and the F2A-3 (used at Midway) is around ~1000 lbs. Same airframe, same wing surface area, slight differences in powerplant hp...you don't even have to do all the fancy math to begin to understand why the B239 out performs the F2A-3.
Tango
412th FS Braunco Mustangs
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Also, spewing the "weighted down by armor" line is false. We took the armor OUT, the Finns put it back IN. Net gain: zero.
The reason the -3 was so heavy was the fuel it carried, and many sources will back this up. It had a 1600 mile range, longest range of any fighter at the time (so one source claims).
Fuel weight alone won't account for the handling issues present, and it wasn't armor. The empty weights weren't that far off from the previous models.
EDIT: Just saw dtango's post. Don't know why AHT has that much bloat between early and later models, did a sampling of online sources and they had the F2a2 and B239 as much heavier with empty weight.
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+280 increased airframe weight (+172 for just the wings with no change in surface area)
+547 in new powerplant
+215 in fixed equipment
We haven't even tacked on differences in fuel weight (110 gals vs. 240) nor ammunition (.30/.50 mix vs. 4x.50's).
Tango
412th FS Braunco Mustangs
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From everything I've ever seen the 339C and D used by the Dutch was an ENTIRELY different animal from the F2A-3. She was actually much closer to the US F2A-2 (because the 339 was derived FROM the -2, NOT the -3) in weight and performance. The Dutch birds acquitted themselves fairly well against the Zero and Oscar, it was overwhelming numbers that really did them in.
I disagree. The B-339C/D/E was essentially a land-based version of the F2A3. The export versions varried very little from the end-of-production heavy, bloated models. As early as 1939 the USN put in the order for F2A-2s, and by Sept 1940 they had F2A-3s, and the first exports to Belgium which were diverted to the RAF may have been F2A2 standards, but all the other couple-hundred ordered after that were later standards. Even these first, earliest, models were trounced by Japanese forces the first time they went up in even numbers, losing 6 out of 12 and the Japanese only losing 1 or 2. They were promptly withdrawn and the AVG stepped in to relieve the pressure.
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Also, the Brewster was supposed to be somewhat unstable, and yet in-game is probably one of the better gun platforms.
So, in an early-war PTO setup, what's a better representation of the F2A-3, the B-239 or the F4F-4 with 4 X Mother Deuce?
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I should conduct more tests but often in the MA it feels like brewsters dive a bit too well and hold their e much longer than
I would expect (compared to the I-16). Sadly all I have is anicdotal information, "pilot A says a f4f could out dive a brewster", etc..
main question...
Unlike the P51 or Me 109s or many of the more 'famous' planes of WW2, there doesn't appear to be much information on the filght characteristics of the finish version of the arplane. furthermore, there are almost no finish Buffalows in exsistance today. What sources have people found?
If you don't have any data, maybe you should have started by doing some testing. If you think Brewster dives too well or holds E too well, why don't you test it against that I-16 for example. Allthough I suggest testing against planes with western airscrews at first because just by looking at the primary source data on I-16, it's pretty clear that its prop efficiency must have been quite poor.
Obviously testing against hard data on the Brewster is a better way to go but you could have at least done the above before starting one of these threads again.
"It is a capital mistake to theorize before one has data. Insensibly one begins to twist facts to suit the theories, instead of theories to suit facts." (Sherlock Holmes)
Thank you Tango! A voice of reason. :)
The problem just is that threads in this forum usually have such a poor signal to noise ratio that the voice of reason seems to get lost into the mindless blah blah blah. :( I wish most people would at least try to approach these topics with some sort of analytical thinking.
The most popular line of thought in here seems to go like this...
Witch? Wood? Wooden Witch! BUUUURRRN!
B-239s may have had one engine, but that engine wasn't necessarily what the Finns put into it. Remember they were scrambling for anything they could, similar to the AVG. I think they put the engines from a DC-3 in them, or some other transport?
Model 239 had 1000hp G5 Cyclones from beginning to the end if we don't count couple experiments with Soviet M-62/63 engines. F2A-1 had a 940hp -34 variant of the Cyclone. -34 was a military variant and therefore was under the export ban.
Saxman, the 339 was an export version of the F2A3.
Incorrect. B339 is "export version" of the F2A-2.
239s would have less horsepower and less efficient props than the F2A2s.
"less efficient prop"? The 239s prop had a smaller diameter but it doesn't make it any "less efficient" per se. 239s had to harness 200hp less power so I'm sure that the actual prop efficiency coefficients were very comparable.
Also, the Brewster was supposed to be somewhat unstable,
Hmm...everything I've read says exactly the opposite.
From British Report No.B.A.1689. (July, 1941), Handling tests on Buffalo (Brewster A.S.430):
"Banked turns with one control fixed: Excellent turns with very little sideslip can be done on ailerons alone. Sudden application of the ailerons increases the rate of entry and also the sideslip on going into a turn and during the recovery. More use of control is always needed to recover than enter."
Brewster was rather directionally unstable until Pyro fixed it in the latest version. It is very nice and stable gun platform now as it should be, apart from the slight tendency for the combat trim to trim it tail heavy. Therefore I toggle combat trim once to trim the plane and then dial in negative elevator trim manually.
Before being shipped to Finland, the pilot armor, the self-sealing fuel tanks, and the tail hook were removed. Note that the Finns themselves restored the pilot armor once they received them.
<sigh> The integral 80 gallon wing tanks were never protected, on any of the Brewster fighters. F2A-2 and F2A-3 had other protected tanks though. Krusty, these kind of facts simply aren't that hard to double check. If you are uncertain of something it's better left unposted. Makes for less noise and more signal.
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Also, the Brewster was supposed to be somewhat unstable, and yet in-game is probably one of the better gun platforms. Before being shipped to Finland, the pilot armor, the self-sealing fuel tanks, and the tail hook were removed. Note that the Finns themselves restored the pilot armor once they received them.
And when they arrived in Finland, the Brewsters received pilot armor, self sealing fuel tanks, new gunsights, new radios and also had the armanent upgraded. The Brewster in Finnish service were not just lightened acrobatic planes but fully equipped combat aeroplanes.
I also dare to disagree about the unstable comment. All pilot reports tell how pleasant the Brewster was to fly, how good its dive characterics were, how well it handled and how it was excellent gunnery platform.
g
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Also, spewing the "weighted down by armor" line is false. We took the armor OUT, the Finns put it back IN. Net gain: zero.
Krusty, the Finns put a 50 pound steel plate behind the seat, that did not replace the U.S. Navy armor that was in it originally. And yes the DC-3 used one version of the R-1820 Cyclone engine as did the Douglas SBD.
According to Janes Fighting Aircraft of WWII HP ratings at alt for R-1820 engines used in the Buffalo:
The R-1820-G5 model used by by the B-239(F2A-1) was rated at 1000 h.p. for take off, 850 h.p. at 6000 ft, and 750 h.p. at 15.200 ft. (2100 rpm).
The R-1820-G105A used by the B-339(F2A-2) export models was rated at 1100 for take-off, (2.350 r.p.m.) 900 at 6700 ft. (2300), and 800 h.p. at 2350 rpm at 17,200 ft.
The R-1820-G205 used by the B-439(F2A-3) was rated at 1200 h.p. at 2,500 rpm at take off, 1000 h.p. at 2300 rpm at 6700 ft.; and 1000 hp at 2500 rpm at 14,200 ft.
Are the variances in HP ratings at altitude modeled in AH for any aircraft?
I also found that the engines suffered from "oil starvation" and oil leaks during high-g combat. LOL, if only that could be modeled in AH with people yanking on the stick for prolonged periods.
So, in an early-war PTO setup, what's a better representation of the F2A-3, the B-239 or the F4F-4 with 4 X Mother Deuce?
Actually, yes it would be a better sub for the F2A-3 but that's just my take on it. The B-239 in AH is great in early war ETO setups since that was its historical AO.
The F2A-3 had 4 Browning M2 .50 cal machine guns and max speed of 320mph at 14,500ft. The F4F-4 had 4 or 6 Browning M2 .50 cal machine guns and a max speed of 320mph at 18,000(?)ft. The flight characteristics are closer to what is described for the F2A-3 as well.
Side note, do any of the Brewster skins have FAF Major Luukkanen's(sp?) victory markings on the tail? I understand he used labels of Karelia beer instead of paint. LOL
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Are the variances in HP ratings at altitude modeled in AH for any aircraft?
Yes, off course they are, in all aircraft...allthough the hp isn't really used as normal power unit for the jets and the rocket ship. ;) But yes, change of power/thrust is modelled per altitude and/or speed.
Side note, do any of the Brewster skins have FAF Major Luukkanen's(sp?) victory markings on the tail? I understand he used labels of Karelia beer instead of paint. LOL
The beer was called Lahden Erikois Olut but yes, it is in game courtesy of Greebo. :) Check out the BW-393 in game, the most succesful fighter aircraft in the history of aviation in terms of kills scored.
More about Luukkanen's plane:
http://www.kolumbus.fi/kari.stenman/2004_theme_14.html (http://www.kolumbus.fi/kari.stenman/2004_theme_14.html)
(http://i46.photobucket.com/albums/f147/Wmaker/262kill.jpg)
(http://i46.photobucket.com/albums/f147/Wmaker/Lahden_Erikois_Olut.jpg)
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Are the variances in HP ratings at altitude modeled in AH for any aircraft?
As wmaker says the answer is of course yes. We wouldn't expect anything less from HTC :). To prove it let just look at the level speed charts for the B239 and I-16 in AH.
(http://thetongsweb.net/images/b239.jpg)
Notice how the lines are raggedy and also slope off? That's because of the engine HP variation as it changes with altitude.
I also purposely used this picture to compare the B-239 and the I-16. Why are the shape of the curves so similar? The I-16 uses Russian M-63 engine which were license built Wright R-1820's. According to Graham White because of the shortage of parts when it came time to replace the original R-1820's in the B-239's the Finns used captured Soviet M-63's as replacements.
Tango
412th FS Braunco Mustangs
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Thank you Tango! A voice of reason. :)
The problem just is that threads in this forum usually have such a poor signal to noise ratio that the voice of reason seems to get lost into the mindless blah blah blah. :( I wish most people would at least try to approach these topics with some sort of analytical thinking.
The most popular line of thought in here seems to go like this...
Witch? Wood? Wooden Witch! BUUUURRRN!
You betcha. You can't defy aerodynamics. You'll lose every time trying. ;)
Tango
412th FS Braunco Mustangs
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You can't defy aerodynamics. You'll lose every time trying. ;)
Yeh...
At times it seems like people think they can chuck bunch of anecdotes into some converter which comes up with the flight model.
And it obviously must be the wrong anecdotes in their mind that get chucked in. :lol
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Here's a subjective tidbit from Dean's AHT regarding diving the Brewster:
An old Navy pilot recalled with evident relish "We used to dive those things; the Brewster would pick speed in a hurry." Diving characteristics, particularly if the aircraft center of gravity was not too far aft, were considered good, though the Finns reported "Ailerons became a little twisted while diving."
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Here's a subjective tidbit from Dean's AHT regarding diving the Brewster:
An old Navy pilot recalled with evident relish "We used to dive those things; the Brewster would pick speed in a hurry." Diving characteristics, particularly if the aircraft center of gravity was not too far aft, were considered good, though the Finns reported "Ailerons became a little twisted while diving."
Difference in flight characteristics would be indicative of differences in models. That Navy pilot would have been talking about the F2A-2 or F2A-3. The B-239/F2A-1 had a shorter fuselage than the F2A-3/B-439 and didn't they change something on the wings between the F2A-1 and the F2A-2 due to some control quirk found in early dive tests? If so that would explain the Finns report.
Gets mind boggling trying to keep up with the differences between US Navy and export models. :rolleyes:
If anyone wants a photocopied version of a Brit Brewster pilots manual, here you go:
Britsh Brewster Pilot Manual (http://dl.dropbox.com/u/405468/AH%20Stuff/buffpilotmanual.pdf)
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Difference in flight characteristics would be indicative of differences in models. That Navy pilot would have been talking about the F2A-2 or F2A-3. The B-239/F2A-1 had a shorter fuselage than the F2A-3/B-439 and didn't they change something on the wings between the F2A-1 and the F2A-2 due to some control quirk found in early dive tests? If so that would explain the Finns report.
The basic geometry and aerodynamics are very close between the models and the Navy did have F2A-1s aswell. What of course affects diving is the weight...or the lack of.
Not that it matters, but I haven't noticed anything special in the dive acceleration of the AH Brewster. As a matter of fact, my subjective feeling is that lack of weight is very much noticeable and that prolonged dives against most fighters is just a sure way to blow the little E/altitude that you have. Again, just my experience.
The point I'm trying to make is that those that think Brewster in AH "dives a bit too well" should do some testing and put this "issue" into some sort of perspective and context.
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Didn't the U.S. Navy only take somewhere around 10-15 F2A-1s before the F2A-2 went into production? The rest of the order that wasn't accepted were the ones that went to Finland. And I know the U.S. Navy converted most if not all of the F2A-1's they had into F2A-2s.
I think it dives better than the A6M2 and the I-16...but that's about it.
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Didn't the U.S. Navy only take somewhere around 10-15 F2A-1s before the F2A-2 went into production? The rest of the order that wasn't accepted were the ones that went to Finland. And I know the U.S. Navy converted most if not all of the F2A-1's they had into F2A-2s.
11 F2A-1 remained and yes, they were converted but they also saw service as F2A-1s. Doesn't change the fact that you can't totally rule out the possibility. Not that it makes any difference either way. Just thought that I'd post something relevant regarding the question in the original post.
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"The B-239/F2A-1 had a shorter fuselage than the F2A-3/B-439"
I think it's the other way around. The engine weighed more in later models so the nose was shortened to get CoG back in place so the B-239 was actually the longer one.
-C+
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Actually Charge, if you read what manufacturing changes took place between the F2A-2 and the F2A-3 from the Naval Historical Center website:
The Navy ordered a final 108 Brewster fighters in January 1941. These F2A-3s featured a longer fuselage, increased fuel and ammunition capacity, additional armor and considerably greater weight. Range was better, but speed, maneuverability, climb rate and service ceiling were substantially degraded. By the beginning of the Pacific War, the F2A, by then also known by the popular name "Buffalo", was passing out of carrier squadron service in favor of the F4F-3. The "Buffalos" were transferred to the Marines, who assigned them to units defending Pacific island bases.
According to Wiki there was a 4 inch difference in length and ~900 lbs difference in weight between the A-1 and the A-3.
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At times it seems like people think they can chuck bunch of anecdotes into some converter which comes up with the flight model.
And it obviously must be the wrong anecdotes in their mind that get chucked in.
That got a good laugh, thanks!!
Badboy
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That got a good laugh, thanks!!
Badboy
I liked it so much I put it in my bbs sig :D
Tango
412th FS Braunco Mustangs
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LOL guys! :)
Tango, had I known you were going to do that I would have phrased it better! :rofl
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Sadly its clear that any statement questioning the Brewster is a 'personal attack' on wmaker and he goes all out to defend it, even when it's off. I will post my videos soon here too.
Maybe it shouldn't be called the brewster-Buffalo but rather it should be called Brester - 'wmakers other child'.
There's no need to do anything based on whining, except have fun on the whiners' expense.
Oh so it accelerates to fast now I see. :lol
Well, have fun testing. :)
I guess we are all whiners because we question its in game performance... hmmmm :headscratch:
go ahead flame away, but sadly my feelings about its handling aren't unique.
You have a plane that was death trap anywhere else against anyone else , that performed well against an enemy that had suffered an incredible purge that in particular hurt any technical part of its military . I know it is not the same exact plane , but it is not light years different either . I think there is alot more wrong then acceleration if it is so light how does it zoom so well , if it zooms so well how does it sustain climb so well ? No armor or self sealing tanks why is it so hard to shoot down ? I can't think of a test to answer these questions .Acceleration I could . Don't believe me it out accelerates the FW190 try it . How ever save the insults and argue from the merit of your position as you see it . It is all moot anyway . If this plane could do what it does here . No wildcat or hellcat would have ever been built .
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Sadly its clear that any statement questioning the Brewster is a 'personal attack' on wmaker and he goes all out to defend it, even when it's off. I will post my videos soon here too.
Maybe it shouldn't be called the brewster-Buffalo but rather it should be called Brester - 'wmakers other child'.
I guess we are all whiners because we question its in game performance... hmmmm :headscratch:
go ahead flame away, but sadly my feelings about its handling aren't unique.
(http://tech.icrontic.com/files/2009/08/facepalm.jpg)
"It is a capital mistake to theorize before one has data. Insensibly one begins to twist facts to suit the theories, instead of theories to suit facts." (Sherlock Holmes)
Ardy, try reading the above once more and see if it sinks in this time.
Btw, Ardy, the reason for your post became evident right away by just looking up your score. You got shot down by couple Brewsters and instead of trying to take a look at your tactics, you started typing. :)
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Wmaker does take it as a personnel attack.
If I cared enough to go and research Wmakers other child I would, but alas I don't. Who knows it could have been a clown car in real life.
With your plethora of knowledge on the Finnish buffalo you had to come across some negative reports on it though wmaker (and others)
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Wmaker does take it as a personnel attack.
No I don't, and the plane type here is actually irrelevant. It's the illogical approach and the apparent thick-headness that does get to me though when it gets repeated enough.
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(http://tech.icrontic.com/files/2009/08/facepalm.jpg)
Ardy, try reading the above once more and see if it sinks in this time.
Btw, Ardy, the reason for your post became evident right away by just looking up your score. You got shot down by couple Brewsters and instead of trying to take a look at your tactics, you started typing. :)
your statement doesn't make any sense, I always stated that I was looking for the FACTS yet you seem entrenched on trying to prove that I'm looking to support a pre-established belief.
I do have a hunch, but thats it! And more importantly, everyone starts an investigation with a hunch and attempts to prove or disprove it. The very fact you went as far as to look up my score seems to imply that you are out on a witch hunt, aimed at flaming people who possibly threaten your beloved plane rather than do anything productive or useful.
Look at my original post... What did I ask for (I state my hunch and I'm looking to prove or disprove it).
Unlike the P51 or Me 109s or many of the more 'famous' planes of WW2, there doesn't appear to be much information on the filght characteristics of the finish version of the airplane. furthermore, there are almost no finish Buffalows in exsistance today. What sources have people found?
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a 4 inch difference in length
That's not a significant difference
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your statement doesn't make any sense, I always stated that I was looking for the FACTS yet you seem entrenched on trying to prove that I'm looking to support a pre-established belief.
I do have a hunch, but thats it! And more importantly, everyone starts an investigation with a hunch and attempts to prove or disprove it. The very fact you went as far as to look up my score seems to imply that you are out on a witch hunt, aimed at flaming people who possibly threaten your beloved plane rather than do anything productive or useful.
Look at my original post... What did I ask for (I state my hunch and I'm looking to prove or disprove it).
Stating a hunch is ok. You're right in saying that's where it all starts. However, one thing that a lot of us tire of is having to combat the hunch and the hunch alone. HTC has always done exhaustive amounts of research when modeling these aircraft, so on that assumption, we typically feel that the obligation to prove something is on the person raising the issue, and not HTC.
That being said, there's a lot of research available out there if you're willing to look. Tango posted some really data-centric resources. But, at least try to do some sort of presentation to support your hunch, and then it will be pretty well received. Otherwise, it simply looks like just another "whine" about an aircraft that doesn't live up to historical misconceptions.
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your statement doesn't make any sense, I always stated that I was looking for the FACTS yet you seem entrenched on trying to prove that I'm looking to support a pre-established belief.
Oh please!
(http://bloodywellwrite.files.wordpress.com/2009/06/clown_car_shinny.jpg)
(http://techpaul.files.wordpress.com/2009/02/clown-car.jpg)
You posted these pics and your "clown wagon comments" to this thread:http://bbs.hitechcreations.com/smf/index.php/topic,271940.30.html (http://bbs.hitechcreations.com/smf/index.php/topic,271940.30.html) about at the same time as you started this thread. Your attitude was clear from the start.
So, no use to try to play the victim card here.
I do have a hunch, but thats it! And more importantly, everyone starts an investigation with a hunch and attempts to prove or disprove it. The very fact you went as far as to look up my score seems to imply that you are out on a witch hunt, aimed at flaming people who possibly threaten your beloved plane rather than do anything productive or useful.
Look at my original post... What did I ask for (I state my hunch and I'm looking to prove or disprove it).
Don't worry, I've flown plenty of planes through their flight model revisions in this sim. I'm not too worried. :lol
I'm not flaming anyone but yes, if ignorant people aren't willing to learn and spout the same BS over and over I, like anyone else, get irritated. If everything I post simply gets ignored every time and same thing starts again in couple months. Then yes, my comments will get more abraisive with every new thread and for a good reason. There is no use to provide any info since it won't sink in, why should I bother? No one grasps anything anyway and the same BS just starts again within couple of months.
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Oh please!
You posted these pics and your "clown wagon comments" to this thread:http://bbs.hitechcreations.com/smf/index.php/topic,271940.30.html (http://bbs.hitechcreations.com/smf/index.php/topic,271940.30.html) about at the same time as you started this thread. Your attitude was clear from the start.
So, no use to try to play the victim card here.
Don't worry, I've flown plenty of planes through their flight model revisions in this sim. I'm not too worried. :lol
I'm not flaming anyone but yes, if ignorant people aren't willing to learn and spout the same BS over and over I, like anyone else, get irritated. If everything I post simply gets ignored every time and same thing starts again in couple months. Then yes, my comments will get more abraisive with every new thread and for a good reason. There is no use to provide any info since it won't sink in, why should I bother? No one grasps anything anyway and the same BS just starts again within couple of months.
lol that was from a completely different thread where I was making a joke which was in reference to something I said on chann 200 the day before. Yes I bet I can dig around the forums and find a joke you made and take it out of context and say some BS too... (I understand the joke hurt your feelings, you took it personally, I'm sorry).
yes, if ignorant people aren't willing to learn and spout the same BS over and over I, like anyone else, get irritated.
so now I'm ignorant too?
:lol :lol
Actually, I am, hence why I started the thread and asked for FACTS, so that I would no longer be on the subject.
There is no use to provide any info since it won't sink in
So you are smart and everyone else is stupid?
OR
By questioning your baby, they are ignorant because everyone should assume everything you say and do is always perfectly correct?
No one grasps anything anyway and the same BS just starts again within couple of months.
Have there been many threads about Brewsters?
Ok on to the meat...
what is the "Trailing edge ailerons"?
"The low effectiveness of the trailing-edge ailerons
can be attributed, in a large measure, to the excessive
elasticity in the aileron, control system, which reduced
the aileron-deflection range attainable i n f l i g h t to
considerably lsss than the design range of t17.5O even
a t the lower speeds. For example, the maximum aileron
deflection obtained w i t h f u l l stick deflection was about
160 at a service indicated airspeed of 90 miles per hour
and about 12O a t 216 miles yer hour;"
The above quote from this document, page 8 http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19930092639_1993092639.pdf (http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19930092639_1993092639.pdf)
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lol that was from a completely different thread where I was making a joke which was in reference to something I said on chann 200 the day before. Yes I bet I can dig around the forums and find a joke you made and take it out of context and say some BS too... (I understand the joke hurt your feelings, you took it personally, I'm sorry).
<sigh> Whatever. I wasn't replying to you in the thread you quoted either. It was a general comment. If you search the BBS you'll find quite a bit of stuff about the Brewster after its inclusion to the game.
so now I'm ignorant too?
:lol :lol
Actually, I am, hence why I started the thread and asked for FACTS, so that I would no longer be on the subject.
So you are smart and everyone else is stupid?
OR
By questioning your baby, they are ignorant because everyone should assume everything you say and do is always perfectly correct?
Have there been many threads about Brewsters?
It is very hard to put facts out to you when you haven't really numerically defined what you think is wrong in the first place. Tango posted plenty of material. That alone should keep you busy for quite a while. I will say one thing. The reach of the .50 cals or shooting distancies in general can skew the situation for the "turn fighter". But still, Brewster is either easy pickings for the G-14 or the situation will be a draw where the E-fighter won't get a shot but won't screw up either and flies away. If someone gets shot down by a Brewster in a G-14 in a clear 1 vs 1 situation, they have screwed up and screwed up royally. Unless of course they started turning on purpose just to see what happens. :)
Anyways some "facts" for you from the British Brewster handling tests I quoted earlier:
4. Conclusions
....
(v) All the controls are light and effective except that at low speeds (about 80 m.p.h.) the response with less than 1/4 rudder is poor, and at high speeds (above about 300 m.p.h.) the rudder is too light and the response great for small displacements. The ailerons are particularly good at high speeds, the stick force for aileron at 400 m.p.h. being about 25 lb. and the time to bank 45° about 1 1/2 secs.; Kb2 for ailerons is -0.0. Lowering the flaps and undercarriage makes the ailerons and rudder a little less effective. The controls of the Buffalo are a definite improvement on those of the Hurricane and Spitfire.
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l
what is the "Trailing edge ailerons"?
If you'd actually read the report, you'd know. And you'd also know that they have nothing to with the B239.
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If you'd actually read the report, you'd know. And you'd also know that they have nothing to with the B239.
<sigh> I'm trying to skim it at work will still doing work... but here we go again, with your defensive confrontational attitude.
It is very hard to put facts out to you when you haven't really numerically defined what you think is wrong in the first place.
As I said before, I have a hunch that it may accelerate in a dive and hold that speed better than I expect. As I said before, I was working on some films, and 'skimming' the docs as we 'furiously type' but as for 'hard facts', other than films, what are expecting as 'numerically defined'?
I'm not sure on all the math to calculate the 'projected dive speeds' or to calculate the drag created by the wings and fuselage of the aircraft to give an accurate mathematical calculation do you know the formulas?
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<sigh> I'm trying to skim it at work will still doing work... but here we go again, with your defensive confrontational attitude.
It is not my job to hold your hand and read it for you. Do your research. Pyro has. If you find something that you think is wrong, make a thought out thread about it.
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It is not my job to hold your hand and read it for you. Do your research. Pyro has. If you find something that you think is wrong, make a thought out thread about it.
lol, wow, didn't ask you to, only asked a simple question which I believe your previous statement has caused me to revisit and already answer.
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As I said before, I have a hunch that it may accelerate in a dive and hold that speed better than I expect. As I said before, I was working on some films, and 'skimming' the docs as we 'furiously type' but as for 'hard facts', other than films, what are expecting as 'numerically defined'?
“Numerically defined” as in actually based on physics vs. the anecdote converter flight model ;).
I'm not sure on all the math to calculate the 'projected dive speeds' or to calculate the drag created by the wings and fuselage of the aircraft to give an accurate mathematical calculation do you know the formulas?
Maybe we’ll make an aerogeek out of you yet. Study away my friend and join the darkside! I have a hunch. My hunch is after you complete your aerodynamic pilgrimage you’ll come to the conclusion that HT and Pyro actually know a thing or two about aero and the B239 they’ve modeled is remarkably sophisticated & consistent with physics, and that you’ll beg HT to personally induct you into the sacred order of the propeller heads. :airplane:
Tango
412th FS Braunco Mustangs
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Maybe we’ll make an aerogeek out of you yet. Study away my friend and join the darkside! I have a hunch. My hunch is after you complete your aerodynamic pilgrimage you’ll come to the conclusion that HT and Pyro actually know a thing or two about aero and the B239 they’ve modeled is remarkably sophisticated & consistent with physics, and that you’ll beg HT to personally induct you into the sacred order of the propeller heads. :airplane:
Tango
412th FS Braunco Mustangs
lol, I never intended to create a whine thread, I was hard pressed to find stuff on the finish brewster so I asked, others have posted stuff they have found. I never intended to be an insult to HTC, I had a hunch and I wanted facts.
Sadly all I have is anicdotal information, "pilot A says a f4f could out dive a brewster", etc..
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I had a hunch and I wanted facts.
You've got it backwards. Let the facts lead you to your hunch. How did you develop your hunch to begin with without facts?? ;)
Tango
412th FS Braunco Mustangs
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lol
others agree with me, a hunch is needed to spurn the desire of facts :neener:
Stating a hunch is ok. You're right in saying that's where it all starts.
ok enough with the circular bs, is there a Open source/Free Fluid dynamics simulator, at least I could plug in the NACA airfoil, wing dimensions and the air velocity and calculate how much drag is created by the wing? This would be a starting point to calculating its dive characteristics.
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lol
others agree with me, a hunch is needed to spurn the desire of facts :neener:
Didn't your mother teach you by rhetorically asking you "if others jumped off a cliff would you do the same"? :) All hunches are not equal; some are more equal than others ;), which tell us something about how good or how bad the hunch is let alone figuring out how you actually test them.
ok enough with the circular bs, is there a Open source/Free Fluid dynamics simulator, at least I could plug in the NACA airfoil, wing dimensions and the air velocity and calculate how much drag is created by the wing? This would be a starting point to calculating its dive characteristics.
What flavor of CFD would you like - RANS, LES, or DES? That's some serious blackbelt aerogeek kungfu when you decide to skip past Kutta-Joukowski and Prandtl and deal directly with Navier-Stokes *whistle*. Of course you could spend weeks trying to make sense of all that and only get an indication of drag for the wing or you could just look over flight test and wind tunnel reports and get the drag coefficient for the entire airplane like this...
(http://thetongsweb.net/images/f2a2cd.jpg)
...or drag polars like this....
(http://thetongsweb.net/images/f2a3polar.jpg)
...or even see how closely the B-239 in AH diving matches a real life ~5500 lbs F2A-2 diving from 20,000 ft like this..
(http://thetongsweb.net/images/f2a2400dive.jpg)
And by the way, let me know if you find a good CFD program along with all the grid-generators etc. that will run on my pedestrian PC running Vista will ya? Thanks!!
Tango
412th FS Braunco Mustangs
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LOL Tango! :)
You are far more patient than me! :)
<S>
AFAIK, that little under 0.03 Cd is after NACA's modifications to the cowling/etc. The original, before the modifications, was at 0.0377. When I plugged basic Brewster's parameters to the speed equation with the estimated prop eff of 0.8 and compared it to the speed obtained in Finnish testing at sea level, I got the Cd of 0,02957. :)
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"The Navy ordered a final 108 Brewster fighters in January 1941. These F2A-3s featured a longer fuselage, increased fuel and ammunition capacity, additional armor and considerably greater weight. "
Thanks Gyrene81. I found this page where the changes were listed and indeed the -3 was longer than -1.
http://www.cybermodeler.com/hobby/kits/ca/kit_ca_4100.shtml
-C+
PS. An anecdote on diving: IIRC Cpt. Karhunen claimed to have dived BW fast enough so that upon pull-up the wingtips were slightly bent upwards, permanently! Afterwards the aircraft was sent for repairs and the wings were fixed/(replaced?).
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OK my hunch the flight model on the b239 is inaccurate . My evidence . In level flight with combat trim applied at 1k alt it ,acceleration was tested from 100 to 250 mph IAS against several other aircraft in AH2 . Results F4u4 super buff less then 3 seconds slower . Against the FW190 a5 and a8 it out performed both of them by a higher margin then the F4U4 was able to out accelerate the Finnish buffalo . Data on the 190 is easy to find . The Finnish buffalo , it is not . Every piece of information regarding stability in turns on the Buffalo , I am able to find . I find another reference to conflict it . Now since I am unable to find adequate reference on Buffalo's Finland received . Since the majority of the data was provided by the Finns on the 239 to HTC to model the Brewster please allow us to see it to . My last test and the one that really made my eye brows raise . The Brewster EQUALED the D9's acceleration in my test in game . You will reject out of hand any reference provided concerning US versions of this aircraft that say that it is impossible for this to happen . I would say it is your burden to provide the data saying that it can . As far as high tech flight model accuracy , I have to agree . Over all it is the best there is . How ever there are some places I doubt it is as good as it can be . The stall characteristics of the F4U leaps to mind . I won't post a film of how it stalls in game .http://www.youtube.com/watch?v=n-PwTTQz6Zw&feature=related (http://www.youtube.com/watch?v=n-PwTTQz6Zw&feature=related) Here is a film of it going into a stall and the comment on how it is "abrupt with very little warning little to no buffeting " . Would you care to say that is how it is in game ? I will only argue about objective data with nothing that can be explained by different pilot skill level or any other subjective variable . My hunch , one that I won't argue is that the Finns did well against Russian and end of war German pilots . That the enviable k/d ratio achieved by them with this plane , is a result of the difference in pilot skill . Both the Russian and late war German pilot skill level was uneven at the very best . My hunch is the Finns were probably man for man the best in the world for this time period . Like the saying goes its the man not the machine . If I get any sarcasm or ridicule , I will know why there is always the whine comment . If I can be shown data that confirms my in game test , I will be relieved . I really expect nothing but sarcasm and ridicule in answer . Wmakers reply where he actually provided data concerning the 239 showed the 239 with a higher wing loading than an a6m5 . How ever in game it out turns the A6M5 .
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I really expect nothing but sarcasm and ridicule in answer .
Why should you get anything else? You can't even type coherent sentences using some sort of paragraphing let alone present the results of your testing in any sort of logical manner. I mean seriously, you actually did something that gives you plain straight numbers to present. And you just ramble on without presenting your results properly. :rofl
I did some testing myself, here are the results:
Acceleration from 100mph to 250 mph at sea level:
Brewster: ~45s
Fw190A-5: ~32,5s
Fw190D-9: ~30s
Nothing suprising in those results that I can see.
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Any time someone does testing in this game, they should post their methodology along with the data. That way we can either critique the methodology, or use it to replicate the test, and see if we get the same results.
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Any time someone does testing in this game, they should post their methodology along with the data. That way we can either critique the methodology, or use it to replicate the test, and see if we get the same results.
You are completely correct there. It's just hard to bother considering the quality of replies from the "other corner".
My methodology:
Using auto pilot I throttled back over sea at few hundred yards of altitude and let the plane decend on autopilot. Flaps were used on both of the Focke Wulfs so that 100mph flying speed could be reached. As the altitude was around 30-40ft above sea level and plane was stable at 100mph for a few secs I hit full throttle/WEP at the same instant as I started the stop watch and immediately pulled in the flaps as fast as they came in. Speed was observed only from the E6B during the test. As the speed hit 250mph the watch was stopped. The test was repeated two times per plane. Because the variation in the results was so small, two runs were deemed sufficient considering the purpose of the test.
50% Fuel on all planes. Zero fuel consumption, no wind, offline.
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OK my hunch the flight model on the b239 is inaccurate . My evidence . In level flight with combat trim applied at 1k alt it ,acceleration was tested from 100 to 250 mph IAS against several other aircraft in AH2 . Results F4u4 super buff less then 3 seconds slower . Against the FW190 a5 and a8 it out performed both of them by a higher margin then the F4U4 was able to out accelerate the Finnish buffalo .
Wall of text responses are hard to read. Let's just start at the beginning. Testing methodology and the different numbers your tests vs. wmaker's are producing aside, let me give you kudos for actually testing something and providing data points. On the logical front however, I'm sorry to say you haven't proven anything except how to collect some data points. The piece that is missing is your physics logic behind why these numbers are wrong. That's on you to demonstrate.
Let me throw you another riddle for you to ponder in hopes it'll make you think about the aerodynamics. Looking at the AH climb charts how come the B-239 will actually marginally outclimb the 190D-9 below 4000 ft, outclimbs the 190A-8 up to 16,000ft, but not the 190A-5 at all? (military power only).
Tango
412th FS Braunco Mustangs
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AFAIK, that little under 0.03 Cd is after NACA's modifications to the cowling/etc. The original, before the modifications, was at 0.0377. When I plugged basic Brewster's parameters to the speed equation with the estimated prop eff of 0.8 and compared it to the speed obtained in Finnish testing at sea level, I got the Cd of 0,02957. :)
Wmaker- I have a "hunch" if you haven't factored in exhaust thrust yet, just a few lbs of it would bring that number to .03 ;).
Tango
412th FS Braunco Mustangs
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Wow! This is alot of reading. :lol I've been conducting my own little 51 vs Brewski tests in the DA for a few weeks now. Here's my uneducated take on the plane.
It will lite you up if ya get too close to it. :lol It turns like a bat, snappier then a zeke at higher speeds and takes a good half minute at least, for a 51D to get out of a good gun range (d800). It will stay with the 51 in a dive under 5K or so....which surprises me actually. It's also a tough little bird that needs a real solid hit to bring it down.
To be perfectly honest, I've never heard of the Brewster before it was added to the plane set and can not speak to if it's over or under modeled. The way I look at things is we have what we have, and I just try to learn how to deal with each aircraft on that basis. Pages upon pages of performance data is meaningless to me, as there are so many variables when 2 planes meet in a random dogfight, i.e. weight, speed, E state, altitude, skill level...so on and so forth.
The Brewski is a wonderful little plane just the way it is. It can be quite a challenge or it can be a easy kill. :salute
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Wmaker- I have a "hunch" if you haven't factored in exhaust thrust yet, just a few lbs of it would bring that number to .03 ;).
Well I purposefully left it out considering the exhausts are basically pointing straight down. One thing to consider is that the tests were probably flown painted with the overall aluminum bronze, with no camouflage. The surface finish was most likely better than with the camouflage. Either way, my point was just show that the numbers are on the ballpark. Those Finnish tests were done using the continuous power setting (850hp) which is also mentioned in the Brewster's specification report. Finnish tests agree with the specification. If one extrapolates using those numbers, they arrive to the speed AHII Brewster makes on the deck.
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:D Wmaker - I was just being playful about your CD precision of 0,02957. Close enough to .03 for me!
Tango
412th FS Braunco Mustangs
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:D Wmaker - I was just being playful about your CD precision of 0,02957. Close enough to .03 for me!
LOL!!! I'll post you the spread sheet, you'll probabaly start questioning my sanity! :D
Here's the extrapolation, AHII Brewster is as fast on the deck and couple mph faster after that:
(http://i46.photobucket.com/albums/f147/Wmaker/Brewster_speeds.jpg)
Here's the performance spces from the Specification:
(http://i46.photobucket.com/albums/f147/Wmaker/Powersetting.jpg)
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any chance you could add the AH brew to that chart for comparison? :)
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any chance you could add the AH brew to that chart for comparison? :)
I replaced it. The curve is before the official charts came available. I hadn't tested them at higher alts at the time. I might sometime update the graph to include the higher alts aswell.
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That looks to be pretty much on par for the U.S. specs I've found.
(http://i48.tinypic.com/2058pc8.jpg)
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I replaced it. The curve is before the official charts came available. I hadn't tested them at higher alts at the time. I might sometime update the graph to include the higher alts aswell.
not sure I understand, I just meant add this curve (no testing):
(http://bbs.hitechcreations.com/newscores/genchart.php?p1=101&p2=34&pw=0>ype=0)
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not sure I understand, I just meant add this curve (no testing):
I know, I'll do it...later. :) That's what I had ready. :)
The purple curve is basically that one, but only till 8k.
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ok ty :)
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Sorry fellas, I'm trying to figure out how hlbly figures the wing loading on the Brewster is considered high.
F2A-1 = 24.1 lbs/ft
A6M2 M 21 = 22.0 lbs/ft
FW190-A8 = 49.4 lbs/ft
FW190-D9 = 48.7 lbs/ft
Bf109-G6 = 40.9 lbs/ft
Spit Vb = 24.56 lbs/ft
Correct me if I'm wrong here gurus, but high wing load does not mean less maneuverability any more than low wing load means more maneuverability. Comparing maneuverability characteristics between 190s, 109s and Spit my understanding has been that high load wings offer better maneuverability at higher speeds vs lower load wings and vice-versa.
With a wing load of 24.1 lbs/ft there isn't any wonder that Brewster can turn like it does.
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Lower wing-loading usually means better instantaneous turn performance. For sustained turns however it gets a lot more complicated and all bets are off.
Tango
412th FS Braunco Mustangs
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Lift coefficient vary quite a lot among airfoils, so wing loading isn't really a figure you should judge turn performance by.
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Wait, my understanding is that a high wing load has a faster instantaneous turn performance and poor sustained turn capability, whereas a lower wing loading has slower instantaneous turn performance and better sustained turn capability. Angle of attack, airfoil dimensions, drag and thrust affect the coefficient of lift in that the higher the angle of attack, the more drag is produced which requires more thrust to maintain lift.
Brain freeze... :headscratch: :confused: :rolleyes: :headscratch: I'm so confused.
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Wait, my understanding is that a high wing load has a faster instantaneous turn performance and poor sustained turn capability, whereas a lower wing loading has slower instantaneous turn performance and better sustained turn capability. Angle of attack, airfoil dimensions, drag and thrust affect the coefficient of lift in that the higher the angle of attack, the more drag is produced which requires more thrust to maintain lift.
Brain freeze... :headscratch: :confused: :rolleyes: :headscratch: I'm so confused.
As dtango said, wing with more lift (lift depends on surface area, shape of the foil, speed, air density etc) is better for turning. But the more lift is generated, the more lift induced drag you get, which can be good for instantaneous turn, but bad for sustained turning.
That's really extremely simplified answer, so take it with a caution...
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Brewster at 1k alt 150 to 250 mph ias `22 seconds
FW190a8` at 1kalt 150 to 250 mph ias 25 seconds
Could not figure out how to do it at sea level . Was unable to keep gear on while on the ground at that speed . :rofl :rofl :rofl :rofl
Test conducted at 1000 k alt auto level on . E6b used for recording speed . 1k alt was obtained throttled back until speed was 120 ias . Full throttle then applied .2 stop watches started by myself and wife as speed hit 150 ias. watches stopped at 250 ias . Test repeated 5 times . Differences in times below .5 seconds for both watches , each test . AC were augured after each test . Fuel level was 25% no ords and lightest gun package .
http://bbs.hitechcreations.com/smf/index.php/topic,290564.0/topicseen.html (http://bbs.hitechcreations.com/smf/index.php/topic,290564.0/topicseen.html) Gyrene here is a link to the chart I was referring to it is on the 1st page of the thread .
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Wait, my understanding is that a high wing load has a faster instantaneous turn performance and poor sustained turn capability, whereas a lower wing loading has slower instantaneous turn performance and better sustained turn capability. Angle of attack, airfoil dimensions, drag and thrust affect the coefficient of lift in that the higher the angle of attack, the more drag is produced which requires more thrust to maintain lift.
Brain freeze... :headscratch: :confused: :rolleyes: :headscratch: I'm so confused.
Wing-loading is merely a single aircraft characteristic. With respect to "turn" ability, it should be judged only in its proper aerodynamic context, which is pretty narrow. It'd be like saying the P-47M is the fastest prop plane in the game, without any other caveat. High or low wing-loading has no direct correlation to the turn capability of the aircraft taken out of context. All it really tells you is whether or not a plane will have to generate more or less lift for a given condition of flight.
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Brain freeze... :headscratch: :confused: :rolleyes: :headscratch: I'm so confused.
Don't be confused :). Let's see if I keep from confusing you even more!
Let's first start with the instantaneous level turn performance case. That's easier to explain. A simple way to explain it is this. When you turn an airplane the lift is used to both support the weight of the airplane as well as turn it. In a turn the higher wing-loaded aircraft will have to expend more of it's lift capability just to support the weight of the aircraft and has less usable lift to turn the aircraft compared to a lower wing-loaded aircraft. Therefore the lower wing loaded aircraft has a better instantaneous turn.
Here's another way to explain it: mathematically we can express turn rate and turn radius like this:
Turn Radius:
(http://thetongsweb.net/images/turnradius.jpg)
Turn Rate:
(http://brauncomustangs.org/images/eq1-2.jpg)
where n=g-loading, g=gravity, V=velocity
So to minimize turn radius and maximize turn rate you want velocity as low as you can get while g-loading as high as you can get. Well n (g-loading) of an airplane is bound by the maximum structural limit the airframe can take. In AH though there's a structural limit we usually hit a virtual limit of our pilot blacking out around 6g's.
How do we minimize maneuverable velocity of an airplane? One way is by decreasing wing loading. Doing a bunch of fancy math we can derive the following equation:
(http://brauncomustangs.org/upload/vcorner.jpg)
This nice little equation gives us the corner velocity of an airplane as a function of wing loading (the W/S term in the equation - weight / wing_surface_area ). So corner velocity then varies directly with wing loading (W/S). As wing loading increases, so does corner velocity. As wing loading decreases so does corner velocity. As we've stated already reducing velocity reduces turn radius and increase turn rate thus lower wing loading improves the instantaneous turn performance of an airplane.
Sustained level turns are much more complicated animals to explain. It'll take more time for me to come up with an explanation of how sustained turns work with wing loading factored in.
Tango
412th FS Braunco Mustangs
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Brewster at 1k alt 150 to 250 mph ias `22 seconds
FW190a8` at 1kalt 150 to 250 mph ias 25 seconds
1) I assume you used military power and not WEP for the A8?
2) And is this result wrong? If so why do you think it's wrong? ;)
Tango
412th FS Braunco Mustangs
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dtango, I think I'm getting mixed up on the term "intstantaneous turn performance". When I see that term, and from everything I've been busting blood vessels on trying to understand for the past 8 months, that means the ease at which an airplane can enter a turn from level flight at x velocity based on wing load, power to weight ratio and angle of attack. But you're saying based on the calculations the lower wing load can not only enter a turn faster at a higher relative velocity, it can sustain that turn for a longer period? I fully understand the equations as relating to sustained turn and turn rate, but not instantaneous turn performance. Maybe I'm just mixing up the term.
*takes 2 tylenol* :rolleyes:
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dtango, I think I'm getting mixed up on the term "intstantaneous turn performance"....means the ease at which an airplane can enter a turn from level flight at x velocity based on wing load, power to weight ratio and angle of attack.
Remove power-to-weight ratio from your definition of instantaneous turn, then that's a better definition of it.
But you're saying based on the calculations the lower wing load can not only enter a turn faster at a higher relative velocity, it can sustain that turn for a longer period? I fully understand the equations as relating to sustained turn and turn rate, but not instantaneous turn performance. Maybe I'm just mixing up the term.
No, that's not what I'm saying :).
Working on another response to you on all this. Use tylenol as needed until then!
Tango
412th FS Braunco Mustangs
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Just as a general note (And to what Tango was getting at with his questions, I believe. ;)): if the climb rate is correct, so is the acceleration. Plane climbs with whatever amount thrust isn't needed to maintain the speed it is doing at that precise moment, otherwise it would be accelerating.
(http://i46.photobucket.com/albums/f147/Wmaker/Brewstercimbratejpg.jpg)
Something that doesn't make sense to me is the shape of the curves that depict Brewster's climb rate in both the Pilot's Viewpoint II and AHT (the black curve is from the former book) considering Cyclone has two speed supercharger. Looking at the Cyclones power curves, HTC's climb curves make much more sense in that regard. Are those real life curves averaged out after the first gear. I mean that's how it looks like but doesn't really make much sense to depict them that way IMO?
Any ideas?
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Remove power-to-weight ratio from your definition of instantaneous turn, then that's a better definition of it.
:old: I get it!!! Because power to weight ratio affects speed and flight, not the ability to enter a turn. :x
Thank you sir.
*now to go find my tylenol*
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Just as a general note (And to what Tango was getting at with his questions, I believe. ;)) is that if the climb rate is correct, so is the acceleration. Plane climbs with whatever amount thrust isn't needed to maintain the speed it is doing at that precise moment, otherwise it would be accelerating.
(http://i46.photobucket.com/albums/f147/Wmaker/Brewstercimbratejpg.jpg)
Something that doesn't make sense to me is the shape of the curves that depict Brewster's climb rate in both the Pilot's Viewpoint II and AHT (the black curve is from the former book) considering Cyclone has two speed supercharger. Looking at the Cyclones power curves, HTC's climb curves make much more sense in that regard. Are those real life curves averaged out after the first gear. I mean that's how it looks like but doesn't really make much sense to depict them that way IMO?
Any ideas?
Wmaker, are you sure you have those horsepower ratings correct? The cyclone engines the B-239s were shipped with were rated at a higher take off BHP than what you have depicted, from what I've seen the 850hp was at 6000 feet.
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Just as a general note (And to what Tango was getting at with his questions, I believe. ;)) is that if the climb rate is correct, so is the acceleration. Plane climbs with whatever amount thrust isn't needed to maintain the speed it is doing at that precise moment, otherwise it would be accelerating.
Yep. And if hlbly is surprised by what he's seeing in his test between a 190A-8 and B239, wait until he tries his test between the 190A-8 and the I-16 :x. EDIT- especially around 4,000 ft.
Tango
412th FS Braunco Mustangs
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:old: I get it!!! Because power to weight ratio affects speed and flight, not the ability to enter a turn. :x
Thank you sir.
Yep, you're getting there! We could be much more precise than that but you're getting the idea. Just adding a little more to your statement to increase the clarity just a tad I would modify it to...
"Because power to weight ratio affects speed and flight, not the ability to enter a turn at that instant in time."
EDIT: ... I like the following even better ...
"Because power to weight ratio affects speed and flight, not the maximum turn ability at that instant in time."
Maybe tequila shots are better than tylenol?
Tango
412th FS Braunco Mustangs
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Wmaker, are you sure you have those horsepower ratings correct? The cyclone engines the B-239s were shipped with were rated at a higher take off BHP than what you have depicted, from what I've seen the 850hp was at 6000 feet.
Check that speed chart I posted earlier. Never said that it would the all-out output. ;) It's the max. continuous rating. As you can see, the first gear produces 850hp close to 7000ft in practise due to ram.
edited: Corrected the alt as I remembered/read it wrong.
EDIT2: The black graph is actually with the 1000hp MIL setting. When I made the graph I named the power setting according the MAP gauge in AH. But in reality the FTHs match with the 1000hp setting. The probable reson why the MAP gauge displays the 950hp MAP is that I wasn't able to find the MAP-figure for the 1000hp setting. It isn't mentioned in the original docs.
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No tango at 190a8 used WEP in the test . You think this acceleration is correct comparatively ?
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Brewster's fuel load is much bigger portion of its weight than A-8s fuel load is from its weight. The HTC charts are with full fuel load. Hlbly used 25% fuel loads in his test. My guess is that the power loadings agree nicely with real life figures. :)
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Yep, you're getting there! We could be much more precise than that but you're getting the idea. Just adding a little more to your statement to increase the clarity just a tad I would modify it to...
"Because power to weight ratio affects speed and flight, not the ability to enter a turn at that instant in time."
EDIT: ... I like the following even better ...
"Because power to weight ratio affects speed and flight, not the maximum turn ability at that instant in time."
Maybe tequila shots are better than tylenol?
Tango
412th FS Braunco Mustangs
Yes the second statement is much clearer. And after re-reading the mounds of information to the point of hairy eyeballs, the whole picture is clearer, and I've been struggling to digest this stuff for months. :cry
I enjoy tequila a little too much and it makes me stupider than I already am :D ...last episode was 15 years ago in a bar in Slidell, La.
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No tango at 190a8 used WEP in the test . You think this acceleration is correct comparatively ?
Why do you think it isn't?
Tango
412th FS Braunco Mustangs
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Yes the second statement is much clearer. And after re-reading the mounds of information to the point of hairy eyeballs, the whole picture is clearer, and I've been struggling to digest this stuff for months. :cry
:cheers: You have leveled up in Hitech's sacred order of aerodweebs. Don't you know that hairy eyeballs, confusion, and brains exploding are part of Hitech & Pyro's rites of initiation into the order?? Silly you for missing that when you joined AH. :D
EDIT: I hear HiTech would recommend scotch over tylenol! Personally the stuff tastes like gasoline to me - bleh!
Tango
412th FS Braunco Mustangs
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:cheers: You have leveled up in Hitech's sacred order of aerodweebs. Don't you know that hairy eyeballs, confusion, and brains exploding are part of Hitech & Pyro's rites of initiation into the order?? Silly you for missing that when you joined AH. :D
LOL...must have been part of that really tiny print at the bottom of the sign up sheet...you know, the stuff you don't read because it looks like "blah blah blah".
EDIT: I hear HiTech would recommend scotch over tylenol! Personally the stuff tastes like gasoline to me - bleh!
I hear ya, I've tried lot of different brands/types of scoth out of curiosity and I'd rather gargle with hi octane racing fuel.
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If you get taken out by a Buffalo in any 109 short of an E, your a complete boob or asleep at the stick.
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"Something that doesn't make sense to me is the shape of the curves that depict Brewster's climb rate in both the Pilot's Viewpoint II and AHT (the black curve is from the former book) considering Cyclone has two speed supercharger. Looking at the Cyclones power curves, HTC's climb curves make much more sense in that regard. Are those real life curves averaged out after the first gear. I mean that's how it looks like but doesn't really make much sense to depict them that way IMO? "
It does look a bit strange.
http://llv24.com/main_files/historia/brewster.html
"Parhaan nousukyvyn saamiseksi ahdin vaihdettiin korkealle vaihteelle, kun ahtopaine pieneni arvoon 75 cmHg täydellä kaasulla (tämä tapahtui noin 3 km:n korkeudessa)."
-> "To obtain the best climb speed the supercharger was switched to high gear when boost reduced to value 75cmHg on full throttle (this took place approximately at 3 km height."
And that fits the AH chart close enough. Only explanation I can think of for the BW-366's climb curve is the use of high gear from the start and the pilot has had to limit the throttle manually for not to over boost. Due to worse initial climb the arrival to optimum height of high gear is left unnoticed except that at maximum height the curves are again close indicating the use of high gear.
Would that explain it?
-C+
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Would that explain it?
Yeh, that would explain it IMO. But why would they do it? Seems really strange thing to do.
Since the gear shift had to be done at low power setting and took a few moments...I guess one reason could be that the shifting of the gear wouldn't "mess up" the results as they probably were timing it at the same time?
I sure would like to get my hands on that original Finnish report... I've been meaning to do some digging but haven't gotten around to it.
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If you get taken out by a Buffalo in any 109 short of an E, your a complete boob or asleep at the stick.
Yeah, so says the 1337 experten. Try using a 109F-4 and taking on a Brew with a good stick flying it...you will get boobed.
Is there an english translation of that link Charge? The one time a pilot would want "best climb speed" is just after take off to reach safe altitude. Considering the process of attaining best climb speed, wouldn't they do that while enroute to their AO?
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"Is there an english translation of that link Charge?"
Couldn't find any, sorry. Does Wmaker know?
Lots of interesting info there, though. Maybe enough beer and bad luck online and I'd cool myself by translating best parts of it.
-C+
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Like Wrongway I agree that there is a methodology to dispatching Brewsters. They are far too slow to extend away or catch up to you. Just rinse and repeat. Kudos to the pilots willing to BNZ them from alt. I don't have the patience to climb them up that High. Like any plane with superior alt, they will get some kills. If you get caught TNB'ing on the deck by a Brewster then this is just simple bad SA.
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Does Wmaker know?
Well here's the most interesting part of it translated by my squadmate Ville "Camo" Pitkänen probably around 10 years or so ago. I'm sure he won't mind and most probably Mr. Raunio won't mind either. :)
Translated from:
Lentäjän Näkökulma 2 ("Pilot's Point of View 2")
Jukka Raunio 1993
ISBN 951-96866-0-6
Raunio is an aeronautical engineer working at the Finnish state aircraft factory (Patria nowadays) and has written numerous books on the Finnish Air Force.
Brewster Model 239
Structure and Flying
The one part wing went through the fuselage. The wing profile in the root was NACA 23018 and in the tip NACA 23009. The V-angle was 5.5 degrees, and the wing had a negative arrow shape of one degree at the quarter point of the wing span. The main part of the load bearing structure was a stiffened box spar made of aluminium alloy. It was divided into two integral fuel tanks. The parts of the wing in front and behind the spar were of a half-shell construction, made of duraluminium. The wing was water tight to make it float in water. To reduce air drag, all the surface plating was countersunk riveted. The wing tips were separate and detachable. The wing spar had provision to attach two 100 lb (45 kg) bombs. The ailerons had a duraluminium frame, which was cloth covered. The left aileron had a trim tab, adjustable from the cockpit. The aileron was aerodynamically balanced from the leading edge (20 %). In addition, it was mass balanced both statically and dynamically. The hydraulic flaps were of all metallic structure. They were freely adjustable up to 60 degrees.
Also the fuselage was of typical half-shell structure: fuselage ribs, longitudinal stiffeners and surface plates. The plates were countersunk riveted. The front part (engine mount and attachment for the side strut of the landing gear) was welded crome-molybdenum tube and was bolted into the fuselage. The fuselage was short and barrel-like. Under and behind a pilot, one could transport for example two passengers and a dog. Transporting a mechanic, although officially forbidden, was not uncommon during transfer flights. The claustrofobia of the passengers was eased by the open floor of the cockpit area and the bombing window at the bottom, although it was often covered or painted over. The tail planes were of half-shell construction. They had an aluminium frame, cloth cover and an aerodynamic leading edge easening (22.6 and 18 %). Both the rudder and elevator had trim tabs.
The landing gear was retracted hydraulically. The pump was driven by the auxiliary equipment gear of the engine. The set value of the excess pressure valve was 1100 psi (77 kg/cm^2). The retracting cylinder was in the center of the fuselage and connected to the oblique spars with two hoisting struts. The diameter of the main landing gear tires was 27 inches. Also the tail wheel retracted. The brakes were separate, pedal type and easy to use. The integral fuel tank of the wing was separated into two, the volume of each was 300 liters. A part of the left tank formed a 95 liter auxiliary tank. The fuel tank switch had four positions: right and left main tank, auxiliary tank and shut. The oil tank was located in the forward part of the fuselage, in front of the firewall. The volume of the oil tank was 41 liters.
The take off power of the nine cylinder Wright R-1920-G5 engine at sea level was 950 HP, corresponding to 2200 RPM and 104 cmHg boost pressure. "Combat power" (1000 HP on the deck, 800 HP at 4900 meters) was limited to 5 minutes. Nominal power was 850 HP at sea level (2100 RPM / 93 cmHg) and 750 HP (2100 RPM / 86 cmHg) at 15000 ft (4570 meters). The blower was two stage. Normally the low gear was used, but at altitudes above 10000ft (3 km) the high gear could be used to improve climb performance. The three blade Hamilton Standard constant speed propeller had a diameter of 9 ft (2.74 m). The restrictor setting range was 13 to 31 degrees.
The engine used a 15 V generator, powering the cruise lights, landing spotlight (retractable, under the left wing), cockpit lights, radio, the machine gun firing mechanism and the electric cockpit gauges. The battery was originally a 12 V Exide S-17, but it was changed into a Varta battery in Finland. The radio (transmitter RCA AVT-7B, receiver RCA AVR-8D) operated at 6100 and 6240 Hz frequencies. The receiver had a homing device, but there were no homing beacons used in Finland. The range of the radio was good at the time, several tens of kilometers between planes. The BW had an oxygen system (5 liter bottle) with the necessary controls. A fire extinguisher was also installed, which would empty itself in to the engine compartment if used. The original armament was two 0.50 inch (12.7 mm) Colt MG 53-2 machine guns in the wings (400 rounds / gun), a third syncronized in the fuselage (200 rounds) and one 0.30 inch (7.7mm) Colt MG 40 (600 rounds) syncronized in the fuselage. By 1943, all planes but one had been installed with a fourth heavy machine gun (12.7mm). The Brewsters had a simple bead sight when imported, then a binocular sight for a while, and eventually a Revi 3c / Väisälä reflector sight.
Cockpit Arrangements
The carrier plane had steps and handles for cockpit entry on both sides of the fuselage. The canopy could be easily opened during flight, and it could be locked fully open and in two partly open positions. The cockpit was roomy and well arranged. Throughout the times, the American war planes have been designed to large pilots rather than medium sized or even smaller. Visibility was good to all directions, especially behind. However, the forward visibility was hindered a bit by the angle of the side window screens. The seat could be adjusted about 14 cm vertically. The slightly angled seat back gave a comfortable seating position. The range of the stick was quite big: 22 cm forward and to both sides of the neutral position and 24 cm back of the neutral position. The machine gun trigger was located at the top of the control stick. The pedals moved 8 cm forward-back and they could be adjusted. Also the brake pedals could be adjusted in relation to the rudder pedals.
The instrument panel was rigidly attached to the fuselage structure. As a peculiarity the plane had a sliding chart board for maps. The gauges were mainly aqcuired by the Finns and had european units. The prop pitch control knob was located in the lower left corner of the panel. The forward position of the knob corresponded to take off rpms (small pitch angle) and the back position of the knob corresponded to large prop pitch angles. The pitch angles could be freely adjusted in between by turning the knob. Primer pump, carburator heat switch and starter switch were located in the lower right corner of the panel. The throttle lever, blower gear switch and mixture lever were located in the lever box in the left wall of the cockpit. The fuel hand pump was in the side of the lever box. The wheels for the elevator-, rudder- and aileron trims were in their own console on the left.
The landing gear was extended by pressing the T-shaped lever, which was located right of the seat, in to free the lock, then push the lever down. When the landing gear indicator, located below the instrument panel, showed the gear to be fully extended and simultaneously the hydraulic pressure rose, the lever was returned to the mid position. The lever had a safety switch, which prevented accidental retracting of the gear. When retracting the gear, the safety had to be released, before pressing the T-shaped lever and pulling the landing gear lever up. If the system malfunctioned, the gear could be extended and retracted with the hand pump (on the right side of the seat) or by just opening the auxiliary valve and pulling the "emergency extension" handle (in the bottom part of the instrument panel). After that the landing gear had to be locked by pulling down on another lever. A light lit up on the instrument panel when the RPMs were under 1200 and the gear was up.
The flaps were operated with a switch (right of the seat). When extending the flaps the switch was turned down. When the flaps were in the preferred position, the switch was returned to the mid position. The flap position indicator was located in the bottom part of the instrument panel. When retracting the flaps, the switch was turned to the up-position. If the system malfuctioned, the hand pump was used. 31 pumping motions corresponded to the full 60 degrees of extension. The ignition switch was in the console on the left wall. All the electric switches and the reostat-switch (?) of the lighting was in the console on the right wall. The handles to load the guns were at the bottom of the instrument panel and on the floor on the right side of the cockpit. The switches for the oxygen system, radio and fire extinguisher were on the right wall of the cockpit.
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Start Up, Taxiing and Takeoff
During start up, takeoff and landing the left side fuel tank had to be used. The mixture lever was set to full rich and the hand pump was used to get approximately 0.2 kg/cm^2 of pressure. Five primer pushes were given to a cold engine. Pumping with the throttle was forbidden by the manual. The throttle was set to correspond to 800-1000 RPM. Making sure that the prop pitch control knob was fully forward, the blower at small gear, the ignition was switched to both magnetos. The pilot maintained the fuel pressure with the hand pump, as the mechanic turned the starter crank (in the forward fuselage on the right side). When the starter had accelerated enough, the pilot engaged it to the engine, which also switched on the starting ignition. For the warm up the prop control knob was pulled back. Before the engine test run, the oil had to heat up to approximately 30 degrees. The oil heated quickly, because the oil tank thermostat routed the cold oil past the oil cooler. During the test run the brakes kept the plane in place, and the tail didn't try to rise. The BW taxied at 700 RPM on a level air field. With the tail wheel unlocked, the turning radius was only approximately 12 meters. Using the brakes the plane could be turned on the spot.
The pre flight check was simple and quick: tailwheel locked, prop pitch small angles, blower at small gear, mixture rich, fuel tank switch on left tank, air intake cold, trims set, controls unobstructed and flaps retracted. The throttle was opened fully. The propeller screamed exceptionally nasty at low pitch angles. The takeoff itself was a quick event. The tail lifted after approximately 30 meters, swaying was minimal and the direction was easily kept. The BW lifted off at a speed of 120 km/h. The length of the takeoff run on a calm day was 140-160 meters, taking 8-9 seconds. Total distance to 15 meters altitude was approximately 350 meters. Using the flaps wasn't necessary during takeoff. British tests with a Brewster model 339B showed that 26 degrees of flap reduced the takeoff run by approximately 10 %, but reduced the initial climb rate. After liftoff, the gear was retracted, manifold pressure was set to the continuous range (93 cmHg or below) and the RPMs below 2100. Retracting the landing gear created a noticeable nose-up moment. The best climb speed was approximately 220 km/h. Rolls and slips were levelled with the trims. During summer, the cylinder head heat came close to the maximum values (briefly 260, continuous 235 degrees Celcius).
Performance in Level Flight and Climb
The Brewster was one of only a few of our fighters that which performed according to the manufacturer specifications. The promised climb time to 15000 feet, 4572 meters, on nominal power was exactly 6 minutes with 2275 kg and 6.7 minutes with 2387 kg takeoff weight. A Finnish Brewster, equipped with a seat armor and other modifications, weighed 2020 kg with all accessories, weapons loaded and with the oil tank full. With the pilot and 300 kg's of fuel, the typical take off weight was 2415 kg. Figure 1 shows the climb times and the calculated climb rates at different altitudes, from the test flight with BW-366. The take off weight is not known, but had to have been somewhere between 2300-2400 kg. The manifold pressure was 93 cmHg at takeoff and RPMs at 2100. The climb performance corresponds fully to the manufacturer specifications. Climb speed was 220 km/h IAS at low altitudes, reducing to 180 km/h at 5 kilometers.
To achieve best climb performance, the blower was switched to high gear when the manifold pressure dropped to 75 cmHg on full throttle (this happened at approximately 3 km altitude). When changing the gear, the throttle was reduced to soften the change. The blower gear could not be changed again in 5 minutes. The clutch had to be allowed to cool off. The automatic mixture control of the carburator functioned when using the low gear of the blower. If the engine ran roughly on high gear, the mixture had to be manually adjusted. On high power settings, the mixture lever had to be fully forward, corresponging to full rich. Below 550 HP (low gear) and 450 HP (high gear) then mixture had to be in the cruise setting. Flying with the high gear during cruise was not recommended due to the knocking risk.
Figure 2 shows the flight speed test flown with BW-366. This particular plane was one of the best front line planes during the Continuation War. Top speed at sea level was 428 km/h and the top speed of 480 km/h was achieved at the blower operational altitude (4750 meters on nominal power in static conditions. In practise, due to the intake ram effect, a little higher). The correlation to the manufacturer specifications is, again, excellent. According to those, the top speed at altitude is 484 km/h and 427 km/h at sea level. The Brewster was clearly faster than any other main fighter type we had during the beginning of the Continuation War. The Cyclone-Curtiss, which we had in small numbers, was about as fast even though it had 200 HP more engine power.
On the maximum continuous power, nominal power, fuel consumption was approximately 370 liters/hour at low altitudes. The full 600 liters was good for approximately 1.5 hours of flight. The range was 600-700 km, depending on flight altitude. A normal cruise power setting at 2000 meters altitude was 1850 RPM / 65 cmHg (65% power). The corresponding indicated air speed reading was 330 km/h and true air speed 390 km/h (the air speed gauge showed approximately 25 km/h too slow at cruise speeds). Fuel consumption at lean mixture was 170 liters/hour, corresponding flight time without reserves was 3h30min and range 1350 km. By flying with lower speeds, flight times of well over four hours could be achieved. BW was well suited for patrol and escort missions otherwise, but the oxygen lasted for only 30-40 minutes.
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Flight Characteristics
Longitudinal stability with normal loading (center of gravity 27-29 % MAC) was slightly positive. The stick force gradient was small but sufficient. The plane could be trimmed relatively easily in all flight states and power settings. Clean, with power on, the plane took a while to set. When changing the flight state (gear/flaps?) the changes in trim were clear and quite large. Stick force per G was suitable for a fighter, in the order of 3 kiloponds/g. During turns and levelling from dive the G was easily controlled. When the center of gravity moved towards the back (wooden wing Brewster and some other experiments) the plane first became unstable in maneuverability (tended to tighten the pull) at approximately 32 % MAC CoG and unstable in all directions at 33 % MAC. (MAC = Mean Aerodynamic Chord).
Directional stability was positive. When the plane was disturbed from level flight with the rudder, it returned to direct flight after a couple of sharp yaw and roll motions. The feel of the rudder was a bit poor in slow flight, but got better at speeds over 150 km/h. In a dive, at speeds over 500 km/h, the rudder was very sensitive. V-angle stability was especially good, due to the mid wing and 5.5 degree V-angle. Clean banked turns could be made with just the rudder or just the ailerons. In a straight side slip (clean, engine on idle) at 150 km/h the rudder was fully pressed and counter elevator was given, approximately half of the stick limit. The bank angle was approximately 15 degrees. Correspondingly, during landing the bank angle was approximately 10 degrees.
Aileron forces were quite small, but the ailerons were not over sensitive. At 320 km/h IAS a quarter deflection needed a 5 kilopond force and at 620 km/h 11 kiloponds. At high speeds, the ailerons were even lighter than the ailerons of the Curtiss-Hawk. BW went into a turn clearly faster than a Curtiss or a Spitfire. During turns the control harmony was good. BW warned with a tremble when the stall was near, but didn't tend to snaproll. The BW could be pulled without care and even flown incorrectly. Turning ability was quite good, a 180 degree turn from 350 km/h IAS took 7 seconds at 2 km.
Aerobatics, Stall and Spin
The maximum allowed stress for the Brewster at 2300 kg flying weight was 9 G positive and 4 G negative. Aerobatics was easy and effortless. A loop could be pulled from cruise speed. At 1500 m altitude the radius of the loop was 400 m and the speed at the top 130 km/h, when starting at 360 km/h. At the same starting speed an immelman resulted in an end speed of 150 km/h and an altitude gain of 700 m. From a slight dive, an extra kilometer of altitude could be easily gained. Two and a half turns in a climbing spiral at 45-60 degrees angle gave 800m altitude gain from a starting speed of 440 km/h. The speed at the end of the maneuver was 150 km/h.
Stall speed clean was approximately 130 km/h and in landing state approximately 110 km/h. With power on the stall speed reduced by approximately 10 km/h. The BW dropped the nose and slightly banked on its wing. It straightened itself out from the stall quickly and didn't go into a spin even if the stick was held back. The spin had to be started by kicking full rudder when the plane stalled. The spin was "normal". When straightening from the spin, full opposite rudder was given and after half a roll of waiting, the stick was pushed straight forward. The stick had to be pushed with exceptionally large force. A ten roll spin to the left took two rolls to straighten, and a spin to the right three rolls, correspondingly. If the controls were not fully deflected, the straightening took longer. When the wing guns were removed, the BW straightened about one roll faster. According to the manual, only spins of two rolls were allowed. Nothing out of the ordinary was noticed in dives. The maximum allowed speed was 620 km/h IAS and 2730 RPM.
Approach and Landing
The flaps could be extended at 260 km/h. Landing gear speed was not specified in the manual. Extending the flaps and landing gear was followed by a strong nose-down moment. The pitch trim wheel had to be turned rigorously, the full range needed nine turns of the wheel. Extending the flaps made the controls lighter and reduced their power. Aprroach speed was approximately 140 km/h, visibility and controllability good in all respects. The BW could be pulled to a three point landing without worries. By pulling with the engine in a partial stall, the BW could landed on a very short strip. The landing run could be easily controlled due to the wide landing gear. The landing run was approximately 230 meters when using the brakes, approximately 380 meters without the brakes.
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Wow, thanks Wmaker. That's the most complete information yet. Noticed a couple of things that explain some damage characteristics, fabric covered ailerons and elevators...unless you hit part of the framework, even explosive and tracer rounds would pass right through causing minimal damage. And it used a wheel for pitch trim...must have been fairly small to require 9 full rotations for landing approach. Busy pilot at that point, explains some of the accidents mentioned in other sources.
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Thanks Wmaker :salute
That was very interesting.
I know now my next Christmas gift :D
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gyrene: sorry it's taking me a lot longer to draft a response for you on clarifying turn performance factors for you. I'm not happy with any of my approaches to an explanation thus far. I'm regurgitating stuff in aero textbooks, explaining similarly to how others have in the past, or making it too complicated and not clear enough. I think I've come up with an approach but it requires more work. Not sure how long it'll take me but if and when I do I'll post it in a separate thread by itself.
Tango
412th FS Braunco Mustangs
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Brewster's fuel load is much bigger portion of its weight than A-8s fuel load is from its weight. The HTC charts are with full fuel load. Hlbly used 25% fuel loads in his test. My guess is that the power loadings agree nicely with real life figures. :)
A guess is your evidence ? Show me the data that supports the claim that irl the buff should out accelerate the 190 with its much higher horsepower and much lower drag .
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A guess is your evidence ? Show me the data that supports the claim that irl the buff should out accelerate the 190 with its much higher horsepower and much lower drag .
How much lower drag? What kind of drag? In what condition?
Show me the data that supports the claim of the lower drag.
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A guess is your evidence ? Show me the data that supports the claim that irl the buff should out accelerate the 190 with its much higher horsepower and much lower drag .
Well, let me commend you for starting to shed light on the logic behind your statements that something is off with the Brewster's acceleration.
Some more questions for you to delve a bit deeper into it all:
1) Are you implying total drag coefficient of an airplane remains constant in level flight from minimum to maximum airspeed?
2) What leads you to believe the drag of the 190 is lower than the B-239 and is it always lower than the B-239 in level flight no matter what the airspeed is (assuming we're comparing drag of the 190a-8 and b-239 at the same airspeeds)?
As a tangent I should mention I replicated your tests following your test procedures (though using TAS instead so that I can reverify timing using film recorder). I got the following values:
B-239, 25%, 150-250 TAS, 1.3k, ~33s
190A-8, 25% 150-250 TAS, 1.3k, ~25s (WEP)
Regardless of the values, based on your statements we need to straighten out the physics logic you've been assuming. I'm purposely asking questions not to embarrass anyone but to help shed light on where the logic might have gone awry.
Tango
412th FS Braunco Mustangs
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Brewster at 1k alt 150 to 250 mph ias `22 seconds
FW190a8` at 1kalt 150 to 250 mph ias 25 seconds
Could not figure out how to do it at sea level . Was unable to keep gear on while on the ground at that speed . :rofl :rofl :rofl :rofl
Test conducted at 1000 k alt auto level on . E6b used for recording speed . 1k alt was obtained throttled back until speed was 120 ias . Full throttle then applied .2 stop watches started by myself and wife as speed hit 150 ias. watches stopped at 250 ias . Test repeated 5 times . Differences in times below .5 seconds for both watches , each test . AC were augured after each test . Fuel level was 25% no ords and lightest gun package .
How on earth did you get the brewster from 150 to 250 in 22 seconds in level flight? I tested this myself today and got 41 seconds with full fuel and 35 seconds with 25% fuel.
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Hlbly, I'll throw you a bone. Your numbers or our numbers are inconsequential in relationship to the logic you've laid out. Not picking on you but your claim about the Buffalo being "wrong" in AH is like the 10,000th claim that "something is amiss in the land of Denmark". It follows a familiar pattern: IF it doesn't fly in a way I expect or can explain it THEN the FM must be wrong.
Here's the problem. Just because you can't explain it doesn't mean that it's wrong. Like the past 10,000 other claims has it occured to you that maybe what's wrong is not the FM but your understanding of the physics? That's why to prove something is wrong it's not enough to make observations. You need to EXPLAIN the logic behind the conclusions you made about your observations.
In your last post you finally revealed some of your logic. The FW190A-8 has greater horsepower (thus greater thrust) and a lower drag compared to the B-239 therefore the FW190A-8 should out accelerate the B-239. Sounds logical. However there a couple of problems with this that I've been throwing hints at to get you to think about them. Let's explain.
Let's use a simplistic example assuming fixed thrust & drag to demonstrate. We have two airplanes:
Plane A: weight=8,900 lbs, thrust=2,500 lbs, drag=525 lbs
Plane B: weight=4,400 lbs, thrust=1,800 lbs, drag=725 lbs
Which airplane accelerates faster than the other? Basis your logic Plane A would because it has greater thrust and lower drag. This would be wrong however because Plane B actually accelerates faster.
Plane A: a=7.1 ft/s^2
Plane B: a=7.9 ft/s^2
Why? Acceleration in the direction of flight in level flight simplifies to:
a = (thrust-drag) / mass
So the first problem in your logic is that you've only factored in thrust and drag in your assessment but not mass. Ignore variables at your peril because they will bite you in the butt. So acceleration is a function of thrust, drag, and mass and as you can see in our example mass can make a difference. How much of a difference does the mass make? That leads to the 2nd problem with your original logic.
To know how much of a difference mass makes on acceleration you also have know the VALUES of thrust and drag as well. Both thrust and drag are non-linear for our piston-prop airplanes and vary with velocity. In other words they change in way that makes generalized statements like "thrust is greater, drag is less" between planes meaningless unless you specify where in the flight envelope you're talking about. So the 2nd problem is that you have to factor in the non-linear changes of thrust, drag, and thus also the non-linear changes in acceleration before you can even know if one plane out accelerates another over a portion of the flight envelope.
"Young cat! If you keep your eyes open enough, oh the stuff you will learn! The most wonderful stuff....The more that you read, the more things you will know. The more that you learn, the more places you'll go." (I Can Read With My Eyes Shut - Dr. Seuss)
Tango
412th FS Braunco Mustangs
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LOL!
I truly admire your patience Tango! :) <S>
For me however, it's best if I keep from trying to reason with hlbly.
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LOL!
I truly admire your patience Tango! :) <S>
If someone really has an honest attempt to learn then I entertain that the best I can. I have my limits though. 9 pages is already feeling uncomfortable. I made it to 16 pages once! Now this 40+ page one in the recent past- no thanks. :D
Sometimes the questions are complicated and the answers are simple. (Dr. Seuss)
Dr. Seuss aerodynamics would be grand, but sadly it only applies to green eggs and ham.
Tango
412th FS Braunco Mustangs
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honest attempt to learn
Personally, I think that there's a problem right there but hopefully I'm wrong. I'll sit back and see how this pans out. :)
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Perhaps some one could test if the Brewster does close to these (me busy):
Acceleration/deacceleration test at 2000m
320 -> 380km/h IAS 43s
380 -> 320km/h IAS 12s
These values are from Finnish data tested on squadron (Pyro have this data).
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"These values are from Finnish data tested on squadron (Pyro have this data)."
When?
Which aircraft is that, BW-???
Which engine, Cyclone or M63?
Engine settings?
-C+
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The 190a8 has too much mass in AH today, something Pyro and HT aknowledged and will look into at in a future release/version/star date / *
so be advised comparing it with any other plane
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The 190a8 has too much mass in AH today, something Pyro and HT aknowledged and will look into at in a future release/version/star date / *
so be advised comparing it with any other plane
Anyone who is hoping for a drastic difference as a result of a change will be disappointed. The weight difference is not large at all, if indeed it is changed. Ultimately, the 190A8 will perform quite like it does now.
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With less mass I expect 190a8 to be more nimble - and a bit closer to some of its competitors - every mid -44 plane outclasses it - including the 190a5 it was suppose to superceed.
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If the Luft had our A8 in the war they would say "Ze 190, she ist a schwein!". Let's hope it gets put on a diet soon.
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I just encountered a Brewster today in an F4F. I had 2K of alt and obvious E (him getting off a climb, same as me. Probably me going about 300 and him going 250. I pull vertical and he does too, except he climbed right up to me and pinged the crap out of me. Any other plane I would have been dead .
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I just encountered a Brewster today in an F4F. I had 2K of alt and obvious E (him getting off a climb, same as me. Probably me going about 300 and him going 250. I pull vertical and he does too, except he climbed right up to me and pinged the crap out of me. Any other plane I would have been dead .
I had 2k alt in a jug25 last night vs. a brew that had just finished a fight.
Merged, went vertical and like you said it climbed right up there with me.
(gentle merge w/o much Energy bleed btw)
There is indeed something not quite right about the Brew if it can out zoom a jug when it has less alt and e.
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I had 2k alt in a jug25 last night vs. a brew that had just finished a fight.
Merged, went vertical and like you said it climbed right up there with me.
(gentle merge w/o much Energy bleed btw)
There is indeed something not quite right about the Brew if it can out zoom a jug when it has less alt and e.
Why do you think it's wrong? Please explain :). And please don't tell me because the Jug is heavier thus it has more "N-R-G" ;).
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I had 2k alt in a jug25 last night vs. a brew that had just finished a fight.
Merged, went vertical and like you said it climbed right up there with me.
(gentle merge w/o much Energy bleed btw)
There is indeed something not quite right about the Brew if it can out zoom a jug when it has less alt and e.
I've experienced this too, but I have always thought it was because the Brewster did a little dive, prior which led me to think that the e-retention of the Brewster was in some way off.
By the way a p47D-40 should out climb a Brewster
(http://bbs.hitechcreations.com/wiki/images/d/d9/P47d40clmb.jpg)
(http://bbs.hitechcreations.com/wiki/images/d/d6/239climb.png)
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Are you talking zoom climb or steady climb? Why do you think the p47d40 should outclimb the brewster?
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double post.
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Are you talking zoom climb or steady climb? Why do you think the p47d40 should outclimb the brewster?
Uh, because it does okay?
According to the chart, the Jug DOES outclimb the Brewster.
The ratio of thrust-to-weight is better, as evidenced by the D40's superior climb rate.
The ratio of thrust-to-drag is better, as evidenced by the D40's vastly faster top speed.
Thrust is good, weight and drag are bad, the more thrust you have in relation to these two, the better in a zoom, right?
So how can the Brewster BEGIN to match the zoom performance of the D40?
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Dont forget that weight does help with E retention. The heavier an object, the greater the mass, and thus, the better it stores momentum. This explains great E retention in planes like the Jug, P38, and Mossie.
I just dont understand why the Brewster zooms so well if it is lightweight and underpowered? Then there are people saying that the Brewster has some instability problems in real life that is not present in game.
If somone is knowledgeable about this, please shed some light for me.
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So many things amiss with statements above but I'm headed out the door to see a movie with the kids! No time to reply. Will be back later ;).
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I had 2k alt in a jug25 last night vs. a brew that had just finished a fight.
Merged, went vertical and like you said it climbed right up there with me.
(gentle merge w/o much Energy bleed btw)
There is indeed something not quite right about the Brew if it can out zoom a jug when it has less alt and e.
Lute and Spikes, with respect to both of your experience, did you guys film these engagements to know definitively the relative e-states of yours and the other aircraft?
Power Available - Power Required = excess power. Excess power equals the ability to either accelerate or climb. So, what we should consider is whether or not there are situations where a Brewster may have more excess power than the Jug.
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Dont forget that weight does help with E retention. The heavier an object, the greater the mass, and thus, the better it stores momentum. This explains great E retention in planes like the Jug, P38, and Mossie.
I just dont understand why the Brewster zooms so well if it is lightweight and underpowered? Then there are people saying that the Brewster has some instability problems in real life that is not present in game.
If somone is knowledgeable about this, please shed some light for me.
Personally, I think the Jug stinks at retaining energy, unless the nose is pointed down, and I've fought it in just about every possible situation in this game. Its heavy, and the engine is constantly having to work hard to keep the big, fat, beautiful hunk of American Iron airborne. The advantage the P-47 has it that it keeps 2200-2800BHP under the hood. A large part of the reason the P-38 and Mossie "retain" energy as well as they do is because they have two engines creating a lot of thrust, not because they are heavy.
You say "I just don't understand why the Brewster zooms so well if it is lightweight and underpowered?" Is the Brewster underpowered? What's your definition of "underpowered". You've got a 5000 lb aircraft with 940 HP compared to a plane that weighs 14,000 lbs when its svelt, that makes 2600 HP. In that comparison, the Brewster has a slightly better power to weight ratio than the Jug.
Honestly gents, if you want to learn about this stuff, do some research on power required and power available. Then, read up on specific energy and how you can use it to compare dissimilar aircraft performance.
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Last comment...
dTango reminded me of this thread in an offline discussion we were having. If you read through the entire thing, you'll find the most thorough treatment of this topic on the boards.
http://bbs.hitechcreations.com/smf/index.php/topic,266321.0.html
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OK guys, I don't have a lot of time to explain so I'm going to be brief. I'm headed to Central Texas for the long weekend and playing aero babysitter isn't anywhere near the top of my list of things to do so ;).
1) Specific Excess Power (Ps)
Ps gives us a measure of the energy rate of change for an aircraft. Want more info on it you can dig it up from this thread among other places:
http://bbs.hitechcreations.com/smf/index.php/topic,209163.msg2488778.html#msg2488778
The general equation for it is:
Ps = (T - D) * V / W = dh/dt + (V/g)*dV/dt
Honestly I have no idea how you guys can magically estimate what an aircraft's "energy retention" should be in your head without working through what the value of Ps in every situation and flight condition. For a constant speed climb at least it's easier to calculate but for a zoom I have to resort to numerical methods to solve it to have even a clue because being a mere mortal I can't do the math in my head with the number of variables and non-linearity involved. You guys are gods to do all that ciphering in your head! I bow down, unworthy.
To show that E retention is wrong you have to show where the Ps relationship has been violated.
2) F4F vs. B-239
This one is a little easier to explain because we can use the steady climb charts to demonstrate.
(http://thetongsweb.net/images/brew-f4f.png)
As you can see the B-239 pretty much outclimbs the F4F across the envelope in a steady climb. In a steady climb dV/dt=0 therefore our Ps equation resolves to:
Ps = (T - D) * V / W = dh/dt where dh/dt is the rate of climb
As alluded to by Stoney specific excess power tells us about the amount that T>D which can be used for accleration or steady climb. Because the F4F W > B-239 W we can safely assume that the B-239 will probably also out zoom an F4F just as the RoC difference indicate for steady climb.
3) Well what about the P-47's you say?
That's a little more complicated. Firstly let's just plot out a couple of RoC charts.
(http://thetongsweb.net/images/brew-d11.png)
(http://thetongsweb.net/images/brew-d25.png)
(http://thetongsweb.net/images/brew-d40.png)
First thing to notice, without WEP the P-47 D11,25,40's are outclimbed by the B-239 roughly below 5k at Military Power. But at WEP for the most part the D11 (marginally except below 5k), D25 & D40 all have better RoC's. So there must be something wrong with the B-239 then right??? Not so fast.
a) the speeds that you're comparing the climbs matter. The charts above are at best RoC for each aircraft and they are different. If the P-47 however is climbing in a steady climb but at a lower speed than it's best climb speed then it's RoC will get worse because of greater induced drag.
b) this is different than the F4F vs. B-239 case because the P-47 is much heavier bird than the B-239 so you have to understand what the impact of that's going to be in an accelerated zoom climb. The forces in the direction of travel in a zoom climb resolve to:
F = ma = T - D - W*sine(climb_angle)
At steady climbs climb_angle is small therefore the impact weight is lower. However where climb_angle increases the impact of weight increases. In a zoom climb the climb_angle is pretty high which means weight has much more of a detrimental impact on zoom climb peformance. So it's totally conceivable that the B-239 could zoom better than the P-47 D11, D25, & D40. Again I have no idea how you guys can factor all that in your head to know what the impact is for sure. To figure out how the above relationship varies I have to resort to numerical methods for resolving integration of partial differential equations to even estimate it.
4) But doesn't greater weight mean more mass which means heavier things retain energy better?
This is a partial truth which is wrongly applied to aircraft. Where airplanes are concerned increased weight overall reduces zoom climb performance. See mace and my posts in this thread for an explanation of this fact (Stoney - thanks for pointing the thread out):
http://bbs.hitechcreations.com/smf/index.php/topic,266321.msg3328531.html#msg3328531
Bear in mind that I'm only assuming 1g load factor in all the above. In n>1 Apples to apples this would generally make it even worse for the heavier plane. Bottom line for me: Could there be something wrong? Yes. However maybe folks should start asking why what you observe is actually RIGHT instead and look for the explanations for why it's right instead of assuming it's wrong.
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I'm paying special attention to your post BnZs because you should know better :)!!
Uh, because it does okay?
According to the chart, the Jug DOES outclimb the Brewster.
The ratio of thrust-to-weight is better, as evidenced by the D40's superior climb rate.
See my post above for explanations.
The ratio of thrust-to-drag is better, as evidenced by the D40's vastly faster top speed.
You've over-generalized. This is true for a portion of the flight envelope. However thrust and drag are nonlinear across the entire peformance envelope and you can't assume this relative relationship between planes remains the same across the entirety of the flight envelope.
Thrust is good, weight and drag are bad, the more thrust you have in relation to these two, the better in a zoom, right?
Yes this statement is true. But for our specific situation you're assuming you know what the values of thrust and drag are and discounting the effect of weight.
And yes, my fingers do get really tired of typing all this stuff to you too! :D
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I'm paying special attention to your post BnZs because you should know better :)!!
See my post above for explanations.
Uh, actually in this case I don't really understand.
Ok, first, how I define a zoom climb for our purposes-Straight vertical, or darn close to it. The wings are unloaded or close to unloaded at this sort of angle. The way it usually gets down in combat. I can easily see how the Brewster might climb better at 120mph IAS than the D40, even though the D40 climbs better at its Vy. But I don't think we are talking about an angled climb when we speak of vertical performance generally, we are talking about maneuvers that involve pointing the nose at the noonday sun until one of you runs out of airspeed. Lighter wingloading would seem the Brewster's only performance advantage over the D40. In this case, I don't see why lighter wingloading would come into play as an advantageous factors, cause like I say, the wings are unloaded anyway. This is the sort of climbs where people are finding Brewsters with lower initial airspeeds chasing them up for surprisingly long amounts of times.
You've over-generalized. This is true for a portion of the flight envelope. However thrust and drag are nonlinear across the entire peformance envelope and you can't assume this relative relationship between planes remains the same across the entirety of the flight envelope.
Yes this statement is true. But for our specific situation you're assuming you know what the values of thrust and drag are and discounting the effect of weight.
Well, like I say, I thought better climb rate was a pretty dead indicator of better better thrust-weight. And I thought top speed was a good indicator of thrust versus drag for the airplane at low AoA. An airplane zooming straight up is at low AoA, in fact like I say, its unloaded. As for weight, isn't weight unimportant except as it relates to thrust? Same thing with drag? So I still can't see why the D-40 doesn't hold all the cards in vert performance against the Brewster.
Edit: I was a little stunned to learn that the Brewster's charted climb rate is so poor. Just from playing around in the pond with them, I had figured they'd have roughly the same climb rate as an A6M5b. And Lute posting also caught my eye...that's not some random yahoo who can't judge E states speaking there.
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Then there are people saying that the Brewster has some instability problems in real life that is not present in game.
There are lot of people saying lot of things on this BBS and everywhere else. Regarding the Brewster on this BBS roughly about 5% of the comments stated have anything to do with reality.
Regarding the stability, the stability problems were in the longidutinal axis on the later models when the CoG was close to it's aft-limit. This happened when the plane was close to it's maximum take-off weight ie. the aft fuselage tank was full of fuel. These problems have absolutely nothing to do with the variant we have in the game.
A good source for further describtions is Dean's America's Hundred Thousand.
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playing aero babysitter
Bweehehehehhe... :rofl :rofl
Glad I wasn't drinking anything. :)
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Well, like I say, I thought better climb rate was a pretty dead indicator of better better thrust-weight.
Don't use the term "thrust to weight" for propeller aircraft. "Power to weight" is the proper comparative term. In jet engines, maximum thrust is constant regardless of speed, whereas in a prop aircraft, thrust varies with speed.
And, climb rate is an indicator of excess power, not thrust-to-weight or power-to-weight.
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Good point and no I didn't film it BUT the Brew had just finished turn fighting with another plane and I had a good alt advantage AND had been in level flight for a bit so I am ASSUMING that I had more E.
It is possible the Brew had just dove and dispatched it's opponent quickly and was holding more energy than I had thought.
I just found it "odd".
I am a fairly good judge of E states and can usually tell these things but for the Brew I tend to be off on my "guess" by a good 500' constantly.
I could have just been wrong on this occasion as generally I don't have a problem fighting and killing 'em.
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Uh, actually in this case I don't really understand.
Ok, first, how I define a zoom climb for our purposes-Straight vertical, or darn close to it. The wings are unloaded or close to unloaded at this sort of angle. The way it usually gets down in combat. I can easily see how the Brewster might climb better at 120mph IAS than the D40, even though the D40 climbs better at its Vy. But I don't think we are talking about an angled climb when we speak of vertical performance generally, we are talking about maneuvers that involve pointing the nose at the noonday sun until one of you runs out of airspeed. Lighter wingloading would seem the Brewster's only performance advantage over the D40. In this case, I don't see why lighter wingloading would come into play as an advantageous factors, cause like I say, the wings are unloaded anyway.
Most of my post above didn't really address wing-loading. Let's assume your 90 degree zoom climb case. With that because sine(90)=1 our forces in the direction of flight resolve to:
F = T - D - W
As you see the greater the weight the more it counteracts thrust thus weight has an impact.
In reality it's a great deal more complicated than that. I can toss out generalizations and simplifications to try to make the point more but in the end I think that only leads to more questions that can only be resolved by much more in depth modeling of it all which I do not have the time or patience to do.
This is the sort of climbs where people are finding Brewsters with lower initial airspeeds chasing them up for surprisingly long amounts of times.
Too much conjecture. It's very likely that these "people" are experiencing "Tango's 1st Law of Air Combat - you can't defy aerodynamics" meaning if you don't understand and factor in the aero nuances you'll end up with nasty surprises.
Well, like I say, I thought better climb rate was a pretty dead indicator of better better thrust-weight. And I thought top speed was a good indicator of thrust versus drag for the airplane at low AoA. An airplane zooming straight up is at low AoA, in fact like I say, its unloaded. As for weight, isn't weight unimportant except as it relates to thrust? Same thing with drag? So I still can't see why the D-40 doesn't hold all the cards in vert performance against the Brewster.
Already answered in this post and above but let's focus on your drag statement here. The plane with a higher level speed probably has the lower drag coefficient (but not necessarily because it could be just offset by an overload in thrust). However the absolute value of drag for the faster airplane could be even higher than the slower aircraft. For instance take the P-47D40 vs. the lowly B-239. Knowing that at level flight T=D here's what we get at sea level:
plane bhp p.e. mph drag
47d40 2600 0.8 340 2294
b-239 1000 0.8 280 1071
So in this case absolute drag of the faster airplane is higher. Aero is full of nuances like these.
Signing off for awhile guys. Headed to Belton TX!
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If a noob may be allowed to voice an opinion:
The brew was the biggest surprise for me in AH. I took one up simply because I was having a crappy day in the arena and thought it might be fun for a few seconds (before I got shot down again). By the end of the day I'd found some interesting things.
1. I could turn inside just about anything. (Not a surprise after I'd read Soda's evaluations).
2. In a low altitude furball i could follow enemy aircraft in climbs and get good shots as they came over the top and dived. I would loose them as they picked up speed, however.
3. The gun package was adequate enough for my purposes. :)
4. People tended to ignore me in fights, which was a wonderful advantage.
5. I can't catch anything.
I'm also finding that building alt, while still useful, doesn't help me that much because the Brew really doesn't gain much speed in dives and low speed just seems to be where it handles best. So I actually look to get pounced, so I can bring the fight into the low-speed turnfight where the Brew excels. I would never take this bird into a base cap situation, but when you don't have time to build altitude it's a great little plane to fly. The major problem I have is that you have to let the enemy come to you. That said, I got more kills in the Brew then I did flying any other ride.
-Muzzy