Aces High Bulletin Board
General Forums => Aircraft and Vehicles => Topic started by: Emu on February 15, 2010, 01:14:08 PM
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http://www.wwiiaircraftperformance.org/me109/me109g6-tactical.html
The tests would indicate the 109G6 pretty much sucks, even against the Mustang. Funnily, I think the 109G6 is a much better turner in this game against the Mustang and Tempest.
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That is comparing the 109-G6 against the Spit XIV, P-51B and Tempest V...it's a give and take, but pretty much in those flight tests (which we done by British pilots who were not as adept at flying 109s) showed the G6 could not keep up with the other aircraft in basic combat maneuvers, climb, dive, turn, at various operational altitudes...not exactly what a toon pilot with no fear of losing his life can do in a toonville 109.
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General
2. The Me.109G/6 is a small low wing, single seater, single engined, short range fighter, with fittings under the fuselage to enable it to carry a jettisonable fuel tank. A 250 K.G. bomb may be carried under the fuselage in place of the fuel tank. The undercarriage is fully retractable and the tail wheel partially retractable. This aircraft has a re-designed fin and rudder which is approximately 1 ½ square feet larger in area than those fitted to earlier Marks.
3. The power unit is a DB.605A-1 engine which develops approximately 1550 h.p. at 22,000 feet.
4. The armament consists of 2 x 13 m.m. M.G.’s mounted above the engine, 1 x M.G. 151/20 m.m. cannon firing through the airscrew hub, and 2 x M.G. 151/20 m.m. cannon in under-wing gondolas.
5. The all-up weight of the aircraft with full war load including pilot is approximately 7,488 lbs, and the wing loading is 43.6 lbs/sq.ft.
The section of the report I bolded is not insignificant in the outcome of some of these tests.
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True. It wasnt clear to me whether the gondolas were or were not part of the test.
In any case, I thought it was an interesting doc; nothing intended by it. definitely nothing like that Mosquito thread.
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Nice catch Karnak, I looked at that and just skipped to the rest without noting the actual implications.
brain flatulence...
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Except for the gondolas nerf (and probably feeding the poor DB605 with fuel that suited allied planes - not german planes, the 109g14 was available in numbers by the time this document was written, and gave a good pilot a good chance 1 vs 1.
Luftwaffes big problem late-44 was not the quality of the planes, but pilot skill.
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One thing I dislike about wwiiaircraftperformance is that it removes all the valuable context from the information it presents, and sometimes (okay, often?) folks mis-use the scans of old tests or just mis-represent them to fit their needs, such as in this 109G6 case. It's been brought up a few times before.
For example, the spit14 used a spit9 frame but a different engine (for the most part). The Spit9 with 25lbs boost was easily out-dove by the 109, but the same 109 was left in the dust by the lesser-boosted 18lbs spit14. The whole story is not being told.
Not even counting the allied gas, allied pilot skills, and other issues, just the fact that the tests use gondolas totally nerfs all turn, roll, level speed, and climb rate tests. On top of that, the "war loadout" weights listed on this test are (for some reason?) about 700lbs heavier than our own Aces High G6 with single 20mm and 75% gas. Even loaded out with full gondolas, internal gas, DT (dropped), it's still a bit heavier. They mention the tall tail, which means something closer to a G14, but still it's about 500lbs heavier than a single-cannon G14 with full gas. Totally loaded with 100% internal fuel, a Mk108 30mm cannon, 2 gondolas, a centerline rack (those are what? 150 lbs?) it is pretty close to the weights listed in that report, but that's not a fighting condition for the most part. That's grossly overweight. Might as well test the P-51 with the aux tank filled. No mention about that, eh? The Mustang III clearly wasn't at full fuel state, because it "easily" out-turned the 109. Surely it was loaded with half or less of its total capacity of gas.
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For example, the spit14 used a spit9 frame but a different engine (for the most part). The Spit9 with 25lbs boost was easily out-dove by the 109, but the same 109 was left in the dust by the lesser-boosted 18lbs spit14. The whole story is not being told.
If any of that were true, or relevant, you might have a point.
1) The Spitfire Mk XIV used a Spitfire Mk VIII airframe as the base and it was modified beyond that.
2) A Spitfire Mk XIV at +18lbs boost is faster than the Spitfire Mk IX at +25lbs boost. In other words the Griffon 65 at +18lbs boost puts out more power than the Merlin 66 at +25lbs boost. Why you think the "lesser-boosted 18lbs spit14" should perform worse is beyond me as even you should know they have entirely different engines.
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I'm saying there shouldn't be such polar opposites on airframes. The spit8/spit9 airframe is very similar (wing gas tanks, pointed rudder... that's about it), but for some reason very similar airframes with very similar performance envelopes both reacted very differently to a third comparison point (the 109G6).
You're right about the different boosts not meaning anything, different engines. My point still stands, though. They're not telling the whole story in the tests because the results are so irregular.
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I'm saying there shouldn't be such polar opposites on airframes. The spit8/spit9 airframe is very similar (wing gas tanks, pointed rudder... that's about it), but for some reason very similar airframes with very similar performance envelopes both reacted very differently to a third comparison point (the 109G6).
You're right about the different boosts not meaning anything, different engines. My point still stands, though. They're not telling the whole story in the tests because the results are so irregular.
Ermmm tail wheel?
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The section of the report I bolded is not insignificant in the outcome of some of these tests.
True.
First thing I noticed was the U-2 designation.
Second was this: "Prolonged unserviceability of the Me.109 prevented completion of the trials."
IIRC, the RAF test of the 190A-4 (maybe an A-3?) that was well documented and extremely detailed had the same issue. IIRC, further, the problem was equal parts gasoline and non-OEM spark plugs which fouled quickly. Engine performance would be reduced some but, at least specific to the 190, the RAF pilots were reluctant to fly the aircraft aggressively - including at full throttle due to excessive vibration.
In any event... great read, thanks. Some other things that stuck out to me:
1.) Cant tell whether its a late or early G6. Partially retractable tail wheel and redesigned rudder - BUT - "This aircraft has the old type canopy."
2.) It does appear that the gondolas were fitted for the test: "Armament consists of 2x13mm MG's mounted above the engine, 1xMG 151/20mm cannon firing through the airscrew hub and 2xMG 151/20mm cannon in underwing gondolas."
3.) Test weight was 7,488lbs. Im not a "technical AH flyer." Anyone have the weight figure for the G6 in AH with gondies? I'd up one quick myself but Im at work. We might be able to guess how much fuel they had on board for the tests, if nothing else.
4.) "Engine revs and boost are interconnected and are operated under normal conditions by the throttle control. provision is made, however, for independent operation..." Didnt know that. Thought integrated engine management was, primarily, a 190-only feature.
5.) "The tail wheel locking device on this aircraft has been disconnected..." Why on God's Earth would they do that? Its a small miracle that the plane lasted more than a single flight.
6.) Regarding the Spitfire Mk IX: "Comparative dives between the two aircraft have shown that the Me109 can leave the Spitfire without any difficulty." plus... "The climb of the Spitfire is superior to that of the Me109 at all heights... at 18lbs boost... this is naturally pronounced when using 25lbs boost." Surprised by that. Figured it would be backwards.
7.) Regarding Spitfire Mk XIV: "The Spitfire has no difficulty in out-turning the Me109 in either direction." Figured they would be close.
8.) Regarding the Tempest Mk V: "The climb of the Me109 is superior to that of the Tempest at all heights..." What?!
9.) Regarding the P-51B (III): "When the aircraft are dived and subsequently climbed there is very little to choose between their performance." If only this were the case in AH! ...the Mustang has no difficulty outturning the Me.109 in either direction." Wow, again.
Fascinating stuff. Tanks for posting.
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Digging further into the site I noticed that they did all the me109 tests without the GM Boost.
"Performance is converted to standard temperature. Combat power without GM 1"
The boost on the 109s is large and does have a very appreciable improvement on performance.
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I'm saying there shouldn't be such polar opposites on airframes. The spit8/spit9 airframe is very similar (wing gas tanks, pointed rudder... that's about it), but for some reason very similar airframes with very similar performance envelopes both reacted very differently to a third comparison point (the 109G6).
You're right about the different boosts not meaning anything, different engines. My point still stands, though. They're not telling the whole story in the tests because the results are so irregular.
My personal bet as to why the results are listed as they are is simply because when they tested them either the Spit XIV pilot was more effective in the test against the Bf109 or the Bf109 pilot was more effective in the test against the Spit IX. Simply because humans cannot perform exactly the same each time.
And yes, that means all these basic combat trial reports need to be taken with a grain of salt.
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Digging further into the site I noticed that they did all the me109 tests without the GM Boost.
"Performance is converted to standard temperature. Combat power without GM 1"
The boost on the 109s is large and does have a very appreciable improvement on performance.
GM-1 is a nitrous oxide injection for extremely high altitudes. Very few LW planes had it installed. There's almost no chance this 109G-6 had it. You may be thinking of MW-50 which is a methanol-water mixture much more common, and giving quite a bit of performance boost. That's what gives the Aces high G-14 and K-4 their nice "kick" when you hit the WEP key.
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True.
First thing I noticed was the U-2 designation.
Second was this: "Prolonged unserviceability of the Me.109 prevented completion of the trials."
IIRC, the RAF test of the 190A-4 (maybe an A-3?) that was well documented and extremely detailed had the same issue. IIRC, further, the problem was equal parts gasoline and non-OEM spark plugs which fouled quickly. Engine performance would be reduced some but, at least specific to the 190, the RAF pilots were reluctant to fly the aircraft aggressively - including at full throttle due to excessive vibration.
According to Price's book it was an A-3.
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1.) Cant tell whether its a late or early G6. Partially retractable tail wheel and redesigned rudder - BUT - "This aircraft has the old type canopy."
-> That is why they made the G14 -to get rid of random variation of features in those many G6 variants.
4.) "Engine revs and boost are interconnected and are operated under normal conditions by the throttle control. provision is made, however, for independent operation..." Didnt know that. Thought integrated engine management was, primarily, a 190-only feature.
-> IIRC the engine controls were automated from F onwards. You could control the engine revs through a switch in throttle column and IIRC the constant speed unit from dashboard.
5.) "The tail wheel locking device on this aircraft has been disconnected..." Why on God's Earth would they do that? Its a small miracle that the plane lasted more than a single flight.
-> Providing that the 109 was as notoriously unstable to land and take off as is commonly thought? And novice 109ers (Brits) could still operate the plane without incidents, strange indeed. In Finnish use leaving the tailwheel unlocked was considered very very dangerous. Somehow I suspect this statement in report. The surface from where the 109 si operated makes also a difference. Soft grass field, no probs, but concrete RW could pose a problem.
7.) Regarding Spitfire Mk XIV: "The Spitfire has no difficulty in out-turning the Me109 in either direction." Figured they would be close.
-> Again novice 109ers cannot use the 109s strengths but however the result is foreseeable. In able hands the 109 should be somewhat competitive -at least without gondolas.
8.) Regarding the Tempest Mk V: "The climb of the Me109 is superior to that of the Tempest at all heights..." What?!
-> No too surprising.
9.) Regarding the P-51B (III): "When the aircraft are dived and subsequently climbed there is very little to choose between their performance." If only this were the case in AH! ...the Mustang has no difficulty outturning the Me.109 in either direction." Wow, again.
->Indeed, again. :)
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http://www.wwiiaircraftperformance.org/me109/me109g6-tactical.html
The tests would indicate the 109G6 pretty much sucks, even against the Mustang. Funnily, I think the 109G6 is a much better turner in this game against the Mustang and Tempest.
As far as the 109G-6 (w/gondo) comparison to Spit IX, this comparo is more informative: http://www.spitfireperformance.com/spit9v109g.html
I note the G-6 is a trop model. I'm wondering if the increased air filtration has any impact on engine performance.
Exec Summary: It confirms your report's results, at least for climb and speed, subject to the Gondo/Trop caveat. I'd also note the dive limitation on the G-6 of 750 kph - which limits the utility of its superior dive accel.
Some of the pilot testimonials are interesting, especially w/r the whole FW190 issue. I'd direct you to Alan Deere, here. I recall Gaston questioning the low-speed modeling of the 190 within AH.
I think, given the record of a guy like Jonah, for example, using the A-8, the 190 is perfectly capable of being quite deadly without us faking in some undocumented low-speed handling to boot.
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Some of the pilot testimonials are interesting, especially w/r the whole FW190 issue. I'd direct you to Alan Deere, here. I recall Gaston questioning the low-speed modeling of the 190 within AH.
I think, given the record of a guy like Jonah, for example, using the A-8, the 190 is perfectly capable of being quite deadly without us faking in some undocumented low-speed handling to boot.
I did not go to your link yet (at work and just logged on for a quick fix), but just about every 190 test Ive read indicated both a very high stall speed and a rather violent wing dip.
As for pilot testimonials... I read them because they are interesting but there are simply too many variables, in my opinion, to take the "results" at face value.
For example, a "first hand account" of a 190A turning inside a Spit IX should not (theoretically) be possible in sterile conditions - like we have in AH. Mathematically, it simply cant be done, all things being equal.
However, in reality, the list of items that can influence (and invalidate) what is observed by the pilot is long.
The list starts with the pilot sitting down and trying to recall 30-45 seconds of adrenalin-soaked action with his hands still shaking on the typewriter. His recollection may be flawed, etc, etc. He may be grossly under- or over-estimating speed, altitude, relative positioning, etc, etc. Something as simple as a half circle flat turn to a top profile snapshot could be considered "turning inside" the EAC in the mind of that pilot. In addition to this; consider that most of these guys were, at the oldest, in their mid-20's and probably embellished their encounter to get their 'truly exceptional skills' on record. It wouldn't even be on purpose.
From the typewriter backwards, the list of variables only increases in complexity. Air density, air temperature, humidity, wind direction and speed, relative E states, speed & altitude, fuel load, weapons load, any existing damage, pilot experience, etc, etc, etc.
Hell; maybe a 190 driver finds a Spit in a lazy right-hand turn, scanning for a bandit in the middle of a multi-con engagement, turns with him and lights him up after a half-circle because the pilot in the Spit wasn't looking in the direction that counted most.
Put yourself in the shoes of the 190 driver after that. Boots on the ground, your first kill and yeah, youre probably going to type it up as "...full elevator deflection, turned inside Spitfire for guns solution. Fired. Strikes on right wing root, fuselage and cockpit."
Meanwhile, the Spit was only applying 30% elevator authority.
See where I'm going?
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I did not go to your link yet (at work and just logged on for a quick fix), but just about every 190 test Ive read indicated both a very high stall speed and a rather violent wing dip.
As for pilot testimonials... I read them because they are interesting but there are simply too many variables, in my opinion, to take the "results" at face value.
For example, a "first hand account" of a 190A turning inside a Spit IX should not (theoretically) be possible in sterile conditions - like we have in AH. Mathematically, it simply cant be done, all things being equal.
However, in reality, the list of items that can influence (and invalidate) what is observed by the pilot is long.
The list starts with the pilot sitting down and trying to recall 30-45 seconds of adrenalin-soaked action with his hands still shaking on the typewriter. His recollection may be flawed, etc, etc. He may be grossly under- or over-estimating speed, altitude, relative positioning, etc, etc. Something as simple as a half circle flat turn to a top profile snapshot could be considered "turning inside" the EAC in the mind of that pilot. In addition to this; consider that most of these guys were, at the oldest, in their mid-20's and probably embellished their encounter to get their 'truly exceptional skills' on record. It wouldn't even be on purpose.
From the typewriter backwards, the list of variables only increases in complexity. Air density, air temperature, humidity, wind direction and speed, relative E states, speed & altitude, fuel load, weapons load, any existing damage, pilot experience, etc, etc, etc.
Hell; maybe a 190 driver finds a Spit in a lazy right-hand turn, scanning for a bandit in the middle of a multi-con engagement, turns with him and lights him up after a half-circle because the pilot in the Spit wasn't looking in the direction that counted most.
Put yourself in the shoes of the 190 driver after that. Boots on the ground, your first kill and yeah, youre probably going to type it up as "...full elevator deflection, turned inside Spitfire for guns solution. Fired. Strikes on right wing root, fuselage and cockpit."
Meanwhile, the Spit was only applying 30% elevator authority.
See where I'm going?
Indeed, and I second the motion. Those aren't "tests", they're anecdotes. RW is different - and far richer in variables.
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Another thing about turning ability that is not taken into account in AH is pilot posture. I have read that in both the 190s and the 109s, the pilot was slouched a bit. This allowed the pilot to withstand more 'G's in a turn. This could allow a 190 out turn a spit at high speeds, simply because the pilot of the 190 didn't black out.
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Don't foget the ever-forgiving AH flight model for all spits.
Spits in WW2 didn't turn so well at slightly higher speeds. They had great low-speed turning. Similar to zeros, though, you get faster by a hundred mph or so and that degrades.
A Fw190 would out-turn a spit at 350mph, maybe be even at 250, and be totally whipped by a spit at 150 (to make up an example).
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Another thing about turning ability that is not taken into account in AH is pilot posture. I have read that in both the 190s and the 109s, the pilot was slouched a bit. This allowed the pilot to withstand more 'G's in a turn. This could allow a 190 out turn a spit at high speeds, simply because the pilot of the 190 didn't black out.
I understand that later Spitfires had an elevated foot position on the rudder pedals to try to do the same. I could be mistaken though, as it is merely from a pilot anecdote.
Don't foget the ever-forgiving AH flight model for all spits.
Spits in WW2 didn't turn so well at slightly higher speeds. They had great low-speed turning. Similar to zeros, though, you get faster by a hundred mph or so and that degrades.
A Fw190 would out-turn a spit at 350mph, maybe be even at 250, and be totally whipped by a spit at 150 (to make up an example).
You have any evidence to back that up? It contradicts everything that I've ever read about Spitfire handling at high speed. The elevators were too light, not too heavy, making it a risk for the pilot to pull too hard and break the airplane due to excessive Gs, a problem that actually happened in Mk Vs before they added resistance on the elevators.
They absolutely had issues with roll rate at high speeds, but never have I heard of any issue at all with turning at high speed. Unless you can provide some evidence I will have to call you on that as having been made up.
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Has to do with the number of pounds of stick pressure require, pilot position (G related) and the airframe itself.
I'm not saying "it's as bad as a zero" -- just saying something along those lines happens. I've read a numbre of stories (including the one I think mentioned above, where a 190A out-turns a spit) where the Focke Wulf was superior in turning, but they all take place at higher speeds than Aces High's stall-turn-yank-and-bank fest.
It's like a P-40E being more manuverable at 200-250mph than at 150mph, and FWs had the power/speed to spare, they'd be fighting at higher speeds.
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Krusty,
It can't have anything to do with pounds of stick pressure required. As I just pointed out, the Spitfire's elevators were excessively light at speed. The Bf109 does seem to have an issue with heavy elevator forces at speed though. Are you sure you didn't get that mixed up with the Spitfire?
You will really need to post some supporting data as none I have ever seen, and I have seen a lot on Spitfires, supports you on this.
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"I think, given the record of a guy like Jonah, for example, using the A-8, the 190 is perfectly capable of being quite deadly without us faking in some undocumented low-speed handling to boot."
Well it's not actually "undocumented". This claim is based on Russian claims that "190s always offer turn fight with minimum speed" which is a rather strange claim considering how we see 190's slow speed handling at high AoA. IIRC the FW is said to compete in turning even with LA5 which is lighter and has slats to aid turning with hihg AoA and I have no reason to believe the slats would be any worse in LA5 that they are in 109. So it could be as well said that 190 would beat a 109 in a turn fight. Maybe it could, who knows. At least Egon Mayer and Julius Meimberg could not solve whihc plane is better and that was G2 against A6, again IIRC.
Technically the 190 had a NACA23015 profile with 2 deg washout at 20% of its wingtip which in theory would enable it to hang with AoAs up to maybe 16 to 18 deg (depending on Mach number). I have previously given quite a lot of weight on washout but I realized that that 20% of wing tip, even if it has lower AoA that the rest of the wing, only has a NACA 23009 profile which cannot support flow at 15deg of AoA. So while providing warning about imminent stall the washout could not "hang" the FW in the air on its wingtips. It probably enabled the 190 to regain control quite quickly after an accelerated stall but it did not help in turning, as far as I understand.
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"I think, given the record of a guy like Jonah, for example, using the A-8, the 190 is perfectly capable of being quite deadly without us faking in some undocumented low-speed handling to boot."
Well it's not actually "undocumented". This claim is based on Russian claims that "190s always offer turn fight with minimum speed" which is a rather strange claim considering how we see 190's slow speed handling at high AoA. IIRC the FW is said to compete in turning even with LA5 which is lighter and has slats to aid turning with hihg AoA and I have no reason to believe the slats would be any worse in LA5 that they are in 109. So it could be as well said that 190 would beat a 109 in a turn fight. Maybe it could, who knows. At least Egon Mayer and Julius Meimberg could not solve whihc plane is better and that was G2 against A6, again IIRC.
Technically the 190 had a NACA23015 profile with 2 deg washout at 20% of its wingtip which in theory would enable it to hang with AoAs up to maybe 16 to 18 deg (depending on Mach number). I have previously given quite a lot of weight on washout but I realized that that 20% of wing tip, even if it has lower AoA that the rest of the wing, only has a NACA 23009 profile which cannot support flow at 15deg of AoA. So while providing warning about imminent stall the washout could not "hang" the FW in the air on its wingtips. It probably enabled the 190 to regain control quite quickly after an accelerated stall but it did not help in turning, as far as I understand.
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Whoa, please clarify... Are you saying the wing has an inboard 23015 with geometric washout (or twist) while the outboard section is the 23009? I can't imagine why they'd effectively have an aero "wash-in" if this is the case - e.g., in the example you cite as I posit here, tip stall would be quite severe since the 23009 would hit max alpha well before the inboard washed-out 23015.
I note that my (brief and offline only) experience with WB in past would recall a severe tip stall in the 190 - the very problem the 109 gets around with their self-deploying slat.
Regarding the "undocumented" - I concede readily. I should've said "anecdotal"... My only point in citing the Biggin Hill stick was that, for every anecdote cited pro, I can come up with one con. Anecdotes are like that.
As for some of this other stuff about speed-dependent turn rate - it'd be really interesting to see some data on the impact of speed versus turn rate on a type-by-type basis. I'd expect most types will pull to their "generative" (coining) g-limit, the radius increasing (likewise the rate decreasing) as speed increases, yet that generativ elimit clearly changtes radically across the speed range of the AC - a readily available example is the 190, for example... It clearly pulls higher g at speed, unless I've totally lost the plot, and is painfully slow to point or make g at low speed.
THe other thing rearing it's ugly head: instantaneous turn rate versus sustained turn rate. I believe a fine example might be the Mustang - good in the former, provided the interval is sufficiently small (and it's really NOT all that small, key word being "sufficient), poor in the latter relative, to say, the beloved Hurri.
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i think the stall character programed is more drawn from anecdotal sources than a result of modeling wing foils ...
the 190s stall seems to be more in line with the f5 USN testing than any operating force reports, or even RAF/USSR opinions ...
it is "funny" as by all accounts one of the easiest planes to fly in TRW is one of the hardest in WB/AH ...
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i think the stall character programed is more drawn from anecdotal sources than a result of modeling wing foils ...
the 190s stall seems to be more in line with the f5 USN testing than any operating force reports, or even RAF/USSR opinions ...
it is "funny" as by all accounts one of the easiest planes to fly in TRW is one of the hardest in WB/AH ...
Speculating, I'd guess you're about half right. I doubt they do much 2d airfoil modelling either. Rather, I suspect HTC bases A/C performance off empirical data fits. I doubt they use the anecdotes at all, since translating would be guesswork at best.
But I'm speculating. Why can't we get HiTech to weigh in on this one? Don't be afraid to hit us with something complicated, Dale. Many of us are technical people, it seems. Remember the old joke about engineers and wrestling with pigs...
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i just think they have a predetermined stall character taken from one report or another ...
the idea that they are actually modeling airflow behavior in relation to the wing surface is pretty far fetched ...
you just get to speed (a) at AOA (b) combined with whatever other conditions they decide to model and away you go ...
i don't really have much trouble with how it stalls, when it stalls can be problematic but you get used to it ...
it is a relative handful compared to other aircraft though, and that seems strange for a plane who's handling was so well regarded by all accounts.
EDIT: and there is that coffin corner where the low speed handling is to difficult to perform the maneuvers you need to perform very easily, and yet you are too fast to deploy your flaps to improve your lift and help you out ...
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What charge is talking about is the high propensity for the FW-190 to tip stall due to a combination of planform (slight) and airfoil thickness (high) taper. Deploying flaps would exacerbate this situation as the inboard portion of the wing near the root would fly much further into a tip stall than when flaps were not deployed. Interestingly enough, almost all WWII fighters suffered from tip-stall tendencies as a result of thickness taper, since the thinner airfoils do not perform as well at the higher AoAs, and are also exposed to lower Reynolds numbers due to the planform taper. The 15% root/9% tip thickness profiles were very common among the FW-190's peer aircraft. The FW-190 airfoil will still be able to achieve the same angles of attack as most other WWII fighters, but its resulting lift coefficient at the same AoA would be less, due to the much smaller wing area and resulting high wing-loading. Therefore, it will always suffer from higher stalling speeds compared to its peers, even with the same airfoil and thickness ratios. All of these characteristics would be exacerbated at high g-loads, or when operated at low dynamic pressure. While the washout should help alleviate some of these tendencies, its my understanding that the FW-190 suffered from the wing tips' tendency to flex/twist, which in essence, removed the washout from the wing. That it should be very maneuverable about the roll axis and a pig in the turn is, from an aerodynamic standpoint, very easy to explain.
As we've said many times before, defining exactly what "out-turn" means in these reports is extremely difficult, because there is never any quantitative data (such as degrees per second, etc.) in the report. They always rely purely on the test pilots' annecdotal statements.
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What charge is talking about is the high propensity for the FW-190 to tip stall due to a combination of planform (slight) and airfoil thickness (high) taper. Deploying flaps would exacerbate this situation as the inboard portion of the wing near the root would fly much further into a tip stall than when flaps were not deployed. Interestingly enough, almost all WWII fighters suffered from tip-stall tendencies as a result of thickness taper, since the thinner airfoils do not perform as well at the higher AoAs, and are also exposed to lower Reynolds numbers due to the planform taper. The 15% root/9% tip thickness profiles were very common among the FW-190's peer aircraft. The FW-190 airfoil will still be able to achieve the same angles of attack as most other WWII fighters, but its resulting lift coefficient at the same AoA would be less, due to the much smaller wing area and resulting high wing-loading. Therefore, it will always suffer from higher stalling speeds compared to its peers, even with the same airfoil and thickness ratios. All of these characteristics would be exacerbated at high g-loads, or when operated at low dynamic pressure. While the washout should help alleviate some of these tendencies, its my understanding that the FW-190 suffered from the wing tips' tendency to flex/twist, which in essence, removed the washout from the wing. That it should be very maneuverable about the roll axis and a pig in the turn is, from an aerodynamic standpoint, very easy to explain.
As we've said many times before, defining exactly what "out-turn" means in these reports is extremely difficult, because there is never any quantitative data (such as degrees per second, etc.) in the report. They always rely purely on the test pilots' annecdotal statements.
I buy your Reynolds number argument (lesser characteristic length -chord here - at the tips) and your wing torsional flex argument - center of pressure on the section would tend to cause reduced geometric washout since load resolves to something like quarter chord...
But, can you answer my question about the F-dubs outboard airfoil section? Because, if it is as posited, it strikes me as a bit dumb to have a lower max alpha on the outboard section, even if re-oriented w/r freestream with geometric washout.
As for Thorsim, I think he just reiterated what I posited about data fits - but I seriously doubtr HTC used some anecdotal basis for relative fits.
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But I'm speculating. Why can't we get HiTech to weigh in on this one? Don't be afraid to hit us with something complicated, Dale. Many of us are technical people, it seems. Remember the old joke about engineers and wrestling with pigs...
Patented or not; I don't think HTC would be well served by revealing the method by which they simulate aircraft performance on a public message board.
Just a guess.
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Patented or not; I don't think HTC would be well served by revealing the method by which they simulate aircraft performance on a public message board.
Just a guess.
I'm only looking for a broad-brush treatment here. There's nothing especially secret about doing simulations. Like I said, I was doing ADAMS models (that's all Lagrangian dynamics - a method I seriously doubt they'd use for this, unless computing power has gotten way ahead of my estimates) for about 10 years. You get valuable after 3, really useful after 5. Thus, the barrier to entry is high enough, the incentive to copy low enough, that I doubt anyone's going to take too much notice - unless they're dying to compete in a market that draws about 5000 complaining WWII air combat geeks of elevated self-regard (I can't exclude myself here)...
What, do you think if he tips his hand a little WB is going to eat his lunch? I've got a subscription over there. I never use it. Those guys suck.
But you're probably right that he considers the info highly proprietary. I'm just interested in a word or two on methodology.
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I buy your Reynolds number argument (lesser charactersitic length -chord here - at the tips) and your wing torsional flex argument - center of pressure on the section would tend to cause reduced geometric washout since load resolves to something like quarter chord...
But, can you answer my question about the F-dubs outboard airfoil section? Because, if it is as posited, it strikes me as a bit dumb to have a lower max alpha on the outboard section, even if re-oriented w/r freestream with geometric washout.
As for Thorsim, I think he just reiterated what I posited about data fits - but I seriously doubtr HTC used some anecdotal basis for relative fits.
Well, remember that NACA's airfoil research, presented in NACA report 824, was pretty revolutionary. No one, even aircraft manufacturers/designers had conducted anything like this before. When these aircraft were being designed, we were only 35 years removed from Kitty Hawk. Aircraft introduced 2 years later than another then represented leaps in technology that we would consider generational today. Everything was changing all the time--powerplants, materials, design. What NACA 824 did to the industry though, was paint it, almost in its entirety, into a corner, attempting to achieve the "mythical" elliptical lift distribution through airfoil taper and planform design. You see it in everything designed and introduced in the 30's--those curved and rounded wing tips, horizontal and vertical stabs, etc. Almost all of the most famous designs possessed thickness taper. F6F, F4U (to a lesser extent), P-47, Spitfire, P-51 etc. all suffered from the same airfoil thickness taper issue. You see a lot of bad planform designs especially, during this period. Look at the T-6 Texan planform and consider that it was supposed to be a trainer. It introduces wing sweep, planform taper, and thickness taper all in the same package, which truly made it more of a handful than it could have been. Also, the 23000 series airfoils are probably one of the worst airfoil designs that have ever been produced in quantity. That airfoil was probably used on more designs in the 30s-40s than any other, all because designers thought that a zero-pitching moment airfoil was the most important characteristic.
So, short answer is that they just didn't know any better. The presence of washout in most of these designs shows that they were aware, but obviously, not very concerned. Most of the washout in these designs did little more than add drag to the wing. The German and Russian slat designs are the only evidence I've seen of designers trying to truly combat the tip stall tendencies, even if they did make them useful by designing poor planforms--especially the Russians with their extreme planform tapers.
I believe that HTCs modelling of these aircraft is probably as accurate as you can get with a vector-based approach, with the exception of what I perceive in their trim mechanic--but I understand why its modeled the way it is.
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Interesting take on the matter...
Going to the Abbott and Von Doenhoff on the olde bookshelf, I note that they characterize the leading edge slat to be worth approx. 8 degrees of alpha above the alpha max w/o slats. Kudos to Herr Messerschmitt for recognizing this.
I also verify, in the section data herein, that the 23015 has a max alpha of about 18 degrees - the man didn't lie.
As for the outboard section of the 190 wing, this site seems to verify the assertion for at least the d-9: http://www.ww2aircraft.net/forum/aviation/fw-190-dora-9-vs-p-51d-mustang-3151.html
This lends credence to your theory.
The 23009 foil I cannot find in A &vonD but, based on his record, I'd say it's probably correct as posited. So, it may be as you say - KT might've done a dumm thing. How can this be? Everyone says he's a genius...
As for the planforms...
I always postulate two schools of thought here. I think the British went for the elliptical planform as a means of getting the magic elliptical lift distribution- and the induced drag benefit of same. It looks ike the German school of thought recognized the significance of aspect ratio... Either one has a tradeoff, the former in manufacturing, the latter in efficiency.
Bottom line: your opinion appears to have a factual basis.
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KT might've done a dumm thing. How can this be? Everyone says he's a genius...
I think he was, and this single design aspect doesn't mean he wasn't. He was doing the same thing every designer in the world was doing--using airfoil taper.
As for the planforms...
I always postulate two schools of thought here. I think the British went for the elliptical planform as a means of getting the magic elliptical lift distribution- and the induced drag benefit of same. It looks ike the German school of thought recognized the significance of aspect ratio... Either one has a tradeoff, the former in manufacturing, the latter in efficiency.
Bottom line: your opinion appears to have a factual basis.
Well, I personally think aspect ratio is moot for fighters at the dogfight level. The Ta-152 aspect ratio had a singular purpose, and that was high-altitude performance, where the extreme low dynamic pressure insured that a high aspect ratio wing would combat the high induced drag, and give it a performance advantage. At low altitude, high aspect ratio only contributes to drag and lessens roll performance (generally speaking). The Dora still had the stock FW-190 wing, so it was going to have to rely on power to give it performance at altitude versus the wing planform. And, ultimately, I think the Spitfire wing-loading had more to do with its performance than "near elliptical" lift distribution. The compounded its design by building in drag with washout as well. They look really cool though, and in my book, that's almost as important... :)
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I think he was, and this single design aspect doesn't mean he wasn't. He was doing the same thing every designer in the world was doing--using airfoil taper.
Well, I personally think aspect ratio is moot for fighters at the dogfight level. The Ta-152 aspect ratio had a singular purpose, and that was high-altitude performance, where the extreme low dynamic pressure insured that a high aspect ratio wing would combat the high induced drag, and give it a performance advantage. At low altitude, high aspect ratio only contributes to drag and lessens roll performance (generally speaking). The Dora still had the stock FW-190 wing, so it was going to have to rely on power to give it performance at altitude versus the wing planform. And, ultimately, I think the Spitfire wing-loading had more to do with its performance than "near elliptical" lift distribution. The compounded its design by building in drag with washout as well. They look really cool though, and in my book, that's almost as important... :)
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Wingloading is another matter entirely. Here I think you deal with the obvious tradeoff between speed and handling at a given power level.
I like this description: Aircraft with low wing loadings tend to have superior sustained turn performance because they can generate more lift for a given quantity of engine thrust. The problem with low wingloading is the other component of drag - Cd0.
The other big thing about aspect ratio is its impact on climb performance - because of the shrinking denom of the CDi ( decreasing dynamic pressure) as you noted, and the fact that climb is all about thrust in excess of drag. The guys at Supermarine got both climb and turn because they have minimized induced drag with their planform (remember the form factor K - 5-10 percent higher for non-elliptical) AND a low wingloading AND a reasonable AR in the denom. It looks like they give up a little top end in the trade, though.
I suspect the Germans optimized around their needs: quick time-to-alt (for interception purposes) a strong top end (same reason), and big firepower (snapshots and bomber kills) and gave up a little on yank and bank. By most accounts, the vast bulk of kills happened as a result of the quick swoop and boom anyway, not as a result of long 1v1 battles. The FW is wellsuited to this tactic. In AH we've got perfect knowledge, mostly, and the Icon (a red billboard, imj). That kind of buzzkills things for F-dubber - and is probably something WORTH complaining about. Even so, I saw one of my squaddies get vaporized by an A-8 the other day. I got as far as, Look out, Short, there's an A-8 <BOOM>.
As for Tank - he was, likely, some kind of genius - I look at his mechanical systems, though, rather than his aero work. Consider this: Komandogerat. Innovative, undeniably...
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"While the washout should help alleviate some of these tendencies, its my understanding that the FW-190 suffered from the wing tips' tendency to flex/twist, which in essence, removed the washout from the wing."
I saw this claim first time in D. Lednicer's analysis of WW2 airfoils and already then the claim looked a bit suspicious. Let me elaborate my suspicions a bit:
If we consider the structure of 190's wingspar to be very rigid and also the source of much of the design's weight I'd say that the 80% of the span was very rigid compared to other contemporary designs. After all that was also one of the factors, along with aileron design, which made it so phenomenal in roll performance. At wing redesign phase from A6 onwards the structure was changed so that it became a bit lighter, although I have no information how this was done or what kind of effects it had in handling but, AFAIK, there was none to mention. The outer 20% section was a separate part from the "box" which formed the inner wing spar but the amount of riveting does not suggest that it lacked in density compared to inner wing. Also the much less span and size of the wing, when compared to allied counterparts, does in fact make it less prone to such behavior in my mind, since the loading momentum might actually be smaller than in a large wing due to its inability to force its way through the air due to weight/wing-area distribution.
I think that the idea of excessive flexing would originate from test reports where the reasons for sudden departures were speculated, mainly because they did not know that 190 was very sensitive of its aileron adjustment which could induce an uneven stall behavior when left unadjusted. My understanding is that while different to Spitfire the approach of stall was somewhat similar, if the ailerons where adjusted correctly, with a difference that Spit could ride the stall awhile, where as in 190 the buffeting was a sign of imminent stall which would happen as a very sudden "flick" that would rotate the plane even more than 180 degrees in its roll axis if pulled a slightly more after the onset of buffeting.
Interesting theory would be that the rigidness of the wing was the factor that made 190 different in stall warning from Spitfire, since while having a larger and less rigid wing the Spitfire could ride the stall due to increasing washout because of wing flexing in hard turns. That would be because the airstream tends to bend the wing tip to less AoA due to loading momentum the airstream poses especially to wingtip in turns since the momentum of the wing possibly moves outboards in high AoA flight, especially at the onset of inboard stall of the wing.
That would mean that 190 would have needed even more wash-out to its wing tip but -2 degrees was considered a sensible limit, and rightly so, since any more would have adverse effects on load distribution and the effects of high wingloading would still have been present all the same.
Just a theory though.
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I've only skimmed through the thread. Seems similar to some from before. One thing pops out at me.
The 190 wing may have had greater possibility to tip-stall, but are you all taking into account that the wings were built with a twist? The wingtips didn't flex, but rather were built with the tips at a lower angle than the root, so that during stalls they (or the wing?) would stall more evenly.
Just curious if folks are forgetting that, or if they are already taking into consideration?
EDIT: -2 degrees on the wingtips, I think?
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I've only skimmed through the thread. Seems similar to some from before. One thing pops out at me.
The 190 wing may have had greater possibility to tip-stall, but are you all taking into account that the wings were built with a twist? The wingtips didn't flex, but rather were built with the tips at a lower angle than the root, so that during stalls they (or the wing?) would stall more evenly.
Just curious if folks are forgetting that, or if they are already taking into consideration?
EDIT: -2 degrees on the wingtips, I think?
That's the clear diff b/w geometric washout and aerodynamic washout. I'm not sure what the geometric w/o was on the 190 - I guess I'd ask you to cite source here for the 2 degree figure.
Mr. Krusty, I'm still disappointed that you haven't responded to the story of Muto in his N1K2... Like I say, I think he's the guy on which all this latewar uberhikoki bullsh*t is based.
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I haven't responded because I haven't seen it. Sorry.
IMO doesn't matter where it started, it's a common occurence. Sorry to hijack this thread.
End of hijack.
As for the 2 degrees, I can't cite that just now, going from memory. Might have been more (hence the question mark), but I've read in a number of places that the 190 wing had "washout" built in. It's even been mentioned on these forums before. You can even see it in some pictures, such as the new 190A-8N (the one they built a couple years back based on original plans) in some photos like this:
(http://www.zap16.com/zapnew/wp-content/gallery/duxford-autumn-2007/imgp4810-dux07-focke-wulf-fw190a-8-n-luftwaffe-980554.jpg)
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Just curious if folks are forgetting that, or if they are already taking into consideration?
Yes, if you read the details, we did discuss the 2 degrees of washout built into the wing. The best description I've found of the FW-190 wing design is from David Lednicer's CFD analysis he performed.
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I haven't responded because I haven't seen it. Sorry.
IMO doesn't matter where it started, it's a common occurence. Sorry to hijack this thread.
End of hijack.
As for the 2 degrees, I can't cite that just now, going from memory. Might have been more (hence the question mark), but I've read in a number of places that the 190 wing had "washout" built in. It's even been mentioned on these forums before. You can even see it in some pictures, such as the new 190A-8N (the one they built a couple years back based on original plans) in some photos like this:
(http://www.zap16.com/zapnew/wp-content/gallery/duxford-autumn-2007/imgp4810-dux07-focke-wulf-fw190a-8-n-luftwaffe-980554.jpg)
Well, looking back, Stoney cites 2 degrees of geometric washout but, as we noted earlier in the thread, the aerodynamic washout is negative - since they go to a section with a lower alpha max (from 18 degrees inboard to about 15-16 outboard). The net impact would be something like a wash, so to speak - and likely not mitigating the tip stall effectively.
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Well, looking back, Stoney cites 2 degrees of geometric washout but, as we noted earlier in the thread, the aerodynamic washout is negative - since they go to a section with a lower alpha max (from 18 degrees inboard to about 15-16 outboard). The net impact would be something like a wash, so to speak - and likely not mitigating the tip stall effectively.
Exactly, and the bottom line is that washout is a poor technique for combating tip stall. From a manufacturing standpoint, retarding planform taper, which would create a longer tip chord is easier to manufacture than washout, which creates the need for precise jigs to set up the washout. For the most part, at this point in aerodynamic technology, they hadn't figured out that the airfoil thickness issue was compounding the problem, nor that they were using one of the worst airfoils in existence, with respect to stall behavior. In my opinion, washout does nothing but add drag and compensate for poor wing design. There are many who would disagree with me.
Ironically, if the FW-190 stays in a conventional "interceptor" envelope, washout excepted, the wing design works well. Keeping the wing area as small as possible, relative to the desired landing speed, minimizes drag, and increases top speed. Just don't try to pull a lot of alpha with it, especially in low dynamic pressure conditions (slow and/or at high altitude).