Aces High Bulletin Board
General Forums => Aircraft and Vehicles => Topic started by: BnZs on July 11, 2010, 11:15:18 AM
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Due to my own observations of the Brewster's vertical hanging ability and the fact that several (non-idiot) AH pilots have commented on that same, I decided to put it to the actual test, against the gold standard of AH zoom performance, the P-38L. For an additional data point, I tested against the A6M5b.
Test consisted of multiple iterations of my usual procedure for testing zoom climb, dive to sea level, speed was allowed to bleed off 'till it reached 375mph IAS, at which point a 3g pull-up was used to bring the plane straight vertical, then shift-x was used to hold the plane in this attitude until it departed by its own devices.
The P-38L consistently regained 5.5K of alt in such a zoom.
The Brewster consistently regained 5K.
The Zero consistently regained 4.9K.
I find the closeness of these results quite startling, in light of the fact that the P-38 is a torque-free, low drag airframe with a superior climb rate-as I said, the gold standard for vertical maneuvering performance. I find the Zeke's inferiority in the vertical flat dumbfounding, since I cannot see a single factor that should give the Brewster even parity with the Zero in this area.
(http://bbs.hitechcreations.com/newscores/genchart.php?p1=18&p2=101&pw=1>ype=2)
(http://bbs.hitechcreations.com/newscores/genchart.php?p1=25&p2=101&pw=1>ype=2)
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I think it has been said in other threads that you can not equate sustained climb rates with zoom capability. Sustained climb rates use lift from the wings, whereas zoom climb is only thrust and momentum vs. drag and gravity.
Since your testing methodology is to go straight vertical, there is no lift benefit from the wings, so the sustained climb charts are not a valid comparison or necessarily a good predictor of zoom performance.
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What did you expect? that the 38 will zoom into outer space while the zeke stall out after 500 feet?
The difference you got was 600 feet between the 38 and zeke, that is not a little.
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I am never able to out zoom climb a zeke no matter how fast he is going, that prop will keep him in the air forever, or just long enough to kill me.
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As an avid A6M flier I wouldn't hold it light in zoom, usually one of the few things that actually scare me to zoom against are P38s. Few other things will match if the speeds are close and the original starting distance isn't too far.
This is my experience in MW of course, I'm not entirely sure how she hold against all the late 44' and up planes.
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I'd be curious to see what the result were at other climb angles, however I imagine consistently getting the same angle on all three airframes would be a little difficult.
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Surely after all the discussion in the Brewster vs. P-47 thread a few weeks ago, you can sift through it, and understand a better methodology for comparing those three aircraft.
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BnZs, the problem is you didn't learn gazinta's in math...you know like Jethro Bodine says- 2 gazinta 6 three times, 3 gazinta 12 four times, velocity gazinta's thrust and drag,...weight, thrust, drag, and velocity gazinta's zoom climb performance...etc. So let me bet next to line up and try and slap some "gazinta" sense into you!
http://www.youtube.com/watch?v=i0GW0Vnr9Yc
(http://thetongsweb.net/images/slap.jpg)
Let's commence with the slapping shall we??? :D
Due to my own observations of the Brewster's vertical hanging ability and the fact that several (non-idiot) AH pilots have commented on that same,
Presuming that there is an FM problem based on this is a logical fallacy- either an “Appeal to Authority” or a reverse “Ad Hominem”. “An appeal to authority is an argument from the fact that a person judged to be an authority affirms a proposition to the claim that the proposition is true.” Deductively the strength of an argument lies on the soundness of the logic not the traits of an individual. You can be an authority on a subject yet be completely wrong if your logic is wrong. In our B-239 case no “authority” has yet to lay out an FM dispute on the B-239 based on sound physics logic.
I decided to put it to the actual test, against the gold standard of AH zoom performance, the P-38L. For an additional data point, I tested against the A6M5b.
Blah blah blah...test results...blah blah blah
Inconclusive for various reasons, some already mentioned. Let’s demonstrate this by answering your questions with my favorite....more questions! ;)
1) If the FM is wrong, how do you know which airplane the FM is wrong for- P-38L, A6M5b or B-239? :headscratch:
2) How do you know the relative difference between the aircraft in question of thrust, drag, velocity, and weight does not change between steady best rate of climb vs. a zoom climb?
3) What were the weights of the aircraft (because that’s one of several variables that are terribly important)?
4) What is the rate of energy bleed of each aircraft during the 3g wings level pull-up to vertical and its impact on final zoom climb performance (hint: weight is a big factor in this)?
I find the closeness of these results quite startling, in light of the fact that the P-38 is a torque-free, low drag airframe with a superior climb rate-as I said, the gold standard for vertical maneuvering performance. I find the Zeke's inferiority in the vertical flat dumbfounding, since I cannot see a single factor that should give the Brewster even parity with the Zero in this area.
(http://bbs.hitechcreations.com/newscores/genchart.php?p1=18&p2=101&pw=1>ype=2)
(http://bbs.hitechcreations.com/newscores/genchart.php?p1=25&p2=101&pw=1>ype=2)
First regarding the closeness of the results: what did you think the delta would be and why? For instance let’s even assume that steady ROC differences mean something. Wow, by looking at the charts that gap between the B-239 vs. the other airplanes is huge therefore the climb differences are huge! That’s very deceptive though. Here’s a really simple & crude example to illustrate using sea level ROC from the charts:
plane fpmin fps 25_s d_ft d_yds
b239 2850 48 1188 --- ---
p-38l 3700 62 1542 354 118
a6m5 3350 56 1396 208 69
In 25 seconds of climb the a6m5b has an outstanding 208 ft / 69 yd advantage over the B-239. Better yet, the “gold standard” P-38L has an incredible whopping 354 ft/118 yd advantage over the B-239. Woooweee, now that’s something to write home about!! The point is what on earth are you trying to compare and what quantitative values will that result in?
Second, here’s how I understand your argument:
A) The B-239 has a worse steady rate of climb compared to the A6M5b & P38L
B) Because best ROC is worse in the B-239, zoom climb should also be worse vs. the A6M5b & P38L
C) My zoom climb test results show that B-239 zoom is different than steady ROC therefore the B-239 is wrong
The problem is that you presume that statement B is true. However to show that statement B is true, you have to show that you’ve answered my question #2. Until you do so it’s obvious why you “cannot see a single factor” that COULD give the B-239 even parity with the Zero because you haven’t gone through the analysis and eliminated all the factors yet.
I'm not saying there isn't anything wrong. What I am saying is that the bar is set high to actually prove that something is wrong.
Slapping finished. Next!
Tango
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Dang Dtango, you done good!
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Good post Tango.
1) If the FM is wrong, how do you know which airplane the FM is wrong for- P-38L, A6M5b or B-239? :headscratch:
Yep, this was my first thought as well. :)
I'm not saying there isn't anything wrong. What I am saying is that the bar is set high to actually prove that something is wrong.
Totally agreed. I'm not either, even though several people have implied that I'm somehow "defending" "my ride" ie. saying I'm biased. I've never said there can't be anything wrong. I just get irritated when the argumentation and logic is usually fairly flawed and the (I'm not really talking about this thread but the previous threads/posts.) knowledge of the subject matter is non-existant. There are so many people that have a lot to say about the Brewster but they don't know what they are talking about. It gets rather frustrating when there's roughly 5% signal and 95% noise.
The biggest reason (along with the Finnish community) why I've been flying this sim for so long are the flight models. For me, it's very important that the planes are as accurately modeled as they can be. I'm not here only to "win" in "a game". I'm here to "fly" the virtual counterparts of these planes. So there's really nothing in it for me if the plane I fly is somehow unrealistically better than it should be, on the contrary, it would be something that would drive me away.
The coolest thing about this sim is that the planes match their real life performance figures so closely. I really don't care were the radar alt/ranges are set up or anything else really. I'm just here to fly the planes. Of course those other things that I mentioned are important in creating action between players. But as long as there is action I really don't worry much about them. Ok, a bit OT, sorry.
If we take a look into the basic equations of speed and climb rate and think about the parameters that are basically not debatable (power output, wet area, etc.). If the max. climb rates and max. speeds match the real life data, that alone rules out quite a few things that can be wrong.
If the basic performance figures match, the only (plausible) thing that could cause better real life zoom climb performance on top of my head is wrongly shaped prop efficiency curve. I mean something that would be close to 1.0 at speeds below the sustained climbing speed. If the prop eff. would be at realistic levels at sustained climbing speeds and above but way too high at low speeds. This would enable a plane to "hang on its prop" better but at the same time produce realistic climb and speed performance. I still think that the effect of too high prop eff at low speed would be minuscule in a test of this type due to the short time spent in this speed region due to the vertical climb angle because the thrust to weight ratio would still be very very far from 1:1.
Of the WWII fighters, I've only seen prop eff curve for BF109G and even for that plane there is significant variation on the values between two different sources. So because of the fact that this type of data is quite rare and most probably doesn't even exist nowadays for all the planes in AH, it could be possible that there are some differences in thrust at different speeds in AH compared to real life. On the other hand, I have full confidence in Pyro/HT's ability to approximate things like this very accurately.
From flying faster planes with higher wing loadings like the Dora, I really haven't experienced anything out of the ordinary when it comes to Brewster's performance.
Tango, if I talked total BS here please slap away. :)
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...real life zoom climb performance...
What would this be anyway? I've never seen any quantitative data on "zoom climb" rates among the various aircraft. The definition of "zoom climb" itself is dubious at best. We know that, in general, it refers to an aircraft climbing faster than its sustained rate as a result of excess energy. Beyond that, we have no real idea how to characterize it.
There's really no way to dumb down this issue. It is very complex and requires very detailed and focused analysis. The task is exacerbated by the "retains its energy better" myth that heavier aircraft somehow have an advantage here.
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The definition of "zoom climb" itself is dubious at best.
Agreed.
I worded what I meant rather poorly obviously. Sorry.
What I meant to say was that the virtual aircraft would climb slightly higher in BnZs' test if it would have unrealistically high prop eff at low speed region compared to its real life counter part which obviously would have its "real life" prop efficiency through out the speed range.
I'm quite sure you still understood what I meant initially, though.
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I'm quite sure you still understood what I meant initially, though.
Yes. I actually meant my comments to compliment yours, but didn't word them very well.
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All I can tell you is whats in the game, and fighting the little buffalo thingy is like grabbing a tiger by the tail. Lets thank gOD that at least they never installed 4x20s in the damned thing.
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Dang Dtango, you done good!
Ha! Channeling your inner Uncle Jed I see :D
Tango
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Eric Shilling discusses dogfighting a Brewster with a P-40 (anecdotal?) :D :
http://staff.jccc.net/droberts/p40/p40bb.html
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Eric Shilling discusses dogfighting a Brewster with a P-40 (anecdotal?) :D :
http://staff.jccc.net/droberts/p40/p40bb.html
Not a fin brewster now is it.
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Eric Shilling discusses dogfighting a Brewster with a P-40 (anecdotal?) :D :
http://staff.jccc.net/droberts/p40/p40bb.html
Anecdotal yes, germane to this discussion? No.
ack-ack
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Eric Shilling discusses dogfighting a Brewster with a P-40 (anecdotal?) :D :
http://staff.jccc.net/droberts/p40/p40bb.html
This is the type of "noise" I was talking about.
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"Noise" maybe but from everything said about this aircraft it is probably the rarest aircraft of WWII having fewer built than any example in the game. Even the Finnish records dont say much about performance other than it didnt have trouble against Hurricanes and was showing age by the time of the La-5 or Yak 9. Probably it shouldnt even be in the game.
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Probably it shouldnt even be in the game.
:headscratch:
Hmmm...Arguably, it was the most significant aircraft in the Winter and Continuation Wars.
Oh, and this part: "the rarest aircraft of WWII having fewer built than any example in the game." is incorrect.
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Voss ran out of oxygen at 40k... he's now spouting hyperbole.
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"Noise" maybe but from everything said about this aircraft it is probably the rarest aircraft of WWII having fewer built than any example in the game. Even the Finnish records dont say much about performance other than it didnt have trouble against Hurricanes and was showing age by the time of the La-5 or Yak 9. Probably it shouldnt even be in the game.
Why not trying to post something that's relevant to this thread?
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I just did. Maybe you cant work it through but Im sure there are some that can.
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:headscratch:
Hmmm...Arguably, it was the most significant aircraft in the Winter and Continuation Wars.
Oh, and this part: "the rarest aircraft of WWII having fewer built than any example in the game." is incorrect.
You are talking about the Finnish Brewster with the DC-3 engine? Because from what you just wrote it sure didnt sound like it. There were only 44 built. What other airplane in the game had fewer built?
I dont have any doubt that Hitech knows what he is doing but I doubt there is any way to quantify the vertical zoom of the Brewster in the game with the one from Finland. For one thing the very act of zooming is dependant upon entry speed. You cannot tell if the real aircraft held to the same example BNZs used. For another thing the perception of humans in witnessing the performance of an airplane is subjective and not a realistic measure.
I very seriously doubt there was all that much special about the Brewster that Finland had in their defense than any of the other Brewsters from the same factory. You should bear in mind that the Finnish aircraft had only 900 h.p. compared to 1200 h.p. available to the model tested in the 'anecdotal' competition with a P-40.
Please if you have hard written evidence of test aircraft from the period that indicates this particular model was superior to the others than share it with us all. I have been told that the model in the game was elevated to its current abilities through anecdotal evidence (actually no evidence at all except a verbal "no thats not quite right"). Well I for one think what we have in the game doesnt fit with reality but like I said... despite looking there doesnt seem to be any evidence either way... except anecdotal.
The "experts" in this case cant prove it either way but they will certainly circle the wagons to protect their own baseless positions.
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Voss ran out of oxygen at 40k... he's now spouting hyperbole.
:lol Quite some time ago.
I'm not a WW2 history buff, but by proving him wrong, the best one can accomplish is running him off with facts. He will never admit fault, a character flaw that Voss has always had.
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:lol Quite some time ago.
I'm not a WW2 history buff, but by proving him wrong, the best one can accomplish is running him off with facts. He will never admit fault, a character flaw that Voss has always had.
You seem to be quite taken with this individual. You must miss him terribly. So sorry for you. :rolleyes:
Nice contribution to the thread.
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You are talking about the Finnish Brewster with the DC-3 engine?
What's the point of this comment? If you're doing that then whey so conveniently leave out the fact that Wright 1820's also powered the B-17, SBD, & FM-2 as well besides the C-47 just to name a few. Oh nevermind, I get it. It's a thinly veiled potshot at how crappy the Buffalo "should" be by associating it to a slow lumbering airplane.
I dont have any doubt that Hitech knows what he is doing but I doubt there is any way to quantify the vertical zoom of the Brewster in the game with the one from Finland.
So what you're really saying is that infact Hitech and Pyro don't really know what they are doing. Nice. :aok
I very seriously doubt there was all that much special about the Brewster that Finland had in their defense than any of the other Brewsters from the same factory. You should bear in mind that the Finnish aircraft had only 900 h.p. compared to 1200 h.p. available to the model tested in the 'anecdotal' competition with a P-40.
You ask Stoney for facts yet you choose to ignore facts yourself. Wow what a strange world you live in.
FACT: Wright 1820-G5 1000 hp not 900.
FACT: F2A-2/B-339 was ~700-1000 lbs heavier - that's adding an additional whopping ~20% more weight to the B-239. You don't think this would mess with the performance any? The least that you could do is run a few simple calcs to get an inkling.
Please if you have hard written evidence of test aircraft from the period that indicates this particular model was superior to the others than share it with us all. I have been told that the model in the game was elevated to its current abilities through anecdotal evidence (actually no evidence at all except a verbal "no thats not quite right"). Well I for one think what we have in the game doesnt fit with reality but like I said... despite looking there doesnt seem to be any evidence either way... except anecdotal.
You actually think that HTC uses the aeromythnamics method of FM by relying on anecdotes for the B-239? That's what you get for listening to the clueless.
The "experts" in this case cant prove it either way but they will certainly circle the wagons to protect their own baseless positions.
The only thing I've seen that's been baseless around here is the weak to non-existent logic associated with the whines about the B-239.
EDIT: and for the record, I actually liked the anecdote you posted but couldn't let your other ranting & raving go without a response.
Tango
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So what you're really saying is that infact Hitech and Pyro don't really know what they are doing. Nice. :aok
That right there proves your true agenda and lack of real argument.
No I pointed out the aircraft the engine came from so you could look up the power straight away. Nice attempt at nit-picking one possible intention while ignoring the real and stated reason.
You and three others (now four) in this thread specialize in bloviation only on this BBS with a side-helping of self-congratulation. None of you are fooling anyone.
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None of you are fooling anyone.
Neither are you (as usual), you have provided ZERO actionable information to pinpoint an error in HTC's modeling of the B-239. You then spend all of your time arguing about how everyone else is responding. Why don't you take your own advice, and try and provide a real contribution to a thread with actual data for once.
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Hmmm, whats all this fuzz about the B239 lately? :headscratch:
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When you look at a the numbers, assuming that the Brewster is using the same engine as the FM2 and the F4F, you can see why a Brew' might seem to have an obviously better "climb" in some circumstances. An F4F with 4 guns and half a tank of gas weighs in at 7503#. An FM2, same configuration weighs 7108#. The Brewster weighs 5161#. That's a whole TON less. Power to weight, a Buff' should be a monster. Given the way an FM2 and an F4F can dance around, it's no wonder a Buff can turn the way it does. If the numbers are correct, this really isn't a mystery.
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None of you are fooling anyone.
This, coming from you scorpion boy? :rofl :rofl :rofl
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Even the Finnish records dont say much about performance other than it didnt have trouble against Hurricanes and was showing age by the time of the La-5 or Yak 9.
And you base this on what evidence?
There are complete flight tests with several airframes, comparisons to Finnish test's numbers to Brewster factory papers, technical journals and books researching the performance, flight capabilities, handling and about every possible detail in the plane.
But well, if you haven't seen it, it doesnt exist?
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Hmmm, whats all this fuzz about the B239 lately? :headscratch:
Basically the thing it racking up kills, so clearly it's over modeled. :rolleyes:
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I just did. Maybe you cant work it through but Im sure there are some that can.
Heh, ok. :)
Considering the original post of this thread, your opinion on whether or not the Brewster should have been included to the planeset is totally irrelevant when it comes to this thread. As is that anecdote you posted even though it is very interesting bit of history and very interesting read. AH has neither the "AVG-edition" of the P-40 line nor the Buffalo Mk.I.
I very seriously doubt there was all that much special about the Brewster that Finland had in their defense than any of the other Brewsters from the same factory. You should bear in mind that the Finnish aircraft had only 900 h.p. compared to 1200 h.p. available to the model tested in the 'anecdotal' competition with a P-40.
You don't think 800-900lbs does anything to the maneuverability of an aircraft? I don't have my AHT at hand as I'm out of town but IIRC G105-Cyclone didn't produce 1200hp. The take off power that I seem to remember is 1100hp. So based on that Buffalo Mk.I would be roughly 800lbs heavier while having only 100hp more. No a very good trade off and totally irrelevant variant when estimating the performance of the B239 we have in AH. Someone with AHT can double check my figures.
Also the P-40 that AVG flew had ~200hp more power compared to the AH's P-40B and also at least ~480lbs less weight as AH's seems to be currently over weight by that amount. So the comparison is totally apples to oranges. But because of the way you posted it, someone who doesn't know these facts will compare AH's Brewster to AH's P-40B and more confusion is created. That is why I dubbed the link as "noise" as far as this thread is concerned, even though it is an interesting historical account.
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One thing I have observed through my decades of interest in WWII aircraft is that most people have expectations that the differences in performance between one extreme, say A6M2, and another extreme, say F6F-3, were much greater than they were in actuality. In a dive, the F6F-3 will pull away from the A6M2, but it won't end up a mile ahead after a short dive like people seem to expect. Generally, whatever your intuition tells you the difference should be in a dive or zoom test, quarter it or eighth it and you might be in the ball park.
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Anecdotal yes, germane to this discussion? No.
ack-ack
The *&^ dang Germans ain't got nothing to do with it!
Sheriff Buford T Justice of TEXAS!!!
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That right there proves your true agenda and lack of real argument.
No I pointed out the aircraft the engine came from so you could look up the power straight away. Nice attempt at nit-picking one possible intention while ignoring the real and stated reason.
You and three others (now four) in this thread specialize in bloviation only on this BBS with a side-helping of self-congratulation. None of you are fooling anyone.
I disagree with your allegations in your response, but don't see any value in further debating them because it will just ratchet up the rhetoric. There is a topic you bring up that I want to elaborate on however and that’s my agenda. Yes I do have one.
In my experience the majority of FM disputes follow this approach:
1) I think theres’ something wrong with [blank].
2) I don’t have to prove why or how my assertion is right, but someone else must prove why or how my assertion is wrong.
Philosophically I have a problem with this approach. 2ndly let’s say you know why or how someone’s assertion is incorrect but to demonstrate it means painstaking effort to explain it. If you want to correct the assertion I see two ways of doing it:
A) Spend all sorts of time and effort yourself to explain why or how the assertion is flawed
B) Have the person making the assertion spend the time and effort to work through why or how the assertion is flawed
Which would be more convincing? I find myself in the camp B nowadays. Two reasons worth mentioning are IMO 1) someone is more easily convinced when they discover the flaw for themselves & 2) that someone will actually learn more in the process of discovery.
So yes, I do have an agenda in FM disputes where there is misinformation and that is to hint, needle, prod, question, & cajole folks to prove themselves why or how their assertion is right instead of putting that burden on someone else in hopes they will discover for themselves why it's actually flawed. If I've come across as a pompous bellybutton in the process then I sincerely apologize to anyone I've offended including you. I certainly don't intend to come across arrogantly and can see where I can't be the best judge of that because I can't predict how someone will receive what I say & the way I say it.
In this specific thread I judged that I've had enough "dialog" with BnZs over the years on this BBS that it was OK for me to tease him in what I thought was a good natured way while tossing questions back at him to get him to think. As complicated as the topic can be I have total confidence he can eventually sort it out and doesn't need me to do so for him. But if he honestly wanted some help in the process and was really really stuck, then I'd be happy to help if he asked for it.
Tango
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Yeah, I'm a little dismayed by your post to Tango, I don't deserve this. From what I've read, (from stuff YOU posted), the prime factors that influence zoom climb are power vrs. weight and power vrs. drag. I just haven't seen the figures where the B-239 is all that great in either category. Now, not knowing exactly what engine HTC has modeled the Brew with, the only thing I have to go by to guess at these two factors is climb rate and top speed. I'm ASSUMING that ROC correlates pretty strongly with power to weight ratio (I've heard Hitech say it does), and I'm also ASSUMING that power to drag ratio in level flight corresponds pretty well to thrust drag, because, well, as far as I know it does. Now if you can show me some various detailed and tedious figures on why the B-239 should outzoom the faster, better-climbing Zero, I would be much obliged and forgive the undeserved pictorial commentary. You'll note for instance, you haven't heard me say a thing about the airplane's formidable turning ability, the wingloading figures jive pretty well with what it can do there, so I'd appreciate it if you'd not treat me like an idiot who is doubting the FM because of an isolated combat anecdote or the like.
BnZs, the problem is you didn't learn gazinta's in math...you know like Jethro Bodine says- 2 gazinta 6 three times, 3 gazinta 12 four times, velocity gazinta's thrust and drag,...weight, thrust, drag, and velocity gazinta's zoom climb performance...etc. So let me bet next to line up and try and slap some "gazinta" sense into you!
http://www.youtube.com/watch?v=i0GW0Vnr9Yc
(http://thetongsweb.net/images/slap.jpg)
Let's commence with the slapping shall we??? :D
Presuming that there is an FM problem based on this is a logical fallacy- either an “Appeal to Authority” or a reverse “Ad Hominem”. “An appeal to authority is an argument from the fact that a person judged to be an authority affirms a proposition to the claim that the proposition is true.” Deductively the strength of an argument lies on the soundness of the logic not the traits of an individual. You can be an authority on a subject yet be completely wrong if your logic is wrong. In our B-239 case no “authority” has yet to lay out an FM dispute on the B-239 based on sound physics logic.
Inconclusive for various reasons, some already mentioned. Let’s demonstrate this by answering your questions with my favorite....more questions! ;)
1) If the FM is wrong, how do you know which airplane the FM is wrong for- P-38L, A6M5b or B-239? :headscratch:
2) How do you know the relative difference between the aircraft in question of thrust, drag, velocity, and weight does not change between steady best rate of climb vs. a zoom climb?
3) What were the weights of the aircraft (because that’s one of several variables that are terribly important)?
4) What is the rate of energy bleed of each aircraft during the 3g wings level pull-up to vertical and its impact on final zoom climb performance (hint: weight is a big factor in this)?
First regarding the closeness of the results: what did you think the delta would be and why? For instance let’s even assume that steady ROC differences mean something. Wow, by looking at the charts that gap between the B-239 vs. the other airplanes is huge therefore the climb differences are huge! That’s very deceptive though. Here’s a really simple & crude example to illustrate using sea level ROC from the charts:
plane fpmin fps 25_s d_ft d_yds
b239 2850 48 1188 --- ---
p-38l 3700 62 1542 354 118
a6m5 3350 56 1396 208 69
In 25 seconds of climb the a6m5b has an outstanding 208 ft / 69 yd advantage over the B-239. Better yet, the “gold standard” P-38L has an incredible whopping 354 ft/118 yd advantage over the B-239. Woooweee, now that’s something to write home about!! The point is what on earth are you trying to compare and what quantitative values will that result in?
Second, here’s how I understand your argument:
A) The B-239 has a worse steady rate of climb compared to the A6M5b & P38L
B) Because best ROC is worse in the B-239, zoom climb should also be worse vs. the A6M5b & P38L
C) My zoom climb test results show that B-239 zoom is different than steady ROC therefore the B-239 is wrong
The problem is that you presume that statement B is true. However to show that statement B is true, you have to show that you’ve answered my question #2. Until you do so it’s obvious why you “cannot see a single factor” that COULD give the B-239 even parity with the Zero because you haven’t gone through the analysis and eliminated all the factors yet.
I'm not saying there isn't anything wrong. What I am saying is that the bar is set high to actually prove that something is wrong.
Slapping finished. Next!
Tango
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...Now if you can show me some various detailed and tedious figures on why the B-239 should outzoom the faster, better-climbing Zero, I would be much obliged...
The Brewster consistently regained 5K.
The Zero consistently regained 4.9K.
This counts as the same zoom. Is your accuracy really better than 100 feet out of a 5000 ft zoom?
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Now if you can show me some various detailed and tedious figures on why the B-239 should outzoom the faster, better-climbing Zero, I would be much obliged...
Because you can't whip up this type of analysis quickly or easily. What Tango was trying to say earlier is that the burden should rest with the person highlighting the perceived error. Otherwise, just push the "I believe" button on the assumption that HTC did their part right. The correct methodology to make this comparison was in the Brewster vs. P-47 thread. Tango put together a very detailed analysis, that probably took a number of hours. You want him to repeat that again?
Obviously if the Brewster can "out zoom" the Zero in your test, there is more to the comparison than simply those characteristics you've identified so far.
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Gents... I am the PERK THE BREWSTER! guy. That said, a component you are all missing is the cd. Look it up, you may be amazed, I know I was. Drag and gravity are what slows a plane down in the vert. The Brewster is ridiculously slippery. How they got the airframe that slick, I don't know. I am a combat engineer, not an aero guy.
The Brewster does so well because people get into its fight, not staying in the fight of the ride they are in. This is a tough one to fathom, Wmaker got me to swallow my pride on that several times since the plane was introduced. Has to do with folks just not taking the time to look at the numbers. HP has nothing to do with this discussion. Hell you want to prove that one, do the test with the climb master, a K4. It has a 1000 hp advantage to the Brewster. Yet, CO E, the Brewster has a much lower cd and therefore offsets part of the HP difference. Yes it will not out zoom the K4, but it will remain in gun range until the K4 stalls. So.....
1. Stay above a Brewster.
2. Don't give up E to turn into one, he will reverse and you will die.
3. Work on your aim and shoot them piecemeal.......
4. PERK Wmaker.
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I have been told that the model in the game was elevated to its current abilities through anecdotal evidence (actually no evidence at all except a verbal "no thats not quite right").
You've been told so? Right, ok. You do realize that not everything that gets told is correct and true. I hope you've already heard about the Santa Claus and Tooth Fairy? If not, you're in for a real shock, sorry. :(
Anyways, here's the thread discussing about the changes made to the Brewster's flight model in the last version update: http://bbs.hitechcreations.com/smf/index.php/topic,270213.0.html (http://bbs.hitechcreations.com/smf/index.php/topic,270213.0.html)
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Due to my own observations of the Brewster's vertical hanging ability and the fact that several (non-idiot) AH pilots have commented on that same, I decided to put it to the actual test, against the gold standard of AH zoom performance, the P-38L. For an additional data point, I tested against the A6M5b.
Test consisted of multiple iterations of my usual procedure for testing zoom climb, dive to sea level, speed was allowed to bleed off 'till it reached 375mph IAS, at which point a 3g pull-up was used to bring the plane straight vertical, then shift-x was used to hold the plane in this attitude until it departed by its own devices.
The P-38L consistently regained 5.5K of alt in such a zoom.
The Brewster consistently regained 5K.
The Zero consistently regained 4.9K.
I find the closeness of these results quite startling, in light of the fact that the P-38 is a torque-free, low drag airframe with a superior climb rate-as I said, the gold standard for vertical maneuvering performance. I find the Zeke's inferiority in the vertical flat dumbfounding, since I cannot see a single factor that should give the Brewster even parity with the Zero in this area.
(http://bbs.hitechcreations.com/newscores/genchart.php?p1=18&p2=101&pw=1>ype=2)
(http://bbs.hitechcreations.com/newscores/genchart.php?p1=25&p2=101&pw=1>ype=2)
Since when did zeros and brewsters get WEP? :huh :confused:
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Yes, I understand the Brewster is a tiny plane with a relatively small drag footprint compared to many bigger monsters, but isn't the critical factor the amount of power vrs. weight AND drag?
Gents... I am the PERK THE BREWSTER! guy. That said, a component you are all missing is the cd. Look it up, you may be amazed, I know I was. Drag and gravity are what slows a plane down in the vert. The Brewster is ridiculously slippery. How they got the airframe that slick, I don't know. I am a combat engineer, not an aero guy.
The Brewster does so well because people get into its fight, not staying in the fight of the ride they are in. This is a tough one to fathom, Wmaker got me to swallow my pride on that several times since the plane was introduced. Has to do with folks just not taking the time to look at the numbers. HP has nothing to do with this discussion. Hell you want to prove that one, do the test with the climb master, a K4. It has a 1000 hp advantage to the Brewster. Yet, CO E, the Brewster has a much lower cd and therefore offsets part of the HP difference. Yes it will not out zoom the K4, but it will remain in gun range until the K4 stalls. So.....
1. Stay above a Brewster.
2. Don't give up E to turn into one, he will reverse and you will die.
3. Work on your aim and shoot them piecemeal.......
4. PERK Wmaker.
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The Brewster is ridiculously slippery...HP has nothing to do with this discussion...
Wrong and wrong. According to Dean, the Brewster had the highest Cdo of any U.S. production fighter built during the war. Vertical performance is all about weight and thrust. Thrust is a function of power available, so horsepower has everything to do with this discussion.
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BnZs,
I think your expectations of size of the difference in the test results is the problem here, not the actual results.
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Since when did zeros and brewsters get WEP? :huh :confused:
That has nothing to do with this discussion and nowhere in this thread has anyone mentioned the Brewster or the Zeke having WEP.
ack-ack
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That has nothing to do with this discussion and nowhere in this thread has anyone mentioned the Brewster or the Zeke having WEP.
ack-ack
Uhhh...did you see the chart at the very beginning? It has Brewster and A6m5 wep, since when did they have WEP? :headscratch:
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Uhhh...did you see the chart at the very beginning? It has Brewster and A6m5 wep, since when did they have WEP? :headscratch:
That's just an artifact of the AH chart comparer thingy.
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Yeah, I'm a little dismayed by your post to Tango, I don't deserve this.
“Derserve’s got nothing to do with it.” (William Munny, Unforgiven)
I’m kidding with this statement BnZs ;). I’ve always liked Clint Eastwood muttering that phrase. (I was actually also trying to make fun of myself by suggesting I “learnt” my “gazinta ciphering” from Jethro but all of my attempt at humor obviously went over like a bunch of lead balloons!)
Please allow me to be serious for a bit. I’m very sorry you felt I was treating you like an idiot. Please accept my apologies.
I’d like to rant philosophically for a minute. The following applies for any FM dispute. Your specific dispute is an example. Put yourself in my shoes for a moment.
A) You’re still making the same assumptions that I’ve said you can’t make. I’ve explained why you can’t in a variety of ways and in different BBS threads. From my point of view you are ignoring what I (and others) have said over and over again.
B) You’re also asking me to spend my time and my effort to produce the “details and tedious figures” of why you can’t categorically assume what you’ve assumed. I’ve already told you why, but from my angle you’re not listening. What would lead me to believe that you would respond any differently if I provide the details to the why?
C) Why is it that I have to provide all the intricate details and not you? The argument isn’t between you and me. The truth is that the argument is between you and Sir Isaac Newton. I’ve already given you the basis for you to go have your fight conceptually and in details with Sir Isaac.
So how am I supposed to interpret your actions & how should I respond? From one vantage point the above are classic signs that you’ve already formed an opinion and have closed your mind. If I respond by providing more details then I open up myself to the risk of you wanting to further debate the details to prove that you are right instead which drags on and on. There’s a high probability that all the effort I put in explaining will be a complete waste of time to me.
What incentive do I have to subject myself to the probability of some tortuous & exasperating debate where the debate really should be between the person with the FM dispute and Newton? I already know the outcome of that. Newton always wins. But some people will argue until the cows come home to try and prove otherwise because they’ve already closed their minds. To be clear, I’m not saying you’ve closed your mind but from your responses it’s hard to know.
So that’s my philosophical dilemma. I’ve already given you the basis for testing & analyzing your assumptions. If you aren’t willing to go examine that yourself, why on earth would it make sense for me to spend even more time and effort on my part in explanation? I could be doing plenty of other enjoyable and useful things.
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Moving from the philosophical to the conceptual aero…because I actually do think you sincerely are trying to understand let me try stating the key concepts one more time. Forget everything about B-239’s. Forget A6M’s. Forget your flight test results. Push them out of your mind for a moment. We need to first deal with the conceptual basis of your premise which is best steady rate of climb charts and best top level speed charts are good indicators of zoom climb performance.
You’re trying to extrapolate key variables from two narrow parts of the flight envelope (best ROC & top level speed) and then categorically apply them to a much broader range of an airplane’s flight envelope. You just simply can’t do that because all the key variables are all changing with respect to velocity, altitude, & configuration (weight). Of course complicating matters even more, velocity & altitude are dependent on the variables that they are changing. All the things you’ve said about the key variables at best ROC & top level speed are mostly true, BUT they are only true for that specific flight condition. 2ndly you are also trying to take these variables independently to arrive at a conclusion which of course will mislead you.
The only way I know of estimating zoom performance is evaluating the variables across the range of the flight envelope and not just looking at best ROC & best level speed. There are two ways you might approach this:
Evaluate the specific excess power (Ps) of the aircraft with respect to changing velocity, changing altitude, and a specific weight
Ps = (T – D) * V / W
The aircraft that has the highest time average Ps over the zoom climb will zoom “better”. Let me emphasize, thrust & drag vary with changing velocity and altitude. 2ndly velocity itself varies with changing thrust, drag, & altitude. All of this is effected by weight which of course changes as fuel and ammo are expended. The best ROC & speed charts are for narrow band of the flight envelope (specific velocity, specific drag, specific thrust, specific altitude) and a fixed config (specific weight). Zoom climbs will occur at a larger portion of the flight envelope and could be at altogether different weights too compared to the charts.
You could also approach it evaluating this:
F = ma = T - D - W*sine(climb_angle) – for simplicity if you’re interested in a 90 degree zoom that resolves to
F = ma = T - D - W
You can rearrange that equation and use that as your basis to solve for acceleration, velocity, distance etc. REMEMBER THOUGH – all of it varies and the only way to estimate zoom is calculate and factor what the variables are especially outside of the narrow band of best ROC and speed.
So there it is. Do you want to deal with the details or are you still asking me to do so? I very much prefer that you do it yourself. You’ll learn a lot in the process.
Tango
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Someone's gonna hit his head hard into integral calculus. ;)
...or not. :frown:
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I love Tango to death, but I ain't got a clue what the hell he just said. :confused: Altough I did understand this part....
That's just an artifact of the AH chart comparer thingy.
:lol
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I love Tango to death, but I ain't got a clue what the hell he just said. :confused: Altough I did understand this part.... :lol
Uptown- try reading the part you don't understand after a few beers :D. Does wonders for me!
Tango
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You don't think 800-900lbs does anything to the maneuverability of an aircraft? I don't have my AHT at hand as I'm out of town but IIRC G105-Cyclone didn't produce 1200hp. The take off power that I seem to remember is 1100hp. So based on that Buffalo Mk.I would be roughly 800lbs heavier while having only 100hp more. No a very good trade off and totally irrelevant variant when estimating the performance of the B239 we have in AH. Someone with AHT can double check my figures.
Most of what you posted I snipped out because you (as several others) assume wrongly about the airplane I mentioned. I believe if you check you will find that the aircraft mentioned in the "anecdotal" article was in fact one delivered to the West Indies and not to the RAF. That would mean 1200 hp and not the 1100 you mentioned (which is incorrect either way... the RAF models were 1000 hp). I would like to know where you get your weight figures from.
dtango... as I said (and obviously you didnt read) I have heard online that the 239 was introduced into the game and then "performance boosted" because it didnt meet someones expectations (a single individual). Again I repeat my assertion that if that is in fact the case the airplane is a fiction and should be removed.
However... as I already said (also) I have greater faith in Hitech than that. I do not believe it to be the case.
Sometimes I think you guys get so wrapped up in your online "nametags" you lose your grip on reality. In five minutes I will have forgotten about all of you. Carry on.
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you lose your grip on reality.
Irony at its finest.
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Irony at its finest.
Ha! I mentioned you to someone this weekend (I dont know why). I said "I know a clown just like you online." I cant remember his name either. :devil
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Most of what you posted I snipped out because you (as several others) assume wrongly about the airplane I mentioned. I believe if you check you will find that the aircraft mentioned in the "anecdotal" article was in fact one delivered to the West Indies and not to the RAF. That would mean 1200 hp and not the 1100 you mentioned (which is incorrect either way... the RAF models were 1000 hp). I would like to know where you get your weight figures from.
Like I said I'm out of town and can't check my copy of America's Hundred Thousand where I get my weight figures from. All the B339s were several hundred pounds heavier than the B239. Exactly how much depends on the different sub variants and the configuration of individual airframes. Anyone with a copy of AHT could check the exact weights. I'm just wondering why RAF pilot would be flying a Dutch Brewster? If you are so certain of it I'm sure you can provide a source which confirms it? All I've ever heard from this particular mock dogfight is that it was a RAF Buffalo Mk.I. It is true that the Dutch Buffalos were better machines than the RAF planes from the Belgian order. Anyway, it doesn't matter either way which B339 it was as all of them are still different airplanes when it comes to weight/power compared to the B239.
dtango... as I said (and obviously you didnt read) I have heard online that the 239 was introduced into the game and then "performance boosted" because it didnt meet someones expectations (a single individual). Again I repeat my assertion that if that is in fact the case the airplane is a fiction and should be removed.
However... as I already said (also) I have greater faith in Hitech than that. I do not believe it to be the case.
If you don't believe that Hitech/HTC would do such a thing (I wouldn't either) then why keep repeating it?? I already posted a link to the thread which discusses the flight model changes of the B239. Everything you hear isn't necessarily true. Here's the link once again: http://bbs.hitechcreations.com/smf/index.php/topic,270213.0.html (http://bbs.hitechcreations.com/smf/index.php/topic,270213.0.html)
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Ha! I mentioned you to someone this weekend (I dont know why).
LMAO Grzz you in his head now. :rofl
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Like I said I'm out of town and can't check my copy of America's Hundred Thousand where I get my weight figures from. All the B339s were several hundred pounds heavier than the B239. Exactly how much depends on the different sub variants and the configuration of individual airframes. Anyone with a copy of AHT could check the exact weights. I'm just wondering why RAF pilot would be flying a Dutch Brewster? If you are so certain of it I'm sure you can provide a source which confirms it? All I've ever heard from this particular mock dogfight is that it was a RAF Buffalo Mk.I. It is true that the Dutch Buffalos were better machines than the RAF planes from the Belgian order. Anyway, it doesn't matter either way which B339 it was as all of them are still different airplanes when it comes to weight/power compared to the B239.
I have a copy of AHT here, according to a couple tables on Pg. 441. The British Brewster had an empty weight of 4268.2 and a "normal" gross weight of 6112.2. Another variant which is listed as "Dutch.2nd Ord." has an empty weight of 4282.0 and normal weight of 6094.5. The F2A-3 in USN service comes in at 4765.3 empty and 6518.6 normal. By comparison the B239 is listed at 3744.1 empty. On the next page is lists gross weights ranging from 5014.1 to 5314.1 depending on load (guns and fuel).
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Ha! I mentioned you to someone this weekend (I dont know why).
In game or on Air Force One?
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I have a copy of AHT here, according to a couple tables on Pg. 441. The British Brewster had an empty weight of 4268.2 and a "normal" gross weight of 6112.2. Another variant which is listed as "Dutch.2nd Ord." has an empty weight of 4282.0 and normal weight of 6094.5. The F2A-3 in USN service comes in at 4765.3 empty and 6518.6 normal. By comparison the B239 is listed at 3744.1 empty. On the next page is lists gross weights ranging from 5014.1 to 5314.1 depending on load (guns and fuel).
Thank you Soulyss! :aok
That pretty much covers it. There are some differences due to what is listed in those weight break downs. For example that B239 is with less fuel than the full (160gal) load and obviously not with 4*50cals...not that the guns make much difference. Like I said before the difference is still several hundred pounds.
If it's not too much trouble could you check the power output of the Buffalo Mk.I?
I'm still interested in hearing what a Dutch Brewster was doing in China when it was supposed to be in Dutch East Indies... :)
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I'm still interested in hearing what a Dutch Brewster was doing in China when it was supposed to be in Dutch East Indies... :)
Secret mission for the OSS that was cut short when the commander of this super secret squadron was bitten by a Chinese Red Scorpion.
ack-ack
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If it's not too much trouble could you check the power output of the Buffalo Mk.I?
Table 63 on page 436 lists the B-339E as having the Export Designation of "Buffalo I", table 66 on page 439 lists the following engine ratings.
| Model: | Engine: | Rating: | HP: | RPM: | Altitude: |
| 239 Finland | R-1820-G5 | Takeoff | 950 | 2200 | Sea Level |
| G.R.=1:1 | Military | 1000 | 2200 | Sea Level |
| | Military | 800 | 2200 | 16000 |
| | Normal | 850 | 2100 | 6000 LOBLO.36.5 |
| | Normal | 750 | 2100 | 15200 LOBLO.34.0 |
| Model: | Engine: | Rating: | HP: | RPM: | Altitude: |
| 339E,U.K. | R-1820-G105A | T.O. | 1100 | 2350 | Sea Level |
| G.R.=16:11 | Military | 1100 | 2350 | 1500 LO.BLO. |
| | Military | 800 | 2350 | 17100 HI.BLO. |
| | Normal | 900 | 2300 | 6700 LO.BLO. |
| | Normal | 775 | 2300 | 17300 HI.BLO. |
*edit*
Both engies are described as having a one stage, two speed supercharger.
*edit*
Fixed typo.
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Secret mission for the OSS that was cut short when the commander of this super secret squadron was bitten by a Chinese Red Scorpion.
ack-ack
Chinese Red Scorpion! :O Man, I bet he was one sick puppy! :neener:
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Table 63 on page 436 lists the B-339E as having the Export Designation of "Buffalo I", table 66 on page 439 lists the following engine ratings.
| Model: | Engine: | Rating: | HP: | RPM: | Altitude: |
| 329 Finland | R-1820-G5 | Takeoff | 950 | 2200 | Sea Level |
| G.R.=1:1 | Military | 1000 | 2200 | Sea Level |
| | Military | 800 | 2200 | 16000 |
| | Normal | 850 | 2100 | 6000 LOBLO.36.5 |
| | Normal | 750 | 2100 | 15200 LOBLO.34.0 |
| Model: | Engine: | Rating: | HP: | RPM: | Altitude: |
| 339E,U.K. | R-1820-G105A | T.O. | 1100 | 2350 | Sea Level |
| G.R.=16:11 | Military | 1100 | 2350 | 1500 LO.BLO. |
| | Military | 800 | 2350 | 17100 HI.BLO. |
| | Normal | 900 | 2300 | 6700 LO.BLO. |
| | Normal | 775 | 2300 | 17300 HI.BLO. |
*edit*
Both engies are described as having a one stage, two speed supercharger.
Thank you very much Soulyss!! :)
1100hp for take off for the Buffalo Mk.I just like I said/remembered. :)
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Thank you very much Soulyss!! :)
1100hp for take off for the Buffalo Mk.I just like I said/remembered. :)
No problem, glad all these books sitting here are actually useful from time to time. :)
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*GASP* Chalenge was wrong? Oh wait, he was wrong in the Iwo Mustang thread too. Par for the course.
ack-ack
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In game or on Air Force One?
seriously I would stop ifn I was joo he knows people in high places and will have the feds at your door in short order :noid
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*GASP* Chalenge was wrong? Oh wait, he was wrong in the Iwo Mustang thread too. Par for the course.
ack-ack
He won't post again in this thread either. That's what he does, spouts techno blabble with no actual facts, gets called on it by those who actually have facts, and then disappears off to another thread to do the same thing. Like when he said a nuclear bomb being detonated at the sea bed in the gulf of mexico would cause a 1000 foot wall of water over Louisiana.
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I guess I could settle alot of this debate by just asking what the weight/hp ratio of the Brew we have in game is...
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I guess I could settle alot of this debate by just asking what the weight/hp ratio of the Brew we have in game is...
What ever your in-game test weight is per the E6B divided by 1000 HP MSL. You'd have to interpolate for higher altitudes until you got to 16000 feet, then again above.
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I guess I could settle alot of this debate by just asking what the weight/hp ratio of the Brew we have in game is...
Well I don't see how it could settle much but it's rather easy to find out...
It's ~2,55kg/hp with max. take-off weight. Very close to a FM-2 for example.
If you want a figure in lbs to the last decimal you can check the weight in game and divide it with 1000hp. Then you'll get what it is from sea level to 3000ft. The MAP gauge shows the MAP for 950hp setting but the FTH is for the 1000hp setting.
EDIT/Stoney beat me to it./EDIT
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What ever your in-game test weight is per the E6B divided by 1000 HP MSL. You'd have to interpolate for higher altitudes until you got to 16000 feet, then again above.
The thing is, I don't know what engine HP is used in the game. Sources list several possibilities.
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The thing is, I don't know what engine HP is used in the game. Sources list several possibilities.
As I said, the FTHs pretty much prove it has 1000hp. The MAP gauge shows 950hp-setting figures due to the fact that the MAP for 1000hp setting isn't listed anywhere in the original docs.
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I get .19 HP per pound at 50% fuel for the Brewster.
BUT, I get .20 HP per pound at 50% for the A6M5b, IF the specification of 1130 hp for its powerplant is correct.
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I get .19 HP per pound at 50% fuel for the Brewster.
BUT, I get .20 HP per pound at 50% for the A6M5b, IF the specification of 1130 hp for its powerplant is correct.
Looking at the climb chart, Zeke's sea level power output starts dropping right from the sea level while Brewster's output remains constant to 3k where it starts dropping sharply. With 50% fuel, the power loadings at sea level are already within 5% of each other.
If you want you can integrate the average power loading from the slopes on the climbrate charts using your power loading figures with enough accuracy. Considering all of the above, especially if you did your tests using 50% fuel I don't see anything surprising in them.
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Okay then...things are looking better for the Brewski!
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Okay then...things are looking better for the Brewski!
That default climb chart can be deceptive due to the fact that Brewster carried quite a bit of fuel (~420kg) for a small/light fighter. That makes the power loading improve quite nicely as the fuel is consumed compared to the planes like the FM-2. Probably most of my sorties are flown with 50% fuel.
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all this talk of the brewster.....guess I am gonna go fly one :D
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Guys guys, you're still tossing about figures of merit like "power-to-weight" ratio to make conclusions about zoom climb. It's erroneous to do so.
Tango
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Guys guys, you're still tossing about figures of merit like "power-to-weight" ratio to make conclusions about zoom climb. It's erroneous to do so.
True enough I guess.
My main point was that at smaller fuel loads Brewster's power loading is closer to the Zeke's than one might imagine just by looking at the default climb charts. That's all. :)
Here's what I said about the power loadings couple posts ago:
Well I don't see how it could settle much but it's rather easy to find out...
I'd agree that the original issue is more complicated. I guess what I'm trying to say is everything "seems" to be in the ballpark so I press the "believe button" as Stoney says. After all I haven't been saying that anything's wrong to begin with. :)
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I understand Wmaker. However that's why BnZs is getting derailed. He and others will get derailed again in the future on another plane if they don't understand the complexity behind the scenes. First is misapplying aero figures of merit. On that basis I'm working on a detailed response. Yes BnZs, you got your wish because after evaluation too many folks have tripped on and will continue to trip on the issue. Badboy has touched on a similar concept in the past related to turn performance. I'll put together something similar for zoom climbs.
Tango
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I understand Wmaker. However that's why BnZs is getting derailed. He and others will get derailed again in the future on another plane if they don't understand the complexity behind the scenes. First is misapplying aero figures of merit. On that basis I'm working on a detailed response. Yes BnZs, you got your wish because after evaluation too many folks have tripped on and will continue to trip on the issue. Badboy has touched on a similar concept in the past related to turn performance. I'll put together something similar for zoom climbs.
Tango
Is the gist of what you told me in relation to power to drag ratio that sometimes the relative ratios of power to drag for two different planes can be different in an unloaded state (straight vertical zoom) than it is in when both planes are in straight and level, 1G flight? If so, I think I get it.
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Is the gist of what you told me in relation to power to drag ratio that sometimes the relative ratios of power to drag for two different planes can be different in an unloaded state (straight vertical zoom) than it is in when both planes are in straight and level, 1G flight? If so, I think I get it.
Power-to-drag is sort of a funky way of looking at it but the answer to your question is "well....sort of" ;). I will attempt to explain without confusing everyone.
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BnZs you’re focused on power-to-weight, best rate of climb, & top level speed. Before we discuss your AH flight tests these concepts need to be cleared up. They are the basis for your premise of zoom climb performance and your logic runs into trouble first here.
Aerodynamic figures of merit (FOM) like L/D, P/W (power-to-weight), T/W, CD (drag coefficient), S/W (wing-loading), etc. give us some indication of an airplane’s performance. Figures of merit are often used for their simplicity. Their simplicity is also their danger because simplification abstracts and hides the complexities underneath. The key is understanding what a FOM means and applying it in the right context. Because they are simple it’s easy for people to use them to make erroneous conclusions about an aircraft’s performance because they misapply the FOM, usually in the form of over-simplification.
Precautions with Aerodynamic Figures of Merit
Take lift-to-drag ratio (L/D) for instance. Quoting Dr. Warren Phillips,(Mechanics of Flight) “This maximum value for L/D is often referred to simply as the lift-to-drag ratio for the aircraft. For example, you may hear it said that a particular airplane has a lift-to-drag ratio of 12. This manner of speaking could erroneously lead the student to believe that this airplane will always produce 1 pound of drag for each 12 pounds of aircraft weight. Nothing could be further from the truth...the ratio of lift to drag for an airplane varies greatly with airspeed. It must be remembered that when an aerodynamicist specifies an unqualified lift-to-drag ratio for an aircraft, he or she is referring to the maximum lift-to-drag ratio for that aircraft”. (Bold emphasis added).
Conceptually Dr. Phillips’ warning applies for other aerodynamic figures of merit, in our case power-to-weight related to climb performance. We can’t assume key aero variables and thus figures of merit stay fixed, nor do they remain fixed relative to one airplane to another. Thrust, drag, and power all change with changing velocity, altitude and configuration.
Power-to-Weight Ratio & Climb Performance
Let’s focus on power-to-weight ratio since this is important for us. You’ll hear that climb performance is a function of airplane power-to-weight ratio but you have to understand what all that means.
- First, to be precise it’s actually excess-power-to weight ratio that determines rate of climb performance. Excess-power-to-weight ratio is NOT = engine-HP/weight (more on this later). Excess-power-to-weight ratio, otherwise known as Specific Excess Power (Ps) is:
Ps = (Thrust– Drag)*Velocity / Weight
- Second just like L/D ratio Ps varies with respect to other things. The value of Ps changes when velocity, altitude, or weight changes. Just like L/D ratio, Ps does not remain constant across the full flight envelope of an airplane.
- Third best rate of climb performance occurs at the maximum excess-power-to-weight ratio for a propeller plane. (Best rate of climb usually means best STEADY rate of climb, or in other words when an airplane climbs at a constant velocity.) All this implies that maximum Ps for the best steady rate of climb occurs only at a specific point in the flight envelope.
Let’s use an example to illustrate. Suppose we have Airplane A with the following specs: BHP=1000 hp, Weight=5577 lbs, Prop Diam=9 ft, CD0=.028, Wing Area (S)= 208 ft^2.
(http://thetongsweb.net/images/zc1.jpg)
This is a graph of Plane A’s steady climb performance at sea level. In this example we’ve FIXED the altitude of the airplane (at sea level) and the weight (5577 lbs) so that we can further isolate other variables to visualize how they vary with respect to velocity. Plotted on this graph are:
Airplane Steady Rate of Climb (ft/min) – solid blue line
Airplane Power Available (HP) – dashed blue line
Airplane Power Required (HP) – dotted blue line
The rate of climb curve is nothing more than a plot of the Ps function:
Ps = (Thrust – Drag) * Velocity / Weight or,
Ps = (Thrust*Velocity – Drag*Velocity) / Weight or,
Ps=(power_available – power_required)/Weight where
Thrust*Velocity = power available
Drag*Velocity = power required
Thus climb performance is a function of excess-power-to-weight ratio. Note that the rate of climb is a curve and varies with velocity. Rate of climb = Ps = excess-power-to-weight ratio. This means excess-power-to-weight ratio varies and is not a fixed value. Infact it varies by the difference between power available and power required (Pav minus Prq) as they change with velocity: the greater the difference, the better the ROC.
In our example across the velocity envelope the engine BHP is operating at 1000 HP at full throttle. If you look at the power-available curve however you’ll notice that it is a range and not a fixed value. Also we don’t even actually hit 1000hp. For Plane A it tops out around 800hp. It’s because an airplane’s ability to convert engine BHP into power available depends on the efficiency of the propeller. The power available curve changes with velocity because propeller efficiency changes with velocity. The point is power available is not a fixed constant value. Nor is power required.
I’ve drawn a reference line through points A, B, C, & D on the graph. Plane A has a best rate of climb at 3000 fpm at the peak of the ROC curve at point C. There is only ONE velocity (point A), ONE power required (point B), and ONE power available (point D) that results in the best rate of climb at point C. Maximum steady rate of climb occurs where the difference between power available minus power required is greatest. This is represented and is validated by visual inspection of the difference in HP between points B & D compared to other parts of the graph.
When we talk about best steady rate of climb we’re really focusing on where Ps (excess-power-to-rate ratio) is at a maximum. This is essentially a single point. We’re not concerned with Ps outside of this maximum point. The AH ROC charts are just a plot of each maximum point at each altitude for a given weight. String them all together and you get the ROC chart. However they don’t tell us anything about Ps outside of maximum excess-power-to-rate ratio.
Where Does Simple Power-to-Weight Ratio for Best Steady Climb Performance Come From?
If best climb performance is at maximum excess-power-to-rate ratio, where do we get this notion of using an even simpler figure of merit like “power to weight” (engine HP/ weight) from? It’s nothing more than a proxy for maximum excess-power-to-rate ratio.
Why does this simple figure of merit work as a predictor of best climb performance? Look back at our rate of climb figure. Notice that at maximum rate of climb:
Point D – power available ~700 HP
Point B – power required ~150 HP
Because at best rate of climb power_available >> power_required, as an approximation we ignore power required and drop it from the Ps equation which gives us:
Ps= ROC ~ power_available / weight
We further approximate power available = max engine BHP because power available at best rate of climb is closer to maximum rated power of the engine (For Plane A 700hp~1000hp). Applying this 2nd approximation we get:
ROC ~ engine_power / weight
So basic “power-to-weight” ratio is nothing more than a simple approximation to estimate best steady rate of climb performance. It’s actually a decent proxy for best steady rate of climb performance.
The key is that basic power-to-weight ratio is only an approximation for MAXIMUM excess-power-to-weight ratio which is only a SINGLE POINT on the Ps curve. It is not a proxy for the whole Ps curve to predict Ps over the full flight envelope. So when we use power-to-weight ratio we have to be mindful of this limitation. (There’s a 2nd limitation in that simple power-to-weight ratio is also impacted by altitude as well which is altogether another topic.). It doesn’t give us any indication of how Ps varies outside of the point of best rate of climb.
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Putting It Altogether – Relative Performance Comparisons Between Aircraft
OK, it’s now time to do some basic comparisons to add additional complexity when comparing different aircraft. Let’s assume we have 3 airplanes: our original Plane A with the addition of Plane B and Plane C.
Plane A: BHP=1000hp, S=208ft^2, Prop Diam=9ft, CD0=.028, Weight=5577lbs
Plane B: BHP=1100hp, S=229ft^2, Prop Diam=10ft, CD0=.023, Weight=5750lbs
Plane C: BHP=2600hp, S=300ft^2, Prop Diam=13ft, CD0=.021, Weight=14250lbs
The following chart compares their best rates of climb at sea level:
(http://thetongsweb.net/images/zc2.jpg)
So for best rates of steady climb we have the planes ranked 1)Plane B @ 3450fpm, 2)Plane C @ 3200fpm, 3)Plane A @ 3000fpm. Calculating simple power-to-weight ratio (engine BHP/weight) we get:
Plane B P/W = .191 hp/lb
Plane C P/W = .182 hp/lb
Plane A P/W = .179 hp/lb
Simple power-to-weight ratio is a pretty fair indicator of best steady rate of climb performance as can seen from the calculations vs. our ROC chart. However, this applies for a single point and simple power-to-weight ratio doesn’t tell us much about the Ps curve and how it varies outside of this point. If we overlay the rate of climb curve with this single point we get the following chart:
(http://thetongsweb.net/images/zc3.jpg)
Examining the chart notice first ROC (Ps) is not a point or flat line (fixed value) but a curve. 2nd where and how the ROC curves fit in relationship to each other is important. Note that in our case we have overlaps between them. What the overlaps tell us is that you can’t assume that the difference between excess-power-to-weight ratio between aircraft will remain the same in flight. As you can see there are times when Plane C’s ROC is better than Plane B and times that Plane A’s ROC is better than Plane C.
Now let’s assume Plane A, Plane B, & Plane C zoom climb at 90 degrees nose above horizon (straight up). Each has the same initial start speed of 360mph and 100ft altitude. Which plane zooms the highest? If we take simple power-to-weight ratio or best steady rate of climb as the measure we would conclude that the rank would be 1) Plane B highest, 2) Plane C 2nd, 3) Plane A 3rd.
Well, we would be wrong. Here’s the zoom performance of Plane A, B, & C:
(http://thetongsweb.net/images/zc4.jpg)
As can be seen Plane C actually zooms the highest of the three topping out at 5400 ft. Plane B is 2nd at 5200 ft and Plane A is 3rd at 4950 ft. Simple power-to-weight ratio is not an accurate predictor of zoom climb performance. Nor is best rate of climb. The reason is because for a zoom climb we are interested in the specific excess power Ps (excess power-to-rate ratio) across the full flight envelope and not just a single point. In other words Ps is not a constant value. Simple power-to-weight ratio is just a point approximation for max excess power-to-rate ratio which is also a point. In fact the airplane that has the greatest time average of Ps over the zoom climb will out zoom the others. In other words we have to add up all the values of Ps across the full Ps curve to predict zoom climb performance.
2ndly we also can’t assume that the Ps curve relative relationships between aircraft will remain the same either for all situations. If we change the weight of Plane A from 5577lbs to 4750lbs here is the outcome of that both for steady rate of climb and zoom climb height:
(http://thetongsweb.net/images/zc5.jpg)
Plane A now has the best steady rate of climb at 3700 fpm. In zoom climb Plane A and Plane B are now also roughly equal in zoom altitude of 5200 ft. The point is that relative differences in weight will change climb performance as well and we can’t assume that the same Ps relationship difference between aircraft at one weight remains consistent at different weights too.
Well, if you haven’t figured out already my generic planes A, B, & C are models of existing WW2 aircraft which are:
Plane A: B-239
Plane B: A6M5b
Plane C: P-47D-40
I purposely left it that way so that the focus would first be on the aero concepts. This is just Part 1 of my detailed discussion. In Part 2 we will dive into more depth regarding zoom climbs themselves
To summarize the key concepts:- We must use aerodynamic figures of merit wisely and cautiously.
- Using simple power-to-weight ratio or best rate of climb performance as approximations for zoom climb performance are unreliable and can lead you to erroneous conclusions. They describe only a point and not the full Ps curve.
- Many aerodynamic variables are not fixed but vary with respect to velocity, altitude, and configuration (e.g. weight).
- We can’t assume that an airplane’s performance relative to others remains the same as velocity, altitude, and configuration (e.g. weight) change.
We haven’t addressed the flight test results yet. Be careful not to make hasty conclusions about what my model projects compared to BnZs flight tests. We’ll talk about that in Part 2.
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You didn't mention the zoom TIME and this fools many people. In the last figure, plane A's zoom takes 1.5-2 second longer than plane C, but the height difference is achieved already a few seconds earlier and stays constant - till plane C stalls. What will happen next is that place C is falling but A is still hovering underneath. From the POV of plane C pilot, he will observe plane A still pointing at him and getting closer. Typically, the chasing plane will start its zoom in short delay with respect to the leading plane which will enhance this effect. It gives the illusion to pilot C that plane A zooms much higher than it really does.
Power to weight has more direct implication on the zoom time that on the height. This is because at the beginning (high speed) the drag is still significant compared to weight. Nearer to the top, drag drops close to zero (speed squared...) and what is left is much closer to simple prop pull vs. gravity, even if the plane is as aerodynamic as an elephant. Still, because the speed is slow, not much altitude is gained per unit time, but deceleration rate is directly affected by the difference between gravity and the prop pull. Of course, if the prop thrust at low speeds starts to get close to the weight, that last stage can take a log time and even slow speed will gain some real height, but this is not the typical case for WWII fighters.
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On behalf of all us geeks who actually "find this stuff interesting", TYVM and WTG Tango. :salute
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Part 2
Rehashing Part 1 simple P/W to predict zoom climb is unreliable because it’s a simplification that ignores key variables and their rates of change in flight. Similar issues apply to using max level speed as a proxy for relative drag differences and trying to spread that out like peanut butter across the flight envelope. It’s not appropriate because drag also changes.
If you leave with nothing else from this thread it’s this: Aerodynamics is complex. Using simplifications without understanding the assumptions for them and when they apply likely lead to erroneous conclusions. As an aero Phd once told me “in aerodynamics you can’t avoid the maths”. :cry This is particularly true for a zoom climb.
Trying to break zoom climb performance to a primary variable is incoherent. Zoom climb is an interaction of many variables all at once and how they change. It’s appropriate to isolate a variable to understand the implication & influence but trying to reduce zoom climb to a single variable or simple figure of merit doesn’t make much sense. Because it’s a dynamic problem we can’t “avoid the maths”. I don’t know of a better way to predict zoom climb but to use an iterative numerical solution to do so.
There are other key aero concepts we could address. There’s some cool stuff we could break down in terms of details of zoom climb performance too. But we’ll cut to the chase since there’s so much angst with the B-239. For those interested there’s another exhaustive thread done in the past that covers zoom climbs in a fair amount of detail here:
http://bbs.hitechcreations.com/smf/index.php/topic,266321.msg3328531.html#msg3328531
Zoom Climb Results: Tango’s Model:
So what do the numerical solutions tell us about zoom climb of the B-239? There are at least three indicators of zoom climb performance we could look at:
1) zoom climb height,
2) zoom “hang-time” (as Bozon has pointed out already),
3) rate of energy change
To keep things simple we’ll just look at zoom climb height for the B-239, A6M5b, & P-47D-40.
B-239: BHP=1000hp, S=208ft^2, Prop Diam=9ft, CD0=.028, Weight=4857lbs
A6M5b: BHP=1100hp, S=229ft^2, Prop Diam=10ft, CD0=.023, Weight=5321lbs
P-47D-40: BHP=2600hp, S=300ft^2, Prop Diam=13ft, CD0=.021, Weight=14250lbs
I reset the weights for the B-239 & A6M5b equal AH 25% load out. Assuming a pure 90 degree vertical zoom climb, 360mph initial velocity, 100 ft starting altitude, & airplanes zooming until mph=0 this is what my model predicts:
(http://thetongsweb.net/images/zc6.jpg)
B-239: 5100 ft in 24.5s
A6M5b: 5300 ft in 25.7s
P-47D-40: 5400 ft in 23.3s
The B-239 technically doesn’t zoom as high but as we can see by the height reached it doesn’t really matter. As we see the greatest gap is a mere 300 feet between the B-239 and the P-47D-40 which in our AH world would be a separation of D 100 only, pretty much a point blank firing solution for the B-239 to shoot the tail feathers off the Jug.
Anyone surprised by the result? I’m sure you would be if you had a perception about the Brewster that doesn’t match real world physics. And that’s the point. What is our basis for perceptions of how a plane should perform? Is it anecdotes, imaginary / erroneous physics, or real world physics? Usually anecdotes trump physics for a lot folks which is completely exasperating. Worse though are folks that will argue based on flawed physics because the math is all there to test their hypothesis for themselves. “In aero, you can’t avoid the maths.” :)
AH Flight Test Comparisons
So how does AH compare to my predictions. I tested the B-239 and A6M5b at 25% load using BnZs test approach: dive from a higher altitude to near sea level, stay wings level until airspeed was at 375mph (IAS from E6B), pull up into a vertical zoom climb as near 90 degrees as possible.
A couple of notes: A) On the procedure, trying to do a constant G pull-up at 3g’s per BnZs technique was nearly impossible for me. The pull-up phase will impose a heavy induced drag penalty and worse for the heavier plane. This will fluctuate based on the g-loading which for me was hard to keep constant. B) I totally ignore the pull-up phase in my projections because the math modeling behind that is even more complicated than the integral math used for just a zoom climb.
Nevertheless these are the average results after making many attempts:
A6M5b: 5.05K, 25s
B-239: 4.85K, 23s
First, they don’t match BnZs results. 2nd despite some of the variability that the pull-up might have on the outcome the results are remarkably close qualitatively to what I calculated: The separation between the aircraft is ~200 ft & the zoom time is in the same ballpark of my predictions.
So why is there a discrepancy of about 250 ft between my calculations and the AH flight tests (and a slight difference in time?). This could almost be a meaningless thought exercise because the variability of pull up and actual initial speed at 90 degrees nose up is enough to throw it off, a very real possibility.
An even more intriguing possibility is the fidelity of the flight models. There are a variety of things I have not modeled because it would take me long hours to do so which AH does model. One is aircraft stability. I totally ignore that and assume that all my airplanes can reach 0 mph at peak of the zoom. In AH that is factored in and it is difficult to keep the airplane pointed nose up 90 degrees when airspeed gets low without some heavy control input and you may not actually top out at 0 mph but between 10-40 mph because of departed flight.
Second, AH also models engine HP variation with altitude and RAM air. Engine BHP output can vary as per the way they were designed. For my favorite airplane, the P-51D the Packard V-1650-7 Merlin has a saw tooth BHP range over the altitude range with it increasing from sea level to critical alt, then decreasing, then increasing etc. The point is that engine max power output isn’t a fixed value but varies with altitude and each engine has its own unique “curve”. AH models this. My model assumed a fixed BHP for all altitudes because modeling the propulsion system would require much more detailed data then I have available as well as a lot more time and sophistication to do so.
(http://thetongsweb.net/images/zc7.jpg)
Here are the AH ROC graphs for the B-239 compared against the P-51D and the A6M5b. As you can see the P-51D has an increasing ROC with altitude to about 10,000 ft. This matches the data I have on the V-1650-7 hp variation. Note for the B-239 ROC remains constant to almost 4000 ft and then drops off indicating that the Wright 1820-G5 outputs a constant BHP until about 4k. Looking at the A6M5b you’ll notice that ROC is decreasing with alt from SL to 8K which means engine power output is dropping off.
So the 250 ft lower difference between my predictions and the AH results is also a likely result of the detailed engine modeling in AH since both the B-239 & A6M5b power drops off.
The point is of course HTC takes their modeling of real world physics and aircraft very, very seriously. The fidelity is incredibly high. Maybe this will encourage others who have an FM dispute in the future to take the time and effort to seriously test their hypothesis before they bring an FM dispute in here because I dare say that 98% of the time HTC has got it right.
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On behalf of all us geeks who actually "find this stuff interesting", TYVM and WTG Tango. :salute
Thanks, but much more preferrable would be from you...
$170/hr * 25 hours = $4,250.00 + $250.00 for an expensive dinner and lots of beer (and that's with a discount for teasing you!). :D.
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One of the advantages of using the P-47 in your comparisons, is that it makes constant power up to 32,000 feet or so... :)
I wish there was a way to condense this thread down to the important parts and make it a sticky. Awesome effort and posts!
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One of the advantages of using the P-47 in your comparisons, is that it makes constant power up to 32,000 feet or so... :)
Well, yes and no. If you look at the level speed charts for the P-47 it has constant power output to 32k as you say. However look at ROC chart and you'll notice it dropping off sooner than that. The difference has to do with how much RAM air has an effect to help boost MAP. In level flight you reach higher airspeeds where RAM air assists to keep MAP high. In a steady climb your airspeed is much lower and thus you're not getting the benefit of freestream RAM air which means lower output sooner. Again this just to goes to show you some of the level of sophistication in the AH flight model. :aok
I wish there was a way to condense this thread down to the important parts and make it a sticky. Awesome effort and posts!
Thanks but if you only knew how much time it took away from playing with my kids, flying in AH, playing my guitar, etc. etc....!!! :mad:
Tango
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Well, yes and no. If you look at the level speed charts for the P-47 it has constant power output to 32k as you say. However look at ROC chart and you'll notice it dropping off sooner than that. The difference has to do with how much RAM air has an effect to help boost MAP. In level flight you reach higher airspeeds where RAM air assists to keep MAP high. In a steady climb your airspeed is much lower and thus you're not getting the benefit of freestream RAM air which means lower output sooner. Again this just to goes to show you some of the level of sophistication in the AH flight model.
Tango
Ok, now I'm confused. How does an aircraft with a turbo-supercharged induction system benefit from ram-air? All the induction air is compressed by the induction system before it gets to the engine. The waste-gate opens or closes as it needs to in order to maintain a constant manifold pressure, right?. I thought that was what the turbo regulator did? I know some of the other aircraft in-game benefit from ram-air, but not the Jug. MP stays a constant 54" in our Jug until you hit critical altitude.
[edit] I thought the ROC decreased due to lessened dynamic pressure not changes in MP?
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Stoney take a look at AHT pg 107, figure 148. A turbosupercharged engine has an intake for ram air. The engine still needs outside air. You can also take a look at the figures from John Deakin's Pelican's Perch series of articles (his articles are awesome!). Here's one he has on turbocharging and has some WW2 diagrams too. Note the ram air for the turbosuperchargers (diagrams lower down the page).
http://www.avweb.com/news/pelican/182102-1.html
Lessened dynamic pressure means less velocity which means lower ram air and lower MAP. Air density is the same for a given altitude but higher velocity means higher dynamic pressure for that altitude. I'll have to see if I can dig up MP readings on the P-47 climb vs. level speed.
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Stoney - just to clarify, yes you're correct that the P-47 turbosupercharging stays rated at 52" for a large range of the altitude & you are correct that the drop off of steady ROC when MP is 52" is related to changing air density and the effect of dynamic pressure on thrust and drag.
However there's more to it. Take a look at the rating for the P-47D from the flight test report from wwiiaircraftperformance.org:
http://www.wwiiaircraftperformance.org/p-47/p-47d-74616.html
Critical altitude for level flight is at 27,000 ft and 52" is obtained up to this level. However for climb critical altitude is 23,800 ft and 52" is rated to here. After that it starts to drop off. I believe the reason why we have crit alt differences between level flight and climb is due to ram air.
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Excellent explanation. A few remarks on the results:
300 feet (100m) is not a small distance in real life. It does not make a big difference to your survival if you pull from 0 to 100 head, but it makes a much bigger difference if you pull ahead from 200 to 300 meters and move out of the effective AIMING range of the chasing plane (aiming is harder when hanging on the prop than a normal 300 shot). On top of that, this is the extra separation that you will gain after you point down that will give you a short opportunity to recover and turn from hunted to hunter.
The relative results may change significantly with altitude. At 25kft the P47 will have a much better relative power loading than it has at 0, as other planes will loose more engine power. Generally, the loss of thrust at high alts will give a lot more "weight" to the kinematic part, i.e. the drag/weight of the plane.
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Critical altitude for level flight is at 27,000 ft and 52" is obtained up to this level. However for climb critical altitude is 23,800 ft and 52" is rated to here. After that it starts to drop off. I believe the reason why we have crit alt differences between level flight and climb is due to ram air.
I don't know enough about other aircraft, like the P-38's induction system, but I don't think the Jug is affected by ram air. Critical altitude for the Jug is ironically controlled by the turbo RPM. As the WWII performance report shows, the reason the climb critical altitude occurs at a lower altitude is because you hit the magic 18,250 rpm on the turbine RPM. Once the induction system hit that speed, an indicator light would light up in the cockpit, and the pilot would have to reduce power to maintain max turbine RPM. From my understanding, the turbo speed increased due to the decrease in pressure of the intake air.
Yes, there is "ram" air coming in the inlet, but it doesn't get to the cylinder intakes before it is compressed further by the turbo. As long as the turbo operates below 18,250 rpm, its going to produce 52" of MP at the carburetor regardless of the pressure of the induction intake air. Now, I don't know how this affects other aircraft in-game, but I think the Jug is immune to this one... I know that naturally aspirated engines certainly benefit from ram air, but I think the turbo neutralizes the affect of ram air. I could be wrong.
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Where did Chalenge go? :headscratch:
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Where did Chalenge go? :headscratch:
His old wingman, Ironman from his days in the CIA, called and left a message. It seems like Chalenge and a relapse of brain cancer and was bitten again by a red scorpion and will be MIA until the next time he sticks his foot in his mouth.
ack-ack
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His old wingman, Ironman from his days in the CIA, called and left a message. It seems like Chalenge and a relapse of brain cancer and was bitten again by a red scorpion and will be MIA until the next time he sticks his foot in his mouth.
ack-ack
It's a good thing that he unearthed the antidote years ago in the Iraqi desert when he had to ditch his F16 and dig 20 feet deep for water. It shouldn't be long till he returns me thinks.
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Good thing he was merely bitten by the giant red scorpion and not stung. If being bitten causes insanity, just think what actually being stung by one would do.
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Good thing he was merely bitten by the giant red scorpion and not stung. If being bitten causes insanity, just think what actually being stung by one would do.
Being bitten causes a sudden heart attack, being stung would be instantly fatal.
ack-ack
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It shouldn't be long till he returns me thinks.
You're right...this time he's going after Guppy again.
http://bbs.hitechcreations.com/smf/index.php/topic,293300.0.html
ack-ack