some reading material about the P40 (with notes on parts where the game doesn't appear to match)

[19//Moach]

this is the complete pilot training manual for the P40 - it covers all types, and observes to any differences between as they appear across the many topics:

 

http://www.avialogs.com/index.php/en/aircraft/usa/curtiss/p-40warhawk/pilot-training-manual-for-the-p-40.html

 

 

one solid data fact - pages 41 and 42 absolutely confirm the incorrect startup procedure being followed in game - in reality, the lengthy manual cranking steps are only performed in case of over-priming (or on a cold start, it should be done before even getting to the startup itself)

 

that's one thing we have well established here, though another thread exists for it anyways 

 

 

 

from page 49 onwards, you'll find the handling characteristics section - which I find to be a very interesting read 

 

page 58 describes turning characteristics of the airplane in a way that doesn't necessarily translate to the best advice in the sim -- particularly, it notes that it is possible to maintain a turn (and obtain maximum performance from it) at the point where the plane begins to shudder - in the simulator, the plane will lose energy extremely fast at this same flying condition,  adding power to compensate produces a very powerful yaw force, most likely from torque and whatnot (especially "whatnot"), which may escalate enough to overcome the flight controls ability to counter it at such low speeds (how/why?)

 

this is precisely where our p40 exhibits its most vicious trick - as you add the level of power required to sustain such a turn, following published procedure, the propeller torque can somehow exceed the effect of the control surfaces (which aren't necessarily stalled yet) - at that point, the plane then begins to swing sideways and "tips over" onto a deadly spin - this requires supreme concentration and a certain degree of luck to overcome, and there is no warning of its onset as the manual suggests, the first sign of trouble being the uncontrolled swing of the nose to the side, which only occurs after (at least partial) departure can no longer be prevented

 

 

page 66 then describes aerobatic performance, and details the procedure for a loop with no mention to the need to use left rudder when pitching up - if this is performed by-the-book on the simulator, the loop will "flop" into a spin somewhere around the top, or at the very least, will exit the maneuver at a different heading from that of entry

 

in the sim, left rudder has been observed to be a requirement on all pitch-up inputs in order to maintain coordination, and even to prevent spinning on more intense maneuvers or tight turns

 

the simulator plane requires a method of rudder control which is alien to any other aircraft featured - this involves using left rudder to coordinate upward pitch, and right for down, in such a scale that in certain condition it'll require left rudder to coordinate even a right turn -- the workload this imposes is not commonly found in fixed wing aircraft, and is more commonly associated with helicopters

 

why this happens is still not clear (could be a secondary result of other factors interacting) - it is impossible to determine the real nature of this behavior without access to real-time flight calculation values 

 

 

no similar phenomena is mentioned in the manuals - there is no documentation to backup the huge degree of pitch/yaw coupling that is found in the sim - which indicates this could very well be exaggerated

 

 

 

continuing on, another manual:  http://www.avialogs.com/index.php/en/aircraft/usa/curtiss/p-40warhawk/t-o-01-25cf-1-pilot-s-flight-operating-instructions-p-40d-and-p-40e-airplanes.html

 

 

very specific data, complete with charts on climb performance and similarly useful information

 

 

 

and the british version:  http://www.avialogs.com/index.php/en/aircraft/usa/curtiss/p-40warhawk/ap-2014a-pilot-s-notes-the-kitty-hawk-i-aeroplane.html

 

 

this one contains even the data for correcting positional error on the airspeed indicator -- wasn't one of us looking for this?

 

 

also, it makes several remarks towards unstable low-speed behavior that corresponds to that observed in the sim (though no mention of heavy pitch/yaw coupling), but this is specifically for a case of the C.G. being near/at the aft limit

this would be the case with fuel in the fuselage tank - which is not to be used for combat - in the simulator, this same behavior persists regardless of fuel loadout -- which begs a few very important questions:

 

 

where exactly is the modelled CoG on the kittyhawk? does it change with fuel load? -  how come we experience instability similar to what's expected from a full aft tank even when that tank is empty?

 

 

 

 

more information, general purpose:  http://www.avialogs.com/index.php/en/aircraft/usa/curtiss/p-40warhawk/to-01-25cf-1-handbook-of-operation-and-flight-instructions-for-the-models-p-40d-and-p-40e-pursuit-airplanes.html

 

and more even, which I haven't yet filtered through: http://www.avialogs.com/index.php/en/aircraft/usa/curtiss/p-40warhawk/curtiss-p-40-flight-manual.html

 

 

 

curious fact - each manual lists a slightly different set of stalling speeds (presumably due to small variations from different tests) -- it is fair to suggest, somewhere in between them lie the best interpretations of this data -- similarly, slightly varied engine limitations are listed 

 

 

 

 

anyways - manuals are written by engineers who're usually not on the receiving end of a 109 or Zero - so a more practical account should be taken from a pilot

a brief search reveals that yes, books have been written about this: https://books.google.ca/books?id=NFTEPiyEiSsC&pg=PA146&lpg=PA146&dq=p40+kittyhawk+engine+limits&source=bl&ots=RNXvsiHQN1&sig=lIBbwSrT8jrbfX-qwyL898RvWuw&hl=en&sa=X&ved=0ahUKEwjdoKSK_N7SAhVCwGMKHY3_AzQQ6AEIiAEwFA#v=onepage&q=p40%20kittyhawk%20engine%20limits&f=false

 

 

 

and finally, see this page and all the documentation attached for specific flight testing data on all P40 models: http://www.wwiiaircraftperformance.org/P-40/P-40.html

 

at the bottom you'll find a list of assorted documents, among which sits a letter from a GM representative (then producing the Allison engine) responding to inquiries from the commander of a squadron reportedly running prolonged periods at power levels alarmingly above the recommended engine limits -- supporting the repeated claims made by players that the simulated engine is limited much too conservatively

 

 

 

this was originally posted as a response to another thread, but since it collects a good deal of documentation about this type, I figured it was worth "promoting" to a new topic, that way we can continue to expand on it  - so, if you have any further data such as this about the kittyhawk, please post the links here so that we can have all this information in one same place

 

 

and PLEASE -- don't let this turn into yet another p40-versus-109 type exchange of pointless retorts -- this is only about the Kittyhawk - as far as this thread is concerned, pretend it is the only plane ever constructed and flown by man in the entire history of ever

Edited March 18, 2017 by 19//Moach

[ACG_KaiLae]

PEC information does not list information near stall speed. Others have stated that the AoA can cause the speed indication to become unreliable at stall, so without a specific test at that speed it is of little value.

[Holtzauge]

”Some pilots admit operating for prolonged periods at around 70” Hg. (20lbs./sq.in.) of boost”

 

Assuming the information in this document is correct, we can then draw two conclusions: One being that the engine could be run at much higher boost than the official limits without failing and the second that pilots were apparently doing this.

 

So again, why is it so difficult to reconcile pilot accounts that the P-40 could be competitive and that what we have in-game does not tab with that? When would one expect a pilot to overboost up to 70” and get a power output of up to 1700-1800 hp other than in combat?

 

An in-game P-40 that could run at 70” boost for prolonged periods of time would be a beast. I did some quick C++ simulation runs for a weight of around 8500 lb and here is a sample:

 

Benchmark: With 1150 hp a turn time of 23.4 s sea level and 1925 fpm climb rate.

 

However, with 1780 hp the improvement is dramatic: A turn time of 18.8 s and a 3410 fpm climb rate.

 

Of course 70” is an extreme but the calculation still shows what a dramatic effect on performance overboosting has.

 

I’m all for fixing the handling characteristic but for the performance part no, I don’t see that what we have in-game today is off: It’s simply a result of implementing the official boost limits which by the way it looks like the developers are doing consistently so the P-40 is treated like any other plane in this respect.

[19//Moach]

I’m all for fixing the handling characteristic but for the performance part no, I don’t see that what we have in-game today is off: It’s simply a result of implementing the official boost limits which by the way it looks like the developers are doing consistently so the P-40 is treated like any other plane in this respect.

 

I have actually considered this and with some experience flying the "Old Crate" in game - I agree, the engine limits are generally fine

 

what I reckon most of those who say "it died too quick" have encountered is maybe not failure from overboosting, but from (perhaps unawarely) over revving it --   above 3000 rpm, it will not fare well for more than 30 seconds, and that is perfectly normal

 

but I have noticed that at 2600, one can sustain "combat mode" power almost indefinitely (or long enough at least that it seldom causes damage), if temperatures are observed - I have held it at that power for over 5 minutes at a time without any issues, even with the intermittent burst of "emergency mode" which can also be held for long enough to reach the desired airspeed before any damage is done

 

however - it is surprisingly easy to run it at "don't go there" RPMs without noticing, and even a shallow dive can lead to that happening if you don't keep an eye on that gauge (your ears can fool you if you rely on engine sound alone)

 

 

so yes, I personally have little objection with the engine model - it does sustain some abuse, as advertised -- it bothers me quite more that it cools so fast on the ground that the cowl flaps are never needed open before takeoff - despite all the procedures we've seen listing that as an item

 

but really - even more so than even flight dynamics, my biggest personal gripe with it is the twofold duration of the startup sequence which mistakenly takes the corrective steps for over priming as part of the standard procedure (really what it's doing is to undo each primer stroke right after pumping it) -- the 30s extra time this adds feels like an hour in a scramble scenario (very common in multiplayer) when all hell's blowing up around you

 

 

but besides that, the engine seems to be all in accordance, once we're in the air -- the performance issues are probably unrelated to that...   reading the manuals over again seems to suggests our planes handles like it's got the CoG too far back - the tail swings are actually described as a thing that should happen when that aft tank is loaded, yet I have tested it with 100% fuel vs 50% or less, and it did not seem to handle any different

 

could it be not correctly shifting the CoG forward enough according to fuel load?

 

that would explain a LOT

Edited March 18, 2017 by 19//Moach

[Holtzauge]

Don't get me wrong Moach: I think it would be good if the in-game P-40 performance came closer to how I believe it performed IRL in combat which was probably significantly better than today due to overboosting. So I'm not defending or saying that the current boost limits are "fine" it's just that I can't see any good way of implementing overboosting in the simulator that's all. IMHO it would be close to impossible to come up with a good model that everybody was happy with and how on earth would you find data on how long the engine could  run at 45, 50, 55.........70" boost? Buy a few hundred Allisons and run them at different boosts and see how long they last?

 

Concerning the CoG shift due to fuel burn: I'm pretty sure it's modeled but that should be easy to test: Simply decide on a speed and altitude and run with 50% and 100% fuel load and carefully trim in both cases. I predict you will get a different trim % for the different fuel loads indicating that the CoG has shifted.

[19//Moach]

sure enough - there's probably never gonna be any engine limits that make EVERYONE happy... people can only be bothered en masse, never pleased

 

not saying it's "fine" - but it's one of the least objectionable things I find with the plane as it is now.... it's about as critical for me as the lack of an audible landing gear horn when power is reduced... that is to say:  not a lot

 

anyways, the GM letter says they tested it at 70" in the factory, and it lasted about 30 seconds... they also said at sea level it's not even possible to reach that kind of boost pressure without over revving it quite a bit.... it's very much a "kids, don't try this at home" kinda business

 

 

 

well, the CoG probably does change (or so I hope), which I will try and find out just by how much shortly

 

though it seems to me, that the plane continues to exhibit behavior that is described for a full aft tank when that tank is empty... I generally fly it with no more than 300 liters loaded (aft tank empty) - and it always shows all the same tendencies that the manual say it would with the CoG at the aftmost limit...

 

I recall running that thing almost empty a few times and didn't really notice the tail-heavy-like behavior change much anyways - gotta try it again and see

 

maybe it doesn't shift forward enough?

 

the aft tank sits further from the reference point than the other two tanks - it is also the largest of the three, so a linear fuel-percentage-to-CG-shift logic would be somewhat off towards the rear for the most part...  basically the aft tank should affect the CoG more than the other two combined, and the latter would probably cause little to no noticeable shift, since they're pretty much centered, not sure if it behaves like that ingame though

 

 

the manuals should have all that information in proper detail on them, so it should be fairly simple for devs to make sure the CG is where it's meant to be throughout the flight....

 

another thing that might perhaps affect it is, how much does our sim-pilot weigh - maybe he needs to be put on a diet?

Edited March 18, 2017 by 19//Moach

[19//Moach]

flight tests were done, stick centered, 200mph at 2450rpm, boost set to hold speed at 4000m (~13000ft)

 

at 50% fuel, trim required to stay level was between 45~50% nose up

 

at 100%  this dropped to between 35~40%

 

at 10% it was between 50~55%

 

 

seems the rear tank does have a larger influence on the CoG than the other two, however, the plane continues to demonstrate the unstable behavior described for a tail-heavy loadout at any fuel load...

 

I was kind of expecting to see a bigger difference with all full tanks relative to with the aft one empty, it took indeed a bit less trim, but I it's hard to say if this is what would be considered normal.... the change from 50% to almost empty was smaller than that between 50% and 100% - as expected.... can't tell if this is correct without a proper weight and balance chart though - does anyone have that?

 

 

I'm gonna try maneuvers with different loadouts next, and see if there's any noticeable difference in responsiveness with that aft tank full or empty

Edited March 18, 2017 by 19//Moach

[Farky]

anyways, the GM letter says they tested it at 70" in the factory, and it lasted about 30 seconds...

 

 

Allison memo ("GM letter") do NOT says that, read it again please.

 

 

reading the manuals over again seems to suggests our planes handles like it's got the CoG too far back - the tail swings are actually described as a thing that should happen when that aft tank is loaded, yet I have tested it with 100% fuel vs 50% or less, and it did not seem to handle any different

 

could it be not correctly shifting the CoG forward enough according to fuel load?

 

that would explain a LOT

 

 

I don't know if CoG vs. fuel load is not correct, but shift of CoG is there for sure. From my subjective point of view I have not experienced an appreciable change in the behavior/handling of the P-40 in relation to the amount of fuel. According some manuals and documents, P-40E was "unstable" with more than 20 Imperial gallons of fuel in fuselage tank. This means that with the total 414 liters of fuel (74%), P-40E should be much more stable than with 560 liters (100%).

[19//Moach]

well, curiously it felt to me that the plane is a bit LESS stable with the aft tank empty

 

 

seems to suggest the moments of inertia are somewhat odd - a heavier tail would increase the pitch yaw MoI's a bit, which perhaps is what made it more resistant to wobbling and easier to prevent spinning out... 

 

odd thing is - I started noticing the plane has more stable pitch than it has roll... that should basically not happen due to the shape of an airplane - when pitching, all the mass of the wings is close to the center of rotation, though when yawing, the whole span of the wings adds to basically the MoI you would have for pitch

 

basically, for a plane of the same configuration as the P40 would be to say that the yaw MoI should be something in the vicinity of the sum of both pitch and yaw MoI's -- given how mass is distributed around each axis

 

no plane of similar shape should have less rotational inertia on yaw than it does on pitch, since there'll be more mass moving further from the axis -- the P40 here seems to be oddly contrary to that notion, and displays a stiffer pitch than yaw

 

it is very weird - a stiffer pitch than yaw could only be the result of aerodynamic forces on the tail - though the amount of wobble it gets from yaw compared to pitch does not seem to match the difference in area between the vertical and horizontal tailplanes

 

 

alas, how can we measure "wobble"?

 

 

curious too, the rudder also appears to lose authority almost completely once a certain slip angle is reached... from then on, it carries on basically uncontrolled through the spin - it can reach that state without any warning or shuddering, in other words:  it'll apparently spin before stalling (as far one can tell from the cockpit)

Edited March 19, 2017 by 19//Moach

[19//Moach]

Allison memo ("GM letter") do NOT says that, read it again please.

 

 

 

ok - so what it said was, their dynamometer tests showed that 70" can only be reached at 3200 rpm (which is not ok to do) - and I wrongly confused that with the other statement further on that mentions other tests, which showed that it will fail in 30 after detonation starts -- it didn't imply that detonation happened on the first test

 

which means, god damn! what a beast of an engine is this 

 

 

apparently it can take a LOT of crap and be ok with it.... and/or the ppl in Allison really underestimated what they had built

 

 

nevertheless, I have not been able to get any improvement in turning performance in the game by using "Moar Powah!" - which the manual suggests would help - if anything, the engine torque makes it easier to lose rudder control and spin out

Edited March 20, 2017 by 19//Moach

[-=PHX=-SuperEtendard]

However, with 1780 hp the improvement is dramatic: A turn time of 18.8 s

 

Interesting, are you be able to calculate more or less how many HP would be needed to achieve the Soviet 19.5 turn time? (and which manifold pressure would be neccesary for that amount of power).

[19//Moach]

well, in a turning fight with the P40, the most often it isn't the engine self-destructing that kills me - it's the fact that in a turn fight, it cannot sustain a maximum turn for any useful periods without getting dangerously close to stall - and at that speed, rudder authority is dismal

 

in slow flight (by slow I mean any speed from 200mph down) the lateral wobble which results from pitch movements alone is enough to exceed the "point of no return" slip angle -- once that happens, it does not matter if your wings have stalled, the plane will still enter a spin regardless

 

 

I have never had any experience with a plane in which the RUDDER will stall before the wings -- this most unusual phenomenon happens all but regardless of power settings - as if for some bizarre reason, the slipstream would not stick with the fuselage, but instead it'd "weathervane" with the incoming airflow - and once the rudder is outside the "wake" - it has zero authority

 

of course, that's impossible... but then again, the results are generally indistinguishable from it being the case

 

 

I have actually tested this out - and it is in fact quite possible (easy, really) to have the plane depart before stalling 

 

 

this remarkable feat can be accomplished by simply giving it full rudder to either side, for just about one second, at any speed below 300mph (probably faster too, but I didn't test it that far)

 

also, pitching up and down a few times without coordinating* with the rudder will also induce the same pre-stall spin

 

 

*this is unique of our P40, that it requires more rudder input to coordinate pitch movements than it takes for turns - to such extent that in a right turn, it can even require left rudder (from a cruise trimmed position) to keep the ball centered if just a little back pressure is applied on the stick

Edited March 19, 2017 by 19//Moach

[unreasonable]

 

I have actually tested this out - and it is in fact quite possible (easy, really) to have the plane depart before stalling 

 

 

How can you possibly know this?

[19//Moach]

How can you possibly know this?

 

 

easy thing to do in game - put full rudder for about a second, don't pull back - you'll be out of control even if you're not actually stalled - hold the nose level to be sure, and slide it sideways as flat as you can manage

 

it will not hold a full deflection side-slip 

 

 

of course I did not mean it about the real plane - I'm not nearly lucky enough to have one around to fly (and I don't think they'd let me, anyway)

Edited March 19, 2017 by 19//Moach

[unreasonable]

What I mean is how do you know you are not stalled - at least on one wing?  You can stall at any speed, flying yawed changes the AoA of the wings differentially, so given that the P-40s has dihedral, and that you are artificially maintaining a level attitude, and given the  mysteriously low critical AoA, perhaps what you are doing in your extreme sideslip example is to stall one wing.

[19//Moach]

What I mean is how do you know you are not stalled - at least on one wing?  You can stall at any speed, flying yawed changes the AoA of the wings differentially, so given that the P-40s has dihedral, and that you are artificially maintaining a level attitude, and given the  mysteriously low critical AoA, perhaps what you are doing in your extreme sideslip example is to stall one wing.

 

perhaps - there's really no way to tell for sure (I wish we have a flight debug data option, it would REALLY help)

 

 

but - I've repeated this several times, making sure to keep wings levels and nose flat on the horizon - it seems that it'll always start oversteering before the stall rumble can be heard

 

 

which is why I said it departs (not "spins") before stalling - the spin happens in consequence, but it certainly loses directional control before either wing loses lift

 

 

 

it seems to me the thing has just about no damping whatsoever on yaw - directional stability is absurdly lacking, almost as a cartoon depiction of what "unstable" is like

 

 

in all other planes, a forced spin from over-rudder feels very different, with a largely more "crisp" departure -- the P40 is unique that at a certain slip angle, it will start  "sliding" - this happens very quickly, but once the point-of-no-return is reached it behaves very much the same as if the tail had been shot off

 

 

I've been scrutinizing it for several days, and my reckoning is that, historical accuracy aside - some aspects of how it behaves are close to being physically impossible

 

 

this plane NEEDS to be fixed, there's no two ways about it - presently, it just does not meet the quality standards set by the rest of the BoX fleet

Edited March 19, 2017 by 19//Moach

[6./ZG26_5tuka]

There have been changes made to the rudder behaviour of all aircraft which will probably be implemented in one of the next updates so there's no need to continue the argument about whether the current model is right or wrong.

[19//Moach]

There have been changes made to the rudder behaviour of all aircraft which will probably be implemented in one of the next updates so there's no need to continue the argument about whether the current model is right or wrong.

 

 

well here's hoping that does that  -- there's a few details besides it which aren't performance related anyways - but well, if that solves it for the rudder then there'll be a bunch of happy folks here.... alas, there's no ETA on it or much word on how it actually affects this particular plane, so as far as that goes, what you say is still largely speculation and some very wishful thinking

 

but damn, I hope you're right

[6./ZG26_5tuka]

Well there are indications that work is well underway

Really a great experience though and thanks to Petrovich for setting it all up. We also had some good discussions about our FMs and I've seen some of the improvements he's made to the rudder inputs and feels much better than before. I think you guys will like it.

 

And from DD150 (March 3rd)

Our lead engineer has finished preliminary preparations and now works on making behavior of a plane while using rudder or side slipping even more realistic.

Edit: Petrovich made a poll on the russian forum a while back for collecting user opinion on which aims of DD120 they prioritize. Later he explained he had 1 month to work on any of these feautures and that the rudder behaviour is the leading choice from both the comunity as well as him personally.

Edited March 19, 2017 by 6./ZG26_5tuka

[Farky]

Holtzauge, on 18 Mar 2017 - 11:08, said:

However, with 1780 hp the improvement is dramatic: A turn time of 18.8 s

 

Interesting, are you be able to calculate more or less how many HP would be needed to achieve the Soviet 19.5 turn time? (and which manifold pressure would be neccesary for that amount of power).

 

It is indeed interesting. Soviet turn time 19.2 s is for 1000 meters (3281 ft.) of altitude, maximum achievable power of V-1710-39 in this altitude is approximately 1550 bhp (some 58inHg/3000rpm). So it seems to me that reaching this time was not possible even in theory. And yet the Soviets reported that they archieve this time with P-40E (and 18 s with P-40C).

[unreasonable]

I wonder - tentatively - if that is simply because the altitude could not be measured with complete accurately.  Presumably the theoretical times calculated by JtD and Holzauge assume exact maintenance of height - and speed for that matter. When you do it in a real aircraft this will never exactly be the case so I would not be surprised if a little height (and possibly speed) was lost, which I think would allow for a fractionally faster turn.  

[Holtzauge]

Interesting, are you be able to calculate more or less how many HP would be needed to achieve the Soviet 19.5 turn time? (and which manifold pressure would be neccesary for that amount of power).

 

The way I have it modeled is simply a power altitude chart that the program looks up in. Then I use that as  a starting point and iterate speed compensating for increased critical altitude and  power loss due to ram. so there is no manifold pressure involved.

 

It is indeed interesting. Soviet turn time 19.2 s is for 1000 meters (3281 ft.) of altitude, maximum achievable power of V-1710-39 in this altitude is approximately 1550 bhp (some 58inHg/3000rpm). So it seems to me that reaching this time was not possible even in theory. And yet the Soviets reported that they archieve this time with P-40E (and 18 s with P-40C).

 

True, and I think there is something wrong with that figure in the TSAGI table. However, it's not only the P-40 that is off, the Me-109E3 turn time is stated as 23.3 to 26 s which is clearly wrong as well. This was discussed earlier as well here.

 

I wonder - tentatively - if that is simply because the altitude could not be measured with complete accurately.  Presumably the theoretical times calculated by JtD and Holzauge assume exact maintenance of height - and speed for that matter. When you do it in a real aircraft this will never exactly be the case so I would not be surprised if a little height (and possibly speed) was lost, which I think would allow for a fractionally faster turn.  

 

Not maintaining altitude could of course affect the result but hardly to the level needed in this case since the TSAGI table states 19.2s and the combat power turn time of the P-40 at 1000m should be in the order of 25 s which is why I would not be surprised if the P-40 and Me-109E3 numbers in the TSAGI table are simply a transcription error.

[JtD]

From recent reading, a definitive 'no' on the last issue. The 19-20s turn time can also be found in about every Soviet flight manual for the P-40, details reading: 70° bank, 180mph IAS and 42" boost. Total efficiency: ~70%, twice as good as it is now in game, and 50% better than a) the best figures achieved in game and b) what could reasonably be expected from WW2 fighters.

[unreasonable]

If you mean "no" not a transcription error then having the same number in every manual certainly does not disprove that hypothesis - once an error is made 'upstream' as it were, in this case a TASGI table, all the downstream publications just copy without double checking. I have seen it happen often enough in economic literature. Anyone questioning the number - which would happen very rarely anyway - would be met with the response "Who are you to question an authoritative source?".

 

If you are saying that these numbers are physically impossible then a transcription error is a pretty good guess. The only other feasible hypotheses are a) measurement errors in the test, hence my question about height, or b) deliberate falsification perhaps for morale/survival purposes.

[JtD]

It's not a transcription number in that the figures for the 109E and P-40 are mixed up. The manuals pre-date the TsAGI book and while they may all be referring to the same original source, which may be a TsAGI test, it's not that the figure from the table found its way into the manual. The manuals give "19-19,5s" turn time, so it's not pure copy and paste (or the analogue equivalent thereof). Additionally, 70° bank and 180mph level turn necessitate a turn time of around 20s at 1000m altitude, 25s would be achieved at about 60° bank angle. These details are not given in the TsAGI book, and they match the turn time figure stated.

 

All in all it's very easy for someone to mix up a figure in an overview table or even for an entire book, but it's no longer that simple if a paragraph in other, earlier publications confirm that figure. Holtzauge offered a way out in form of a simple editor error, unfortunately, that's not the case. We still need to dig deeper, ideally until we find the original test report.

 

Paragraph attached for the curious.

 

[Dakpilot]

Surely there must be some other turn time figures to compare, from Western sources/manuals it was (P-40E) used by RAF/SAAF/USAAF/RNZAF/RAAF...does the 19-19.5 figure crop up there?

 

Cheers Dakpilot

[Holtzauge]

@unreasonable: Found a chart in “TB1840 Kurvewendigkeit der Me-Typen III Teilbericht” with the Me-109F turn rate as a function of vertical speed. With a constant height at sea level, turn time in chart is 21 s. To improve the same percentage as for the P-40, i.e. 19.5/25 or 78% (so going from 21 to 16.4 s) I read of a vertical speed of around 16 Km/h or 4.44 m/s so a height loss of only 4.44x16.4=73 m for a full circle. A theoretical figure to be sure since losing 73 m altitude from sea level is not possible in many places but I have to admit the height loss was less than I anticipated.

 

Edit: I'm beginning to suspect the "w" as in vertical speed I read off in the chart may have been m/s not Km/h.......

Edited March 20, 2017 by Holtzauge

[unreasonable]

But still easy enough to see on the altimeter in the cockpit, so I suppose such a miss-measurement in a test is highly unlikely.  But your table does demonstrate that your apparent turning performance can be radically improved if you are prepared to lose a little height.

 

Make the "I turned inside an XYZ" anecdote even harder to analyse .....

[JtD]

Surely there must be some other turn time figures to compare, from Western sources/manuals it was (P-40E) used by RAF/SAAF/USAAF/RNZAF/RAAF...does the 19-19.5 figure crop up there?

 

Cheers Dakpilot

 

Not as far as I have seen. WRT turning, I found in Western sources that a Hurricane could start in front of a P-40E and within 720° be on its tail. Turning capacity of the Hurricane is generally stated to be a little bit better than 19-19.5 seconds, typically 17-20, with TsAGI giving 19-20 for a Hurricane II at 1000m.

[ACG_KaiLae]

A hurricane is more maneuverable than a spitfire, which many forget. It's a really good turning plane, so for a P-40 lose out to one is not that surprising. Most sources also list turn times on a spit at 19s, though this again depends on the model. As the marks went up the spit turned less well and did other things better.

 

 

 

We still need to dig deeper, ideally until we find the original test report.

 

 

 

 

YES PLEASE

Edited March 21, 2017 by Kai_Lae

[19//Moach]

I'd like to point out a fact that's been otherwise overlooked in these discussions -- the alarming lack of brakes

 

 

quote a real pilot:  https://youtu.be/rki8tnsLodQ?t=380 (as said while taxiing it)

 

 

I've tried it in the sim, and it's just impossible to brake hard enough to nose over, like the instructor in the video above warns about

 

in fact, it's actually possible to takeoff with parking brakes set (and not even notice it)

 

 

 

this becomes a big issue when the tailwheel is inadvertently unlocked, and the plane begins to ground loop... it'll keep looping for a while before the dangerously underpowered brakes can put a stop to the dizzying pilot's embarrassment

 

in some cases (in cold denser air, mostly) the engine startup "vrooom" alone is enough to overcome the fully applied brakes, forcing it a few meters up against anyone unlucky enough to be taxiing or parked in front

 

 

this should not be a difficult thing to fix... the problem is a self explaining one, and the solution is obvious:   add more brakes

[Dave]

Maybe DCS won't bugger their P40.

[BlitzPig_EL]

It will be interesting to compare the upcoming Cliffs of Dover P40 with the one we have now in BoS as well.