P-40 turn rate/Flight model check

[19//Moach]

(...) I would argue based on the evidence above and earlier in this thread, that they have ulterior motives.

 

 

 

this kind of comment is completely uncalled for (let alone unfounded) and undermines the merits of this discussion - accusing someone of "deliberately making a mistake" ranks high among the worst possible ways of getting them to listen to you

 

...plus, it's rude -- don't do that

 

 

I cannot confidently assess much about the ClMax of the P40 ingame -- as far as I have found by my own experiments with the model, and continue to do so, I am discovering a degree of "hidden performance" in the plane which can be tapped by extremely careful use of rudder to balance out the erratic (allegedly fixed, update pending) yawing motions

 

it is my theory that the plane is otherwise aerodynamically sound - and discrepancies over lift and stall characteristics are very possibly well within the 5% tolerances set by the devs

 

the main factors I believe are to blame for any shortcomings would be the limited "engine abuse model", which affects all airplanes, in various ways - and most importantly, that the plane slips and slides widely enough to become almost* completely uncontrollable at near-stall speeds

 

* there's a method to overcome the rudder "death slide" issue with sharp elevator inputs to exploit the (too?) large propeller gyro forces in a way that stays the uncontrolled rotation, even at a state where rudder appears to lose all authority:  in short, pull up to break a clockwise departure, and push down for counterclockwise -- do this BEFORE it actually stalls either wing -- takes a lot of practice to get it right

 

 

I have a good deal of confidence that the soon-to-come "rudder updates" will have an impact on this airplane which might be above some expectations here - I have this belief justified by my recent findings with "experimental handling methods" for this airplane in its current state, which have revealed a surprising level of performance, "hidden" behind the difficulty of maintaining a steady nose during sharp turns

 

 

I do have some questions about that propeller though... maybe it's not delivering adequate thrust across the speed range? is there any info on what sources they used to model it? - given how the VDM propeller was "substituted" on the 109 due to devs' shortage of proper data at the time, it begs asking about their sources for the Curtiss prop, and just how this is implemented....

 

does anyone know if devs have used (or even have had access to) the correct propeller specs for the P40?  has anyone ever asked them about this?

Edited April 1, 2017 by 19//Moach

[Dave]

Warbirds Over Wanaka is on right now. If I could there to talk to the P40 guys I would. Anyone nearby?

[JG13_opcode]

Some people believe this is the true CLmax and weight of the P40E (and therefore the actual stall speed). I would argue based on the evidence above and earlier in this thread, that they have ulterior motives.

 

You've consistently acted like a jerk throughout this entire thread while reading selectively and going immediately to ad-hominem when things don't go your way.  You're the new Crump.

Edited April 1, 2017 by JG13_opcode

[ZachariasX]

You've consistently acted like a jerk throughout this entire thread while reading selectively and going immediately to ad-hominem when things don't go your way. You're the new Crump.

You think he's evil enough?

 

Edited April 1, 2017 by ZachariasX

[6./ZG26_Klaus_Mann]

I think it is exceptionally stable in tight, low speed turns, the Problems come with Aileron inputs which have to be Counteracted with very Precise Rudder Inputs. The Yaw, Roll Fix will do some good I guess, but it will remain Tricky to a certain degree.

[19//Moach]

I think it is exceptionally stable in tight, low speed turns, the Problems come with Aileron inputs which have to be Counteracted with very Precise Rudder Inputs. The Yaw, Roll Fix will do some good I guess, but it will remain Tricky to a certain degree.

 

not just aileron - elevator inputs also need to be countered with rudder - it's actually possible to push it past the point of no return and enter a Death Slide™ with pitch movements alone in certain conditions

 

this behavior is far less severe with lower RPMs (and also it seems to get more power at lower than rated revs, which is kinda weird) - at about 2250, the plane becomes very stable - and cruises at 300mph (in cold weather, no bomb) on the deck, with just under 40" manifold 

 

alas, acceleration is quite limited at that setting... it can actually do some bizarre prop-hanging stunts at 2600 (rated) - but at this point, you cannot sustain combat power too long, and it tends to over-speed as you go through some maneuvers (not necessarily going into a dive itself, but pitching down fast often causes a bizarre spike in rpm)

 

 

seems to me, that besides the obvious vertical stabilizer issues, (impossible rudder "stalls" at >critical slip angles, aka: "Death Slide­")  the plane exhibits some rather unusual interactions with the propeller and associated forces... it also does not seem to develop power over RPM and speed variations in the same way one would expect from the behavior of every other plane in this sim (or elsewhere) 

 

 

 

it's definitely weird

Edited April 1, 2017 by 19//Moach

[Farky]

this behavior is far less severe with lower RPMs (and also it seems to get more power at lower than rated revs, which is kinda weird) - at about 2250, the plane becomes very stable - and cruises at 300mph (in cold weather, no bomb) on the deck, with just under 40" manifold

 

 

Good example why we need more complex modeling of engines in game - 40inHg at 2250 RPM is very dangerous setting, you are squeezing some 1230  970 bhp from engine, but you are (well, you should be) in detonation area for sure. In other words, you are abusing the engine, badly.

 

Engine in game do not produce more power at lower than rated rpm, simple experiment - fly with the same manifold pressure at low RPM and than higher RPM, you are always faster with higher RPM.

 

 

... it also does not seem to develop power over RPM and speed variations in the same way one would expect from the behavior of every other plane in this sim (or elsewhere)

 

 

I don't know what do you mean by that, can you be more specific?

 

 

and it tends to over-speed as you go through some maneuvers (not necessarily going into a dive itself, but pitching down fast often causes a bizarre spike in rpm)

 

 

Curtiss Electric propellers (like all "electrical propellers") are known to be much more slower in changing pitch than hydraulic types. Too quick throttle opening or aggresive pitch down maneuvers will result in overloading of propeller and therefore overspeeding. On the other hand, while manuals are limiting maximum to 3120 RPM, V-1710-39 was able withstand up to 4100 RPM for 30 seconds. Repeated running on 4100 RPM for 30 seconds was actually part of USAAF Model test (acceptance test) for this engine.

 

EDIT: 1230 bhp corrected to 970 bhp, I don't know what I was thinking.

Edited April 1, 2017 by Farky

[Venturi]

Yes, overspeeding was definitely possible, and by the way, generated a higher maximum boost (obviously).

Edited April 2, 2017 by Venturi

[19//Moach]

Good example why we need more complex modeling of engines in game - 40inHg at 2250 RPM is very dangerous setting, you are squeezing some 1230  970 bhp from engine, but you are (well, you should be) in detonation area for sure. In other words, you are abusing the engine, badly.

 

Engine in game do not produce more power at lower than rated rpm, simple experiment - fly with the same manifold pressure at low RPM and than higher RPM, you are always faster with higher RPM.

 

 

I didn't really mean "horsepower" by that... probably a poor choice of phrasing there -- I meant to say that it seems to more "willingly" sustain higher speeds at that setting, not necessarily implying that the engine is delivering more power for it

 

what it feels like, which is indeed most weird, is that at such a lower power output, the "blade drag" (which is what it appears to be for the pilot) is so much lower, that the plane actually flies faster

 

therefore I wonder what on earth is going on with that propeller... this isn't the behavior one would normally expect - your experiment holds true (naturally) in any other plane, but the P40 appears to reach higher top speed for a same boost in a bizarrely non-linear way

 

 

and yeah, I was kinda worried about detonation at first... I found out about this during those 3 minutes after a mission ends in WoL where you don't really give a shit what happens, which makes it a very suitable time for this kind of "science" 

 

but well... there is no detonation, and thus, there is no problem.... curiously, here we have one issue being used to overcome another - which seems to be the way of this plane, right now... same goes for how the elevator can be used to stop a Death Slide whereas the rudder is mostly useless: bug vs. bug

 

 

 

it is well that the electric prop is slow, and more prone to overspeeding - of course, as it should be. but I forgot to point out that throttle had not been changed in these pitch down maneuvers which cause this rpm spike before actually entering a dive... it needs more experimenting though, as I have yet to find a way to reliably reproduce this behavior... (could be I had jerked the throttle without noticing it)

 

 

but really -- what is the deal with that propeller?   why are the forces from it so much stronger than on most other planes? (why is the MiG similar in that sense?)  and why does it (seem to) have such a weird relation between airspeed and rpm? - has anyone asked the devs about it?

Edited April 2, 2017 by 19//Moach

[19//Moach]

either way, it is clear enough that the official limitations (not actually implying physical tolerance) for this individual engine are largely underrated in the sim:

 

at 3000 rpm, the engine enters "emergency mode" - regardless of boost setting - and lasts for about one minute (as opposed to the official 5) -- after this is elapsed, the engine spontaneously disassembles with no prior hint or gradual onset of damage from partial excesses...

 

let alone what the engine could ACTUALLY cope with... the official limits (western), though historically known to have been largely underestimated, are themselves beyond the simulator thresholds for powerplant self-destruction

 

 

 

 

5 minutes of "emergency mode" would be recommended as a (fair enough) compromise interpretation of official and reported engine limits for this type

Edited April 2, 2017 by 19//Moach

[JtD]

I've flown at 3000rpm and 30some boost for more than 10 minutes with no damage to the engine.

[Farky]

what it feels like, which is indeed most weird, is that at such a lower power output, the "blade drag" (which is what it appears to be for the pilot) is so much lower, that the plane actually flies faster therefore I wonder what on earth is going on with that propeller... this isn't the behavior one would normally expect - your experiment holds true (naturally) in any other plane, but the P40 appears to reach higher top speed for a same boost in a bizarrely non-linear way

 

 

Measure it, with the same Manifold pressure, you are always faster with higher rpm in P-40E. Is it ok in game.

 

 

either way, it is clear enough that the official limitations (not actually implying physical tolerance) for this individual engine are largely underrated in the sim:

 

 

 

Really? I don't see any largely underrated engine limits you are claiming.

 

I was about an hour ago flying at Military rating (43.5 inHg @ 3000 RPM ), 3 test runs, altitude 1000 ft, map Stalingrad autumn (standard atmosphere map) -

1. run - engine damaged at 6 min 35 sec

2. run - engine damaged at 8 min 51 sec

3. run - engine damaged at 10 min 19 sec

 

Pretty good, absolutely in accordance with limits on picture.

 

Take off (46.2inHg @ 2800 RPM ) - i did just few runs up to 5 minutes +, no engine damage. It's important to understand what Take off limit means and how it works. From pilots POV - during take off run, you set rpm to 2800 and throttle to 46.2 inHg. After Take off, you start climb and you are not moving throttle to maintain 46.2 inHg, you are leaving throttle lever in same position. Therefore, as you climb, your manifold pressure is lower and lower. That is corect procedure how to use the Take off rating.

 

So, Take off rating is also in accordance with real life limits.

 

As for Normal rated power - you can fly at 39.5 inHg @ 2600 rpm for unlimited time in game, which is slightly higher power than real life limit.

 

 

at 3000 rpm, the engine enters "emergency mode" - regardless of boost setting - and lasts for about one minute (as opposed to the official 5) -- after this is elapsed, the engine spontaneously disassembles with no prior hint or gradual onset of damage from partial excesses...

 

 

No, at 3000 rpm engine enters "combat mode", regardless of Manifold pressure. If your engine in game lasts at 3000 rpm for about one minute, your Manifold pressure is too high, out of the limit for "combat mode" ("emergency mode" triggers at roughly 43.7 inHg). I am flying on "combat mode" at 43.5 inHg @ 3000 rpm for prolonged time without any issues. Lower MAP = longer time before engine is damaged, even at 3000 rpm. I can fly for more than 10 minutes at 37 inHg @ 3000 rpm with triggered "combat mode", just like JtD.

 

 

but really -- what is the deal with that propeller? why are the forces from it so much stronger than on most other planes? (why is the MiG similar in that sense?) and why does it (seem to) have such a weird relation between airspeed and rpm? - has anyone asked the devs about it?

 

 

I disagree with you, forces from propeller are not much stronger than on most other planes. For example, take off in P-40E is very easy, much easier than in lot of planes in game. Sometimes it looks like forces in P-40E are much stronger, sometimes not. In my opinion, this is more of a subjective feeling than measured fact. Weird relation between airspeed and rpm, see above.

[19//Moach]

it could well be that the engine CAN in fact take more than it says it will on the ingame specs page - which is historically quite correct... I've noticed that it is possible to fly at combat power some 90% of the time and get away with it damage-free, as long as temperatures are kept in check

 

 

this may be a case of just waiting for those "rudder upgrades" foretold by prophecy (and dev. diary too, but mostly prophecy) - it could just make this a whole new airplane, once the waggle is removed/reduced and sideslips are controllable

 

 

I have lots of hope for that... 

 

 

though I agree with you - sometimes prop forces seem very strong, sometimes very much not so.... this plane has been said (by RL pilots) to require a lot of right rudder on takeoff, though here it seems to require very little of that. so much so that it can even roll out with left rudder trim set in advance for cruise

 

and yet precession seems strong enough that rudder is needed to balance every pitch input - it is very strange... though indeed, very subjective

[Venturi]

I was about an hour ago flying at Military rating (43.5 inHg @ 3000 RPM ), 3 test runs, altitude 1000 ft, map Stalingrad autumn (standard atmosphere map) -

1. run - engine damaged at 6 min 35 sec

2. run - engine damaged at 8 min 51 sec

3. run - engine damaged at 10 min 19 sec

 

Take off (46.2inHg @ 2800 RPM ) - i did just few runs up to 5 minutes +, no engine damage. It's important to understand what Take off limit means and how it works. From pilots POV - during take off run, you set rpm to 2800 and throttle to 46.2 inHg. After Take off, you start climb and you are not moving throttle to maintain 46.2 inHg, you are leaving throttle lever in same position. Therefore, as you climb, your manifold pressure is lower and lower. That is corect procedure how to use the Take off rating.

 

So, Take off rating is also in accordance with real life limits.

 

 

Not quite correct. You should leave the throttle in the same position after takeoff until manifold pressure drops to 42"Hg by altitude increase, then you advance throttle as you climb to maintain 42"/3000rpm until FTH is reached. I'm guessing that at 1,500fpm average climb rate, this would take about 8-10min to get to 12,000' altitude assuming no dawdling.

 

No engine damage should be sustained...

Edited April 2, 2017 by Venturi

[Dakpilot]

Not quite correct. You should leave the throttle in the same position after takeoff until manifold pressure drops to 42"Hg by altitude increase, then you advance throttle as you climb to maintain 42"/3000rpm until FTH is reached. I'm guessing that at 1,500fpm average climb rate, this would take about 8-10min to get to 12,000' altitude assuming no dawdling.

 

No engine damage should be sustained...

 

The manual does not advocate climbing at "Military power" for 8-12 mins, 3000 rpm is not recommended for more than 5 mins and "take off power" is  at 2800 rpm anyway, also 5 min limited

 

Cheers Dakpilot

[Farky]

 

 

Not quite correct. You should leave the throttle in the same position after takeoff until manifold pressure drops to 42"Hg by altitude increase, then you advance throttle as you climb to maintain 42"/3000rpm until FTH is reached. I'm guessing that at 1,500fpm average climb rate, this would take about 8-10min to get to 12,000' altitude assuming no dawdling. No engine damage should be sustained...

 

You are talking about different Take Off rating. I was talking about 46.2 inHg @ 2800 rpm from picture posted by 19//Moach. With this setting, you need at some point shortly after take off make decision - do I want climb on Normal rating ( 38.7 inHg @ 2600 rpm) or do I want climb on Military rating (43.9 inHg @ 3000 rpm). Either way, you need to change rpm.

 

You are using example with Take Off rating 45.5 inHg @ 3000 rpm and procedure established in early 1941 USAAF (actually still USAAC at this point) manual. RAF standard for Take Off was limiting this rating to 1000 ft, then change settings either to Max. climbing continuous power or Max. combat power. But, early 1941 procedure was for V-1710-39 also possible in RAF. Average rate of climb at 42 inHg @ 3000 rpm is at least 2000 fpm.

 

Anyway, if you use this procedure in the game, you reach FTH for 42 inHg @ 3000 rpm without any damage to the engine.

[ZachariasX]

It is still ridiculous that flying at high torque doesn't seem to get punished. From what I can see (please correct me if I'm wrong), I can shove throttle all the way forward and just go sufficiently down with rpm to undercut max. permissible power output. It's torque that wears down youe engine, not "power".

 

As long as you can cool your engine sufficienlty "power" per se is not an issue. And knocking has not much to do with "power", it just comes from excessive manifold temerature for the respective compression.

[=362nd_FS=Hiromachi]

So what's exactly highest rating that one can achieve and use for a decent time, like 10-15 minutes ? You say full throttle but reduced RPM ? To what level reduced ?

[ZachariasX]

So what's exactly highest rating that one can achieve and use for a decent time, like 10-15 minutes ? You say full throttle but reduced RPM ? To what level reduced ?

The way I'm using it now more often than not is once aiborne decrease rpm almost all the way, full throttle (lever all the way forward) then up your rpm until technochat screams "emergency", the decrease rpm so that you are barely below maximum permissible power output before the "evil" timer starts. I can yank around the throttle as much as I want but I will not damage my engine. l'm "pseudo MAP regulated now.

 

The problem with this is that the engine is at a regime where it produces maximum torque to produce maximum permissible power (as it is in game). You will NEVER do that if you owned a real Allison and had to pay for the maintenance.

 

If I upped rpm, I would decrease torque (thrittle back) while remaining at about similar MAP and at exactly the same power output.

 

In short, I can cheat while on contrary I am punished to use higher rpm at a smaller prop pitch, meaning using a higher gearing for climbing for instance. The way I'm flying the aircraft (probably not good enough) I get no penalty for the prop being operated outside its optimal pitch relative to airflow. This is not a Tu-95 that uses for cruise an almost feathered prop, cranked at an obscene torque to keep it revolving so slow while giving the thrust you need.

 

This is so far my impression. Once I have time, I will try to substanciate that with some numbers (if that should be possible).

[Venturi]

Sorry, but although you are correct in your assertions of how to use an engine, the mechanistics you are proposing for it are wrong and that matters if someone was to develop an accurate engine model.

 

We should recover the P40 engine thread and continue this discussion there rather than derail the P40 aeronautics thread. Both have problems and should be dealt with separately.

[ZachariasX]

Sorry, but although you are correct in your assertions of how to use an engine, the mechanistics you are proposing for it are wrong and that matters if someone was to develop an accurate engine model.

We should recover the P40 engine thread and continue this discussion there rather than derail the P40 aeronautics thread. Both have problems and should be dealt with separately.

I am not proposing that. I am just saying that it seems a possible way to use the engine as the game is currently.

 

Proposing that someone coded an engine system for such use I would frown upon. In fact, it shouldn't even be possible that I use engine controls that way.

 

I do agree that this is probably material for a dedicated P40 engine thread. Is there such?

[Farky]

It is still ridiculous that flying at high torque doesn't seem to get punished. From what I can see (please correct me if I'm wrong), I can shove throttle all the way forward and just go sufficiently down with rpm to undercut max. permissible power output. It's torque that wears down youe engine, not "power".

 

 

You are right, torque wears down your engine. However, even at ridiculous settings like 43.5 inHg @ 2000 rpm, your torque is aproximately same as at 56 InHg @ 3000 rpm. And as we know, V-1710-39 was able operate at 56 inHg @ 3000 rpm without any damage caused by torque. Torque is IMHO not a issue in this game. It should be, if we will fly same aircraft multiple times and all bad things we do to the engine (like use of high torque) will after x flight hours wear it down to the point it fails.

 

 

The way I'm using it now more often than not is once aiborne decrease rpm almost all the way, full throttle (lever all the way forward) then up your rpm until technochat screams "emergency", the decrease rpm so that you are barely below maximum permissible power output before the "evil" timer starts. I can yank around the throttle as much as I want but I will not damage my engine. l'm "pseudo MAP regulated now.

 

 

You will sooner or later damage your engine, since you are running on time limited "combat mode". Tested on Stalingrad Autumn, 1000 ft altitude, 43.5 inHg @ 2000 rpm (throttle lever fully forward, 100% throttle). With temperatures within limits of course. I have damaged my engine on multiple runs in less than 10 minutes.

 

To be honest, I don't get benefits of this setting. At time limited 43.5 inHg @ 2000 rpm, you have less power than on unlimited 39.5 inHg @ 2600 rpm. Is it about work load? You don't need babysitting Manifold pressure of course, but on other hand, you are constantly fiddling with rpm lever (if you want most power you can get). 

 

 

The problem with this is that the engine is at a regime where it produces maximum torque to produce maximum permissible power (as it is in game). You will NEVER do that if you owned a real Allison and had to pay for the maintenance.

 

 

You are of course right, nobody in real life was/is using this extreme engine regime, even in case that this regime was possible (it wasn't, because detonations occures, 100%).

 

 

As long as you can cool your engine sufficienlty "power" per se is not an issue. And knocking has not much to do with "power", it just comes from excessive manifold temerature for the respective compression.

 

 

I am not sure if you are reacting on something I wrote about power or not. You are right, power per se is not the issue, pressure in the cylinder and temperature(s) is.

 

 

So what's exactly highest rating that one can achieve and use for a decent time, like 10-15 minutes ? You say full throttle but reduced RPM ? To what level reduced ?

 

Time limits are to some extent random. What I mean by that - same MAP @ rpm setting can damage engine in one flight in lets say 7 minutes and in next flight in 14 minutes.

 

I don't see the point of using full throttle with minimum rpm, since you can get more power with normal (unlimited) rating.

 

It depends what do you mean by highest rating. In my opinion, there are no better settings than in game specifications. Well, almost in game specifications. I am usually using these limits -

Take off - 45.5 inHg @ 3000 rpm * just for the take off when i need a lot of power

Normal power (unlimited time) - 39.5 inHg @ 2600 rpm

Military power (5 min time limit) - 43.5 inHg @ 3000 rpm * my usual take off maximum

Emergency power (few seconds time limit) - more than 44 inHg @ 3000 rpm *only in FUBAR situations, only for few seconds.

 

There is no way around, you can use different combinations of rpm and MAP for "combat mode", there is always trade off however. Your time limit in "combat mode" can be longer with lower rpm or MAP, but maximum power and/or FTH (Full Throttle High aka critical altitude) will be lower. But for example something like 42 inHg @ 2800 rpm is sometimes a good deal.

[Venturi]

44" /3000 is "emergency power" is the problem

[Venturi]

Torque, in engine power terms, is simply the speed at which an engine under load can go from RPM a to RPM b. Since RPM b has more power than RPM a, then you have a power increase. Torque is the rate of power increase from an engine for a given load. It is a measure of an engines ability to respond to throttle changes or increased loads on a given throttle setting. For all intents and purposes, torque is not meaningful in 27L displacement supercharged V-12s, since it is so large as compared to the needs of the task.

 

Horsepower "metric PS" is the absolute term of power output from an engine and is the meaningful term, this is why it is always the one mentioned in power charts.

 

Torque starts out higher than HP at low RPMs and decreases as RPM increases. HP increases with RPM.

 

However, "torque" on engine parts such as crank rods (and thus, pressure on crank bearings, piston skirts) is a different animal than whole engine torque output (measured at the output shaft), and indeed this increases disproportionately with increased cylinder pressure (higher throttle) at too low RPMs. This causes engine parts wear.

 

The more damaging and relevant aspect of incorrect throttle settings (high power, low RPM) is that the cylinder pressure increases and because of slow piston speeds, is maintained too long, heating engine components so hot that they cause detonation/preignition, which will destroy an engine.

[Venturi]

The manual does not advocate climbing at "Military power" for 8-12 mins, 3000 rpm is not recommended for more than 5 mins and "take off power" is at 2800 rpm anyway, also 5 min limited

 

Cheers Dakpilot

The manual also says the plane stalls at 90mph.

[ZachariasX]

I guess I was not clear on the reason why I came up with this weird way of rpm setting.

 

Engine power output and potential for overboosting is one thing, but besides that I have another issue with the engine as it is modelled now.

 

On my speakers at least, the engine gives me no cue at all when the engine starts detonating or is otherwise abused to an extent to render it destroyed within minutes.

 

*It is impossible not to notice when the engine starts knocking*

 

Any other regime that results in a quick meltdown is noticeable. One of the few ways to destroy your engine "discreetly" is low power setting and rads closed. But even then it is difficult not noticing the cooking.

 

In general I doubt that pilots used those boost dials more than just listening to how the engine runs. You check for those dials to establish certain flight regimes, but once you're in business with a customer I doubt they take the eyes off the enrmy to get the MAP dial to a specific setting.

 

As in the game I have almost similar sounds whether I'm cruising nicely or fly at a regime that lets my engine melt down quickly. But I found that using low rpm as power limiter, I am free to work with the throttle in combat. This is something that in real life is a very bad way of doing things, but in the game as we have it now, it works for me.

 

Maybe I should complain "Give me better engine sounds!!1!11"

 

As of now, I have no better solution to the "Allison problem" than what the devs gave us. But let us hear us when we kill the engine. As for increased boost potential, I guess we need more documentation than what we have now...

 

Venturi,

Yes, of course. I didn't want to go in the details of running the engine at high torque, but you're IMHO spot on there.

[Dakpilot]

The manual also says the plane stalls at 90mph.

 

Now you are just being puerile, you do more harm than good, many people are hoping for some changes to P-40, you are just behaving in the same way as some who participated in FW discussions...not helping

 

Perhaps we should just throw out the manual and base things on a few anecdotes from dates after the aircraft in question was used and presented in game

 

Cheers Dakpilot 

[Farky]

44" /3000 is "emergency power" is the problem

 

 

Everytime I need use more than Military power (Combat mode), problem is always between chair and joystick. If I get myself into a situation where I need "Emergency power" for more than 20-30 seconds, I fully deserve to by shot down.

 

 

Maybe I should complain "Give me better engine sounds!!1!11"

As of now, I have no better solution to the "Allison problem" than what the devs gave us. But let us hear us when we kill the engine.

 

 

That is also one of my complaints, I agree 100%. Lack of warnings (signs) that you are hurting the engine. Not only sounds, also temperatures and pressures shown in cockpit.  

 

 

But I found that using low rpm as power limiter, I am free to work with the throttle in combat.

 

 

I understand "unrestricted throttle" benefit of this "pseudo MAP limiter", but you do sacrifice too much power with it for my taste, at least at low altitudes. There are altitudes were this is pretty advantageous, without a doubt.

[JG13_opcode]

The manual also says the plane stalls at 90mph.

Doesn't the in-game P-40 stall at 96 mph? Seems pretty accurate to me.

[unreasonable]

Doesn't the in-game P-40 stall at 96 mph? Seems pretty accurate to me.

 

At minimum operational weight yes, but at max take-off weight it is 109mph: at comparable weights the in-game number and the manual number have a difference that requires explanation. The issue is the explanation.....

 

I suspect that if you were to line up stall speeds from manuals' IAS, test IAS and TAS, and in-game you would see that the "discrepancy" from manual numbers is, if not uniform in proportion, at least present for every fighter in the game. This would help to establish that what is going on is a speed measurement issue rather than a nefarious conspiracy to nerf the Yankee capitalists' planes to demonstrate the superiority of Soviet engineering.    

 

Unfortunately I have been unable to find the numbers to make such a table, German manuals seem not to have stall speeds and I cannot read Russian. But this is most certainly true for the 109E based on the RAE tests and I expect the Spitfire will show the same thing since we have RAE tests and manual numbers for that.

 

If anyone has numbers from manuals or tests for any of the other planes in the game please post them -  they seem very thin on the ground.

[Venturi]

Everytime I need use more than Military power (Combat mode), problem is always between chair and joystick. If I get myself into a situation where I need "Emergency power" for more than 20-30 seconds, I fully deserve to by shot down.

While I agree with you on most technical things, and agree with this in principle, the reality is that the extremely limited time combined with no "seat of the pants" warning means that effectively such power levels cannot be risked in combat, at all.

The engine should run 56"/3000 for at least 5min, since that is its intrinsic capability as demonstrated by its later WEP rating. I would argue much longer, but 5min is a minimum. Evidence posted in engine thread.

 

It should run 42"/3000 for at least 15min before damage. Evidence posted above.

 

It should be able to overboost to 65" at sea level +/- depending on rpm and airspeed and should be able to deal with that for a minute or two at the very least. Engine thread.

 

It should stall at 90mph and have an aerodynamic turning efficiency on par with contemporary fighters. Evidence above.

[ACG_KaiLae]

At minimum operational weight yes, but at max take-off weight it is 109mph: at comparable weights the in-game number and the manual number have a difference that requires explanation. The issue is the explanation.....

 

I suspect that if you were to line up stall speeds from manuals' IAS, test IAS and TAS, and in-game you would see that the "discrepancy" from manual numbers is, if not uniform in proportion, at least present for every fighter in the game. This would help to establish that what is going on is a speed measurement issue rather than a nefarious conspiracy to nerf the Yankee capitalists' planes to demonstrate the superiority of Soviet engineering.  

 

Unfortunately I have been unable to find the numbers to make such a table, German manuals seem not to have stall speeds and I cannot read Russian. But this is most certainly true for the 109E based on the RAE tests and I expect the Spitfire will show the same thing since we have RAE tests and manual numbers for that.

 

If anyone has numbers from manuals or tests for any of the other planes in the game please post them -  they seem very thin on the ground.

 

Basically, the low speed posted in DD123 logically should be at minimum weight, and the max speed should be at max weight. Since these are numbers taken from their sim, they should be right. There are several issues I can see. First, 1CG have never stated what minimum weight and maximum weight are. Max weight could be max fuel, max ammo, and max bombload. Or something else, since it's not openly defined. Same of course for minimum weight, but logic defines something much more obvious here. Last issue is the stall testing I did. Since the P-40 is so mushy at low speeds, I found it damn hard to hold it in level flight during the stall tests. If you looked, in all of them at the stall point I'm in a dive. A slight one, but it's there despite my efforts. So, while I would generally state that the stall speed is somewhat close, I'm not so confident it's right at that point.

 

This is why I'd like to know from 1CG what weights define the stall speed range, so that instead of guesswork we can use hard data from the game instead.

[Venturi]

Yes, that would be helpful.

But maybe they would not like us to test for them.

Evidence based testing two edged sword

[6./ZG26_5tuka]

German manuals seem not to have stall speeds a...

They have it.

[unreasonable]

They have it.

 

Well I have only seen one, for 109 G2 which did not have it: that was in translation, and IIRC the entire months long discussion about the 190 went along with the various people with documents not posting an "offical" stall speed.

 

Anyway, if there are "official" stall speeds available from manuals that you have it would be very helpful if you would post them - it matters quite a lot whether the game TAS - manual IAS difference is peculiar to the P-40 or a general phenomenon.

Edited April 7, 2017 by unreasonable

[Farky]

While I agree with you on most technical things, and agree with this in principle, the reality is that the extremely limited time combined with no "seat of the pants" warning means that effectively such power levels cannot be risked in combat, at all.

 

 

I am using "Emergency mode" in combat regularly, without engine damage.

 

 

The engine should run 56"/3000 for at least 5min, since that is its intrinsic capability as demonstrated by its later WEP rating. I would argue much longer, but 5min is a minimum. Evidence posted in engine thread.

It should run 42"/3000 for at least 15min before damage. Evidence posted above.

It should be able to overboost to 65" at sea level +/- depending on rpm and airspeed and should be able to deal with that for a minute or two at the very least. Engine thread.

 

 

You know that I agree (mostly). However, you should also encounter detonations in some situations and engine should overheat very quickly on extremely high power ratings. I am pretty sure that use of 56 inHg @ 3000 rpm will send your temperatures in some cases out of the limits within a minute.

 

I don't like time limits in simulators at all, there are better ways how to limit use of "special" engine ratings, use of time limits is obsolete. With regard to time limits generally - engines should not be damaged in most cases even after lets say 15 minutes anyway. Time limit in manual do not mean that for example after 5 minutes on Military power your engine is damaged. This is true for all time limited engine restrictions in game of course, not just for Allison V-1710. If you keep all temperatures and pressures within limits (and no detonations occurs), you can run on this power. Give the engine a reasonable life between overhauls, that is real life reason for the time limits. Even official manuals are clear about that and pilots were allowed to ignore these time restrictions. RAF PILOT'S NOTES GENERAL (A.P.2095) - "These figures provide a general guide to the reasonable use of engine. In combat and emergency other considerations may justify the pilot in disregarding these restrictions."

[=362nd_FS=Hiromachi]

 

 

RAF PILOT'S NOTES GENERAL (A.P.2095) - "These figures provide a general guide to the reasonable use of engine. In combat and emergency other considerations may justify the pilot in disregarding these restrictions."

Yup, same I have seen in other manuals. And with other nations. Japanese documents in fact only carried data for Take-off limit. No data were given for Overboost, even though based on tests limit was around 3 minutes, pilots were not schooled on any of those. If need be pilot was given right to use any means to survive, including running engine beyond safe limits.  

[ACG_KaiLae]

Engine issues aren't the cause of the overall mushiness of the FM at under 200 mph. Let's see what next week brings us. I doubt it will change anything substantial.

[Dave]

I'd like to know if FM changes affecting the P40 are even included in 2.009.

[ACG_KaiLae]

Yes, with regards to different rudder behavior because all aircraft are being updated for roll-yaw coupling.