7 1/2 Hour War Emergency Test of Pratt&Whitney R-2800 26 April 1944

[Sgt_Joch]

13 minutes ago, Legioneod said:

Honestly there is a very simple solution that will make everyone happy (for the most part). Just make engine limits a server option that way players who don't want limits can fly without them and players who do want them can fly on a different server.

 

This is the best option imo until the devs come up with a realistic engine model.

 

 

With the current model, aircraft that should be strong are weak due to engine limits even though historically they were more than capable aircraft.

 

that does seem the simplest solution.

 

give the players more options, trying to impose a solution on everyone will not work.

Edited December 3, 2018 by Sgt_Joch

[Ehret]

At least make the "emergency" timer to not eat into the "combat" time. The opposition can switch readily to combat mode, actually it's beneficial to them because it regenerates the "emergency". As it's now you have to "one pass, haul ass" literally if you want to see your AF, again.

 

So to reiterate, the Axis has:

- twice as long combat mode (30m vs 15m) which is at least as strong

- twice as emergency power (10m vs 5m) which is stronger under <7km and only if you are very careful with settings in the P-47

- emergency doesn't eat into combat time (like in P-47, P-39, P-40)

- combat mode regenerates emergency...*

- because of simplified (that's historic, thought) controls of Axis planes and very generous timers the Axis enjoy numerical superiority (not historic in BOBP time-frame) in MP - 2:1 is not uncommon

 

It couldn't get more awful than this. Wait... it can with the Dora and the 262.

 

If this will not change we will see serious backlash once the Tempest and the P-51will be available. Both have "5m" time stated in manuals for the emergency power...

 

* edit: combat seems to regenerate emergency in the P-39 (P-40/P-47 to be tested) but it's enough only for the 0.25-0.5 of the original duration once. After that the nominal is only level left.

Edited December 4, 2018 by Ehret

[Panthera]

23 minutes ago, Ehret said:

At least make the "emergency" timer to not eat into the "combat" time. The opposition can switch readily to combat mode, actually it's beneficial to them because it regenerates the "emergency". As it's now you have to "one pass, haul ass" literally if you want to see your AF, again.

 

So to reiterate, the Axis has:

- twice as long combat mode (30m vs 15m) which is at least as strong

- twice as emergency power (10m vs 5m) which is stronger under <7km and only if you are very careful with settings in the P-47

- emergency doesn't eat into combat time (like in P-47, P-39, P-40)

- combat mode regenerates emergency...

- because of simplified (that's historic, thought) controls of Axis planes and very generous timers the Axis enjoy numerical superiority (not historic in BOBP time-frame) in MP - 2:1 is not uncommon

 

It couldn't get more awful than this. Wait... it can with the Dora and the 262.

 

If this will not change we will see serious backlash once the Tempest and the P-51will be available. Both have "5m" time stated in manuals for the emergency power...

 

It isn't all flowers & butterflies for the Axis though as they are still suffering from the 1 & 3 min WEP limits where'as the Allied aircraft mostly have 5-10 min.

 

In other words I think we should refrain from the "us vs them" attitude and instead just focus on getting each aircraft modelled correctly.

Edited December 3, 2018 by Panthera

[GP*]

31 minutes ago, Panthera said:

 

It isn't all flowers & butterflies for the Axis though as they are still suffering from the 1 & 3 min WEP limits where'as the Allied aircraft mostly have 5-10 min.

 

In other words I think we should refrain from the "us vs them" attitude and instead just focus on getting each aircraft modelled correctly.

 

Very true, it’s not until MW50 territory that the WEP timers get generous for Axis aircraft. 

 

All the more reason everyone should be on board for this. 

[=RvE=Windmills]

47 minutes ago, Panthera said:

It isn't all flowers & butterflies for the Axis though as they are still suffering from the 1 & 3 min WEP limits where'as the Allied aircraft mostly have 5-10 min.

 

Which axis plane in Bodenplatte has a 1-3 min emergency timer?

[Panthera]

2 minutes ago, =RvE=Windmills said:

 

Which axis plane in Bodenplatte has a 1-3 min emergency timer?

 

I wasn't just talking Bodenplatte. 

[=RvE=Windmills]

The guy you are replying to is.

 

 

[Ehret]

1 hour ago, Panthera said:

It isn't all flowers & butterflies for the Axis though as they are still suffering from the 1 & 3 min WEP limits where'as the Allied aircraft mostly have 5-10 min.

 

1st we are talking about BOBP (mostly) where all Axis planes have 10m of emergency including the A8 which can use boost. 2nd even in earlier battles 109/190 combat power is quite strong and it lasts 30m. In the P-39 combat mode lasts only 15m and if you use emergency then you say goodbye to the half of that 15m. So, in very bad case the Aircobra pilot can have 2m of (full WEP) then just 7m of mediocre combat power, then 900hp (at the deck) nominal.

 

It's only survivable because on most MP maps targets and AFs are closely spaced. I usually climb a bit higher then patrol in a shallow dive to save timers as much as I can. If after (at latest) 3rd merge situation is still neutral it means its time to run away and straight to a friendly AF. Otherwise, the plane with shorter (P-39) timer will lose engine and you just gave a victory to the enemy. All because of an artificial mechanism.

Edited December 3, 2018 by Ehret

[Ehret]

Lets do some comparison, too, to see how "thorny" the stuff is for... 109-G2 pilot at combat power.

Kuban autumn map, deck, 50%, no mods except no 0.30"s for the P-39, the latter set to optimal ("60/45" rads).

G2 - 527km/h at the deck for 30m (and there are tricks to run faster)

P-39 - 500km/h (!) 42" @ 2900rpm (it's faster than 3000rpm) for 15m

P-39 - 521km/h 46" @ 2900rpm (still counts as combat mode) for (generously reduced) 10m...

 

That's all when the P-39 is fresh. Dare you use the emergency before... Yup; it's powerful (can +570km/h briefly) but "do quickly or die" or "try once then run and hope an AF is within 20-30km" option.

Edited December 3, 2018 by Ehret

[LColony_Kong]

15min Emergency and unlimited combat solves the problem for all intensive purposes and makes both sides happy I think. And you could make it a non-optional change, that way the online scene doesnt turn into a sea of tiny server pops with 9 gazillion play styles. Some standardization is good frankly. 

 

with 15min of WEP you have enough WEP that you are never likely to run out in combat. But 15min of WEP is too short to run around on it all the time. 

[Panthera]

1 hour ago, =RvE=Windmills said:

The guy you are replying to is.

 

 

 

In that case why did he mention the P-39 & P-40 ?

[-=PHX=-SuperEtendard]

15 minutes ago, Fumes said:

15min Emergency and unlimited combat solves the problem for all intensive purposes and makes both sides happy I think. And you could make it a non-optional change, that way the online scene doesnt turn into a sea of tiny server pops with 9 gazillion play styles. Some standardization is good frankly. 

 

with 15min of WEP you have enough WEP that you are never likely to run out in combat. But 15min of WEP is too short to run around on it all the time. 

 

I agree this could be a nice solution. All the planes with the same standard. 

[Panthera]

41 minutes ago, Ehret said:

Lets do some comparison, too, to see how "thorny" the stuff is for... 109-G2 pilot at combat power.

Kuban autumn map, deck, 50%, no mods except no 0.30"s for the P-39, the latter set to optimal ("60/45" rads).

G2 - 527km/h at the deck for 30m (and there are tricks to run faster)

P-39 - 500km/h (!) 42" @ 2900rpm (it's faster than 3000rpm) for 15m

P-39 - 521km/h 46" @ 2900rpm (still counts as combat mode) for (generously reduced) 10m...

 

That's all when the P-39 is fresh. Dare you use the emergency before... Yup; it's powerful (can +570km/h briefly) but "do quickly or die" or "try once then run and hope an AF is within 20-30km" option.

 

But that's not really what we're talking about though, is it? I thought we were talking about ahistorical engine time limits, which the axis aircraft are also suffering under a lot until the BOBP aircraft. That the 109 has superior performance than the P-39 is just how it is.

 

Sure the 109 can run for longer at combat power, but in an all or nothing fight most Allied fighters have a longer WEP limit ingame atm. So it's not a one sided affair. Both sides need their WEP timers fixed.

 

 

Edited December 3, 2018 by Panthera

[Ehret]

7 hours ago, Panthera said:

 

But that's not really what we're talking about though, is it? I thought we were talking about ahistorical engine time limits, which the axis aircraft are also suffering under a lot until the BOBP aircraft. That the 109 has superior performance than the P-39 is just how it is.

 

Only and only because of artificial timers in the game. If you compare level speeds per engine power you will see what frame is better (at least less draggy). And no - it wasn't as it was historically. Pokryshkin wouldn't survive the war, let alone had many victories, if he would fly in the BoK.

 

Thunderbolt and Airacobra (and Kittyhawk) all have the same handicapping timer pattern. This hasn't any basis in reality and I don't mean power times but interactions between combat and emergency modes. Why P-xx planes have such handicap (emergency eating into combat) and why 109s have such advantage (combat regenerating emergency*) it's just... alien.

 

Also, note that the P-47 has very (VERY) different engine with water injection, an inter-cooler and turbo-supercharger system than the P-39/P-40. Yet, the same combat/emergency timers interaction, remains.

 

* edit: combat seems to regenerate emergency in the P-39 (P-40/P-47 to be tested) but it's enough only for the 0.25-0.5 of the original duration once. After that the nominal is only level left.

Edited December 4, 2018 by Ehret

[Panthera]

1 hour ago, Ehret said:

 

Only and only because of artificial timers in the game. If you compare level speeds per engine power you will see what frame is better (at least less draggy). And no - it wasn't as it was historically. Pokryshkin wouldn't survive the war, let alone had many victories, if he would fly in the BoK.

 

That's abit of an odd way of seeing things IMO, esp. considering how most kills were scored. Also not sure where you're heading with the airframe comparison? If less drag = better airframe with no consideration for anything else then designing an aircraft would be pretty simple and some of the most succesful & iconic fighters of the war sure had some crappy airframes. That ofcourse wasn't/isn't the case. 

 

That said the P-39D's max SL speed was 529 km/h at 57" and 1355 HP as per actual flight testing, the Bf-109F4 by comparison reached that speed with 1153 hp at 1.3ata. 

Edited December 4, 2018 by Panthera

[Ehret]

1 hour ago, Panthera said:

 

That's abit of an odd way of seeing things IMO, esp. considering how most kills were scored. Also not sure where you're heading with the airframe comparison? If less drag = better airframe with no consideration for anything else then designing an aircraft would be pretty simple and some of the most succesful & iconic fighters of the war sure had some crappy airframes. That ofcourse wasn't/isn't the case. 

 

That said the P-39D's max SL speed was 529 km/h at 57" and 1355 HP as per actual flight testing, the Bf-109F4 by comparison reached that speed with 1153 hp at 1.3ata. 

 

We have L in the game so nice cherry picking. Why not P-39-N (50km/h faster than the D) and 109-G4 or G14, even?

From the sim (no mods except no 0.30"s for the P-39, 50% fuel):

39-L - 574km/h (60" @ 2900rpm, 100% mix, 66% mix is faster but may overheat, no 0.30"s, deck, 60/45 rads) 1550hp

G4 - 540km/h 1480hp

G14 - 573km/h 1800 hp

F4 - 548km/h 1350 hp

39-L 543km/h (settings as above except 51" @ 2900rpm, mix 66% gives no overheats) less than 1325 hp which is at 3000rpm but -100rpm is as fast or faster on the deck

 

Should be noted that P-39-L is much heavier (500kg or so) and air drag is proportional to velocity squared. So what when accelerating to +560km/h just on engine power is the very last resort because timer will kill it shortly. No one from any air-force would be returning from combat engagements if engines would behave that way.

Edited December 4, 2018 by Ehret

[JtD]

6 hours ago, -=PHX=-SuperEtendard said:

All the planes with the same standard.

 

Why not go a bit further and give them all the same FM altogether?

 

 

[Legioneod]

54 minutes ago, JtD said:

 

Why not go a bit further and give them all the same FM altogether?

 

 

Here's the difference with having same WEP vs same FM. With same FM all aircraft will behave the exact same.

With same WEP timers all aircraft will have the same allowed times but their top performance remains the same, it's exactly the same as removing the timers altogether. In both situations the aircraft get the same amount of WEP, just one is timed and the other is unlimited.

[Ehret]

Something felt off... rechecked the P-39 in the sim. Now tested times in QMB are:

18-19m of combat power @ 41.5" MP (made mistake reading the gauge; at the 42" it's 15m)

8-9m of combat power @ 46" MP

1m 43s of emergency power @ 60" MP

 

I counted until techno-chat showed "time exceeded".

 

To recover emergency power 10m is needed. Recovery of the combat power starts only when the emergency is recovered first. It takes 1m of nominal for 1m recovery at 41.5", or 2m of nominal if run 1m at 46". After the full use of the emergency 7-8m of 41.5" combat is left. And something funny - the last 7m of combat will recover around half of the emergency time. After that the boost is done - only nominal is left. So you can run like:

9m @ 46"

1m 40s @ 60"

3-7m @ 46"-41.5"

30s-60s @ 60"

nominal

 

I not sure but weren't those exact 15m, 10m (higher combat) and 2m for the full WEP, before? Why the discrepancy between practice and specifications?!

 

edit: made a mistake - read 41.5" as 42" - rechecked the 45" and it's 15m, indeed. However, the rest is unchanged. It's interesting that marginal change of 0.5" results in extending the timer by few minutes, thought.

Edited December 4, 2018 by Ehret

[s9723]

Instead of setting all planes with same timer, how about multiplying current timers by a coefficient? The coefficient can be varied in each server. 

 

For example :

If the coefficient = 2, all planes will get double WEP time.

 

If the coefficient = 20, planes will get 20 times the WEP time ( ~unlimited).

[-=PHX=-SuperEtendard]

26 minutes ago, Ehret said:

Something felt off... rechecked the P-39 in the sim. Now tested times in QMB are:

18-19m of combat power @ 42" MP

8-9m of combat power @ 46" MP

1m 43s of emergency power @ 60" MP

 

I counted until techno-chat showed "time exceeded".

 

To recover emergency power 10m is needed. Recovery of the combat power starts only when the emergency is recovered first. It takes 1m of nominal for 1m recovery at 42", or 2m of nominal if run 1m at 46". After the full use of the emergency 7-8m of 42" combat is left. And something funny - the last 7m of combat will recover around half of the emergency time. After that the boost is done - only nominal is left. So you can run like:

9m @ 46"

1m 40s @ 60"

3-7m @ 46"-42"

30s-60s @ 60"

nominal

 

I not sure but weren't those exact 15m, 10m (higher combat) and 2m for the full WEP, before? Why the discrepancy between practice and specifications?!

 

P-39 limits are 15 min at 42" (Combat), 5 min at 51" (Emergency) and 2 min at 60" (Emergency). 

 

 

[Solmyr]

12 hours ago, Gambit21 said:

That's not practical and will never happen.

 

Could you develop further ? Why not practical, and why couldn't it be a valuable idea ? The goal is to represent the necessary engine care to prevent a premature wear in a sim area where you get a brand new plane everytime you click on the "fly" button, without the introduction of an unrealistic wear/damage of the engine which leads to plenty of problems and breaks the air warfare experience.

 

11 hours ago, Legioneod said:

Honestly there is a very simple solution that will make everyone happy (for the most part). Just make engine limits a server option that way players who don't want limits can fly without them and players who do want them can fly on a different server.

 

This is the best option imo until the devs come up with a realistic engine model.

 

 

With the current model, aircraft that should be strong are weak due to engine limits even though historically they were more than capable aircraft.

 

It would change nothing of the problematic explained above.

 

 

Shouldn't all numbers (overpower durations), in-game tests, in the books, and theoretical in-game, be given for a specified altitude ?

I guess a 2mn emergency power on the desk isn't the same as at 15000ft ? Also, I guess it wouldn't be the same at flight level for testing as in a combat with high average AoA and slower airspeed ? Then comes the cooling aspect ofc.. Looks to be quite complicated to compare all those figures...

Edited December 4, 2018 by Solmyr

[Ehret]

1 hour ago, Solmyr said:

Could you develop further ? Why not practical, and why couldn't it be a valuable idea ? The goal is to represent the necessary engine care to prevent a premature wear in a sim area where you get a brand new plane everytime you click on the "fly" button, without the introduction of an unrealistic wear/damage of the engine which leads to plenty of problems and breaks the air warfare experience.

 

Well... "the air warfare experience" is already broken when multiplayer is concerned, already. IRL no one was counting seconds and mercury inch fractions and checking "techno-chat" to be able to fly properly. Or was sure that engine will seize at the end of the first combat encounter or at the beginning of the second, at latest. Or that after few minutes of "WEP" has to switch to a cruising setting no matter if there is a bandit on six or a friendly needing a help. Or an objective more distant than 50km is one way trip. Or the enemy can fly at sensible power levels for twice as long so from a  (historically accurate) tactical standpoint praying would be just as good as flying at such handicap.

 

I think the current combat/emergency timer system is an artifact from earlier times. For single player a mission designer can "balance" things; for multiplayer most just fly into nearest fur-balls. For the latter current system was sufficient, indeed. VVS vs LW had different strengths - you could find your niche flying both. In the BOBP we will have a rough parity for props at most altitudes in performance but not in combat endurance - this will be the differentiating factor. Lets not forget that only one side will have a jet, an early one but a jet, nevertheless. Neither will be present the historic discrepancy in numbers in a multi-player.

Edited December 4, 2018 by Ehret

[Solmyr]

3 hours ago, Ehret said:

IRL no one was counting seconds and mercury inch fractions and checking "techno-chat" to be able to fly properly. Or was sure that engine will seize at the end of the first combat encounter or at the beginning of the second, at latest. Or that after few minutes of "WEP" has to switch to a cruising setting no matter if there is a bandit on six or a friendly needing a help.

 

So don't you say the same as me ? I don't get your point I must say.

My point is to make the things as realistic as possible 1st. So if your engine should be able to, say hold 1 hour full emergency for example, then it will. But maybe that will come with a drop of 50% (for example) of its expected lifetime. So if you use it that way, you'll have to "put that aircraft in the mechanics hands" twice more often. On the contrary, if you never use more than, say 10mn emergency power, its lifetime will be 100%.

So that it reflects that carefull behaviour is needed to keep the best out of your engine for the next missions you will fly with. But you can burn it depending on the situation. Like IRL.

Of course the figures here are just for example.

Edited December 4, 2018 by Solmyr

[Ehret]

2 hours ago, Solmyr said:

So don't you say the same as me ? I don't get your point I must say.

 

My original point  - no timers but detonation and mechanical wear modeling for engines. Add some rudimentary logistics scaled to fit a single 3h match. It'd have to be accelerated so only partially realistic but still. I think the handicap of badly abused thus worn engine could be set to (close to negligible) -2% hp maximum to be an effective incentive to avoid. Yet, not high enough to make odds significantly worse thus keeping peoples flying for whole match.

 

Logistics would be a very nice thing to have for other reasons, too. We have gas tanks on airfields, right? And repair hangars and ammunition dumps. Making them worth something in a popular MP match would add more depth.

Edited December 4, 2018 by Ehret

[Ehret]

Checked the P-47, briefly. The "emergency recovered" happens after 10m of nominal. After that you have 4m (5m to seizure) of combat power and it (like in the P-39) recovers a bit of the emergency time. Just enough for 2m of emergency and then nothing is left but nominal.

 

And look how it's hilarious..:

1. first 5m of WEP, then 5m of combat mode and engine seizes if you do nothing
2. first 5m of WEP, then 5m of combat mode, then you can switch to 2m of full (!) WEP again and engine seizes, finally

If at the end of "1." the engine is in so bad state that it will seize in seconds then how its life can be extended by running (case "2.") on a different and much more demanding setting for another 2 minutes?!

[sevenless]

1 hour ago, Ehret said:

If at the end of "1." the engine is in so bad state that it will seize in seconds then how its life can be extended by running (case "2.") on a different and much more demanding setting for another 2 minutes?!

 

Yea, completely artificial and obviously false design decision which bears no resemblence to reality.

[Ehret]

Just now, sevenless said:

Yea, completely artificial and obviously false design decision which bears no resemblence to reality.

 

IMHO, It feels more like a bug or an artifact from some old code which no one dares to fix or modify for some reason...

Edited December 4, 2018 by Ehret

[sevenless]

15 minutes ago, Ehret said:

 

IMHO, It feels more like a bug or an artifact from some old code which no one dares to fix or modify for some reason...

 

Yep, that could be the case. Anyways that obviously needs to be looked at. As it is right now, the discrepency to documented functionality is way too high.

[CountZero]

1 hour ago, Ehret said:

 

IMHO, It feels more like a bug or an artifact from some old code which no one dares to fix or modify for some reason...

how that recovery work with other airplanes with emergancy boost, if you use all emergancy and then get message that its recoverd but you cant use full emergancy time again after its recovered looks like bug to me. Did devs ever explained how all this timers and recoverys and bosts work.

 

for me it looks like you can use boost only one time for 5 min or few times for 5 min in total, and after that time your risking blowing up engine, thats why when you try again after recovery message it lasted only 2 min(its probably not new recovered boost but just that buffer zone that will risk destruction of engine after 5min expired). I try it and it also lasts only few min after i used it for 5min and then waited to get recovery message, and i didnt get secound message that it expired but just engine broke.

 

 

Edited December 4, 2018 by 77.CountZero

[Panthera]

16 hours ago, Ehret said:

 

We have L in the game so nice cherry picking. Why not P-39-N (50km/h faster than the D) and 109-G4 or G14, even?

From the sim (no mods except no 0.30"s for the P-39, 50% fuel):

39-L - 574km/h (60" @ 2900rpm, 100% mix, 66% mix is faster but may overheat, no 0.30"s, deck, 60/45 rads) 1550hp

G4 - 540km/h 1480hp

G14 - 573km/h 1800 hp

F4 - 548km/h 1350 hp

39-L 543km/h (settings as above except 51" @ 2900rpm, mix 66% gives no overheats) less than 1325 hp which is at 3000rpm but -100rpm is as fast or faster on the deck

 

Should be noted that P-39-L is much heavier (500kg or so) and air drag is proportional to velocity squared. So what when accelerating to +560km/h just on engine power is the very last resort because timer will kill it shortly. No one from any air-force would be returning from combat engagements if engines would behave that way.

 

Actually it was the P-39Q, not the D (source below), and I'm not cherry picking, I'm using real life data (not game data), and here I see no speed advantage for the P-39 airframe at similar HP levels, none at all. 

 

I mean atm you're suggesting that the P-39 went from 529 to 570+ km/h at SL with just a 195 hp increase in power, nevermind any potential weight increase. 

 

Actual real life performance figures:

P-39Q @ 1355 hp/57" Hg = 529 km/h 

Bf-109F4 @ 1153 hp/1.3ata = 526 km/h

Bf-109G1/2/3/4 @ 1252 hp/1.3ata = 535 km/h

 

Sources: 

- http://kurfurst.org/Performance_tests/109F4_Datenblatts/109F4_dblatt_flown.html  

- http://www.wwiiaircraftperformance.org/P-39/P-39Q-5_42-19615_ENG-19-1631-A.pdf

- http://kurfurst.org/Performance_tests/109G_MttDblatt42may/109_May42dblatt_EN.html

Edited December 4, 2018 by Panthera

[=362nd_FS=RoflSeal]

5 minutes ago, Panthera said:

 

Actually it was the P-39Q, not the D (source below), and I'm not cherry picking, I'm using real life data (not game data), and here I see no speed advantage for the P-39 airframe at similar HP levels, none at all. 

 

I mean atm you're suggesting that the P-39 went from 529 to 570+ km/h at SL with just a 195 hp increase in power, nevermind any potential weight increase. 

 

Actual real life flight figures:

P-39Q @ 1355 hp/57" Hg = 529 km/h 

Bf-109F4 @ 1153 hp/1.3ata = 526 km/h

 

Sources: 

- http://kurfurst.org/Performance_tests/109F4_Datenblatts/109F4_dblatt_flown.html  

- http://www.wwiiaircraftperformance.org/P-39/P-39Q-5_42-19615_ENG-19-1631-A.pdf

 

That P-39Q-5 in the test is mounted with the .50 cal gunpods (paragraph B.2)

P-39N with 4 .30 cal wing guns does 555 kph at 57 "Hg.

P-39Q without gunpods and 3 blade prop does 566 kph at 57 "Hg.

P-39Q without gunpods and 4 blade prop does 573 kph at 57 "Hg.

 

 

 

 

 

 

[Panthera]

1 hour ago, RoflSeal said:

 

That P-39Q-5 in the test is mounted with the .50 cal gunpods (paragraph B.2)

P-39N with 4 .30 cal wing guns does 555 kph at 57 "Hg.

P-39Q without gunpods and 3 blade prop does 566 kph at 57 "Hg.

P-39Q without gunpods and 4 blade prop does 573 kph at 57 "Hg.

 

 

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Alright I didn't notice that, my mistake. Although the 3 bladed prop P-39Q-30 is the fastest at 356 mph and 57" hg and not the 4 bladed one.

 

Other than that what was the difference between the P-39L & P-39Q exactly?

 

Either way looks like the P-39 is maybe faster pr. hp (573 km/h at 1,550 hp is impressive), but like I said earlier looking only at straight line speed vs hp is a very odd way of determining which airframe is better, infact it's a completely wrong way of looking at things. If we were to use this as a yard stick aircraft such as the P-47, Spitfire, F4U etc. were all inferior to the P-39. The Spitfire IX for example needed 1580 hp to reach 540 km/h at SL, but I'd hardly refer to the Spitfire as having an inferior airframe compared with the P-39

 

 

 

Edited December 4, 2018 by Panthera

[=362nd_FS=RoflSeal]

1 hour ago, Panthera said:

 

Alright I didn't notice that, my mistake. Although the 3 bladed prop P-39Q-30 is the fastest at 356 mph and 57" hg and not the 4 bladed one.

 

Other than that what was the difference between the P-39L & P-39Q exactly?

 

Either way looks like the P-39 is maybe faster pr. hp (573 km/h at 1,550 hp is impressive), but like I said earlier looking only at straight line speed vs hp is a very odd way of determining which airframe is better, infact it's a completely wrong way of looking at things. If we were to use this as a yard stick aircraft such as the P-47, Spitfire, F4U etc. were all inferior to the P-39. The Spitfire IX for example needed 1580 hp to reach 540 km/h at SL, but I'd hardly refer to the Spitfire as having an inferior airframe compared with the P-39 

 

 

 

I'm not too sure if the P-39Q graphs are based of flight tests or are calculated. There is one P-39Q-5 test without the gunpods mounted, but that aircraft had engine issues and couldn't develop full emergency power. Still at 11,000ft (the only level flight point given) it is about ~11-12 mph faster.

 

Beyond the gunpods and minor difference in the fuel tank  P-39N removed some fuel tanks, P-39Q added them back in, removed them in some blocks, added them back in. The propellers could be different. According to the list of propellers for 1945 P-39N had 2 propellers available for mounting both 3 blade, one 11ft 7in the other 11ft, P-39Q had 4 propellers available. Two 4 blades of 11ft 7 inch and 11ft and the same two 3 blades as available on the P-39N. AFAIK regarding the 3 blade propellers, when the P-39N was introduced it initially had 10ft 4in propeller and this was changed on the 167th aircraft. Afterwards the 11ft 7inch propeller was standard until some time in the Q production when it was shortened to 11ft. Q-21 to 25 had 4 blade propellers

Edited December 4, 2018 by RoflSeal

[Panthera]

37 minutes ago, RoflSeal said:

I'm not too sure if the P-39Q graphs are based of flight tests or are calculated. There is one P-39Q-5 test without the gunpods mounted, but that aircraft had engine issues and couldn't develop full emergency power. Still at 11,000ft (the only level flight point given) it is about ~11-12 mph faster.

 

Beyond the gunpods and minor difference in the fuel tank  P-39N removed some fuel tanks, P-39Q added them back in, removed them in some blocks, added them back in. The propellers could be different. According to the list of propellers for 1945 P-39N had 2 propellers available for mounting both 3 blade, one 11ft 7in the other 11ft, P-39Q had 4 propellers available. Two 4 blades of 11ft 7 inch and 11ft and the same two 3 blades as available on the P-39N. AFAIK regarding the 3 blade propellers, when the P-39N was introduced it initially had 10ft 4in propeller and this was changed on the 167th aircraft. Afterwards the 11ft 7inch propeller was standard until some time in the Q production when it was shortened to 11ft. Q-21 to 25 had 4 blade propellers

 

Well I think the graphs are probably accurate enough to within 10-15 km/h or so, so somewhere between 560-570 km/h for the clean P-39L at 1550 hp should be plausible depending on airframe surface condition. By comparison the Bf-109G1 to G4 needed 1252 hp (1.3ata) to reach 535 km/h, add another 300 hp and it might reach about the same speed as the P-39 at the same HP rating. In other words they're close, but they are also both quite small aircraft and the NACA 00xx airfoil employed by the P-39 certainly helps reduce drag albeit at the cost of lift, which brings us back to design trade offs and why you can't rate an airframe via a single measure.

[LColony_Kong]

[Panthera]

2 hours ago, Fumes said:

 

Doesn't really get much clearer than that

[Solmyr]

2 hours ago, Fumes said:

 

Very interestning. I'd like to read the next page now. ? (I'm curious about that 2nd point)

Which engines is it written for ? Should we consider some potential substantial discrepancies ?

[LColony_Kong]

1 minute ago, Solmyr said:

 

Very interestning. I'd like to read the next page now. ? (I'm curious about that 2nd point)

Which engines is it written for ? Should we consider some potential substantial discrepancies ?

http://www.avialogs.com/index.php/en/aircraft/usa/northamericanaviation/p-51mustang/an-01-60je-1-flight-handbook-f-51d.html

 

Same plane

[=362nd_FS=Hiromachi]

Not surprising as it was already known how artificial are the ingame engine limits. But its nice to see the confirmation by "paper" that "paper" they are coding into the FMs is just a ... paper. Real aircraft and powerplants are not bound by such limitations. It's also of another note how prolonged use of high power ratings is not a problem for as long as pressures and temperatures are kept within limits. Cant recall how many times my engine in P-40 failed yet no indication on pressure gauge or oil temperature gauge would indicate upcoming disaster and this two seem to be very much disconnected in various FMs.