Jump to content

Modeling of Detonation and Improvment of Engine Performance/Thermodynamic model


Recommended Posts

6 hours ago, c6_lefuneste said:

Engine fire may be the only critical event to keep. I read lot of B29 teams were lost due to engine fire, untill they made B29 engine more reliable.

B-29 was never fixed and never overcame its fatal flaw, it was incapable of flying with it's own engine cowls in the open position, and worse it had heat buildup issues.

Link to post
Share on other sites
7 minutes ago, =621=Samikatz said:

Engine timers are obviously unrealistic, but what do you replace them with that both:

 

- Encourages realistic flying

- Is based on objective, recorded data about the engine, not done by "feel"

 

Would it be based on the expected service lifetime of the engine, maybe? I don't know. I imagine the reason manual advice is used is because it's a concrete number that can be lifted without accusation of bias

 

1st: What is realistic flying? If your Plane is expected to last a low single digit number of flights, like the Fighters intercepting B-17s or the Japanese who had 75% Loss Rates per sortie against American Ships using Radar Guided AA, or Soviet Il-2s in the Great Battles in the East, realistic means something completely different to American Escorts flying up to 50 Sorties with little Challenge or the Guards Unit flying in a quiet Sector.

 

2nd: The current model is "by feel" made to utterly disintegrate your Engine if you go exactly 30 Seconds over.

I see no problem in revising that "feel" to be more proportionate to the actual times, as currently a 30 Minute Setting will kill the Engine at exactly 30:30, which is just plain silly. And the System I propose in my OP, is open to random failures but generally revolves around degrading the Engine, still using Manual Values.

  • Like 1
Link to post
Share on other sites
23 minutes ago, =621=Samikatz said:

Engine timers are obviously unrealistic, but what do you replace them with that both:

 

- Encourages realistic flying

- Is based on objective, recorded data about the engine, not done by "feel"

 

Would it be based on the expected service lifetime of the engine, maybe? I don't know. I imagine the reason manual advice is used is because it's a concrete number that can be lifted without accusation of bias

 

First they should do easy thing by fixing broken techchat messages about when time run out and when it gets recharged. If server has Tech on that should be visable like any other less important message is now visable on tech chat on. Then your informed when game wonts to restrict you and its not random or guess work.

 

Quality of engines, fuel and parts they are build from should make impact, as what we have now is side that was desperate late in war and was lose on restrictions have better performing engines in game because they have long timers, so they already look unrealistic and bias to one side.

Link to post
Share on other sites

An Air Ministry memorandum from the Air Tactics Section in Aug 1942 explicitly states that there is no risk of engine failure if the merlin 45 uses +16 boost for combat only. It even goes further to state that if flying in the vicinity of the enemy to fly max everything and in good time.

 

That doesn't give me the impression that going over 5 mins of WEP in a spitfire V should cause the engine to fail.

 

I admit that some engine power limitations are due to risk to failure and thermal reasons.  But certainly in the case of the spitfire V at +16 boost and in my opinion probably other spitfire marks and other aircraft it is predominantly for maintenance reasons above all else.

Edited by thrila
  • Upvote 5
Link to post
Share on other sites
On 3/7/2021 at 6:12 PM, LukeFF said:

 

I don't find that to be my experience in flying Yaks*. You have to keep the water radiator open to keep the coolant temperature down and full power low-speed climbs will quickly overheat the engine. 

 

*Mainly the Yak-1 and Yak-7B.

Sure, if you climb this baby at 130kph with full gas then ofcourse you gonna overheat. If not then the plane wouldn`t overheat at all.  I tend to keep her a bit faster at lower RPMs so I can use less rads too.

On 3/7/2021 at 8:20 PM, CountZero said:

 

Quality of engines, fuel and parts they are build from should make impact, as what we have now is side that was desperate late in war and was lose on restrictions have better performing engines in game because they have long timers, so they already look unrealistic and bias to one side.

I agree if we`re talking about the Emergency usage. Probably it was never like that IRL. When you take this and the USAF planes problem, the cooling mechanics matter twice as much.

On 3/7/2021 at 7:53 PM, =621=Samikatz said:

Engine timers are obviously unrealistic, but what do you replace them with that both:

 

- Encourages realistic flying

- Is based on objective, recorded data about the engine, not done by "feel"

 

Would it be based on the expected service lifetime of the engine, maybe? I don't know. I imagine the reason manual advice is used is because it's a concrete number that can be lifted without accusation of bias

There also seems to be a disonance between what was historically and not. I don`t think I ever saw a consensus on what exactly was made procedurally to pilots of each airforce and what was tested and learned allowed in field.

Link to post
Share on other sites
On 3/7/2021 at 1:42 AM, 6./ZG26_Klaus_Mann said:

Well, as an avid P-40 and P-47 flyer, the 5 Minute Limitation is especially annoying given the extremely long recovery time.

 

Are the recovery times documented publicly somewhere?

Link to post
Share on other sites
On 1/29/2021 at 11:25 AM, 6./ZG26_Klaus_Mann said:

I think this is a good compromise to effectively Limit Power Spam but also free up Pilots to use Power even past Limits in Emergencies without instant Engine Death and rewards flying lower settings for shorter Cooldowns.

I´m agree, It would be a little more realistic than a strict timer. The engine damage model in game at present day is a joke
 

On 2/24/2021 at 8:07 PM, [DBS]Browning said:

That's not true.

Even car engines that don't have an engine control system can be destroyed in a short time frame if you rev them well over their red-line, even if the temps are still normal.

Unlike car engines, most wartime plane engines can be destroyed by over pressure, supercharger issues and various other methods.

You forgot one important thing. there is not two piston engines who dead instantly at same time, even causing the same failure in both simultaneously, unless you cut the wires of the ignition system or magnetos a same time,. ....and in that case, the engine with more carbon deposits in the cylinder head would be stopped a few seconds later.
There are many cars torture videos in YT where you can see what i'm referring.
By the way, the WWII aircraft in-line V12 engines, or a radial 18 cylinders, were a lot of more resilient than a today car 4 cylinders. Even using it in WEP, an aircraft WWII engine would not dead without tell you a symptom about something bad is happening, such as; noise, hard vibration, misfiring, over temp, etc. ...unlike we have in game today where we have this symptoms when the engine is dead without remedy..

Edited by III/JG52_Otto_-I-
Link to post
Share on other sites
On 2/24/2021 at 2:07 PM, [DBS]Browning said:

 

That's not true.

Even car engines that don't have an engine control system can be destroyed in a short time frame if you rev them well over their red-line, even if the temps are still normal.

Unlike car engines, most wartime plane engines can be destroyed by over pressure, supercharger issues and various other methods.

It is true. Your are assuming erroneously that the war emergency settings on ww2 aircraft are analogous to over-revving a a car engine. The description that the person gave you was accurate. They are only time limited for TBO purposes, or because there is a limit on how much water is available. The list of failure modes you posted have nothing to do with war emergency settings because things like detonation do not occur at war emergency settings unless the wrong fuel is used or there is a lack of water etc.

I personally feel that the limiters should be removed entirely, with some kind of special system for planes like the P-40 that lacked MAP regulators that limited the max MAP to a setting that was within the failure limits of the engine. BUT I do agree that the original posters suggestion would be a huge improvement, and that if it were implemented in the game would go a long way towards fixing this extremely annoying "feature."

 

Capture_2019-11-22-14-20-35.png

 

image.png

 

unknown.png

unknown.png

 

image.png

 

image.png

 

 

 

 

 

 

image.png

image.png.e3eb6b4c39a0fcb07fd2ccefe4422422.png

 

image.png

 

image.png

 

image.png

 

image.png

image.png

image.png

image.png

  • Thanks 9
Link to post
Share on other sites

Additionally to the people who prefer timers, the most common conceit I see voiced after admitting that the current system is not realistic is that they still prefer this system because it stops people from climbing and cruising at max power. There are several reasons why this argument is not great:

 

1) the OP didnt suggest removing the timers, they suggested a much more lenient system where you get more WEP time and the consequences of exceeding it are less devastating and sudden. It also allowed for unlimited time for settings whose time is 15min or more right now.  So really, its neither here nore there to talk about removing the timers.

 

2) Changing the realities of a system on a plane to try to control behavior on and aircraft is dumb because you might as well do this for a whole variety of things. This is mere special pleading on the part of engines, and I suspect it has to do with the fact that modeling engines in this fashion has simply been commonplace in ww2 flight sims for the last 25 years. People do all kinds of things that were not common practice in actual ww2, but they can do so in the game because the plane is physically capable of doing so even if it was not common practice. Much of the fun of a simulator is to see what you the player can make out of a real world system (to the extent that the game in question in accurate), so this seems like a doubly silly argument on this account.

 

3) It is clearly obvious to anyone who knows what they are doing ww2 flight sims that if you had to pick between giving every plane in the game a fairly proportional cruising speed buff, vs having timers that causes planes to have large unrealistic disadvantages when actually engaged with the enemy, that the latter is the worse option. If everyone were to choose to climb faster and cruise faster, for all intensive purposes most planes in the game would maintain the same relative performance. Furthermore, it would do almost nothing to the nature of the combat in the game except increase the speeds at which people first make contact. Timers cause much worse problems. Planes that should be able to out run other planes end up not being able to do so because they dont have enough engine time for it to be practical. OR if they do, they dont have enough time to do it more than once, so everyone either flies around trying to save it or they just go home after the first chase. This is particularly an issue for planes who depend on speed. In other cases, you have planes having to choose between being able to compete in dogfights or run/chase the enemy. As one of many examples of this, observe the P-51. It has similar top speeds and turn performance to the K4 or D9, but if you use WEP to chase/run, you wont have it to dogfight with. The P-47 is in an even more absurd situation I wont even bother elaborating because I feel it is obvious to everyone. Every plane in the game runs into issues like this depending on the matchup, the 109/190 for example if were talking eastern front maps.

 

4) There will still be practical problems to running at WEP or Military all the time. Mainly fuel. Players who use high power too often will run out of fuel very very fast, so fast in fact that they will have to make themselves heavier in order to (maybe) bring enough to offset the problem.

 

 

  • Like 2
  • Thanks 1
Link to post
Share on other sites
On 3/7/2021 at 1:53 PM, =621=Samikatz said:

Engine timers are obviously unrealistic, but what do you replace them with that both:

 

- Encourages realistic flying

 

Deviating from historical accuracy to encourage realistic pilot behavior seems like a fast track to total nonsense.

 

For starters, high-angle deflection shooting was notoriously difficult, and it's no stretch to think that simmers with thousands of hours of simulated combat are probably better at it than actual WW2 pilots were. But you don't hear people clamoring for mechanics to discourage high-angle deflection and encourage chasing the six. If you proposed giving planes partial immunity to bullets fired from high deflection angles, to encourage shooting from a target's six in accordance with 'realistic' flying, nobody would support it. Hamstringing engine performance to force players to abide by what amounted to maintenance guidelines is little different.

 

There's a basic expectation in a simulator that the game will try to simulate the mechanics of the aircraft it depicts, even though virtual pilots with thousands of hours of flight time and no fear of death will certainly not control those aircraft in a way that perfectly matches real life. You can come up with extrinsic motivation to nudge things closer to realism- maybe through score- but compromising the simulation itself is the wrong approach. 

 

So throw 'encourages realistic flying' right out the window. The mechanics should reflect the reality of the planes and engines involved. That's all. If I have to push an Allison to its limits for twenty minutes to survive a dogfight, you can give me a massive score penalty to represent the maintenance crew chief chewing me out, but I expect the engine to survive that because it could in real life.

 

And more to that point, it has been shown repeatedly that what the engine timers produce is not realistic flying. P-40s, Spitfires, and P-51s having to drop their power a few minutes into combat is not how they were flown in real life. So at the very least, any reduction in harshness of those engine timers where there is ample evidence that they do not represent reality will improve the verisimilitude of the sim.

Edited by Catgut
  • Confused 1
  • Upvote 6
Link to post
Share on other sites

IRL they did have recommend times for some engine settings, so timers are not totally inaccurate. Its more the use of emergency power that having timers causes overuse. Thing is this IRL if u are going to die you prob don't care as much about it if it saves your life if you don't. Can't simulate that...

As its a game , timers give consistency for all and thats why its done. Thre are arguments both ways , depending on perspective. (competitive gamer vs simmer)

ie you can make a good case depending on why u play online player , both right and wrong again depending on viewpoint.

Personally I prefer the approach in Tobruk, a kind of mix of the two.

If you really wanted to get really  simmy, no one in ww2  was flying like in a mplayer sim match, when u died u  were dead.

Edited by =RS=Stix_09
typo
Link to post
Share on other sites
2 hours ago, =RS=Stix_09 said:

IRL they did have recommend times for some engine settings, so timers are not totally inaccurate. Its more the use of emergency power that having timers causes overuse. Thing is this IRL if u are going to die you prob don't care as much about it if it saves your life if you don't. Can't simulate that...

As its a game , timers give consistency for all and thats why its done. Thre are arguments both ways , depending on perspective. (competitive gamer vs simmer)

ie you can make a good case depending on why u play online player , both right and wrong again depending on viewpoint.

Personally I prefer the approach in Tobruk, a kind of mix of the two.

If you really wanted to get really  simmy, no one in ww2  was flying like in a mplayer sim match, when u died u  were dead.

Did you read my post above, I posted quite a few bits of evidence that explain the actual real world reasoning behind the time limits. As the game models them, they are indeed totally unrealistic. Time limits existed to preserve a certain desired time before overhaul.

 

image.png

  • Upvote 4
Link to post
Share on other sites

It is very true. Here is another report of using emergency power beyond recommended limits.

image.png.fdf90501fd434872cc1980217963a58a.png

 

The concern for using it all the time in MP is nonsense if we are talking about simulation. Just fuel comsumption and extra ground crews man hours to look after this engines were reason enough to encourage a reasonable use in the normal situations.

If anything, server mision design could implement artificial limits that could somehow "simulate" the effect of exceding those limits in the engine long life. It could be in the form of some penalties in the score as someone has suggested or some limitations in the availability of such a plane in the side planeset ("simulating" the extra work needed by the ground crews) or any other limit.

  • Upvote 1
Link to post
Share on other sites

It seems amazing that every allied air force was not clamouring for  1700hp P-40's in 1941 even if only for 20 mins while everyone else was struggling with 1000 -1200hp max.

 

Why is there not a server with option engine damage turned off, can that be set up? Am sure a lot of people would be happy?

 

Cheers, Dakpilot

  • Upvote 1
Link to post
Share on other sites

Hi folks,

 

Some interesting details on page 224 of this article (link below) regarding Development of the Rolls-Royce Merlin Engine.

 

Standard production Merlin 66 engine, as fitted to the Spitfire Mk IX LF, overload tested @ 3,000 rpm with +18 lbs combat boost for 100 hours endurance (27 hours initially) with no adjustment or replacement and no involuntary stops and usual routine maintenance omitted entirely.  The engine was then stripped down and found to be in excellent condition.  The engine was then rebuilt without any replacement parts being fitted, then fitted to a Spitfire and given a further 100 hours endurance testing.  Development of the Rolls-Royce Merlin from 1939 to 1945 (wwiiaircraftperformance.org)

 

The lecture was by Mr A C Lovesey:

In 1930 Lovesey was awarded Aviators Certificate No. 9350 by the Royal Aero Club.[3] In the late 1930s Lovesey (who had become known as 'Lov' in company shorthand) began working with others on developing the new Rolls-Royce Merlin and just prior to the start of the Battle of Britain was placed in charge of the development programme. His contribution to the Merlin, doubling its power output and improving reliability at the same time, was a major achievement. Post-war, Lovesey adapted the Merlin for civil use and then turned to turbojet development with work on the Rolls-Royce Avon.

https://en.wikipedia.org/wiki/Cyril_Lovesey

 

http://www.wwiiaircraftperformance.org/merlin-lovesey.pdf

 

 

Happy landings,

 

Talisman

http://www.wwiiaircraftperformance.org/merlin-lovesey.pdf

Edited by ACG_Talisman
  • Upvote 3
Link to post
Share on other sites

Regarding the Hawker Tempest V engine.

 

Check out this information, please see link below, on the Tempest V engine.

http://www.hawkertempest.se/index.php/contributions/stories/130-the-greatest-engines-of-all-time-by-ljk-setright

This is an interesting extract regarding endurance testing:

Nor was that 3,750bhp service a typical combat rating that might be maintained for only 15 minutes. It was a figure that could be sustained hour after hour, day after day: Napier tested the Sabre at that rating for 175 hours non-stop. The company's usual endurance test was more varied: 10 hours at cruise rating, three hours at climb rating, one hour at take-off power, and one hour at combat maximum, with the whole 15-hour cycle being repeated non-stop over and over again.

  • Thanks 1
  • Upvote 3
Link to post
Share on other sites

This is not simple subject to the devs and from gameplay reasons i get it why they relied on pilot manuals even it's nonsense when it comes to DM and RL tests.....engines just don't die like that.

Operator and manufacturer engine limitations are given to max prolong life and increase realibility till next overhaul (prolong times between overhauls) and reduce malfunctions as much is possible.

 

Research on each engine tests would take time as well advantages and disadvantages between planes in game would be way less apparent since we're simmers who will exploit that heavily and who get new plane with each respawn so IMO best solution would be just to degrade engine performance after limits being exceeded instead of current engine dying which is total nonsense.

 

S!

  • Upvote 1
Link to post
Share on other sites

As every discussion about physics needs always more anecdotal “evidence” so here we go:

Hptm Helmut Lipfert described in his autobiography that he one day had to fly in Sachsenbergs Me 109. The plane felt wrong and vibrated a lot - until they met VVS planes. When he engaged full throttle the engine ran smoothly again. After the fight he remembered that Sachsenberg had told him he’d always fly at full throttle and concluded the machine had “grown used to this”. 

 

what I took away from that story were two things:

1st Sachsenbergs maltreatment of the engine obviously damaged it

2nd the damage was far from catastrophic 

 

unclear is wether this was a typical or an atypical occurrence and wether full throttle in this context meant combat or emergency power. 

Link to post
Share on other sites

I'd like to see more penalties based on true maltreatment of the engine that's not based on time limits in the manual, like detonation when running at too high manifold pressure and too low rpm, turbo supercharger collapse, etc.

 

Other matters like running at combat power for "too long" would IMO sort themselves out with things like locked lower fuel levels and the fact that some planes just can't fly that long at full combat power without running low on fuel - the distances on the Rhineland map already prove that and will continue to do so with Normandy. 

Edited by LukeFF
  • Upvote 2
Link to post
Share on other sites

Well untill they decided to do that how hard it is to just activate engine timer run out and engine timer recharged mesages so they show up like all other techchat messages when that option is turned on ? 

Then i can know when game wonts me to stop using system they invented, simple, as i dont belive they gona reinvent engine timer system any time sone so existing one should work correctly atleast.

 

this is realy important messages in game with system they decided to use, if your engine will be punished harsh by timers:

'First engine: emergency mode time exceeded!'
'First engine: combat mode time exceeded!'
'First engine: boosted mode time exceeded!'

'First engine: emergency mode recovered'
'First engine: combat mode recovered'
'First engine: boosted mode recovered'

 

And only thouse type of messages dont show up when tech chat is on

Edited by CountZero
  • Upvote 1
Link to post
Share on other sites
Posted (edited)

Absolutely shameless plug, but IMO the solution is simulating detonation and the factors that cause it.

 

 

The timers were mostly to prolong life, and real pilots could push their aircraft for much, much longer. We should be able to do that, but also will need to be sure to manage engine state to keep the engine in the proper regimes. The real killer of engines was detonation and/or overheating (which can also result in detonation itself). If you stray outside the bounds of what the engine can handle, oil, seals, and components start breaking down. Ignition starts occurring too early, and too rapidly (this is pre-ignition and detonation, respectively. Both can reduce power, increase temperatures, and damage the engine).

 

Where historical evidence exists, certain settings/times should be given particularly heavy weight. e.g., the P-47 could not do prolonged (low-speed) climbs in WEP at high manifold pressure, the Spitfire and Mustang's equivalent engines should be able to run the settings of the other safely (to whatever degree the different cooling systems permit). AFAIK, the P-51D and F Mk IX run near-identical engines, yet the latter has climb power for an hour, and the former only 15 at combat, even though the MAP difference between the two is quite small.

 

Mild detonation has little effect, but it will cause an increase in temperatures. If you don't jump on that, it will rapidly compound on itself and lead to more and more severe issues. (This also means risking high temperatures for a desperate high-speed escape is truly a trade-off beyond just having to open up the rads later.)

 

I do also agree with what another poster said where timer excess should be cumulative over a mission. In this case, if you push your engine a little past the limits because you wanted to climb in emergency, that results in some detonation, and while you can cool your engine back down, the seal/oil/cooling system degradation doesn't go away. This means when you get into combat, your engine will have a bit less of a margin past the limits (because you've already done some damage) before you start having severe issues and/or losing power.

 

Also, the "cruise combat"-type settings currently in-game are ridiculous. In-game, pulling back RPM on many allied fighters can provide an extension to how long you can use a cetain MP.  IRL, dropping RPM at a certain MP was a great way to grenade your engine. 

 

I'd love to see the actual degradation and/or outright failure of oil, seals, cooling systems, etc. from detonation and/or overheating, but that's probably hoping for too much. (Still, imagine how cool it would be if you're pushing your plane to the ragged edge, overheat, and have a radiator leak form from boiling coolant?)

Edited by DJBscout
  • Upvote 6
Link to post
Share on other sites

Excellent post.

 

I'm also no expert, but a one note based on what I've read:

 

> too lean a mixture causes detonation

 

It's actually more nuanced than this. From Pelican's Perch #43

 

Quote

Mixture is a major player in all this. Changing the mixture changes the speed of combustion (the speed of the flame front), as well as the temperature and pressure of combustion. For any given conditions, moving away from about 50 ROP in EITHER direction (rich or lean) will typically increase the margin from detonation. This does NOT mean that detonation can occur only at 50 ROP, only that it is most likely there. If detonation is not occurring at 50 ROP, it is pretty much impossible to get detonation with any change in mixture alone, all else remaining constant.

 

For example, if you are already at a 50 ROP mixture setting, and detonation begins, moving the mixture in EITHER direction will tend to reduce detonation. If you are 100 ROP and getting detonation, leaning towards 50 ROP will increase detonation, after which further leaning will reduce it again. On the other hand, enriching more from 100 ROP will decrease detonation.

 

 

  • Upvote 1
Link to post
Share on other sites

Can't remember which DD it was in... Or one of the year end briefings, but this (detonation based damage) was outlined as future long term plan. 

 

It is quite a big subject to tackle as all (most) engines are different and have to be modelled individually. 

 

Cheers, Dakpilot 

  • Upvote 1
Link to post
Share on other sites
On 3/15/2021 at 2:57 PM, Dakpilot said:

It seems amazing that every allied air force was not clamouring for  1700hp P-40's in 1941 even if only for 20 mins while everyone else was struggling with 1000 -1200hp max.

 

Allison's memo on engine performance indicates that some planes were being run at nearly 1800HP continuously, but the company did not feel confident that all examples of the same engine could maintain that performance indefinitely without consequence. They then recommend 1570HP as a more reasonable and sustainable limit.

 

1941 is the year of the Spitfire MkVb with its Merlin 45 capable of outputting over 1500HP, and its longevity and durability are well-known. The MiG-3 was 1941 as well, and that plane was designed to do 1330HP. The idea that everyone else was stuck with 1000-1200HP max is just wrong.

 

And on top of that, the P-40 weighs 3860kg, to the MiG's 3350kg or the Spit's 3070kg. More mass to haul means that impressive horsepower doesn't translate directly into performance.

 

So I mean, yeah, in an alternate universe where every fighter weighed as much as a P-40 and every other engine was significantly worse than they really were, a 1500-1700HP P-40 would have been a pretty big deal. But that's not how it played out, so I don't think your skepticism is appropriate.

Edited by Catgut
Link to post
Share on other sites
12 hours ago, Catgut said:

 

Allison's memo on engine performance indicates that some planes were being run at nearly 1800HP continuously, but the company did not feel confident that all examples of the same engine could maintain that performance indefinitely without consequence. They then recommend 1570HP as a more reasonable and sustainable limit.

 

1941 is the year of the Spitfire MkVb with its Merlin 45 capable of outputting over 1500HP, and its longevity and durability are well-known. The MiG-3 was 1941 as well, and that plane was designed to do 1330HP. The idea that everyone else was stuck with 1000-1200HP max is just wrong.

 

And on top of that, the P-40 weighs 3860kg, to the MiG's 3350kg or the Spit's 3070kg. More mass to haul means that impressive horsepower doesn't translate directly into performance.

 

So I mean, yeah, in an alternate universe where every fighter weighed as much as a P-40 and every other engine was significantly worse than they really were, a 1500-1700HP P-40 would have been a pretty big deal. But that's not how it played out, so I don't think your skepticism is appropriate.

 

Am-35 engine in Mig 3 was nearly 47 litres 

 

Allison V1710 was 28 litres not really a valid comparison. 

 

The Allison memo is from Dec 1942 the V1710 had undergone a lot of development by then. 

 

We are talking about V1710/P-40 as used in 41 early 42 in Russia (our game A/C) 

 

Better to compare DB 601 (33 litres) 

 

Cheers, Dakpilot 

Link to post
Share on other sites
17 hours ago, Dakpilot said:

 

Am-35 engine in Mig 3 was nearly 47 litres 

 

Allison V1710 was 28 litres not really a valid comparison. 

 

The Allison memo is from Dec 1942 the V1710 had undergone a lot of development by then. 

 

We are talking about V1710/P-40 as used in 41 early 42 in Russia (our game A/C) 

 

Better to compare DB 601 (33 litres) 

 

Cheers, Dakpilot 

Th F3R engine is listed in that report. It is a V-1710-39 which is what we have in our Russian P-40.

 

Moreover my point in posting that excerpt is that its absurd to assume that a an engine would fail past its time limit at a power setting if the engines were not failing when being run at 130% rated horsepower for 400% longer than the time limit for the rated power. The point is not request 1700bhp P-40s.

 

The P-40 and other planes without MAP regulators will have to have some kind of system applied to them where the engine can be run up to some power without risk of failure due to time. Over that power setting, the engine should begin to have issues. That power setting at which the engine starts to have problems should not be 1150bhp, but it shouldnt be 1700 either.

Edited by LColony_Red_Comet
Link to post
Share on other sites

It is well known British pilots boosted p-40 tomahawks in the desert up to 70" for up to 20 minutes without any reported catastrophic failures. Is was in an allison factory memo. They frowned upon it, but did not say it was likely the engines with the 8:8:1 supercharger would detonate.

Edited by =AW=drewm3i-VR
Link to post
Share on other sites

The Allison memo is from Dec 1942,  the - 39 had gone though many changes, different casting of blocks, better cylinder head and multiple other upgrades by then. 

 

The aircraft we have in game is modelled as P40 E-1 as delivered in late 41 as export lend lease version. 

 

I would welcome later variants.

 

When the P-40 was released aircraft were more specifically modelled without multiple Mods to cover various upgrades. 

 

I see it is "well known" on the forums but in all the discussions over the years pretty much the only evidence given is that memo. 

 

The lack of MAP regulator is historically accurate on the E-1.

Later versions would be very welcome but what we have for late Moscow campaign and use in early Stalingrad before the E-1 was withdrawn from combat is accurate. 

 

Hopefully a better more detailed look at detonation and engine limits is on the cards

 

Cheers, Dakpilot 

 

Link to post
Share on other sites
1 hour ago, Dakpilot said:

The Allison memo is from Dec 1942,  the - 39 had gone though many changes, different casting of blocks, better cylinder head and multiple other upgrades by then.

Well, but even the early ones had 52"@3000 as an Emergency Take-Off/Go-Around Setting, so I would guess that 45" was perfectly fine.

  • Upvote 1
Link to post
Share on other sites

Suggested new engine limits would use temperature as failure factor but I doubt it's correctly modeled in whole spectrum or individually per plane. For example P40 do  no overeat running for long time on the ground and there are other examples.

  • Upvote 1
Link to post
Share on other sites
4 hours ago, 1PL-Husar-1Esk said:

Suggested new engine limits would use temperature as failure factor but I doubt it's correctly modeled in whole spectrum or individually per plane. For example P40 do  no overeat running for long time on the ground and there are other examples.

 

Neither spitfire overheats as easily as in reality, especially with flaps down.

  • Upvote 1
Link to post
Share on other sites

I agree. Time limit based limitations on maximum power is an annoying feature, and really just needs to be done away with when time and development resources permit further refinement of the engine management model. Ideally I would like to see an engine model that accurately models heat generation of the engine and the cooling systems ability to get rid of excess heat, with engine damage entirely dependent on detonation or not observing prescribed temperature limits, rather than arbitrary timers.

Link to post
Share on other sites
36 minutes ago, VO101Kurfurst said:

I agree. Time limit based limitations on maximum power is an annoying feature, and really just needs to be done away with when time and development resources permit further refinement of the engine management model. Ideally I would like to see an engine model that accurately models heat generation of the engine and the cooling systems ability to get rid of excess heat, with engine damage entirely dependent on detonation or not observing prescribed temperature limits, rather than arbitrary timers.

 

Other than detonation, that's pretty much what we have with the Yaks right now. Sure, they can be run indefinitely at max power, but you have to either open the radiators or reduce the engine power to keep the engine from frying. It's the sort of engine modeling I'd like to see modeled on other planes. 

  • Thanks 1
  • Upvote 3
Link to post
Share on other sites
3 minutes ago, LukeFF said:

 

Other than detonation, that's pretty much what we have with the Yaks right now. Sure, they can be run indefinitely at max power, but you have to either open the radiators or reduce the engine power to keep the engine from frying. It's the sort of engine modeling I'd like to see modeled on other planes. 

 

Do I understand it correctly - the new Yaks have it modelled this way already, and the others (older planes) not yet, but might be reworked to be similar in the future?

Link to post
Share on other sites
7 minutes ago, VO101Kurfurst said:

 

Do I understand it correctly - the new Yaks have it modelled this way already, and the others (older planes) not yet, but might be reworked to be similar in the future?

 

I'm not sure about it being reworked in the future, but on Yaks, yes, the coolant temperature rises rapidly at full power right now. So, it then becomes a tricky balance of trying to maintain an engine setting that allows the player to engage the enemy versus not losing all your coolant, since the Yak's coolant radiator creates a huge amount of drag. 

Edited by LukeFF
  • Thanks 1
  • Upvote 1
Link to post
Share on other sites

Were not likely to see any issues from heat on most other aircraft except in extremely long (like think 30min or more) slow speed climbs at WEP or maybe from prop hanging, although I doubt from the latter that any engine damage would occur from the brief time spent in such a condition, unlike how a certain other sim chooses to model it. The Yak had a notoriously inadequate cooling system whose problems will not show up on planes like 109s and 51s, not to mention their radiators are automatic.

Link to post
Share on other sites

Some interesting information on engine detonation and cooling systems, etc, in the video below, plus lots more associated information too:

 

The Secret History of Fighter Aircraft Engine Development in WW2 - YouTube

 

Overall, a 'must see' and extremely informative video for folks interested in WW2 fighter aircraft engines.  Hope you enjoy as much as I did. 

 

May be useful for the IL-2 developers too, if they have not already seen.

 

Happy landings,

 

Talisman

Edited by ACG_Talisman
  • Thanks 1
Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...