Engines blowing up in WEP or boosted power.?

[MrNoice]

Are you suggesting that it is your opinion that the BF109 F4 should get indefinite usage of 1.4ata?

I think there should be a 5-10sec hard engine shaking before the engine will blow... because 1 min of full power is just to low compared to the others with 1.55+ Ata so that you can throttle down to save your engine

[GridiroN]

I think there should be a 5-10sec hard engine shaking before the engine will blow... because 1 min of full power is just to low compared to the others with 1.55+ Ata so that you can throttle down to save your engine

What plane offers 1.55ata?

[SCG_OpticFlow]

That's not how engines work. Different engines are different. The Klimov was rated to maximum output, the DB60x was rated down.

 

 

 WEP is not a thing in real life unless the plane literally comes with a boost feature like the La-5F. The discussion is about what engines are rated for and how that is simulated in this sim.

 

 

Stop beating around the bush. Are you suggesting that it is your opinion that the BF109 F4 should get indefinite usage of 1.4ata?

 

The Klimov engine was up-rated twice with essentially the same components and to the protest of Klimov himself. First they removed the 5 min boost limit from the -PA and raised the pressure even more at the cost of reduced engine life to create -PF, then they did the same and raised the pressure futher to create -PF2 (in the Yak-3). Actually if you look at the specs, the M-105 (derived from Hispano-Suiza 12Y engine the soviets licensed) is very similar to DB-601 in displacement and static compression ratio and the similar boost levels are directly comparable.

 

I'd love to have all these timer-based engine self-destructs removed for all planes and the only restriction to be temperature limit, just like how it was in the previous games of the series and how it still is in WT. That timer based idea is a novelty that I don't agree with. But that's just me...

[Livai]

For the whole topic sounds like: " Limited WEP to manual-specified times" for that planes and then the other planes who can run it for as long as the engines mechanically can handle it before breaking down, swinging the sledgehammer"

 

For me all WEP methods ( Emergency Power, Boosted Power, whatever)  result in greater-than-usual stresses on the engine, and correspond to a reduced engine lifetime from XXXX hours, higher fuel consuming, higher temps than normal, is this really that difficult to simulate????

 

If I read around I read everytime use of  WEP methods ( Emergency Power, Boosted Power, whatever) were restricted to engine temperatures and use it continuously..................because it correspond to a reduced engine lifetime or breaking down the engine!

[ZachariasX]

I think there should be a 5-10sec hard engine shaking before the engine will blow... because 1 min of full power is just to low compared to the others with 1.55+ Ata so that you can throttle down to save your engine

Although it would be nice to get a more vivid feedback before the engine blows/quits, What you say is just not how an engine works.

 

In short:

For engines with automatic settings this is your rule:

The radiators determine the permissible power output of your engine within its mechanical limits.

 

For manually operated engines, various settings can result in killing an engine such that it will quit on you. Those ways are not completely modelled in BoX, making manual engines much too simple to operate, especially when they are allowed to be maxed out all the time like in the Yak.

 

In fact, in the game we have (a tad oversimplified):

- neutered "automatic" engines for the sake of you flying "as you should"

- overly difficult manual engines like tha Allison that blows up just like that when you set the throttle "as you shouldn't"

- overly easy engines such as in the Yak because what kills the engine as well is not really modelled as many players don't like to pay for that.

 

TL;DR:

The rated power outputs of engines are determined according to a desired service cycle given the mechanical construction of the engine. You use more output, the shorter the service cycle gets. It is as simple as that. German manuals reflect a regime to operate the engine such that the desired service cycles are met. Each power level wear the engine differently. The engine designers thus made a (reasonable) mix of operating regimes that are useful for flight. Like max. permissible for take off, but ONLY for that, then a bit longer outputs (not as high as take off power) for climb/combat. The stresses added up result in the permitted service cycle which they have vouched for when they got the contract. End of the story.

 

A DB 605 engine doesn't quit or detonate when you have it run at max power setting (throttle firewalled) "for too long". It just doesn't. And it doesn't quit if you do it longer than 3 minutes or so. It just doesn't. The Kommandogerät gives you no option at all to run the engine such that it desintegrates like that.

 

What it howerver will do to the engine:

1) make it produce more heat, making it hard to keep temps down for oil and water.

2) reduce service cycles from 200 hours down to even maybe 10 hours, depending on your abuse.

3) use a lot of fuel

 

This means first, pulling your 109 by the hairs around in tight circles on max power will result you in cooking your engine rather quickly. And there we have a problem: In order to simulate "real world" appplication of "firewalling the throttle" you had to simulate heat output and heat exchange with the rads very precisely. This is done right now, but not to the extent of exactly reproducing real world power output limits.

 

As in your car, the radiators determine the permissible power output of your engine within its mechanical limits.

 

Radiators are desigend with a certain power output in mind as well as an expected airflow. Then you add some margins (make it possible to open the rads more), and voilà, you have your "rated power outputs".

 

Now, why only three minutes full power? Simple, the rads are too small in flush open to ensure proper cooling. If it's cold and you're fast, you might get away with it, but slow and hot is bad enough to make said power output unwise.

As an illustration, just cover parts of the radiator in your car and see how much power you get. The engine cooler will notice insufficient cooling and you will notice less accellaration and speed. If you didn't have a "Kommandogerät" in your car (as every modern car has in an elaborated fashion), you would get the same max power, but you would cook the engine sooner.

 

Second point above, about the service cycles: It is obvious that no german pilot fighting outnumbered 1:10 would give a rats ass about that. Why would you try to preserve an engine for 200 hours, when you're dead in 5 minutes when not having the throttle firewalled? They did it too. But engine temperature did set limits. Besides, at that time, they fighting over own territory, thus bailing out is more of an option.

 

The third point, we don't care. The enemy comes to you anyway. So you can even throw away some of the range you don't have for some MW-50 that you might need.

 

With engines that are operated manually (such as the Allison in the P-40), things are a tad different, as you can well set conditions for the engine where you shorten service cycles shorter than your filght was supposedly.

 

Those engines, you can kill by:

- severe overcompression (detonation, your pistons will fail, you engine WILL quit because of that)

- moderate overcompression and/or too lean mixture and predetonation. Your engine will get progressively "weaker" as it may lose compression before it eventually will quit.

- Too much torque, usually at too low RPM. You will ecnourage predetonation with said effects plus you might kill your bearings prematurely. The hotter the engine, the sooner they go.

 

We don't have a deep and comprehensive engine management as of now in BoX. The devs took a decision to enforce conformity beyond of the feedback we get in the sim when operating the engines. It is not perfect. But it is a try to have aircraft in the sim "as they were meant to be flown". It is thus a strategy to enforce Good Piloting Practise (is there an ISO norm for that?). As said, I would be surprised if a 109 pilot between 12 Mustangs had any throttle setting other than have it firewalled.

[Fern]

On the yak-1 engine

 

" More scrupulous analysis of modified powerplant revealed number of drawbacks. Even at normal Summer temperatures 18...23°C horizontal flight with full power was possible for only 2 to 3 minutes. After this oil and water temperatures exceeded allowed maximum. Engine also overheated during climb, and it was necessary to level aircraft every 2500 to 3000m. Overheating resulted in increased oil leaks. Oil spills contaminated radiator surface and the windshield, forcing the pilot to fly with open canopy (15km/h speed penalty). "

 

Hell, right now there's no negative consequences for running an VVS engine at full power besides your engine overheating....just open rads and you're good to go....

 

Maybe simulate oil leaks on windshield once you exceed limits...should happen more often for the m-105 engine. If the 109s are changed to be more "historical", let's make these VVS closer to what they were as well...

[MrNoice]

On the yak-1 engine

 

" More scrupulous analysis of modified powerplant revealed number of drawbacks. Even at normal Summer temperatures 18...23°C horizontal flight with full power was possible for only 2 to 3 minutes. After this oil and water temperatures exceeded allowed maximum. Engine also overheated during climb, and it was necessary to level aircraft every 2500 to 3000m. Overheating resulted in increased oil leaks. Oil spills contaminated radiator surface and the windshield, forcing the pilot to fly with open canopy (15km/h speed penalty). "

 

Hell, right now there's no negative consequences for running an VVS engine at full power besides your engine overheating....just open rads and you're good to go....

 

Maybe simulate oil leaks on windshield once you exceed limits...should happen more often for the m-105 engine. If the 109s are changed to be more "historical", let's make these VVS closer to what they were as well...

 

correct... they should fix that. Mig3 is the best example of being undestructable...

I would like to have no time limit but temp limit... because that would be more realistic

[ZachariasX]

Hell, right now there's no negative consequences for running an VVS engine at full power besides your engine overheating....just open rads and you're good to go.... Maybe simulate oil leaks on windshield once you exceed limits...should happen more often for the m-105 engine. If the 109s are changed to be more "historical", let's make these VVS closer to what they were as well...

109 engines are not "more historical", they are "after the book". The Yak engines are absolutely likewise. It is just that they have a different "book".

 

To do this the realistically correct, you would need to simulate heat dissipation through the rads correctly at all temperatures, pressures etc. Then, based on that you should get the correct water and oil temps. There would have to be a threshold temperature for oil, where the system gets compromised. Amongst others, this is dependent on the oil quality used as well. I do not know if different oil grades were used in winter and summer. Today, this is commonplace to do. Done right, your engine would behave naturally such that following "the book" is a wise choice.

 

From what you are posting, the radiator of the Yak-1 clearly lacks the capacity to dissipate heat sufficiently. It should overheat in the game as well.

 

In another thread, JtD posted a graph (I have to find it yet) showing the course of the water temperature in the Yak in game as well as from the real aircraft. It is a marked difference there.

 

On the other hand, I would doubt that the radiator installed in the 109 has the capacity to dissipate the heat of the engine continuously running at 1.41 ata. The problem there is, the capacity of the radiator comes at a tradeoff with the space required to install it, creating a strong incentive to keep it as small as possible. Also, the rads should be opened only in flush position. Drag is increased otherwise such that you are losing too much speed over the amout of added heat in the system. Throttle firewalled and rads fully open is just a moronic configuration. If you are compelled to operate this way, you did something very wrong before.

 

For our purposes, simulating an engine system in deep details costs money. The cheap shot is what we have now and in a way it makes sense. Just arbitrary hard limits. How much would it be to get the full thing going? Another $5 per plane? $10? No idea. But everyone yelling at the devs, are you ready for compensating them granting your wish?

[Guest deleted@134347]

my gripe with WEP timers is that I have no idea when it actually resets to 0 after I've gone full boost and then returned to normal/or/combat operating procedure. I suspect it doesn't return to 0 as soon as you pull back the throttle, but when does it? There's definitely a time period between full boost sessions but there's absolutely no indication when and what they are.

 

In DCS spit you do have a 5 minute WEP timer, but it's solely dependent on 2 factors - rad temperature and Oil temperature. So you must keep an eye on both of them all the time, but doing so you can engage WEP at any time you're within the allowed temp ranges. And there's no need to constantly count seconds in your head, then lose count, trying to remember if it were 15 or 20 seconds, get distracted, throttle back, lose fight with a completely working engine...

[Blutaar]

Yep, the whole timer based system is just unrealistic. For example, how often you are supposed to use your 1min WEP in a 109? Is it 1min per flight, 1min per day or 1min per engine, who knows? And if it is more then ones usable, how anyone would know when it is rdy again? The timer based system is the worst possible solution in my opinion and cant simulate realistic engine behavior. The only thing such a system produces is unrealistic relative aircraft performances. Sure it ballances the game at some point but who really wants ballance in such a game? For what purpose is the max topspeed written down in manuals if you cant really use it to survive? 1min isnt enough to reach topseed and is to short for an escape.

 

How can it be that for example the BMW engine can do 10min at 1.65ata with fuel injection while in the same configuration it only can do 3mins at 1.42ata? What is the magic there? I mean does it not produce more engine wear while producing more manifold pressure? Shouldnt the c3 fuel injection produce more heat then the normal 1.42 ata setting contrary to the cooling effect of the MW50 later at high boost pressures?

 

How it is modeled is inconsistent and It is like some engines are extremly worn out while others are factory fresh. It kind of contradicts the "allways factory fresh aircraft" choice the devs made. I am for factory fresh engines every flight for everyone, not just for a few. Let me be clear, i dont want people flying with 100% all day long without any consequences, i just want more Notleistung availabe at a time in aircombat so it had an effect inflight and not just on paper like in the 109 for example. There are many good solutions to that and the easiest it seems is via thermal modeling even if it is not 100% detailed. But it would be better then now in any case and is a proven concept.

 

It is obvious that no german pilot fighting outnumbered 1:10 would give a rats ass about that. Why would you try to preserve an engine for 200 hours, when you're dead in 5 minutes when not having the throttle firewalled? They did it too. But engine temperature did set limits.

 

I fully agree! And how long was the average lifespan for german fighterplanes in 1943 and onwards? I would guess much less then the expected engine lifespan of 200 hours lol.

 

What plane offers 1.55ata?

 

The Merlin in the Spit mk V:   Continuous is +7 psi at 2650 rpm (around 1.47 ata, since it's 7 psi over 1 atmosphere which is 14.7 psi, in total 21,7 psi).   Combat is +9 psi at 2850 rpm (around 1.61 ata). Emergency +12 psi at 3000 rpm (1.82 ata). Emergency boosted +16 psi at 3000 rpm (2.09 ata).  

The AM-35 in the MiG-3: Continuous 1040mm Hg at 2050 rpm (1.37 ata) Emergency 1240 mmHg at 2250 (1.63 ata)    

The AM-38 in the IL-2: Continuous 1180 mmHg at 2050 rpm (1.55 ata) Emergency 1280 mmHg at 2150 rpm (1.68 ata)  

For the Allison in the P-40: Continuous 37.2 in Hg at 2600 RPM (1.24 ata) Combat  42 in Hg  at 3000 RPM  (1.4 ata) Emergency 45.5 in Hg at 3000 RPM (1.52 ata)  

Then in the future we'll have the upgraded version in the P-39, with 51 in Hg at 3000 rpm as Emergency, which is around 1.7 ata.  

The ASh-82 in the La-5: Continuous 950 mmHg at 2400 RPM  (1.25 ata) Emergency 1140 mmHg at 2400 RPM (1.5 ata) => this one is continuous in the F version.  

 

So we have a good range of pressures for the different engines, the American and British engines being the ones that operate at higher pressures, for example in the very late war we have the Merlins with around 2.7 ata (+25 psi in the Spitfire and 80 in Hg in the Mustang).

 

I didnt check if all qouted values are 100% correct but it seems right.

Edited October 24, 2017 by Ishtaru

[ZachariasX]

How can it be that for example the BMW engine can do 10min at 1.65ata with fuel injection while in the same configuration it only can do 3mins at 1.42ata? What is the magic there? I mean does it not produce more engine wear while producing more manifold pressure? Shouldnt the c3 fuel injection produce more heat then the normal 1.42 ata setting contrary to the cooling effect of the MW50 later at high boost pressures?

 

 

No. Extra C3 fuel actually cools the burn. No more fuel can burn that what is provided in stoichiometric equivalent O₂. All extra fuel cools the mixture by vaporization and "goes up in smoke" thereafter.

 

Cooler burn means the metal is cooler, means that it can bear higher load. Conversely, 1.65 ata without extra-extra fat mixture translates into a very short flight.

[Blutaar]

Ok thank you for explaining, i allways thought that only MW50 could cool down the burn.

 

But this would mean that heat is the main problem at higher boost pressures and not the boost pressure by itself or the combination of heat and high boost pressure, is that correct? Anyway, I still think that the current implementation is much more unrealistic then what we have in IL2 1946, IL2 CloD, DCS and WT.

[ZachariasX]

Ok thank you for explaining, i allways thought that only MW50 could cool down the burn.

 

But this would mean that heat is the main problem at higher boost pressures and not the boost pressure by itself or the combination of heat and high boost pressure, is that correct? Anyway, I still think that the current implementation is much more unrealistic then what we have in IL2 1946, IL2 CloD, DCS and WT.

Yes heat is the main thing you have to be able to manage in combustion engines. The better you can handle heat, the more power you can draw, regardless whether it is a piston engine or a jet engine. Edited October 24, 2017 by ZachariasX

[SCG_OpticFlow]

109 engines are not "more historical", they are "after the book". The Yak engines are absolutely likewise. It is just that they have a different "book".

 

To do this the realistically correct, you would need to simulate heat dissipation through the rads correctly at all temperatures, pressures etc. Then, based on that you should get the correct water and oil temps. There would have to be a threshold temperature for oil, where the system gets compromised. Amongst others, this is dependent on the oil quality used as well. I do not know if different oil grades were used in winter and summer. Today, this is commonplace to do. Done right, your engine would behave naturally such that following "the book" is a wise choice.

 

From what you are posting, the radiator of the Yak-1 clearly lacks the capacity to dissipate heat sufficiently. It should overheat in the game as well.

 

In another thread, JtD posted a graph (I have to find it yet) showing the course of the water temperature in the Yak in game as well as from the real aircraft. It is a marked difference there.

 

On the other hand, I would doubt that the radiator installed in the 109 has the capacity to dissipate the heat of the engine continuously running at 1.41 ata. The problem there is, the capacity of the radiator comes at a tradeoff with the space required to install it, creating a strong incentive to keep it as small as possible. Also, the rads should be opened only in flush position. Drag is increased otherwise such that you are losing too much speed over the amout of added heat in the system. Throttle firewalled and rads fully open is just a moronic configuration. If you are compelled to operate this way, you did something very wrong before.

 

For our purposes, simulating an engine system in deep details costs money. The cheap shot is what we have now and in a way it makes sense. Just arbitrary hard limits. How much would it be to get the full thing going? Another $5 per plane? $10? No idea. But everyone yelling at the devs, are you ready for compensating them granting your wish?

 

Excellent remarks. I only want to add that we have various maps to fly on, hot summer Stalingrad conditions and frosty winters; this also influences the radiators efficacy and should make a difference on how hard we run the engines.

 

Also, thermal management would come more into play -- whether I run my radiators close to maximum allowed temp. during normal flight, with no reserve should i suddenly firewall the throttle, or do I run cold enough in anticipation to be able even to close them (to reduce drag) when in need...

[ZachariasX]

Excellent remarks. I only want to add that we have various maps to fly on, hot summer Stalingrad conditions and frosty winters; this also influences the radiators efficacy and should make a difference on how hard we run the engines.

 

Also, thermal management would come more into play -- whether I run my radiators close to maximum allowed temp. during normal flight, with no reserve should i suddenly firewall the throttle, or do I run cold enough in anticipation to be able even to close them (to reduce drag) when in need...

In game, weather/season does have an impact on the thermal management of the engines. But unfortunately it has no effect on the scripted hard limits.

 

What I also fail to understand is the rationale that engines are supposedly most powerful closest to their max. permissible operaing temperatures. Is this really the case in the game?

 

You have a set range of temperature, where „the piston fits best in the engine block“, yes. But more importantly, you have a range of temperature, where oil has the right viscosity to properly lubricate the system. Too cool, you just blow your oil system due to excess pressure (the pump is RPM dependent). Too hot, you excessively start losing/burning oil. All of these effects are related to engine operation cycle lenght between service intervals (or outright destruction of the engine), but not really to the expected power output. It is just outright stupid to have an engine run by a hairbreath from overcooking.

Edited October 24, 2017 by ZachariasX

[SCG_OpticFlow]

In game, weather/season does have an impact on the thermal management of the engines. But unfortunately it has no effect on the scripted hard limits.

 

What I also fail to understand is the rationale that engines are supposedly most powerful closest to their max. permissible operaing temperatures. Is this really the case in the game?

 

You have a set range of temperature, where „the piston fits best in the engine block“, yes. But more importantly, you have a range of temperature, where oil has the right viscosity to properly lubricate the system. Too cool, you just blow your oil system due to excess pressure (the pump is RPM dependent). Too hot, you excessively start losing/burning oil. All of these effects are related to engine operation cycle lenght between service intervals (or outright destruction of the engine), but not really to the expected power output. It is just outright stupid to have an engine run by a hairbreath from overcooking.

 

Closed radiator shutters reduce drag and increase airspeed. That's the only rationale.

[6./ZG26_Klaus_Mann]

The Service Life of an Engine is not determined by the running hours all that much. What is far more important are the Number of Engine runs, as about 80-95%of Wear are during the Warm up and Cooldown, as well as during Idle Running. 

Once an Engine is running at optimal Temperatures and running consistent Power they can live almost indefinetly. 

 

That's why Short Haul Engines in City Cars live so much shorter Lives than the same Cars used on the Long Haul on the Highways. 

[ZachariasX]

Ah... radiator drag. Makes sense then. There must be plenty 109 drivers with their rads set to manual.

 

Sure, Klaus. But in cars, average power output is maybe 20% of „rated“ power, so runtime is not much of an issue. But if you are running engines to their max most of the time, you have to be more careful.

 

It is up to the designer of the engine to specify the cycles. They surely depend on the construction of the engine. If you have an original Hirth engine on your Bücker, in theory you have about 100 hours until overhaul. In practise, you are lucky if it lasts a whole flight. With the Rotax or Lycoming in contrast... well, you know.

[Cpt_Siddy]

DB601 would have a piston ring failure if ran at 1.41 ATA, optimum rich for more than few minutes. 

 

That engine had very very tight tolerances, and if the cooling system could not keep up with the heat build up and thus, the metal expanded and, bad thing happened. And while all engines come with tolerances with room to expand in to, those same tolerances shaved off horse powers. DB601/605 was already ridiculously powerful engine to its weight. It had very large bore diameter and comparably little metal to act as a heat sink, thus if the cooling could not keep up, it overheated fast. Also, with very large bore came equally large rings - and more expansion per kelvin. And if anyone of you have ever seen piston ring failure, it is sudden and catastrophic. Piston will friction weld and the engine is kaput. However this arrangement offered 109's the performance that was matched by VVS only by the end of the war.

 

Better cooling could solve this, but ruin the aerodynamics, so the trade off was made to have optimal aerodynamics with optimal engine performance and cooling - a balance was made. Resulting package, the 109, was among the best of fighters of the war.

 

What else you need, my dear "Hartmanns"? German Space program?  

 

http://kurfurst.org/Engine/DB60x/files/Flight_16April1942_DB601N_Engine.pdf

 

Here is some reading if you want to. 

Edited October 25, 2017 by Cpt_Siddy

[VeryOldMan]

In game, weather/season does have an impact on the thermal management of the engines. But unfortunately it has no effect on the scripted hard limits.

 

What I also fail to understand is the rationale that engines are supposedly most powerful closest to their max. permissible operaing temperatures. Is this really the case in the game?

 

You have a set range of temperature, where „the piston fits best in the engine block“, yes. But more importantly, you have a range of temperature, where oil has the right viscosity to properly lubricate the system. Too cool, you just blow your oil system due to excess pressure (the pump is RPM dependent). Too hot, you excessively start losing/burning oil. All of these effects are related to engine operation cycle lenght between service intervals (or outright destruction of the engine), but not really to the expected power output. It is just outright stupid to have an engine run by a hairbreath from overcooking.

 

 

Internal combustion engines are energy exchange devices, operating trough heat exchange between the  cold source and  heated source. The higher the difference between the 2 the higher the power produced.  Only when these values go too high or too low we start o have other systems failing and the  power stops to grow.

[Cpt_Siddy]

Internal combustion engines are energy exchange devices, operating trough heat exchange between the  cold source and  heated source. The higher the difference between the 2 the higher the power produced.  Only when these values go too high or too low we start o have other systems failing and the  power stops to grow.

 

I like how you trow a physics 101 book around here, but the limits of internal combustion engine comes from limitation in combustion characteristics, flame boundary interaction, radical intermediate species, engine material limitations in certain temperature ranges and so on and so on. It is obvious that Carnot heat cycle determines the possible theoretical maximum of this arrangement, but trust me, material limitations will throw a wrench in to that before you even begins to approach the theoretical maximum. This is the reason why jet engines create cool air film to protect parts, direct contact with the chemical reactions, under that pressure, would damage any material know to mankind. Electrons are just not good enough to hold stuff together when we seek them horsepower's :D 

[SCG_OpticFlow]

DB601 would have a piston ring failure if ran at 1.41 ATA, optimum rich for more than few minutes. 

 

That engine had very very tight tolerances, and if the cooling system could not keep up with the heat build up and thus, the metal expanded and, bad thing happened. And while all engines come with tolerances with room to expand in to, those same tolerances shaved off horse powers. DB601/605 was already ridiculously powerful engine to its weight. It had very large bore diameter and comparably little metal to act as a heat sink, thus if the cooling could not keep up, it overheated fast. Also, with very large bore came equally large rings - and more expansion per kelvin. And if anyone of you have ever seen piston ring failure, it is sudden and catastrophic. Piston will friction weld and the engine is kaput. However this arrangement offered 109's the performance that was matched by VVS only by the end of the war.

 

Better cooling could solve this, but ruin the aerodynamics, so the trade off was made to have optimal aerodynamics with optimal engine performance and cooling - a balance was made. Resulting package, the 109, was among the best of fighters of the war.

 

What else you need, my dear "Hartmanns"? German Space program?  

 

http://kurfurst.org/Engine/DB60x/files/Flight_16April1942_DB601N_Engine.pdf

 

Here is some reading if you want to. 

 

The M-105-PF has a very similar weight, power, displacement, speed and compression ratio compared to the DB-601-E but runs for unlimited time on 1.4 ata, why don't you apply your piston welding arguments there? The DB-601-N is not even included in the game, and how this British magazine photocopy is relevant to the discussion? Calling us, Bf-109 pilots "Hartmanns" only confirms your bias.

[SCG_OpticFlow]

The Service Life of an Engine is not determined by the running hours all that much. What is far more important are the Number of Engine runs, as about 80-95%of Wear are during the Warm up and Cooldown, as well as during Idle Running. 

Once an Engine is running at optimal Temperatures and running consistent Power they can live almost indefinetly. 

 

That's why Short Haul Engines in City Cars live so much shorter Lives than the same Cars used on the Long Haul on the Highways. 

 

That is true. That's why taxi drivers here don't turn off their engines while waiting and get 750 000 km city mileage out of cheap Kia 1.4 Otto engines running CNG before engine rebuild.

[ZachariasX]

That is true. That's why taxi drivers here don't turn off their engines while waiting and get 750 000 km city mileage out of cheap Kia 1.4 Otto engines running CNG before engine rebuild.

 

It is only true because in "old" car engines, the oil pump stops when the cranksaft stops. Then the hot oil trickles down and upon next engine start, you have a suboptimally lubricated system. That is how start/stop cause wear on the mechanics. As soon as you have the oil pump connected to an electric motor and continue lubrication when the engine is "stopped", you can start/stop cycle until the cows come home with no damage to the engine to speak of. This decoupled oil pump (plus hooking up most else that was formerly connected to the crankshaft to electric motors instead) is the main feature that enables the "start/stop" feature of modern cars to cheat on the emission cycles.

[Cpt_Siddy]

The M-105-PF has a very similar weight, power, displacement, speed and compression ratio compared to the DB-601-E but runs for unlimited time on 1.4 ata, why don't you apply your piston welding arguments there? The DB-601-N is not even included in the game, and how this British magazine photocopy is relevant to the discussion? Calling us, Bf-109 pilots "Hartmanns" only confirms your bias.

 

By similar you mean roughly 15% less? With 1.2 ATA rated continuous operating? While Yak's struggle to get 15m/s climb at sea level, 109's climb to low earth orbit on "normal" power in no time. Please, stop me.

 

You don't really get it, the 15% is a HUGE difference in power plant of similar dimensions. Hartmann's gona Hartmann. 

 

PS: that photocopy of old magazine has cross sections of cylinder and its cooling and fuel injection, supercharger operation automation and all other relevant things. It also states the fact that DB601 had a HUGE cylinder diameters and long power stroke. Any engineering undergrad knows what that means.  

 

PPS: how about we start modeling in the sub par fuel Germans had at the end of the war? 

 

PPPS: or the fact that German pilots were not rotated and were tired nervous wrecks, some hand shaking when you aim? Hows that for realism? Your pilots breakes down and cries like a girl on runway after some PTSD calculations? 

Edited October 25, 2017 by Cpt_Siddy

[6./ZG26_Klaus_Mann]

It is only true because in "old" car engines, the oil pump stops when the cranksaft stops. Then the hot oil trickles down and upon next engine start, you have a suboptimally lubricated system. That is how start/stop cause wear on the mechanics. As soon as you have the oil pump connected to an electric motor and continue lubrication when the engine is "stopped", you can start/stop cycle until the cows come home with no damage to the engine to speak of. This decoupled oil pump (plus hooking up most else that was formerly connected to the crankshaft to electric motors instead) is the main feature that enables the "start/stop" feature of modern cars to cheat on the emission cycles.

The "Oil Dripping Down" really only applies to Turbo Engines, since the Turbo tends to be in the worst position when it comes to Lubrication and the Problem solves itself after 30 Seconds of Idle.

Oil Temperature is a far more important Factor and the Reason why a Block Heater can prolong your Engine Life tremendously. There are only so many Heat Cycles any Oil can take before it starts to break up. 

 

And one of the best Engines that were shown to me after 800.000km was an Old Audi 80 1.9 TDI, that lived it's life between Germany and Czecheslovakia, at High Speed, had an Oilchange every 6 Months and treated with some care. 

It had never been opened, only the timing belt had been changed, and the Cylinder Hone Marks were still visible. And it's life cycle basically consisted of Warm-Up 15min ---> Full Power for Hours on End ---> 15min Cooldown. 

 

And the Guys at the Test Stand had Petrol Engine that achieved similar Results. Engines do not mind High Power AT ALL, what kills them is lack of Maintenance and Care, as well as Driving Style. 

[VesseL]

 

 

PPPS: or the fact that German pilots were not rotated and were tired nervous wrecks, some hand shaking when you aim? Hows that for realism? Your pilots breakes down and cries like a girl on runway after some PTSD calculations? 

 

What is this? And how does that affect the boost...

Edited October 25, 2017 by VesseL

[GridiroN]

This thread seems to me to be an exercise in ignoring the impossibility of simulating wear and tear in a sim where a match only lasts two hous.

Edited October 25, 2017 by GridiroN

[ZachariasX]

The "Oil Dripping Down" really only applies to Turbo Engines, since the Turbo tends to be in the worst position when it comes to Lubrication and the Problem solves itself after 30 Seconds of Idle.

Oil Temperature is a far more important Factor and the Reason why a Block Heater can prolong your Engine Life tremendously. There are only so many Heat Cycles any Oil can take before it starts to break up. 

 

And one of the best Engines that were shown to me after 800.000km was an Old Audi 80 1.9 TDI, that lived it's life between Germany and Czecheslovakia, at High Speed, had an Oilchange every 6 Months and treated with some care. 

It had never been opened, only the timing belt had been changed, and the Cylinder Hone Marks were still visible. And it's life cycle basically consisted of Warm-Up 15min ---> Full Power for Hours on End ---> 15min Cooldown. 

 

And the Guys at the Test Stand had Petrol Engine that achieved similar Results. Engines do not mind High Power AT ALL, what kills them is lack of Maintenance and Care, as well as Driving Style.

 

The turbo on your Audi will blow anyway.

 

Ever since the old VW Beetle, there is one thing car engines stopped being able to do. This is „running at full power“. Neither the radiator, and neither the parts are dimensioned for that strain. The old Beetle had some 35 hp, but these were indeed „Vollastfest“, so you could drive 100 km/h or so on the Reichsautobahn with the pedal down. Any Audi engine of today will melt away should you try max throttle all the time.

 

And that Audi you mentioned I assume wasn‘t going „fast“. All Audis that I know of that were used mainly on the left lane on German Autobahn were dead, I mean „export to Africa dead“ after 3 to 4 years of such use. But I‘m glad you found one that worked. And didn‘t have to exchange the internal temperature sensor (for which you had to remove and take apart the engine). Or change the cam belt. In the original RS4 that was something waiting for you after 100‘000 km. Just after the warraty expired. Halleluja.

 

Formula 1 is the most extreme example. They can‘t drive 10 km with constant full power without exceeding temperatures and loads. They will litterally come apart should you do that. Normal car engines are not that extreme, but how differently they have become from aircraft engines was nicely illustrated in Porsches attempt creating an aircraft engine. It was just a sad heap of problems and they quit on it.

 

Check the power output of your cars engine on the highway. It is about 30 to 40 hp. Only when accellerating, you have more. And your specified maximum power you will basically never attain realistically. Highway driving at 100 km/h or so is also the optimal thing in terms of cooling. You still have enough power to keep all parts warm but also enough cooling that you can drive even if your water pump fails. Highway driving is a mode of operation that doesn‘t exist with aircraft. This is why your Lycoming and your Rotax indeed do have runtime cycles specified.

[Sgt_Joch]

This gets debated all the time and I don't think anyone will come up with a solution which satisfies everyone.

 

a couple of points:

 

1. it is not true you can run Russian engines at 100% all the time. The Yak-1 engine had a overheating problem and this is modeled in game. In hot weather, a Yak-1 s.69 will start to overheat in as little as 1 minute of hard maneuvering and you will quickly kill your engine if you ignore the warning.

 

2. engine limits were not just to preserve engine life. The DB605 engine in the 109-G2 had all sort of issues: pistons burning out, bearing failure causing loss of oil pressure and engine oil fires. That was the reason why it was limited to 1.3 ATA since running at full power could quickly cause catastrophic engine failure.

[sniperton]

I think the main concern here is that while some engines (Mikulins, Klimovs, Shvetsovs) do not require particular attention, others (DBs, Allisons, even Merlins) can suddenly quit on you without any warning after a hard-coded time limit of 'abuse'.

 

You have to work hard to kill a Klimov, and you also have to work hard not to kill an Allison. How realistic it is, I don't know, but I find it just human that people feel a bit uneasy about it.

[Brano]

https://forum.il2sturmovik.com/topic/14610-p40-thread/?view=findpost&p=496210

Patience is a virtue . Meanwhile just deal with the situation or go and bite a lemon