Proposal: make engine timers a difficulty setting

[Voyager]

Probably proposed a hundred time before, but worth suggesting again: make engine timers a difficulty setting that can be disabled. 

 

Don't really feel like re-fighting it, but making it severable would leave both camps happy. 

[SIA_Sp00k]

To Summon a dead desire from the Underworld a poster who seeks answers which only the dead may provide, must exhume what remains of it, a positive response if able, and bring it to the posters abode and lay it within a circle of candles, scattered thereupon with the very earth that filled its Long dead tomb.

[354thFG_Panda_]

This should be a temporary feature until the developers get along to doing the timer customization system Jason described. I think currently it can almost be simulated in game with invincibility. 

[Voyager]

5 hours ago, LR.SmallTiger said:

This should be a temporary feature until the developers get along to doing the timer customization system Jason described. I think currently it can almost be simulated in game with invincibility. 

Hadn't heard about a replacement system. Could you put a link in? I'm curious how it's planned to work. 

 

At this point, I'm not keen on any timers. I've come to the conclusion the pilot handbook engine time limits are llama requirement that only persist because they have no real-world impact, and would rather rip them out entirely and rely on an engine damage system more skin to what Flying Circus uses. However proving a negative is generally not possible, so would settle for just having a toggle. 

[US41_Winslow]

2 hours ago, Voyager said:

At this point, I'm not keen on any timers. I've come to the conclusion the pilot handbook engine time limits are llama requirement that only persist because they have no real-world impact, and would rather rip them out entirely and rely on an engine damage system more skin to what Flying Circus uses

Flying Circus’ engine damage model is the same as the rest of Il2.  The engines have timers which determine when they break and can be damaged by overrevving or overcooling.  However, I think the timers may be more lenient than for WWII engines because much less is known about them.  For example, full throttle on the 130 Clerget is similar to WEP but the manual doesn’t give a specific time limit, only saying to avoid prolonged use.

[Voyager]

38 minutes ago, Miners said:

Flying Circus’ engine damage model is the same as the rest of Il2.  The engines have timers which determine when they break and can be damaged by overrevving or overcooling.  However, I think the timers may be more lenient than for WWII engines because much less is known about them.  For example, full throttle on the 130 Clerget is similar to WEP but the manual doesn’t give a specific time limit, only saying to avoid prolonged use.

Saying that we know more about the WWII engines is a stretch, when we're relying on manuals that are contradicted by the flight ops and manufacturer training, of which none have paper trails to support them. Especially when following them to their logical conclusion leads to anti-training and completely ahistorical behavior.

 

Seriously, has anyone found actually historical documentation or evident that 62" at 2700 RPM was a recommended engine mode for the R-2800 with 130 octane? 

 

Has anyone found any documentation that the emergency climb to altitude required ten minute breaks for every five minutes of climb, or that it was anything other than 15m of continuous of 64" 3000 rpm operation? 

 

Has anyone found any documentation that Republic Aviation was lying in its pilot training videos, about engines operating way longer than spec in combat? 

 

Has anyone found the engine timesheets and verified that they are representative of actual use? 

 

It really looks like the numbers were some engineer taking a swag. And nobody ever went back to check any of them because it did not matter. And trying to make them real has created an internally inconsistent system that encourages pilots to use behaviors that actually do destroy engines.

 

But, can't prove a negative. And unless someone finds a test that literally nobody had any reason to do, there's going to be a contingent that going to be certain, that since it was in the pre-war manuals it must have been tested and proven to within an inch of its life, so separate settings are the only clean solution I can see. 

[Voyager]

And to be fair, none of that is proof, just a collection of red flags that bother me each time I approach the subject. I'm not even sure proof exists for any of it, save proof that it was a number that was written down.

 

I can neither prove that the timers came from anything real, nor prove that they did not. 

[CountZero]

Game shows that its posible as for now option that turns off timers is unbrakable, problem is that it also makes airplanes not explod when they hit ground, if they can just separate engine timers from it as one option that would be great.

[Roland_HUNter]

On 7/28/2021 at 8:23 PM, Voyager said:

Saying that we know more about the WWII engines is a stretch, when we're relying on manuals that are contradicted by the flight ops and manufacturer training, of which none have paper trails to support them. Especially when following them to their logical conclusion leads to anti-training and completely ahistorical behavior.

 

Seriously, has anyone found actually historical documentation or evident that 62" at 2700 RPM was a recommended engine mode for the R-2800 with 130 octane? 

 

Has anyone found any documentation that the emergency climb to altitude required ten minute breaks for every five minutes of climb, or that it was anything other than 15m of continuous of 64" 3000 rpm operation? 

 

Has anyone found any documentation that Republic Aviation was lying in its pilot training videos, about engines operating way longer than spec in combat? 

 

Has anyone found the engine timesheets and verified that they are representative of actual use? 

 

It really looks like the numbers were some engineer taking a swag. And nobody ever went back to check any of them because it did not matter. And trying to make them real has created an internally inconsistent system that encourages pilots to use behaviors that actually do destroy engines.

 

But, can't prove a negative. And unless someone finds a test that literally nobody had any reason to do, there's going to be a contingent that going to be certain, that since it was in the pre-war manuals it must have been tested and proven to within an inch of its life, so separate settings are the only clean solution I can see. 

 

 

[Voyager]

@Roland_HUNter Interesting.

 

You know, Rolls-Royce and Pratt & Whitney still exist.

 

Has anyone asked either if they still have any of their old design documents? Heck, RR went into receivership and was owned by the British Government for a while, wasn't it? 

[CountZero]

and its carrier pilots, so if anyone need to know if their engines can just poof after 2min is them, as they cant just land in some franch farm and drink vine if they mess up counting time they were on max power in heat of battle. 

 

For example yak/lagg dont have timers, and player still cant fly them on full ower all the time, engine will overheat and they will run out of fuel, same would happend if timers are removed from other airplanes, they cant be flown all time on full power, engines get hot and brake, or you run out of fuel in 20min or so... player just then dont have to be bathered with things real pilots didnt have to be bathered. How its now, you have airplanes with timeres equiped with worst posible engine they can have, engine that is on his last 1-5min of full power life, not maintained for ages, just waiting to brake. While airframes are brand new, and guns never jam, engines are total oposite. 

Edited July 30, 2021 by CountZero

[ZachariasX]

On 7/30/2021 at 12:04 AM, Voyager said:

Has anyone asked either if they still have any of their old design documents?

What you want has little to do with design documents. Engines on the bench are tools that in principle demonstrate the viability of an engine design and it can be used to meter the respective running properties. These are purpose built idividual tools that are of far greater quality than what comes out of the shops and is sent to the aircraft manufacturers. Also those engines on test beds are missing the „other half“ of the engine, the cooling systems, meaning that these runs are done at perfect conditions. Also you are missing out on „the flaw“ behind the controls.

 

You‘d be looking at service reports of actual sorties and what was needed to keep the engines running on those that came back.

 

Knocking is one of many problems that can limit the power of an engine. Engines in fact do often run on timers when you are taxing them, like a notiriously bad crankshaft lubrication system in the DB60X engines. High power settings in the BMW801 that burns valves. Big radials can‘t do high rpm well, hence with 3000 rpm on the DoubleWasp you‘re in essence just asking for it.

 

There is simply no way to generally describe the failure point of an engine in general plain mathematical terms unless you have exact and specific knowledege of every detail of that engine, its cooling systems, lubrication and fuel used. Fuel quality varies. Especially the aromatic turd that (by choice of production economies) comes out of coal hydrogenation, as it forms a raisin when stored and it also attacks tank linings.

 

The only downside I see in our current timers is the 5 min default for the P-47 water injection compared to 10 min on the DB. I would have said that you can do 5 min but set the timer to the same about similar as the German timer for the simple reason of gameplay, that in this case is extremely competitive. But that would be the only reason to make up such.

 

Bottom line is, if engines in this game behaved like real engines, you‘d see many more gliders in dogfights. And people flying at more conservative power settings. A big reason they wanted to put a Merlin on the P-40 was the exact problem we have and also they just couldn‘t pull 70‘‘ without having a bad day from then on. Just because some say they managed to do so in specific circumstances doesn‘t mean you shouldn‘t expect becoming a glider after going that far off your engine manual specs.

 

As for vintage engines, there is only one thing you can expect from them. Failing on you when you need them. And failing they did all the times and they still fail all the times. If you find such engines that don‘t fail all the times, then I show you an engine that is used, if at all, way short of its maximum rating. You know, a New Guinea campaign becomes way more fun if you have persistent engine wear across missions. Especially since bailing out (unless done over your airfield) means almost certain death, either as fish food (sun dried or fresh) or wasting away in the jungle as bug food.

 

So again, if you were given realistic engine behaviour in this game, you‘d be way more careful on the throttle than with the timer now.

 

Some do not like all that. And that is fair. The „unbreakable“ option should indeed have an option to single out engine damage caused by the pilot. If people want it, they should have it. It is a game. It is for entertainment. It should have been in place from the beginning.

 

 

[Pict]

On 7/29/2021 at 9:36 PM, Roland_HUNter said:

 

 

 

All up a great little documentary, thanks for sharing it  Some great bit of info and photos, especially the color ones at the end.

 

=========================

 

The info about the engine boost limits of course is more relevant to the topic and adds even more weight to the idea that the engine egg timers as they are currently implemented in game are not right.

 

The idea promoted by the Rolls Royce representative that you could forget the 2 minute limit for operating a 18 lbs of boost and in fact could run it at that till you either overheated or ran out of fuel (1 hour stated in this particular case) is much more appealing to me than having to count off some time limit that magically resets itself. The magical resetting of the engines ability to self destruct being the single largest flaw of the timer system in my view.

 

After all we have temp and fuel gauges and it would be much more natural and realistic to govern our use of boost / RPM with them uppermost in mind than a roll of the dice with a random egg timer.

 

I seldom use maximum boost for both reasons mentioned above, that is to keep the motor cool for when I need it and to conserve fuel. Having done that, I have no desire to be time limited when I do go through the gate to the firewall. At that point I want all the power I can muster for as long as I can keep it from over heating and have fuel enough to get home with.

 

Having said that, I will add that it's a rare moment when I've wrecked an engine in IL2BOX through high boost and or RPM settings for prolonged periods to the point that I just don't take a note of the times. I have on the other hand cook more than a few motors due to not keeping an eye on my temp gauge and I've run out of gas a few times too  

 

==========================

 

No doubt all engines were not set up the same way as some most certainly were heavily limited and others not so much. Some manufacturers recommendations were pretty tight when experience in the field or even their own reps told the opposite story and so on.

 

To implement a decently realist engine failure model would require masses of data and a fair weight of computing power to churn through it, so is not an expected solution in the near term I don't think.

 

The ability to turn of the engine egg timers would work just fine for many people I think, so I'd be in favor of that. When you cook your motor dead is dead and no magic engine reset would be more realistic. Same goes for running out of fuel.

 

It'd be interesting to at least run a test on a multiplayer server to see how people respond.

 

 

On 7/30/2021 at 1:08 PM, CountZero said:

While airframes are brand new, and guns never jam, engines are total oposite. 

 

This is also a factor.

 

Why have an unrealistic or even a realistic timed engine damage model when the air-fame and weapons are not affected in the same manner?

 

Sure you can fold the wings up pulling out of a dive and you can run out of ammo. But wear though time is not accounted for.

Edited July 31, 2021 by Pict

[ZachariasX]

2 hours ago, Pict said:

After all we have temp and fuel gauges and it would be much more natural and realistic to govern our use of boost / RPM with them uppermost in mind than a roll of the dice with a random egg timer.

You be surprised how much „random egg timer“ you have in these engines. Thise gauges are good for doublechecking that everything is in order while you adhere to rated settings. If the engine decides to be a goner, this can happen way before you see anything wrong on the scales. If your oil pressure drops and temps start to rise, then things have happened already. You are a passenger that better be aware of a nice flat spot below you where you can land at once.

 

It is very easy to burn your engine while everything is in the green. The idea maxing out the dials to the red line will do nothing but guarantee failure at some point later. If you get foam in your crankshaft lubrication by trying the red line, you really think you‘ll get any indication about the bearings that are wasting away? They make metal, Pjotr says after returning. That they brought into literature. Ivan, whose pistons got blown from the engine en route said something else, that I‘m sure.

[Pict]

1 hour ago, ZachariasX said:

If the engine decides to be a goner, this can happen way before you see anything wrong on the scales

 

For sure, in a similar way to running out of gas long before the gauge reads empty.

 

What I was getting at is that you can look after your engine by keeping it cool, not waiting for it to overheat then taking some action, in a similar way to planning ahead with a little reserve fuel for getting home.

 

===================

 

The historical references I've put up elsewhere about the Mustang I and it's use by the RAF and this guy from Rolls Royce above are people on the scene at the time with a decent access to data about the use of higher than book recommended engine regimes. Their evidence must count for something.

 

And they are not alone.

 

Denis Braithwaite was a top Mosquito pilot for the RAF and commanded a pathfinder outfit. His squadron flew on higher than regulation RPM and removed the air intake ice guards to get more speed from their Mosquitoes. Can't remember the number off the top, but it was worth something like 40-50 MPH, so not insignificant.

 

Eventually he was taken to task by the station commander and disciplined for his actions. However at no point was there any question about the longevity of the engines. The whole thrust of the argument both ways was about fuel consumption.

 

If I get a moment I'll scan and up the relevant pages of his book, Target for Tonight. It's worth a read for anyone interested in Mosquitoes.

 

========================

 

It strikes me as odd that manufacturers would downgrade their equipment, while the crews flying them would run outside of their recommendations significantly without issue.

 

Three instances here, Mustang I RAF & USAAC, Seafire II FAA & Mosquito RAF. Different services and different engines.

 

========================

 

The random egg timer may well be the way to go, I don't know. But the idea that you can push an engine hard for 2 minutes then back off for 10 (or whatever it is) and then repeat the whole thing over & over again without indecent is, I think, a little thin on the realism end.

Edited July 31, 2021 by Pict

[Voyager]

13 hours ago, ZachariasX said:

What you want has little to do with design documents. Engines on the bench are tools that in principle demonstrate the viability of an engine design and it can be used to meter the respective running properties. These are purpose built idividual tools that are of far greater quality than what comes out of the shops and is sent to the aircraft manufacturers. Also those engines on test beds are missing the „other half“ of the engine, the cooling systems, meaning that these runs are done at perfect conditions. Also you are missing out on „the flaw“ behind the controls.

 

You‘d be looking at service reports of actual sorties and what was needed to keep the engines running on those that came back.

 

Knocking is one of many problems that can limit the power of an engine. Engines in fact do often run on timers when you are taxing them, like a notiriously bad crankshaft lubrication system in the DB60X engines. High power settings in the BMW801 that burns valves. Big radials can‘t do high rpm well, hence with 3000 rpm on the DoubleWasp you‘re in essence just asking for it.

 

There is simply no way to generally describe the failure point of an engine in general plain mathematical terms unless you have exact and specific knowledege of every detail of that engine, its cooling systems, lubrication and fuel used. Fuel quality varies. Especially the aromatic turd that (by choice of production economies) comes out of coal hydrogenation, as it forms a raisin when stored and it also attacks tank linings.

 

The only downside I see in our current timers is the 5 min default for the P-47 water injection compared to 10 min on the DB. I would have said that you can do 5 min but set the timer to the same about similar as the German timer for the simple reason of gameplay, that in this case is extremely competitive. But that would be the only reason to make up such.

 

Bottom line is, if engines in this game behaved like real engines, you‘d see many more gliders in dogfights. And people flying at more conservative power settings. A big reason they wanted to put a Merlin on the P-40 was the exact problem we have and also they just couldn‘t pull 70‘‘ without having a bad day from then on. Just because some say they managed to do so in specific circumstances doesn‘t mean you shouldn‘t expect becoming a glider after going that far off your engine manual specs.

 

As for vintage engines, there is only one thing you can expect from them. Failing on you when you need them. And failing they did all the times and they still fail all the times. If you find such engines that don‘t fail all the times, then I show you an engine that is used, if at all, way short of its maximum rating. You know, a New Guinea campaign becomes way more fun if you have persistent engine wear across missions. Especially since bailing out (unless done over your airfield) means almost certain death, either as fish food (sun dried or fresh) or wasting away in the jungle as bug food.

 

So again, if you were given realistic engine behaviour in this game, you‘d be way more careful on the throttle than with the timer now.

 

Some do not like all that. And that is fair. The „unbreakable“ option should indeed have an option to single out engine damage caused by the pilot. If people want it, they should have it. It is a game. It is for entertainment. It should have been in place from the beginning.

 

 

 

But where is the test data to support this? You mention poor lubrication on the DB60X engines, and burned valves on the BMW801, but surely these are not issues that correct themselves from running the engine at reduced setting for twice the burn time?

 

Of the issues we do have some accounts of, they seem to be predominantly due to either running the engine on low octane (B-26 engine failures during training) or due to improper power advancement, P-38 issues with advancing boost before RPM leading to engine destruction.

 

The only reports I have seen of engines failing due to power settings, were a batch of R-2800's that were run at the factory at their max rated power without water injection, then shipped to the field, and engines that failed due to salt water corrosion of the ignition coils. If engines were failing due to over-boost or running beyond duration, surely that would have been commented upon or discussed somewhere, yet it was not.

 

Quite the opposite, pilot training videos talk routinely about engines being run beyond rated power, with the only warnings I have seen on that regard are "don't kill your buddy by overstressing the engine" variety.

 

If you look at the black box warnings in the training manuals, they are about smoking in the cockpit, overloading the electrical system, locking the brakes up on taxiing, or setting the fuel system up such that it vents the entire system overboard. They are very clear that these things will break the plane or cause you to walk home.

 

So why the exact opposite behavior on the engine timers? I've yet to see a rational for that.

[ZachariasX]

8 hours ago, Voyager said:

but surely these are not issues that correct themselves from running the engine at reduced setting for twice the burn time?

That is purely a gaming feature that the devs gave us because they are clearly aware what restricting time on high power settings means in terms of gameplay. 

 

The timer is simply the stick to enforce flying by the manual while acknowleging that in principle longer time periods are possible. They must be, you cannot state exact timeframes when engine fail, but you can state timeframes during which engines certainly will last. That is what is in the manual. Engines vary in production quality, environment varies a lot, pilot skill varies. I would even expect an engine built to last 5 minutes at the hands of any idiot in any conditions to last hours in perfect conditions. And they do, test bench runs show this. The timer is nothing but simple way forcing you to fly according to the manual while giving you more time on these settings when you are a good boy and you prove yourself worthy of more high power time, simply because engines in principle can last longer. But only at the hands of the good kids. (In the real world, beyond the stated times in the PN, that is where you start taking bets.) If you however are a naughty boy, then you get yours.

 

Don‘t think of the timer as „reparing the engine“. The recharging of the timer simply gives you the longer WEP time you always had, simply because you are a good kid and treat the engine nicely.

 

I don‘t think that this is in principle a bad concept due to its simplicity. But there are two things that I think should be adjusted:

 

First, I should be able to disable that mechanism should I want to fly full bore for the simple reason that I want to.

The second is that settings absulutely awful to the engine can be used to control the timer, like full power on 2650 rpm on the Merlin. or WEP power with lean mixture in the P-38. There are ways to almost get WEP power in game that would instantly kill an engine that you can use to use less timer. The only thing the timer seems to check is power produced, meaning the product of  rpm*MAP has timer thresholds. And this is where things get unreasonably simple. Simple is good. But not that simple.

 

If the devs were talking about a better complex engine management, I‘m sure they adress these two points.

[Voyager]

@ZachariasX Ok, so going back to basics, assuming I may have found the manufacturer's archives, what tests and test reports would have been used to define the engine timers used in the manuals? 

[ZachariasX]

58 minutes ago, Voyager said:

@ZachariasX Ok, so going back to basics, assuming I may have found the manufacturer's archives, what tests and test reports would have been used to define the engine timers used in the manuals? 

I would look for service reports on operational aircraft. P&W engines were mosty used in controlled environments, where mechanics had time to log engine use. Anything that came back to P&W as a complaint. These indicate points where engines fail first and how they fail and when.

[AEthelraedUnraed]

23 hours ago, ZachariasX said:

I don‘t think that this is in principle a bad concept due to its simplicity. But there are two things that I think should be adjusted:

Adding to that, I'd rather have some probability metric introduced. Meaning it would not be guaranteed to fail after X time, but rather that each second after the time limit, you'd have a (very small) probability of your engine failing. Possibly increasing with time, meaning that the first minute this chance may be e.g. 1% increasing to 50% when *way* over time, but never reaching 100%.

 

That way it would be a calculated risk that you could take if the situation demands it, rather than a set time limit that you may not exceed no matter what the situation.

Edited August 2, 2021 by AEthelraedUnraed

[ZachariasX]

8 minutes ago, AEthelraedUnraed said:

Adding to that, I'd rather have some probability metric introduced.

It might be a way to simulate the unknowns, but I think random functions are not liked in a highly competitive environment. Such probabilities, may they be all sound by themselves, in some cases adds up to a lot of grief in our dear DM. I would use them as a very last resort.

[Pict]

2 hours ago, ZachariasX said:

I would use them as a very last resort.

 

And if they are to be used, have an option for them in the realism so that those who see the game as a purely competitive all things are equal arena, they have that option.

 

Kind of like what this thread is about for the egg timers  

[AEthelraedUnraed]

1 hour ago, ZachariasX said:

It might be a way to simulate the unknowns, but I think random functions are not liked in a highly competitive environment. Such probabilities, may they be all sound by themselves, in some cases adds up to a lot of grief in our dear DM. I would use them as a very last resort.

All good and well, but IL2 is a simulator and not a shooting game. IMO a random function can, as you say, be used to simulate many of the unknows inside an engine, without having to model each individual system and the wear that it may or may not have. The whole point of the entire engine timer discussion is to make the engine behave more realistically, and randomness does exactly that. An engine is expected to last at least as long as the manual says, but after that it might fail instantly or last three entire days, depending on how strict the manual guidelines are written, how worn out the engine is, how well it was manufactured, how well maintained, and the position of Jupiter relative to Sagittarius at sunrise. An added random element makes it possible (though unlikely) for an engine to run extended amounts of time on WEP settings, which anectodes show they sometimes did, while at the same time both giving an incentive to be careful with your engine and giving players the possibility to choose between extended WEP time with a risk of damage, and guaranteed no damage but limited WEP time (in the current system, no such choice exists since going over time instantly and always results in damage).

 

1 hour ago, Pict said:

And if they are to be used, have an option for them in the realism so that those who see the game as a purely competitive all things are equal arena, they have that option.

You do know that there are already random functions involved in e.g. damage, for the same reasons (i.e. simulate many different systems/cables that a bullet may or may not hit)? One player may kill another with a single bullet hit, while for another a hundred hits in the same hitboxes might do nothing. It's both luck and skill (good aiming improves your chances). Random functions inside engine management wouldn't be too different, it would also be both luck and skill (those who do better engine management, i.e. go less "over time", have better chances). Above all, it would still be a very equal arena since everyone has the same chances.

 

While certainly not perfect, I see a timer with damage probabilities as a simple way to make the current system a tad more realistic without having to completely overhaul the game engine and model a lot more engine systems than is currently the case.

 

I certainly support having an additional setting for "no engine timers," but I do not think that yet another difficulty setting for random vs. fixed timers would improve much rather than just make it more confusing for everyone. I see the probability system I propose as a replacement/enhancement of the current system rather than an additional option. IMO it adds realism (your engine might last *much* longer than is currently the case, and no two engines are equal, as opposed to a very game-ish "your engine will fail in 10...9...8...") at relatively little cost to the developers (modeling a complete engine with a "wear and tear" system would be more realistic, but takes way too much time and effort). People who just care about competition and prefer a more arcade-ish system can play with timers off.

[Voyager]

@AEthelraedUnraed Given we have on record a engine manufacturer representative stating that the engine time limits can be ignored, is it legitimate to call removing the engine timers to be arcade?

 

Can we not debate from the standpoint that both parties are arguing for realism above all else? 

8 hours ago, ZachariasX said:

I would look for service reports on operational aircraft. P&W engines were mosty used in controlled environments, where mechanics had time to log engine use. Anything that came back to P&W as a complaint. These indicate points where engines fail first and how they fail and when.

Ok, so that would represent in use numbers, but the timers were defined prior to that during development. Do we know what sort of developmental testing and analysis would have been done to reach those numbers, or what those test reports would have been called? 

[Pict]

1 hour ago, AEthelraedUnraed said:

You do know that there are already random functions involved in e.g. damage

 

Indeed you are correct, I do know that.

 

However that is not what was being discussed at that moment.

[ZachariasX]

23 minutes ago, Voyager said:

Do we know what sort of developmental testing and analysis would have been done to reach those numbers, or what those test reports would have been called? 

Yes we do. These are test runs in the lab that prove the engine being structurally capable of taking the load produced under given thermal stress. The hotter you run a combustion engine, the sooner it fails. You then go with something like applying more heat tolerant material, better cooling or restrict power output. Any report clearing a certain rating means that at least the specified ratings can be reached reliably.

 

I would go for actual operation reports because I imagine them reflect actual failure rates of given engine type in the hope to get an idea of how much power they used and how often an engine blew. It is there where you could compile a list of how much MAP they conveniently pulled and got away with.

 

As we always have factory fresh aircraft, the whole point is slightly moot, as even very defective designs like the DB601 with nitrous injection would probably give you a rather long timer setting on its first mission. It is after only a while that C3 fuel poisons your engine oil and doesn‘t want to leave it because of a very high boiling point. Then that you start out with a defective lubrication system that will make you a glider regardless of how nice you are to the engine or not. And this was an operational engine.

 

But as said, seeing how the squadrons made actual use of the engine I would find interesting.

 

 

[Pict]

5 hours ago, ZachariasX said:

I would go for actual operation reports because I imagine them reflect actual failure rates of given engine type in the hope to get an idea of how much power they used and how often an engine blew. It is there where you could compile a list of how much MAP they conveniently pulled and got away with.

 

Here's one for Allison engines Mustang I's. The report is by the USAAF top dog in theatre reflecting on RAF use and abuse of the Allison and how they had removed restrictions without any problems.

It includes conclusions like how the USAAF should remove rerstrictions on their P-51A's etc.

 

Interesting stuff.

 

 

[ZachariasX]

Yes, I‘ve seen those too. But what I‘d be interested in is what P&W or Allison etc. had to say about such behavior after looking what they brough back as engines.

 

As said, in the game we have factory fresh engines, always due to no persistent damage. A new engine has a much longer time on abuse timers as a worn one. Once your bearings/valves/etc are burnt, the engine is dead. But the engine can be fine (enough) for some flights despite some signs of wear.

 

A question is if you want to have in your game always a totally new engine (that is not realistic) or something of an engine with a tolerance of average wear, something an average pilot could expect from his engine at the start of a mission. That would be different timer settings. How much that wear might be, that I‘d be curious to know.

 

Regarding the Allison, it was IIRC the British that wanted the Merlin on the P-40, not just for the higher power they got, but also for the boost regulator. Not everybody wanted to overboost like that. Probably for good reason.

[Voyager]

@ZachariasX Haven't found engine operation reports, but while trying to find what sort of form would be used for engine time at power reporting, I did find a big pile of encounter reports here: 

 

P-47 Encounter Reports
http://www.wwiiaircraftperformance.org/p-47/p-47-encounter-reports.html

 

Couple of things I've noticed from the ones I've gone through. First is almost nobody reports the power used, aside from a few "poured on the coals" and "everything forward".

 

The other thing is, none of them seem to be using the 425 rounds per gun loadout. Most are reporting less than 400 rounds expended, or that they were expecting to run out of ammo after about 1000 rounds or so. 

 

Going to have to keep digging to see what type of maintenance or usage reports were filed. 

 

 

Hahahahaha! I found the asymmetrical flaps report! 

 

P-47C Tactical Trials
http://www.wwiiaircraftperformance.org/p-47/p-47c-8thaf-tactical.html

 

9d) The relatively complicated hydraulic pressure equalizer for the flaps is far from satisfactory. Although a lever is provided in the cockpit which if actuated will theoretically equalize the pressure on each flap, actually on all ships used for the trials the flaps were continuously giving trouble by one coming down considerably behind the other. The systems were bled thoroughly and check carefully a dozen times during the trials. The airplane is bad enough from a trim standpoint n the landing glide, and becomes a sizeable problem to keep straight and level if the flaps do not open simultaneously.

 

Digging further, it looks like many of the up rated engines were tested at the Power Plant Laboratory, possibly in Wright Patterson Air Force base. There does appear to have been a 7.5h WEP test that was used to certify engines, but the only ones I've found so far are just summary sheets, and do not have the test procedure itself. 

 

It does appear there was some sort of standardized test procedure. I just haven't found it yet. 

 

Addendum 3: First direct report of blowing past engine timers: 353-hinchey-14nov44.jpg (800×1033)
http://www.wwiiaircraftperformance.org/mustang/combat-reports/353-hinchey-14nov44.jpg

 

The P-51 pilot reports chasing a 262 for 15 minutes at 74" manifold pressure and 3000 RPM, and only breaking off because of lack of fuel. 

 

I suspect the indicated airspeeds he was seeing were compressability jacking up the sensor. I've seen a number of other similar test reports with such wild numbers, and they were generally not real numbers. It does lead me to wonder if that's an effect that should be modelled, but that's for another thread.

 

Addendum 4: According to the P-51 75" clearance (75inch-clearance-v-1650-7.jpg (1200×1559)
http://www.wwiiaircraftperformance.org/mustang/75inch-clearance-v-1650-7.jpg) the testing was in accordance with Specification R-28487

 

Have not been able to find it yet, but I did find the records of the Army Air Force here: 

 

Records of the Army Air Forces [AAF] | National Archives
https://www.archives.gov/research/guide-fed-records/groups/018.html

 

It appears to cover through 1947, so it should be in there somewhere. 

 

I think this is where I tap out for the night. I feel like we're on the trail of the actual test data and methodology, and we're finding at least some documented cases where the engine time limits were completely disregarded. Maybe we will finally find something concrete? Work for tomorrow. 

Edited August 3, 2021 by Voyager

[CountZero]

There is complex solutions or simple ones, and just having option to turn timers off is the simplest one.

Then servers can see what option is most popular with players...

Also fix buged tech chat message, so it shows up when timer runs out or gets recovered is another simple solution if turning them of is no go, then atleast you know when game wonts you to stop using that engine mod.

 

[the_emperor]

Regarding the DB605 engine Timer:

By ´44 it could run safely 2.800rpm/min for ten minutes on the bench and in as the DB605AM with MW-50 injection. The Crankshaft lubrication problem seems to be solved.

Shouldn´t then in theory the (by ´44) DB605A also be able to run at that rpm setting? even if not with the same manifold pressure, due to missing aftercooling (the DB605 does not have an aftercooling system for the compressed air-fuel mixture which was then solved by the MW-50 System).

At least the documents no longer have that engine setting as banned but unfortunately leave out anyinformation on how long Notleistung could be applied.

Shouldn´t the 10min limit then be plausible? and where does the 1min restriction for the DB605A come frome, I have not seen any document so far.

So far I have only seen "banned"  or not banned

 

Cheers

 

 

 

 

[AEthelraedUnraed]

20 hours ago, Voyager said:

Can we not debate from the standpoint that both parties are arguing for realism above all else?

I didn't mean to imply that you are arguing for less realism or anything, and if my post came across as such, I apologise. I certainly agree that both parties want realism, and I'm also willing to accept that for some engines at least, no timer at all would be more realistic than the current situation, from the evidence I've seen. However...

 

20 hours ago, Voyager said:

Given we have on record a engine manufacturer representative stating that the engine time limits can be ignored, is it legitimate to call removing the engine timers to be arcade?

...compared to an improved timer system with updated timer limits that better reflect real-world values, yes I do think it is arcade. Compared to the current system/timer values, perhaps not.

 

20 hours ago, Pict said:

However that is not what was being discussed at that moment.

You state that competitive players would not want random functions because it would remove the "all things are equal arena". I intended to show that random functions are already in use, and not being excessively complained about AFAIK.

 

9 hours ago, Voyager said:

The P-51 pilot reports chasing a 262 for 15 minutes at 74" manifold pressure and 3000 RPM, and only breaking off because of lack of fuel.

It does show that, at least under some circumstances, some pilots used WEP for longer than is currently possible, and apparently felt comfortable enough doing so. The problem with such anectodal evidence, however, is that it tells us little else than exactly that. It doesn't state whether, for instance, it was a brand new engine or an old one, or how else it was maintained. Nor does it show if such a thing was commonly done, or if this was simply a very brave pilot that knowingly (or perhaps unknowingly?) took a lot of risk.

[Voyager]

29 minutes ago, AEthelraedUnraed said:

[...]

It does show that, at least under some circumstances, some pilots used WEP for longer than is currently possible, and apparently felt comfortable enough doing so. The problem with such anectodal evidence, however, is that it tells us little else than exactly that. It doesn't state whether, for instance, it was a brand new engine or an old one, or how else it was maintained. Nor does it show if such a thing was commonly done, or if this was simply a very brave pilot that knowingly (or perhaps unknowingly?) took a lot of risk.

 

It may have been less than 2 flights since the spark plugs were replaced. One of the references notes the Merlin at 150 octane has significant fouling problems that led to plugs being pulled every two flights for a time. 

 

What's also interesting about that account is that the pilot was convinced of the engine was rated for 80" that he could have caught it. 

 

Don't have time to dig up the reference right now, but I saw that the V1 units were rated to run at 80" during intercepts. I'm wondering what their mission profiles were and if this pilot had been part of that? 

 

Do you think I could get you to try and run that down while I'm looking for the USAAF 7.5h War Emergency Test Procedure? 

 

I'd expect the buzz-bomb interceptors to take far more risks of engine failure due to their mission objectives and operational profile, so we shoes be able to find records of burning out engines.