Option to turn off engine timer mechanic.

[the_emperor]

I would like to see an option to turn off the current engine timer mechanic.

So the fuel/oil/water&methanol consumption, water/oil temps, and oil pressure/viscosity limits would be the "only" limiting factors of our engines.

Why I would like to see that option?

1. we dont have to conserve our engines for an 100+h service live, we always get a brand new one (what the limits are originally intended for)

2. the current mechanic is not transparent. We dont know when we running out of WEP/Combat time (no way to read that from any gauge in our cockpits).

3. the time can be manipulated by reducing rpms (in some cases quite extreme e.g. La-5fn from 10 to 20min by reducing from 2500 to 2400rpm or Spitfire IX from 5 to 15min when reducing rpms to 2600 at max MAP our Bf 109 G-14 from 10 to 20min with 1.7 ata when reducing to 2600rpm). But it is not made transparent how much by how many. Additionally reducing rpms at high/max MAP contradicts the manuals (discussed here: https://forum.il2sturmovik.com/topic/81983-correcting-rpmmap-correlation-no-longer-timer-for-using-max-map-with-lower-rpms/)and can even be fatal for the engine.

4. essentially the same engines have vastly different timings:

   Spitfire IX: 18lbs/2600rpm 15min

   P-51D: 67inches/2600rpm 5min (again not made transparent how and why)

5. we have no way of telling when and how much our WEP timing has been recovered/”recharged”. There is no way to read that from any gauges in the cockpit. It is not made transparent how much time of “recharge” is necessary for which power setting to regain X-amount of WEP time.

6. Conflicting date: eg. the La-5Fn (and upcoming La-7); its engine is usually rated with a 5min WEP time limit, but a 10min limit was chosen due to a single 10min mentioning in 1943 document. the La-5f engine gets unlimited WEP time due to to one line mentioning (without explanation how this was archived). The DB 603 engine gets a 1min WEP limit, though a time limit is never mentioned anywhere.

So I would like to have the option (just the option!) to switch off that mechanic.

Edit:

@Charon made a good point:

Timer is off as long you are in the approved limits. If you go past them the current mechanic applies and you are on the clock again (e.g. if you dare to disable the automatic in the 190/109 to get higher rpms against the advise ofthe manual or in case of the P39/40 going over manual approved MAP)

Cheers

 

Edited May 24 by the_emperor

[Charon]

6 hours ago, the_emperor said:

the time can be manipulated by reducing rpms (in some cases quite extreme e.g. La-5fn from 10 to 20min by reducing from 2500 to 2400rpm).

Notably, this is exactly the opposite of how every source agrees that it works in real life.

 

----

 

I think the problem with this proposal is that water and oil temps probably aren't realistic enough yet to be a reasonable check. For instance, everyone who flies real warbirds seems to agree that these planes tend to overheat on the ground. Yet I've never seen that in the sim. I think they can (all?) idle indefinitely with no air-flow, even in summer.

 

What happens with a plane like the P-40 that has no manifold pressure governor? In real life, detonation (leading to very rapid cylinder heating) would be the limiting factor. Is engine heating modeled with such fidelity, or can you fly around indefinitely at 3000 RPM and 60" of manifold pressure once the timer is removed?

 

Will optimal use of the DB605  mean switching to manual pitch control and pushing to 3000RPM for every climb?

 

Or is the proposal "remove timers, but only while engines are operated within their limits, and keep the timers outside of that domain?"

[the_emperor]

@Charon

Damage due to overboost (also in case water&MW50 for the P47&109 runs out) and overreving should already part of the engine modelling and not been tied to the engine timer, would be my wild assumption.

and really everything else like realistic water/oil temps should also already be modelled, otherwise we would have an even bigger problem then we already thought we have with the engine timers XD

but yeah easy solution as long as you are within the limits, timers dont count

thx

Edited December 7, 2022 by the_emperor

[-=PHX=-SuperEtendard]

1 hour ago, the_emperor said:

@Charon

Damage due to overboost (also in case water&MW50 for the P47&109 runs out) and overreving should already part of the engine modelling and not been tied to the engine timer, would be my wild assumption.

Overboost damage is made with the timer system, if you take the P-40 or the A-20 and go full throttle at max supercharger compression you will see the timer expends in just a few seconds and then you get engine damage.

Edited December 7, 2022 by -=PHX=-SuperEtendard

[the_emperor]

@-=PHX=-SuperEtendard

bummer! I hoped for more.

Then what @Charon said.  No timer limits as long as you are in the approved limits. When you go above, the current timer mechanic applies 

Edited December 7, 2022 by the_emperor

[the_emperor]

On 12/7/2022 at 5:13 PM, Charon said:

Notably, this is exactly the opposite of how every source agrees that it works in real life.

So reducing rpms at a high MAP setting shouldnt do good fpr the engine?

I thought so too but havent looked for the reports on that thus far

[LukeFF]

[the_emperor]

@LukeFF Thank you very much. That makes the current timer mechanic and engine model with reduced rpms at high MAP at least questionable...

"never reduce rpm before manifold pressure"

From which manual does that come?

Edited December 11, 2022 by the_emperor

[LukeFF]

6 hours ago, the_emperor said:

@LukeFF Thank you very much. That makes the current timer mechanic and engine model with reduced rpms at high MAP at least questionable...

"never reduce rpm before manifold pressure"

From which manual does that come?

 

It's from a P-40 pilot training manual: https://www.docdroid.com/ibKHk6m/curtiss-p-40-warhawk-pilot-training-manual-pdf

[Charon]

I suspect the system works now is basically interpolating between known reference points. "Nominal" RPM + "Boosted" MP seems to result in the timer burning at 1/2 the "boosted" rate. Then for any point on the line between that and "both nominal", the burn rate is probably obtained by interpolation.

 

I'm guessing 1/2 is chosen as an arbitrary factor, and I suspect the same factor is used both for the "boosted rpm nominal mp" and "boosted mp nominal RPM" combinations.

 

I suspect there's also some hidden "penalty" reference point beyond maximum RPM and maximum MP that burns the timer immediately, and interpolation against this is done in the same way as described.

 

AFAIK, mixture has no effect on the timers, only on temperature, fuel consumption, and power.

 

If I were doing a simple rework of this (i.e., keeping the engine timers, not reworking the thermal system entirely to be realistic, which is probably an infeasibly large undertaking) I'd prefer to instead increase the burn rate dramatically (factor of 3x instead of 1/2?) in the low rpm regime, simulating detonation. For the high rpm/low mp case, don't interpolate as discussed: just use the same burn rate as the low rpm/low mp case. Lean mixture can be accounted for by hiding the high power reference points and just interpolating against the "penalty" reference point, so that low-power operations on lean mixture are safe, but high power operations will cause rapid detonation.

 

This would encourage flying engines a little more realistically: it incentivizes increasing RPM before MP, and would let you pin RPM high and worry about only throttle during combat (as I suspect was done in practice). It also makes misuse of mixture relevant. It's simple, but everything at least moves in the right direction, and I think it's simple enough that it could be a drop-in replacement for the current system, without requiring extensive research and calibration.

Edited December 11, 2022 by Charon

[CountZero]

And thats why easy solution is have realisam option that turns of just timers.

 

We have option that turns on Icons, there is no icons in real world but we have option t have them, we have option to turn off preheating of engine, we have option to have modern GPS... and so on... having option for this is not braking anything...  servers can pck any chose what is more popular , on or off... 

 

And unbrakable option already shows that its posible, only problem there is that its turning off engine timer damage also with making airplanes unbrakable on colisions, its good enought for SP i dontr play without it on just to avoid this engine timers BS, they just need to seaparate two and thats it so it can be used in MP... mutch easyer to do then to rework whole arcade system, we all know that aint gona happend, not at this point not ever

 

best we could hope they could do is make it on off option

Edited December 11, 2022 by CountZero

[the_emperor]

On 12/11/2022 at 8:13 PM, Charon said:

If I were doing a simple rework of this (i.e., keeping the engine timers, not reworking the thermal system entirely to be realistic, which is probably an infeasibly large undertaking) I'd prefer to instead increase the burn rate dramatically (factor of 3x instead of 1/2?) in the low rpm regime, simulating detonation. For the high rpm/low mp case, don't interpolate as discussed: just use the same burn rate as the low rpm/low mp case. Lean mixture can be accounted for by hiding the high power reference points and just interpolating against the "penalty" reference point, so that low-power operations on lean mixture are safe, but high power operations will cause rapid detonation.

 

This at least would be a good starting point to get the current mechanic  in the right direction

[the_emperor]

From the P-51 D-5 Pilot´s flight operating instructions of April 5th ´44:

 

WEP must only be used if rpms  are set to full 3000. Rpms must always be set bevor increase of throttle to WEP.

Also: the Engine ist allowed to accumulate a total time of 5h on WEP bevor tear down inspections (one more reason to give us the option to turn off the current mechanic)

 

[354thFG_Drewm3i-VR]

@Wardog5711 Can you pass this request along to the developer? It is long needed and shouldn't be too complicated to implement as a stop gap solution.

[DRosa]

 

Plane information about it would be enought. Obviously you won't have a gauge for all that info, but knowing it in your head would start to give you an idea of what you have to do. I tried to start using the cockpit clock to measure emergency mode times, but the server I was in for some reasons had faster time.

[nesher666]

As a choosable game setting I would greatly appreciate this option, since the current invulnerability setting is just simply an overkill IMO. 

Edited December 20, 2022 by nesher666

[dbuile]

On 12/16/2022 at 4:06 AM, the_emperor said:

the Engine ist allowed to accumulate a total time of 5h on WEP bevor tear down inspections (one more reason to give us the option to turn off the current mechanic)

 

Not sure I'm correctly following your line of thought.  Are you looking to "turn off" engine damage so you can run it 5 hours straight on WEP?

[the_emperor]

6 hours ago, dbuile said:

Not sure I'm correctly following your line of thought.  Are you looking to "turn off" engine damage so you can run it 5 hours straight on WEP?

That was more meant as  a nod to the current mechanic that obligatory damages your engine after 5 min, while in real life it was allowed run a total of 5h on WEP before teardown ?

Edited December 21, 2022 by the_emperor

[dbuile]

If you try to run that engine 5 hours on WEP straight, do you think it'll even come close to making it, as opposed to the reasonable assurance it'll make 5 hours total if done in much smaller increments with cool down periods in between?    

I agree with the basic tenet: that ~perhaps~ with some engines, the "punishment" for exceeding limits is likely handled in a non-realistic way.  But, I can understand the goal of doing so:  it'll also be unrealistic to have everyone flying around on WEP all the time.

I haven't played Cliffs of Dover/Tobruk hardly at all, but it's interesting they have "derated" engines?  

 

[357th_KW]

1 hour ago, dbuile said:

If you try to run that engine 5 hours on WEP straight, do you think it'll even come close to making it, as opposed to the reasonable assurance it'll make 5 hours total if done in much smaller increments with cool down periods in between?    

I agree with the basic tenet: that ~perhaps~ with some engines, the "punishment" for exceeding limits is likely handled in a non-realistic way.  But, I can understand the goal of doing so:  it'll also be unrealistic to have everyone flying around on WEP all the time.

I haven't played Cliffs of Dover/Tobruk hardly at all, but it's interesting they have "derated" engines?  

 

Part of the reason people are arguing for this stuff is because this was actually tested during the war, and in a number of cases the answer was yes.  
 

Document talking about Merlin development - page 224 describes destructive testing of Merlin 66’s (Spit 9, P-51) at constant WEP, where the crankcases failed after 27 hours.

 

7.5 hr WEP run of a P-38’s Allison

 

7.5 hr WEP run of a P-47’s R-2800

 

7.5 hr WEP run of a P-51’s Merlin

In the case of these engines, the fact that they go pop after slightly exceeding their emergency limit is fairly bogus.  There’s even a period manual (I believe one of the P-47 manuals - someone has posted clips from it on the forum before, but finding anything with the 1 minute search delay is a lost cause) that contains a few paragraphs explaining that the engine wasn’t going to just explode from exceeding the admittedly arbitrary emergency time limit - essentially push it as hard as you want if necessary in combat, but otherwise use some common sense and be gentle with it to prolong service life.  
 

And it becomes a problem in game when their direct opponents had a 10 minute limit written in their manuals - so in game, an enemy knows that they can just keep chasing you in a slower aircraft and eventually force you to blow up your engine, or have to fight them at a reduced power setting (and yes, this happens all the time in MP).  But of course the counterpoint is that we don’t want everyone just flying around in WEP constantly.

 

Just turning off the timers is obviously problematic if it means the unregulated aircraft (P-40, A-20 etc) can just wildly over boost all the time.  I think someone suggested some sort of flat timer system where everything gets the same basic limits, which might be the best solution ultimately.

 

 

 

[CountZero]

2 hours ago, dbuile said:

If you try to run that engine 5 hours on WEP straight, do you think it'll even come close to making it, as opposed to the reasonable assurance it'll make 5 hours total if done in much smaller increments with cool down periods in between?    

I agree with the basic tenet: that ~perhaps~ with some engines, the "punishment" for exceeding limits is likely handled in a non-realistic way.  But, I can understand the goal of doing so:  it'll also be unrealistic to have everyone flying around on WEP all the time.

I haven't played Cliffs of Dover/Tobruk hardly at all, but it's interesting they have "derated" engines?  

 

You would not be flying all time on full power, you run out of fuel in 10-20min depending on airplane... your engine would overheat... 

Differance is you look at your gauges and you plan when to save fuel when to go all out as your in battel... you do not fly with this arcade timer in mined... insted counting seconds your looking at gauges... if in real world pilots engine was so dependend like its in game on 1-3-5min timer they would have alarms when they go abow thouse limits... they would not need gauges, only engine timer clock and alarm.

Its more unrealistic what we have now then timers off option...

ALso we have option to turn on of icons, is this braking the game, there was no icons in real world, but there is option for MP for ppl who like to play with icons... i dont here ppl who like to fly with no icons complaining that there is option to turn on icons for ppl who like that...

 

 

Edited December 21, 2022 by CountZero

[the_emperor]

3 hours ago, dbuile said:

If you try to run that engine 5 hours on WEP straight, do you think it'll even come close to making it, as opposed to the reasonable assurance it'll make 5 hours total if done in much smaller increments with cool down periods in between?

Dont take me serious on that?

the time you can WEP is of course still limited as I said in my proposal (eg fuel which will drain very fast on WEP)

[dbuile]

46 minutes ago, 357th_KW said:

In the case of these engines, the fact that they go pop after slightly exceeding their emergency limit is fairly bogus.  

 

Agreed.  

 

1 hour ago, CountZero said:

your engine would overheat... 

 

Do you mean overheating as incentive to NOT run the engine at emergency power for as long as you have fuel?  I not asking as a disagreement, but truly wondering if you think overheating should have a detectable effect on engine performance in the course of a sortie.

 

To your point though, I shouldn't oppose the option, even if my knee-jerk reaction is that everyone will cruise at full power, because heck why not?  I'm sure the kinds of flying I prefer, the option would be off.       

[the_emperor]

2 hours ago, 357th_KW said:

Just turning off the timers is obviously problematic if it means the unregulated aircraft (P-40, A-20 etc) can just wildly over boost all the time.  I think someone suggested some sort of flat timer system where everything gets the same basic limits, which might be the best solution ultimately.

Is edited in my proposal thx to @Charon 

Timers are off as long as you are in the WEP limits of the manual. If you go beyond (overrev, overboost) you are on the clock again

[=MERCS=JenkemJunkie]

21 minutes ago, dbuile said:

 

Agreed.  

 

 

Do you mean overheating as incentive to NOT run the engine at emergency power for as long as you have fuel?  I not asking as a disagreement, but truly wondering if you think overheating should have a detectable effect on engine performance in the course of a sortie.

 

To your point though, I shouldn't oppose the option, even if my knee-jerk reaction is that everyone will cruise at full power, because heck why not?  I'm sure the kinds of flying I prefer, the option would be off.       

If your running WEP your whole flight you'll enter combat with higher temps then if you were "banking" it by cruising in lower settings. Starting the fight with higher temps means you'll have to open your rads more which hurts your performance, or in a plane with auto rads like the 109/51 your rads will automatically open on their own, and you could end up starting the fight at 30% open instead of say 10% if you were banking temps. Also running WEP leaves a nice smoke trail for everyone to see, so even with infinite timers I would still drop out of WEP to bank temps, be stealthy and save fuel. 

[dbuile]

1 hour ago, =MERCS=JenkemJunkie said:

you'll have to open your rads more which hurts your performance

Yes, understood.  However, the context of this discussion is allowing an engine to run at WEP for multiple hours straight, in combat operations, no cool-down periods, and have no engine failure.  That suggests overheating is no longer a factor.  I asked the question because I'm curious if I misunderstood the position.

 

In the end, though, I'm not really invested in whether an "invulnerable engine" option shows up in the game. 

I DO very much enjoy the historical data folks contribute though.  Thank you all for that.  I'm much more interested in the history.

[=MERCS=JenkemJunkie]

Depends then, the tests were done in a non-combat setting where drag costs from radiators weren't a factor, so if all you care about is not breaking the engine, then yes you can run the engine for hours with enough cooling and not have it break, and overheating isn't a concern. But realistically in a combat scenario fighter pilots are always going to want to minimize drag, and overheating is an issue not due to the engines limits, but due to the pilots desire to minimize drag. The main point to take away from the tests isn't really the viability of 5 hour full WEP fur balls though, it's just to show that if the engine can handle 5+ hours running at WEP then it should be able to handle our ~30-60 min sorties here.

Edited December 22, 2022 by =MERCS=JenkemJunkie

[Charon]

9 hours ago, dbuile said:

If you try to run that engine 5 hours on WEP straight, do you think it'll even come close to making it, as opposed to the reasonable assurance it'll make 5 hours total if done in much smaller increments with cool down periods in between?    

If kept within operating limits? Maybe. Maybe not.

 

Sometimes pilots went up and the engine didn't make it 5h despite operating within limits. A damaged spark plug or stuck valve can lead to detonation, even without the pilot doing anything wrong. As virtual pilots, we don't need to deal with that.

 

Here's what Pratt & Whitney's "The Aircraft Engine and Its Operation" (1947, p62) says about military power ratings:

 

Note this is the same book that warns:

 

High power is fine (at least for a while). High power under conditions of detonation is not.

 

Edit: Incidentally, Lipfert claims his friend Saschenberg flew full throttle practically all the time; that as a result his engine wouldn't even run smoothly at anything less than full power. I don't have the reference in front of me, but could dig it up if it's of interest.

Edited December 22, 2022 by Charon

[the_emperor]

10 hours ago, =MERCS=JenkemJunkie said:

I would still drop out of WEP to bank temps, be stealthy and save fuel. 

Good points ?

[dbuile]

Thanks, Charon.  I realize I'm misunderstanding people's intent, and conflating two arguments.  A post linked to the DB605 5 min run-in at 1.42, which, forgive me if I recall incorrectly, I equate to "Take-off and Emergency Power" in German engine parlance.  When I say "WEP", that's what I have in mind:  Emergency power, not Military Rating, which, I equate to Climb/Combat Power.    

 

Are people asking the timer is turned off for Military Power, or for War Emergency Power?

 

No, you don't have to peruse Lipfert on my behalf.  I can look    

[354thFG_Panda_]

7 minutes ago, dbuile said:

Are people asking the timer is turned off for Military Power, or for War Emergency Power?

Both. 

Any power setting above the W.E.P which is achievable in some planes to be limited by RNG means to stop things like the p40 being the 262 of 41

Edited December 22, 2022 by theRedPanda

[the_emperor]

42 minutes ago, theRedPanda said:

Any power setting above the W.E.P which is achievable in some planes to be limited by RNG means to stop things like the p40 being the 262 of 41

Yes, that is spart of the suggestions.

for the p-40 that would mean: as long as you keep it at 3000rpm & 45inches you can fly as long as your fuel, oil, and or temps allow it.

If you boost past the 45 inches the current mechanic applies and you are on the clock again. (this of course allows for small overboost over small amounts of time, and then allows you to settle back to the allowed manual settings. But I guess that would be a good representation of the P-40 Allison engine which is regarded as one of the sturdiest inline engine)

Or for example the Bf 109 G-6. you may run it at 1.42ata/2800 as long as you keep your engine in the operating limits and have fuel and oil.

But if you dare to disable the automatic and use more than 2800rpm, the old mechanic applies (in the DB605a case your engine is gone fast).

Edited December 22, 2022 by the_emperor

[Metrallaroja]

18 hours ago, 357th_KW said:

Part of the reason people are arguing for this stuff is because this was actually tested during the war, and in a number of cases the answer was yes.  
 

Document talking about Merlin development - page 224 describes destructive testing of Merlin 66’s (Spit 9, P-51) at constant WEP, where the crankcases failed after 27 hours.

 

7.5 hr WEP run of a P-38’s Allison

 

7.5 hr WEP run of a P-47’s R-2800

 

7.5 hr WEP run of a P-51’s Merlin

In the case of these engines, the fact that they go pop after slightly exceeding their emergency limit is fairly bogus.  There’s even a period manual (I believe one of the P-47 manuals - someone has posted clips from it on the forum before, but finding anything with the 1 minute search delay is a lost cause) that contains a few paragraphs explaining that the engine wasn’t going to just explode from exceeding the admittedly arbitrary emergency time limit - essentially push it as hard as you want if necessary in combat, but otherwise use some common sense and be gentle with it to prolong service life.  
 

And it becomes a problem in game when their direct opponents had a 10 minute limit written in their manuals - so in game, an enemy knows that they can just keep chasing you in a slower aircraft and eventually force you to blow up your engine, or have to fight them at a reduced power setting (and yes, this happens all the time in MP).  But of course the counterpoint is that we don’t want everyone just flying around in WEP constantly.

 

Just turning off the timers is obviously problematic if it means the unregulated aircraft (P-40, A-20 etc) can just wildly over boost all the time.  I think someone suggested some sort of flat timer system where everything gets the same basic limits, which might be the best solution ultimately.

 

 

 

Just to clear things, 7.5hr WEP runs is just how the test is called but they are not continous, they have a mix of continous and 5 minutes WEP 5 minutes lower power operation.

For example in F8F/F7F/AU-1 7.5 wep endurance test is as follows:

[Sgt_Joch]

The other thing to remember about these 7.5 hour tests is that they were bench tests under ideal conditions. The engines were tested with enough cooling equipment so that engine temperatures remained low enough so that premature detonation of the air/fuel mixture was not a factor. The tests then become strictly a reliability test to see if the internal engine parts could stand up to the wear and tear.

 

Conditions in an actual aircraft are different since cooling solutions are always a compromise to maintain aerodynamics and keep the weight under control, so an engine in an AC will never run as cool as one in a bench test. Exceeding the operating limits of an engine, say WEP at 60" for 5 minutes could push engine temperatures high enough so that there could be detonation and damage or destruction of the engine. Since temperatures vary from one cylinder to another, you could easily have detonation in one cylinder before it registers as a temperature spike on the temperature gauges.

 

Now the problem is that no one knows how hard you could push these engines before blowing them up, the upper limit is always fuzzy. There was an interesting article on testing that was done on the P-38 in 1943 to see what the actual upper limit was:

 

 

"On the other hand, Ben Kelsey (now a Colonel) and Colonel Cass Hough, of the Eighth Air Force Technical Section, had different ideas about CAT. They were of the opinion (as were many of the fighter pilots) that American fighter engines were still being used at conservative, peacetime power settings, which were inadequate for combat. With this in mind they set out to determine just how much abuse a P-38 engine could take, and what they found surprised everyone.

 

The first P-38s to arrive in England were rated at 42" up to about 20,000 feet, 40" at 25,000 feet, with further reductions above that. Colonel Hough decided the best way to find out how much power was actually available without blowing up the engines was to remove the throttle stops and find out for himself. This made full throttle available at any altitude. Operating like this, Hough spent two weeks "abusing the engines", searching for their maximum limit. "We found that below 25,000 feet we could pull up to 60" of manifold pressure without material harm, and we could run as high as 40" at 40,000 feet (60" would yield around 1600 + bhp/ engine). He did warn that this kind of abuse should be of short duration. Col. Kelsey was busy doing the same thing at the Lockheed plant in California.

 

In a February 1943, P-38 Progress Report, Kelsey described how he had been "beating engines unmercifully". The F-10 engines in the P-38G had been run at 51" (1440 bhp) or more for periods of 7 and 8 minutes. "A series of climbs have been made at this power from takeoff to 22,000 feet…" "From our best previous estimates of limiting carburetor air temperature to 45 degrees, 51" could not be pulled above 15,000 feet." "Actually, 70 degrees C. has been run satisfactorily". "We have not yet established actual limits".

 

In March Kelsey reports: "I finally succeeded in reaching limiting carburetor air temperature at altitude. I got excessive roughness, cutting out, and backfires at 190 and 200 degrees F [88 and 93 degrees C]. at about 25,000 feet"… one intercooler was actually blown up". "We very evidently have much larger tolerances in temperature, back pressure and carburetor air pressure than we anticipate".

 

Kelsey and Hough were looking for a compromise…they wanted the most power available without engine damage. Kelsey recommended a combat rating of 47" at 3000 rpm (1325 bhp) to 20,000 feet. He also recommended a 5-minute limit at 50 degrees CAT. Eighth Fighter Command was more conservative; they eventually established a War Emergency Power rating of 45" up to 25,000 feet. Wright Field, with more responsibility, was even more conservative and recommended a Military Power of only 41” (1150 bhp). War Emergency Power was not recommended. This was essentially the same power available to the XP-38 in 1939!

 

In the end, the various U.S. Air Forces set their limits somewhere between Kelsey and Wright Field. Actually, it was the fighter pilots and their crew chiefs that often had the last word on how the powerplant controls were rigged, and it was not uncommon practice to remove the throttle stops on operational P-38s. This provided full throttle (60-70" of manifold pressure) at lower altitudes, but it greatly increased the chance of blowing the engine. Many pilots thought that since they were the ones risking their lives on the cutting edge, it was only fair that they should decide how to use the power. The author has a friend who flew the P-38H, J and L models with the 55th Fighter Group, Eighth Air Force. He told me that he had the throttle stops taken off all three aircraft and, when necessary, used full throttle in combat. He had no problems with the H model overheating."

 

http://www.wwiiaircraftperformance.org/p-38/p-38-wayne.html

Edited December 22, 2022 by Sgt_Joch

[Metrallaroja]

2 minutes ago, Sgt_Joch said:

The other thing to remember about these 7.5 hour tests is that they were bench tests under ideal conditions. The engines were tested with enough cooling equipment so that engine temperatures remained low enough so that premature detonation of the air/fuel mixture was not a factor. The tests then become strictly a reliability test to see if the internal engine parts could stand up to the wear and tear.

 

Conditions in an actual aircraft are different since cooling solutions are always a compromise to maintain aerodynamics and keep the weight under control, so an engine in an AC will never run as cool as one in a bench test. 

Not true at all. This engine tests are for getting data for use in war combat, what sense would they have that they did it on ''ideal conditions''?

[Sgt_Joch]

1 hour ago, Metrallaroja said:

Not true at all. This engine tests are for getting data for use in war combat, what sense would they have that they did it on ''ideal conditions''?

 

 I was replying to an earlier post, not the test you posted. Your test is actually very interesting since the engine was run at WEP for 5 minutes followed by a cool down period of 5 minutes at low rpm/MP before restarting at WEP again for 5 minutes, etc. No reason why that test should cause a problem and that would also not trigger the "timer" in game.

 

The questions to analyse these tests are generally the same: what was the parameters, what cooling solution was used in the tests and how did that differ from the cooling in the actual AC, what was the cylinder head temperature during the test, etc.

[=MERCS=JenkemJunkie]

If it doesn't break during a test that alternates at 5 mins of WEP / 5 mins of low power, that doesn't mean that it needed the 5 min rest. Only a destruction test like the 27 hour Merlin test above would test its upper limits. It would trigger the timer though, as US planes need to rest 15 minutes to get the 5 min WEP back. Why would the US with plenty of resources not run their engines to destruction to find the upper limits? Slapping these gimped limits without destruction tests is about as good as saying high power is loud and scary, I feel like you should only use it for short periods and never too high. I thought men were men in the 40s.

[Metrallaroja]

On 12/22/2022 at 4:46 PM, Sgt_Joch said:

 I was replying to an earlier post, not the test you posted. Your test is actually very interesting since the engine was run at WEP for 5 minutes followed by a cool down period of 5 minutes at low rpm/MP before restarting at WEP again for 5 minutes, etc. No reason why that test should cause a problem and that would also not trigger the "timer" in game.

 

The questions to analyse these tests are generally the same: what was the parameters, what cooling solution was used in the tests and how did that differ from the cooling in the actual AC, what was the cylinder head temperature during the test, etc.

Im saying that this 7.5 WEP run tests all probably follow the same method, the ones described on my report. Only small variations depending on engine.

And as you can see it also includes 4x37.5 minutes of continous wep runs.

Edited December 23, 2022 by Metrallaroja

[Hoss]

Switch it from Expert to Custom or Normal and turn it off yourself.

 

Cheers

 

 

[CountZero]

11 hours ago, Hoss said:

Switch it from Expert to Custom or Normal and turn it off yourself.

 

Cheers

 

 

You cant, only option that turns off timers makes your airplane also unbrakable...