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

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2 minutes ago, Panthera said:

 

Seems like a pretty far fetched connection to make...

You know how the if the speed limit is set to 70mph you can bet a lot of people will be going 75-80, but if you set it at 80 you could expect a lot of people going 85-90? I imagine the manual limits and other precautions (seals/wires you have to break to go balls-to-the-wall) are a lot like that.

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2 hours ago, Rattlesnake said:

You attempted to use higher octane fuel as a reason why the Klimov can run indefinitely a given setting (assuming you can keep it cool), whereas the DB, a physically similar engine, is limited to 30 minutes at the somewhat less stressful settings called "combat" in this game. In order for this answer to make sense you must explain why the 87 octane fuel powering said DB engine is sufficient to protect from detonation at "combat" power for exactly 30 minutes, but insufficient thereafter, justifying a hard timer.

 

 

109s blowing up after 30 minutes at combat power? No one has ever claimed that. Get your facts straight.

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39 minutes ago, Sgt_Joch said:

 

109s blowing up after 30 minutes at combat power? No one has ever claimed that. Get your facts straight.

The *game* claims precisely that. The 109's engine WILL be damaged after a little over 30 minutes at combat setting, whereas the physically similar Klimov engine can be run indefinitely at somewhat higher boost and RPM indefinitely, assuming you can keep it cool. In defense of this mechanic you said the following:

"2.the 109F runs on 87 octane B4 fuel while the Yak-1 runs on 95 octane Russian Avgas which has a similar octane level to german c3 fuel. As you know, as a general rule, the higher the octane level, the higher the boost level you can sustain; 

 

3. the way engine limits work in game, you get much higher limits at an intermediate setting. For example, in tests I ran some times ago you could run a FW190 A3 at 1.37 ATA (with 96 octane C3 fuel) for 15 minutes or more with no issue. So German engines running with similar ATA/boost level and octane level as the Yak will also last a long time in the current system; and"

The problem here your use of the word "sustain". Given the right pressure and temperature detonation can occur immediately, conversely it can be held off indefinitely if that threshold is not crossed. Thus there is no "sustain" to it-you are either at a given moment over that threshold or you are not. So making the claim that it is the higher octane fuel which allows longer *time* at a given boost setting (as opposed to allowing access to higher boost settings that would otherwise result in detonation) is suspect. Now you can say "Well it will hold off detonation if temp rises" and that's just fine. However, this line of thinking does not defend the game mechanic, which is a simple timer, not a temperature thing.

So again for your explanation to be valid, you must explain why the German fuel has sufficiently high octane to protect against detonation for 30 minutes at this setting, but bizarrely will start failing to do so after close to immediately after a half hour has passed, justifying the hard timer. (Does the cooling system suddenly fall behind at the half hour mark, no matter atmospheric conditions and how you fly it? That sounds a little implausible...)

If you cannot do that than your higher octane fuel explanation for the discrepancy I was talking about must be rejected.

My contention is that the difference in settings for these very similar engines reflects nothing other than different levels of concern about engine life on the part of the manual writers, and that there is no justification for one of these engines lasting longer than the other on similar power settings in the game.

Edited by Rattlesnake
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34 minutes ago, Panthera said:

Seems like a pretty far fetched connection to make...

 

At least a correlation is present; attrition rates are there. The Nazi leadership was desperate as knew that would be (for obvious reasons) hang after the defeat thus they pushed performance envelope at any cost. At some point LW's pilots were so inexperienced that that their accident ratio approached combat loses. If so what point of prolonging TBO would be and conservative limits as stated in manuals? None.

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I'm big on realism, not "balance", but I do think that if 109's and 190's are allowed the kind of generous max-throttle allowances that some of you guys are advocating for (no regard for limits because TBO is meaningless , and you believe that pilots could and would always push 10, 15, or 20 minutes of max with no fear), kiss multiplayer goodbye🤣

Edited by SeaSerpent

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1 hour ago, Ehret said:

 

At least a correlation is present; attrition rates are there. The Nazi leadership was desperate as knew that would be (for obvious reasons) hang after the defeat thus they pushed performance envelope at any cost. At some point LW's pilots were so inexperienced that that their accident ratio approached combat loses. If so what point of prolonging TBO would be and conservative limits as stated in manuals? None.

 

Thing is you're the one making the correlation, and based on nothing other than speculation at this point.

 

Meanwhile as far as I can tell the LW had every reason to increase the TBO as much as possible, as they didn't want to loose anymore trained pilots, and they knew that every engine had to last longer between overhauls than recommended due to a general lack of oil. Hence why the reports from the period (1945) clearly state that any blatant violation of boost pressure limits would result in strict punishment. If what you theorize were to have been true, then such an order would've never been issued.

 

In short, correlation does not imply causation.

 

 

2 hours ago, Rattlesnake said:

You know how the if the speed limit is set to 70mph you can bet a lot of people will be going 75-80, but if you set it at 80 you could expect a lot of people going 85-90? I imagine the manual limits and other precautions (seals/wires you have to break to go balls-to-the-wall) are a lot like that.

 

For sure, they are there to keep pilots from treating their engines recklessly, because unlike what some seem to think in here engines weren't in inifinite supply - and even if they were, it took time to get replacements, meaning said aircraft is now grounded until a) a new engine arrives and b) until the mechs can get it installed. Ofcourse this assuming the ideal scenario where the aircraft with the broken engine manages to return home with its even more valuable cargo, i.e. the pilot.

 

 

Edited by Panthera

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35 minutes ago, Panthera said:

Meanwhile as far as I can tell the LW had every reason to increase the TBO as much as possible, as they didn't want to loose anymore trained pilots, and they knew that every engine had to last longer between overhauls than recommended due to a general lack of oil. Hence why the reports from the period (1945) clearly state that any blatant violation of boost pressure limits would result in strict punishment. If what you theorize were to have been true, then such an order would've never been issued.

 

If they had to increase TBO due lack of oil then wouldn't be that admission that they can not service them properly? Actually, if one would be so concerned about avoiding eng failures at any cost then would decrease the TBO as much as it's practically possible; not in reverse.

And LW was losing experienced pilots due the combat and when you lost about 1/3 of your fighter force per month you would increase the TBO?!

At that order from 1945 - isn't it about the already high strung engines running like +1.8 ATA settings? Probably, pilots were so desperate that they were trying go even higher ATA; no wonder then the engines were failing. That's exactly the thing I wrote about.

 

It's important to remember that we are talking about the Nazi leadership. Göring himself made unremarkable comments about German pilots numerous times. That report from 1945 could be just a blame game; you know... when anything gone wrong it was pilots fault. Engines seized because of bad alloys, bad oil, gums in fuel... no... not to people like him.

 

35 minutes ago, Panthera said:

For sure, they are there to keep pilots from treating their engines recklessly, because unlike what some seem to think in here engines weren't in inifinite supply - and even if they were, it took time to get replacements, meaning said aircraft is now grounded until a) a new engine arrives and b) until the mechs can get it installed. Ofcourse this assuming the ideal scenario where the aircraft with the broken engine manages to return home with its even more valuable cargo, i.e. the pilot.

 

At late war Germany had more airplanes than fuel and pilots. So yes - engines were kind of in infinity supply by then.

Edited by Ehret

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1 hour ago, SeaSerpent said:

I'm big on realism, not "balance", but I do think that if 109's and 190's are allowed the kind of generous max-throttle allowances that some of you guys are advocating for (no regard for limits because TBO is meaningless , and you believe that pilots could and would always push 10, 15, or 20 minutes of max with no fear), kiss multiplayer goodbye🤣

It wouldn't make a difference imo. If limits are removed everything will remain the same imo, you'll just use much more fuel.

Multiplayer wouldn't change much at all since when you get into combat you're going maxed out most of the time anyways and using as much power as possible.

The only thing that will change is that no limits will be a more realistic (not perfect) representation.

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56 minutes ago, Legioneod said:

It wouldn't make a difference imo. If limits are removed everything will remain the same imo, you'll just use much more fuel.

Multiplayer wouldn't change much at all since when you get into combat you're going maxed out most of the time anyways and using as much power as possible.

The only thing that will change is that no limits will be a more realistic (not perfect) representation.

 

I disagree with that.  The difference between a Bf-109 that can only do flat out for a minute or two vs one that can do it for 15 minutes or more is pretty significant in my opinion.  In mp, when I fly German, I am most definitely not "maxed out" except in emergencies, or for very short bursts of power.  That makes a heckuva lot of difference, especially during egresses.  In fact, when flying on comms with wingmen, firewalling it for more than a few seconds is a situation noteworthy enough that one of us will declare "going to emergency!!!" and that's almost always because he has a gaggle of bandits on his tail and is up s*&t creek.  You're saying you think it would make no difference, but imo, wow, to be able to just firewall that thing and essentially forget about it for 15+ minutes would be the difference between night and day.

Edited by SeaSerpent
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S! 

 

Maybe my typing as non-english speaker was not clear enough. By extreme cold I meant that a plane flying at 30kft is subjected to totally different temperatures and pressures than an engine strapped into a test bench with a load prop at sea level. Clear? 

 

And I did agree the R-2800 should be able to take the 64" for 15min without breaking, if the proper procedures were used. In game one can abuse stuff to heck and back, if you put time and effort to find those loopholes. 

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52 minutes ago, LLv34_Flanker said:

S! 

 

Maybe my typing as non-english speaker was not clear enough. By extreme cold I meant that a plane flying at 30kft is subjected to totally different temperatures and pressures than an engine strapped into a test bench with a load prop at sea level. Clear? 

 

And I did agree the R-2800 should be able to take the 64" for 15min without breaking, if the proper procedures were used. In game one can abuse stuff to heck and back, if you put time and effort to find those loopholes. 

 

Well, at the very least it is fairly accurate at sea level then.

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9 hours ago, Rattlesnake said:

The *game* claims precisely that. The 109's engine WILL be damaged after a little over 30 minutes at combat setting, whereas the physically similar Klimov engine can be run indefinitely at somewhat higher boost and RPM indefinitely, assuming you can keep it cool. In defense of this mechanic you said the following:

 

1- why would you need to run a 109 at combat power for more than 30 minutes? that is a strawman argument.

2- even assuming you keep temps in check, a Yak at 100% power will run out of fuel before 30 minutes, so no in practice you get the same 30 minute limit.

9 hours ago, Rattlesnake said:


"2.the 109F runs on 87 octane B4 fuel while the Yak-1 runs on 95 octane Russian Avgas which has a similar octane level to german c3 fuel. As you know, as a general rule, the higher the octane level, the higher the boost level you can sustain; 

 

which is a correct statement. I agree.

9 hours ago, Rattlesnake said:

 

3. the way engine limits work in game, you get much higher limits at an intermediate setting. For example, in tests I ran some times ago you could run a FW190 A3 at 1.37 ATA (with 96 octane C3 fuel) for 15 minutes or more with no issue. So German engines running with similar ATA/boost level and octane level as the Yak will also last a long time in the current system; and"

which is also a correct statement. I agree.

9 hours ago, Rattlesnake said:


The problem here your use of the word "sustain". Given the right pressure and temperature detonation can occur immediately, conversely it can be held off indefinitely if that threshold is not crossed. Thus there is no "sustain" to it-you are either at a given moment over that threshold or you are not. So making the claim that it is the higher octane fuel which allows longer *time* at a given boost setting (as opposed to allowing access to higher boost settings that would otherwise result in detonation) is suspect. Now you can say "Well it will hold off detonation if temp rises" and that's just fine. However, this line of thinking does not defend the game mechanic, which is a simple timer, not a temperature thing.
 

 

given equal factors, a higher octane level will sustain a higher boost. That is not a questionable fact or line or argument. Why do you think the U.S./U.K. spent so much time and money developing higher octane fuel.

 

also, no one here is defending the current game mechanism. We all agree it has to be updated, but it has nothing to do with your argument which is why in real life, there was no time limit on the yak.

9 hours ago, Rattlesnake said:


If you cannot do that than your higher octane fuel explanation for the discrepancy I was talking about must be rejected.
 

 

no, that is an incorrect statement.  You can't reject basic chemistry. Given equal factors, a higher octane level will sustain a higher boost.

9 hours ago, Rattlesnake said:


My contention is that the difference in settings for these very similar engines reflects nothing other than different levels of concern about engine life on the part of the manual writers, and that there is no justification for one of these engines lasting longer than the other on similar power settings in the game.

 

which is an incorrect conclusion in this case, since the Yak-1 ran at 1.37 ata on 95 octane gas while the 109 ran on 1.3 ata on 87 octane gas. The extra +1 lb boost can easily be explained just by the much higher octane content.

 

Remember, I am speaking about what happened in real life in WW2. You seem to be getting that confused with a game mechanic. Apples and oranges.

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6 minutes ago, Sgt_Joch said:

2- even assuming you keep temps in check, a Yak at 100% power will run out of fuel before 30 minutes, so no in practice you get the same 30 minute limit.

 

You ever flown the Yak?

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19 minutes ago, Sgt_Joch said:

2- even assuming you keep temps in check, a Yak at 100% power will run out of fuel before 30 minutes, so no in practice you get the same 30 minute limit.

Complete nonsense. You can fly for 50 minutes at 100% easily.

20 minutes ago, Sgt_Joch said:

which is an incorrect conclusion in this case, since the Yak-1 ran at 1.37 ata on 95 octane gas

I think you're confusing ATA with ATM.

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9 minutes ago, Matt said:

I think you're confusing ATA with ATM.

 

If i remember correctly, 1040mmHg is equal to 1.41ata.

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16 minutes ago, RoflSeal said:

"Greater powers to be used for short periods (15-20 minutes) during combat"

🤔

 

And as importantly: "...saved many Eight Air force P-47s."

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9 hours ago, SeaSerpent said:

The difference between a Bf-109 that can only do flat out for a minute or two vs one that can do it for 15 minutes or more is pretty significant in my opinion.

 

You can already go for 10 minutes in the K4.

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On 12/13/2018 at 11:15 AM, Rattlesnake said:

This is the right direction, the problem with the specific numbers you state though is that there is no evidence that destructive overheats would necessarily occur if you left WEP on for 8 minutes instead of 5. In fact, as has been pointed out myriad times there is much evidence that these engines could and frequently did go significantly longer than the manual limit without failure. So to implement this solution correctly you couldn't just say "Engine overheat begins after five minutes", you would need to figure out some plausible figures for how long it *actually* takes a given aircraft to overheat at a given power setting at certain atmospheric conditions. A tough undertaking.

Or you could just give everything about 10-15 minutes of WEP, which would fix about 85% of the logical inconsistencies and problems and get us much closer to how these things were actually flown in combat while consuming almost no man-hours.

 

The numbers are not actually relevant. They are just hypothetical examples.

 

The key is that time spent at a temperature/pressure combination that produces detonation WILL damage the engine. The longer time spent there will create more damage. The higher the temperature or pressure, the more damage. 

 

That damage is progressive and can lead to catastrophic failure.

 

The difficult part in simulating this is the large number of variables involved in the real world. Cooling has a tremendous impact on the equation and that cooling takes MANY forms, environmental and mechanical. The particular metallurgical properties of an individual engine influence the damage. Previous wear plays a big role.

 

In game, we can assume all engines are identical and brand new. Rates of cooling can be easily varied based upon airspeed for air cooled engines, coolant temperature in liquid cooled, mixture setting (fuel is a major coolant inside the engine) and environment for all aircraft.

 

Each aircraft should have easily readable temperature limits that when complied with do not result in engine damage. When exceeded, the damage should be progressive according to the time spent there and the actual value.

 

That is the way it works in the real world from the pilot perspective for all engines. 

 

The idea of a timer causing catastrophic failure is silly. Time spent in excess of the published limit producing progressive damage based upon length and severity of the excursion is simple but reasonably realistic.

 

There is no need to actually simulate all of the physics, chemistry, and materials science that are involved in piston engine failure modes.

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Why would you have your emergency power going for thirty minutes, anyway?

14 hours ago, Sgt_Joch said:

109s blowing up after 30 minutes at combat power? No one has ever claimed that. Get your facts straight.

 

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1 hour ago, Stilicho said:

 

You can already go for 10 minutes in the K4.

 

No kiddin" ?????🙄 From the context of my comment, it was obvious I was talking about aircraft that are currently limited in game to about 1 minute, in response to a comment that removing that limit would make "no difference".    This thread would be a lot more useful if people followed the discussion before commenting.

Edited by SeaSerpent

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2 hours ago, SeaSerpent said:

 

No kiddin" ?????🙄 From the context of my comment, it was obvious I was talking about aircraft that are currently limited in game to about 1 minute, in response to a comment that removing that limit would make "no difference".    This thread would be a lot more useful if people followed the discussion before commenting.

 

My point is that the K4 already gets a longer and more powerful WEP than all the previous 109's, so I don't see how that extra bit that a 190, for instance, would get by going from combat to emergency for longer periods of time would destroy the game.

 

No aircraft in the game will become any more overpowered than they already are, but several aircraft that are horribly handicapped will actually become competitive, like they were historically.

Edited by Stilicho

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1 hour ago, Stilicho said:

 

My point is that the K4 already gets a longer and more powerful WEP than all the previous 109's, so I don't see how that extra bit that a 190, for instance, would get by going from combat to emergency for longer periods of time would destroy the game.

 

No aircraft in the game will become any more overpowered than they already are, but several aircraft that are horribly handicapped will actually become competitive, like they were historically.

 

Sorry man, but regardless of the ongoing discussion about what engine limits/restrictions *should* be in this game (or which side of the discussion you are on) if you can't see the difference between a 109 and 190 being able to run at flat out, balls-to-the wall 1.42 for 10, 15 or more minutes guaranteed vs one that is now limited to doing it for 1 to 3 minutes after which the only thing guaranteed is catastrophic failure, then I don't even know where to begin....

Edited by SeaSerpent

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29 minutes ago, SeaSerpent said:

 

Sorry man, but regardless of the ongoing discussion about what engine limits/restrictions *should* be in this game (or which side of the discussion you are on) if you can't see the difference between a 109 and 190 being able to run at flat out, balls-to-the wall 1.42 for 10, 15 or more minutes guaranteed vs one that is now limited to doing it for 1 to 3 minutes after which the only thing guaranteed is catastrophic failure, then I don't even know where to begin....

LaGGs and Yaks would be worse off but P-39/40 and Spitfire Mk Vb will be better off

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16 hours ago, Ehret said:

If they had to increase TBO due lack of oil then wouldn't be that admission that they can not service them properly? Actually, if one would be so concerned about avoiding eng failures at any cost then would decrease the TBO as much as it's practically possible; not in reverse.

And LW was losing experienced pilots due the combat and when you lost about 1/3 of your fighter force per month you would increase the TBO?!

At that order from 1945 - isn't it about the already high strung engines running like +1.8 ATA settings? Probably, pilots were so desperate that they were trying go even higher ATA; no wonder then the engines were failing. That's exactly the thing I wrote about.

 

Admission? No, that's not quite how things work.

 

The LW was losing experienced pilots due to all causes, and you can be sure they didn't want engine failure to be one of them. Hence why the Germans did everything they could to improve pilot survival chances, being the first to develop ejection seats and blow away canopies etc. Also the TBO's did go down dramatically, they had to, as most of the engines were running for much longer between oil changes. Hence why you have LW pilots saying their engines were overhauled every 50 hours (same as a Jumo 004) at that point in the war, they had to baby every single one of the engines as they simply couldn't afford to have them fail in flight.

 

 

 

7 hours ago, RoflSeal said:

From “EIGHTH AIR FORCE TACTICAL DEVELOPMENT AUGUST 1942-MAY 1945” 
https://ia801906.us.archive.org/23/items/EighthAirForce00/EighthAirForce00.pdf

unknown.png
"Greater powers to be used for short periods (15-20 minutes) during combat"

🤔

 

Yes, water injection is one of the best ways to ensure safe operation at high boost pressures as it cools down the temperatures inside the cylinders directly. Hence why the P-47 (and the MW equipped German aircraft) really ought to be able to run at their max boost pressures for as long as they liked with this enabled.  But since the German aircraft with this system get a 10 min limit ingame then that's also what you have to give the P-47 as well (incl. the ability to recharge at combat power) The current 5 min limit doesn't make any sense for an aircraft equipped with such a system.

 

 

Edited by Panthera

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30 minutes ago, Panthera said:

 

 

Yes, water injection is one of the best ways to ensure safe operation at high boost pressures as it cools down the temperatures inside the cylinders directly. Hence why the P-47 (and the MW equipped German aircraft) really ought to be able to run at their max boost pressures for as long as they liked with this enabled.  But since the German aircraft with this system get a 10 min limit ingame then that's also what you have to give the P-47 as well (incl. the ability to recharge at combat power) The current 5 min limit doesn't make any sense for an aircraft equipped with such a system.

 

 

I still don't think a P-51D should have a 5 minute limit.
Their emergency powers were not much higher then their military powers in comparison to water injection.
61 -> 67 "Hg vs 52 -> 64 "Hg . To me it seems, as expected, water injection increases the threshold to detonation, but there is no reason to assume why 67"Hg for the packard merlin cannot be run long (and it was run longer then 5 minutes), it's power increase is not as large as water injected engines.

Another case in point is the Bf-109s

Combat power at 1.3 ->1.42 ata and 1.7 ata with MW-50

However in the G-14, if you are at 1.42 ata you have you use your WEP allowance in 1 minute (same as the early 109s). This to me doesn't make sense, in my opinion, the load on the engine at 1.42 ata shouldn't be 10x as damaging as 1.7 ata with MW-50.

Same inconsitency with the FW-190A-8 where you can run 1.42 ata for 3 mins only, but 1.58/1.65 ata for 10 minutes (and this was done by tricking the Kommandogerat, thinking the manifold pressure was lower then it actually was, no extra injection of anything)

Edited by RoflSeal

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12 minutes ago, RoflSeal said:

I still don't think a P-51D should have a 5 minute limit.
Their emergency powers were not much higher then their military powers in comparison to water injection.
61 -> 67 "Hg vs 52 -> 64 "Hg . To me it seems, as expected, water injection increases the threshold to detonation, but there is no reason to assume why 67"Hg for the packard merlin cannot be run long (and it was run longer then 5 minutes), it's power increase is not as large as water injected engines.

Another case in point is the Bf-109s

Combat power at 1.3 ->1.42 ata and 1.7 ata with MW-50

However in the G-14, if you are at 1.42 ata you have you use your WEP allowance in 1 minute (same as the early 109s). This to me doesn't make sense, in my opinion, the load on the engine at 1.42 ata shouldn't be 10x as damaging as 1.7 ata with MW-50.

Same inconsitency with the FW-190A-8 where you can run 1.42 ata for 3 mins only, but 1.58/1.65 ata for 10 minutes (and this was done by tricking the Kommandogerat, thinking the manifold pressure was lower then it actually was, no extra injection of anything)

 

I agree that ideally it should be higher for the aircraft without water injection as well, but seeing as the developers apparently insist on having these time limits then 10 min of WEP at a time for those with water injection and 5 min for those without it seems like a good compromise, providing the recharge period is kept equal ofcourse. It's a compromise I could live with at least.

 

 

 

 

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11 hours ago, Sgt_Joch said:

 

1- why would you need to run a 109 at combat power for more than 30 minutes? that is a strawman argument.

2- even assuming you keep temps in check, a Yak at 100% power will run out of fuel before 30 minutes, so no in practice you get the same 30 minute limit.

which is a correct statement. I agree.

which is also a correct statement. I agree.

 

given equal factors, a higher octane level will sustain a higher boost. That is not a questionable fact or line or argument. Why do you think the U.S./U.K. spent so much time and money developing higher octane fuel.

 

also, no one here is defending the current game mechanism. We all agree it has to be updated, but it has nothing to do with your argument which is why in real life, there was no time limit on the yak.

 

no, that is an incorrect statement.  You can't reject basic chemistry. Given equal factors, a higher octane level will sustain a higher boost.

 

which is an incorrect conclusion in this case, since the Yak-1 ran at 1.37 ata on 95 octane gas while the 109 ran on 1.3 ata on 87 octane gas. The extra +1 lb boost can easily be explained just by the much higher octane content.

 

Remember, I am speaking about what happened in real life in WW2. You seem to be getting that confused with a game mechanic. Apples and oranges.

1. Indeed the 30 minute Combat Power limit is not particularly a handicap for players. I bring it up because it demonstrates how arbitrary some of these limitations are, and not related to any physical factors.

2. "given equal factors, a higher octane level will sustain a higher boost."-Higher octane will ALLOW higher level of boost without detonation, yes.  The 109 "combat" power setting under discussion is obviously not causing detonation. How do we know this for certain? Because it is cleared to run that way for *30 minutes.*

Higher octane fuel is not a factor in this comparison because detonation isn't happening for either airplane. So again saying "Well the Russians had higher octane fuel" explains nothing about the situation. Unless, AGAIN, you can explain why the German fuel has adequate octane to protect against detonation at "combat" for the first 30 minutes, but not afterwards, this being independent of temperature and how the airplane is being operated, etc.

"Why do you think the U.S./U.K. spent so much time and money developing higher octane fuel."-Clearly to *allow* HIGHER boost levels, which makes greater power without increasing engine size. For instance, the P-51 could run up to 75" with 150 octane fuel, whereas even the 1.98 ATA with the 109 K4 works out to only around 60". That's why the Merlin could make more horsepower than many of the DBs, despite being smaller. Obviously this is a tremendously desirable situation.

But we are not talking about why some airplanes are allowed to pull higher levels of boost than others. We are talking about why the 109 F4's engine is given a hard limit of about 30 minutes of life at "combat" in game, despite this power setting being lower than that which for the Yak is given no definite limit.


"Given equal factors, a higher octane level will sustain a higher boost."-This is a deceptive bait and switch tactic. Yes, higher octane will allow an engine to use higher boost levels without detonation.  But it doesn't do anything to increase engine life at boost levels that *are not causing detonation in the first place*. And clearly a setting which can be used for 30 minutes at a time falls into this category.

Intoning "it's basic chemistry" over and over will do nothing to conceal the fact that either your logic about the relationship between octane, boost, and engine life is sloppy, or you are being deliberately disingenuous by bringing octane and detonation into a question where it is not a factor.

8 hours ago, =475FG=DAWGER said:

 

Each aircraft should have easily readable temperature limits that when complied with do not result in engine damage.

That would be a vast improvement even without any changes whatsoever in the actual times.

A point I have had in mind but perhaps have not made clear enough is this: If your engine limitation mechanic is going to be "Surprise! Your engine is dead!" then you damn well need destruction to take a plausibly long time, probably at least twice as long as the manual limits, because most of those were clearly written conservatively.

If it's some other sort of mechanic, such as WEP automatically switching off when times are exceeded or a gauge starting to get into the danger zone at the right time, well then the book limit is less onerous.

20 hours ago, SeaSerpent said:

I'm big on realism, not "balance", but I do think that if 109's and 190's are allowed the kind of generous max-throttle allowances that some of you guys are advocating for (no regard for limits because TBO is meaningless , and you believe that pilots could and would always push 10, 15, or 20 minutes of max with no fear), kiss multiplayer goodbye🤣

Balance is very important, and most of us don't want to rid the game of any incentive to avoid running around balls to the wall.

But it does not follow that the current inaccurate, arbitrary, and annoying limits are the ONLY way to create balance. And it is ludicrous to imply that a virpil with 10-15 minutes of WEP has no incentive to throttle back, ever. I mean, 109 K4s currently have 10 minutes of WEP, do they spend entire sorties (in realistic arenas) with it firewalled, or do they save it for when they're actually dogfighting?

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As I've said to some others, if you don't get the obvious difference between going from 1 minute 'limits' (reserved for short bursts of power and true emergencies) to 10 minutes or even unlimited, and understand how that impacts the relative performance of the aircraft during combat and egress, and how people might use that power, then it's not worth my time to bother with any ensuing discussion about it. 

Edited by SeaSerpent

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4 hours ago, Rattlesnake said:

1. Indeed the 30 minute Combat Power limit is not particularly a handicap for players. I bring it up because it demonstrates how arbitrary some of these limitations are, and not related to any physical factors.

2. "given equal factors, a higher octane level will sustain a higher boost."-Higher octane will ALLOW higher level of boost without detonation, yes.  The 109 "combat" power setting under discussion is obviously not causing detonation. How do we know this for certain? Because it is cleared to run that way for *30 minutes.*

Higher octane fuel is not a factor in this comparison because detonation isn't happening for either airplane. So again saying "Well the Russians had higher octane fuel" explains nothing about the situation. Unless, AGAIN, you can explain why the German fuel has adequate octane to protect against detonation at "combat" for the first 30 minutes, but not afterwards, this being independent of temperature and how the airplane is being operated, etc.

"Why do you think the U.S./U.K. spent so much time and money developing higher octane fuel."-Clearly to *allow* HIGHER boost levels, which makes greater power without increasing engine size. For instance, the P-51 could run up to 75" with 150 octane fuel, whereas even the 1.98 ATA with the 109 K4 works out to only around 60". That's why the Merlin could make more horsepower than many of the DBs, despite being smaller. Obviously this is a tremendously desirable situation.

But we are not talking about why some airplanes are allowed to pull higher levels of boost than others. We are talking about why the 109 F4's engine is given a hard limit of about 30 minutes of life at "combat" in game, despite this power setting being lower than that which for the Yak is given no definite limit.


"Given equal factors, a higher octane level will sustain a higher boost."-This is a deceptive bait and switch tactic. Yes, higher octane will allow an engine to use higher boost levels without detonation.  But it doesn't do anything to increase engine life at boost levels that *are not causing detonation in the first place*. And clearly a setting which can be used for 30 minutes at a time falls into this category.

Intoning "it's basic chemistry" over and over will do nothing to conceal the fact that either your logic about the relationship between octane, boost, and engine life is sloppy, or you are being deliberately disingenuous by bringing octane and detonation into a question where it is not a factor.

 

Add to this that no airforce or engine maker would ever clear a boost rating likely to destroy the engine within 1, 5 or even 10 min of uninterrupted use. Hence why 1.42ata was altogether banned until the issue of insufficient cooling was solved. Two of the ways they solved the issue is explained in period documents, the main one I am told being the deaeration of the oil. Deaerating the oil would've greatly reduced friction heat and improved oil cooling rate at the same time, and this alone was probably enough to avoid detonation. But other than that they also redesigned the piston heads, and it's possible the timing of the ignition was adjusted as well. 

 

However to increase the boost pressure beyond 1.42ata in the DB605 and still have a reliable engine they had to either use a higher octane fuel, incorperate water or water methanol injection or "simply" redesign the engine. Thus it's no surprise they went for MW injection in general, and higher octane C3 when possible, as further redesign of the engine would've likely only lead to meagre increases in power at a cost of an unacceptably long development time. 

 

That said they managed to squeeze a remarkable amount of power out a size wise quite small engine. Infact IIRC the DB605 is even a tiny bit smaller dimensionally than the Merlin engine, despite the noticable difference in displacement. 

 

 

 

Edited by Panthera
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9 hours ago, Rattlesnake said:


"Given equal factors, a higher octane level will sustain a higher boost."-This is a deceptive bait and switch tactic. Yes, higher octane will allow an engine to use higher boost levels without detonation.  But it doesn't do anything to increase engine life at boost levels that *are not causing detonation in the first place*. 

To expand on this, the use of 150 Octane MMA fuel actually decreased the life of specific engine parts at cruise power settings, specifically the spark plugs which had to be changed nearly every 1-2 missions. Spark plugs fouled at cruise power settings and to fix it the engine had to be run at max power for a minute or so every so often and when 8AF changed to 150 PEP, the valve seats corroded after 100-180 hours

Edited by RoflSeal
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Simply put. Engines using C3 fuel have 3 minutes@1.42 ata. For example the focke wulf 190 in game. Engines with 87 octane have only 1 minute@1.42. IF even allowed to use that. It is unsafe to use high pressures with low octane fuels thats why it was restricted.

 

Any mention of 3-5 minutes 1.42 ata obviously refers to engine test bench results and or higher octane fuels. As long as the engine is installed into an airplane and with low grade fuel it should not be allowed more than 1 minute.

 

here it says 1 minute

 

 


post-13-0-09839700-1395214059.jpg

post-13-0-67813100-1395216978.jpg

post-13-0-78767400-1395219113.jpg
 

 

 

Edited by Max_Damage
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10 hours ago, Rattlesnake said:

For instance, the P-51 could run up to 75" with 150 octane fuel, whereas even the 1.98 ATA with the 109 K4 works out to only around 60".

You cannot compare it that directly. The Merlin runs at 6:1 compression, the DB engines up to 8.5:1.

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45 minutes ago, Max_Damage said:

Simply put. Engines using C3 fuel have 3 minutes@1.42 ata. For example the focke wulf 190 in game. Engines with 87 octane have only 1 minute@1.42. IF even allowed to use that. It is unsafe to use high pressures with low octane fuels thats why it was restricted.

 

here it says 1 minute

 

  Reveal hidden contents

 

 


post-13-0-09839700-1395214059.jpg

post-13-0-67813100-1395216978.jpg

post-13-0-78767400-1395219113.jpg
 

 

 

 

 

First of all you can't compare two seperate engines like that, the DB605 could for example run at 1.8 ata on C3 alone for 10 min (and obviously longer still, just like the Merlin could run at 18 " Hg for a lot longer than 5 min) without issue, adding MW on top and you could crank it up to 1.98ata (although this did require different spark plugs) .

 

Secondly 1.42ata was altogether banned in the manuals you just listed, hence the 1 min limit. Once 1.42ata was cleared however (late summer 43) no time limit appears for 1.42ata again, and that probably because the deaeration of the oil helped cool the engine so much that the risk of detonation was altogether eliminated at any probable scenario the engine would face within the cleared ratings.

 

 

 

Edited by Panthera
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7 hours ago, ZachariasX said:

You cannot compare it that directly. The Merlin runs at 6:1 compression, the DB engines up to 8.5:1.

 

And had different CRs between cylinder banks.

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Having flown the P47 a bit in actual long sorties, simply having the emergency cool down during combat mode would be an acceptable bandaid pending an actual change to the system.

 

The current limits are 'usable', the punishing part is that its impossible to keep track of where your times are at during a sortie. If you spend 2 minutes at 59 inches with water injection, 1 minute at max emergency, then 4 minutes at max combat, how much time do you have left at emergency until your engine dies?

 

This is absurd and nobody can calculate this on the fly, even assuming you were able to somehow keep track of how long you spend in each mode.

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Just now, =RvE=Windmills said:

Having flown the P47 a bit in actual long sorties, simply having the emergency cool down during combat mode would be an acceptable bandaid pending an actual change to the system.

 

The current limits are 'usable', the punishing part is that its impossible to keep track of where your times are at during a sortie. If you spend 2 minutes at 59 inches with water injection, 1 minute at max emergency, then 4 minutes at max combat, how much time do you have left at emergency until your engine dies?

 

This is absurd and nobody can calculate this on the fly, even assuming you were able to somehow keep track of how long you spend in each mode.

 

Thats why i was thinking before it even got to game not many wll bather with american airplanes after i saw how P-40 engine was modeled in game, didnt bather to get P-39 (was geting hot for ti watching Krupinskii videos but now its 37mms is bad, and you cant count on 1 hit so even more no point in geting it), who will be bathered with timing all that stuff and then you dont know if your engine will just quit if you forgeth to add few seconds.

For short df on berloga its more then fun, im keping wait for Tempest, and i expect it will have same engine limits as Spitfire 9 so thats better then what american metal gets in this game.

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35 minutes ago, =RvE=Windmills said:

Having flown the P47 a bit in actual long sorties, simply having the emergency cool down during combat mode would be an acceptable bandaid pending an actual change to the system.

 

The emergency timer in the P-47 (and the P-39, too) does regenerate in the combat mode. The problem is the emergency mode depletes quickly the combat mode as well. If you use up the whole emergency interval and didn't touch combat you will have about 6m of latter left and that's simply not enough. Worse yet, the combat timer will not regenerate until the emergency (10m needed for 100%) regenerated... In practice it means if you used half of your emergency time already it's time to RTB. To regenerate combat/emergency from fully depleted to fully fresh 25m is needed. No sense doing that; just RTB instead.

 

The way to around that is to refrain from using the 64" MP as much as possible and keep the water injection at 58". It will switch the timer to combat mode and will allow for 15m in one go. So, timers in the P-47 are effectively -6" MP handicap or even -12" if we consider what would be possible with the 150 octane fuel.

Edited by Ehret

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13 minutes ago, Ehret said:

 

The emergency timer in the P-47 (and the P-39, too) does regenerate in the combat mode. The problem is the emergency mode depletes quickly the combat mode as well. If you use up the whole emergency interval and didn't touch combat you will have about 6m of latter left and that's simply not enough. Worse yet, the combat timer will not regenerate until the emergency (10m needed for 100%) regenerated... In practice it means if you used half of your emergency time already it's time to RTB. To regenerate combat/emergency from fully depleted to fully fresh 25m is needed. No sense doing that; just RTB instead.

 

The way to around that is to refrain from using the 64" MP as much as possible and keep the water injection at 58". It will switch the timer to combat mode and will allow for 15m in one go. So, the timers in the P-47 are just -6" MP handicap or even -12" if we consider what should be possible with the 150 octane fuel.

 

Thanks, it's too complex that's for sure. If you could just spend 5 minutes at combat/continuous and know your timers will be fully recharged it would make everything a whole lot easier.

 

The frustrating part is that I actually think the P47 is a really good combat aircraft, even against its current opposition. But this inability to recharge its timers is killing it atm.

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