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

[Rattlesnake]

3 minutes ago, =362nd_FS=Hiromachi said:

Not surprising as it was already known how artificial are the ingame engine limits. But its nice to see the confirmation by "paper" that "paper" they are coding into the FMs is just a ... paper. Real aircraft and powerplants are not bound by such limitations. It's also of another note how prolonged use of high power ratings is not a problem for as long as pressures and temperatures are kept within limits. Cant recall how many times my engine in P-40 failed yet no indication on pressure gauge or oil temperature gauge would indicate upcoming disaster and this two seem to be very much disconnected in various FMs. 

Yep, the inability to effectively monitor is perhaps the worst problem with current WEP system. Other games use temperature gauges, which IS. artificial (most engines could stay cool at WEP under most conditions), yet it does allow comprehensible management.

[=362nd_FS=Hiromachi]

You can realistically inform pilot about something going wrong by other means as Jtd has indicated: 

 

[Venturi]

From a realism standpoint, Detonation is the simple answer to these engine timer limits discussions.

 

It has been a problem for at least a decade or longer in WW2 sims.

 

IN GAME TERMS,

Pilots should not have a timer unless you run into detonation territory of manifold pressure, RPM, and mix.

 

Detonation was the true limiting factor of WW2 engine longevity IN A SINGLE SORTIE.

 

Engine wear occurred over many sorties and thus cannot be easily implemented in a game environment like IL-2 BOx, given the devs' philosophy of "new plane every time".

 

The performance limit that detonation imposes, is why intake manifold water/alcohol injection was invented in the first place... to delay the onset of detonation and thus be able to increase manifold pressure (power) higher than the fuel being used would otherwise permit.

 

The problem... implementing such a detonation system essentially requires fleshing out a large aspect of the core simulation of IL-2. So it would require a lot of work from the devs considering the expansive number of aircraft in IL-2 BOx.

 

A few factors they would need to implement for such a model to be satisfactory to the devs' own standards, I presume:

 

Quote

 

1. Understanding the fuel each engine ran on historically

    (this information is available)

 

2. Understanding the maximum manifold pressure, given optimum RPM and mixture, before the onset of detonation kicked in for each engine / fuel combination

    (this sometimes correlated with published engine power limits, and sometimes not)

    (yes the info is available, I have written on it here before)

 

3. Understanding when the onset of detonation occurs as:

   a. mixtures are leaned when manifold pressures remain high (=detonation)

   b. manifold pressures remain high and RPM is severely reduced (=detonation)

      (yes these are important for simulation accuracy)

      (yes the info is available, I have written on it here before)

 

 

 

Advantages:

 

1. Super conservative pilot's manuals which affect some aircraft much more than others, are eliminated as a consideration. Historical comparative performances are restored without strange FM tweaking.

2. Fuels can be adjusted in aircraft options given the timeframe the map is on, as an "aircraft modification".

3. Pilot behavior becomes more historical re: engine management, without tedious and immersion-breaking "timer watcher", "gamey-ness" is reduced.

[Velxra]

At any rate, the suggested improvements over the current much disliked WEP timer would greatly benefit the game. I like the idea of unlimited combat power for all planes because it was a well within spec rating. US planes having a deteriorating combat power is simply ridiculous by any measure and hugely unrealistic. 

[HR_Zunzun]

4 hours ago, Geronimo553 said:

At any rate, the suggested improvements over the current much disliked WEP timer would greatly benefit the game. I like the idea of unlimited combat power for all planes because it was a well within spec rating. US planes having a deteriorating combat power is simply ridiculous by any measure and hugely unrealistic. 

 

Without simulating wearing, I think that unlimited combat power sound more reasonable than unlimited wep. Even for the p40 and p39 would be very useful.

 

Coming back to the 7 1/2 hours of wep test I found this in a discussion about p47 overboosting in this forum.:

 

https://ww2aircraft.net/forum/threads/overboosting-the-p-47s-engines-need-some-clarifications.34328/

 

"The American standard for WEP was that the trail test engine had to run for 7 1/2 hours at the WEP power level, in 5 min increments. 90 five minute periods separated by 5 min "cool down" periods at idle or a cruise setting. There was obviously some room to "play" with without immediate disaster but again, subject to some limits. Over revving the engine to get more boost was really going to screw things up. "

 

He doesn´t say where it gets it from but sounds plausible.

[ZachariasX]

10 hours ago, Venturi said:

A few factors they would need to implement for such a model to be satisfactory to the devs' own standards, I presume:

Although I love the idea, I'm not sure that this would be a viable way to do it. I mean, it would take A LOT more systems modelling than we actually do have right now.

 

It would require that not only fuel flow and mixture curves are correct over the entire throttle range, it would also need to come up with corresponding EGT/burn temperatures (you can well burn your engine before you have predetonation). You also need to take athmosphere humidity into account to compute these things right. Usually this works when having an engine at hand and you take values from the engine as it runs given settings/ratings, but this is hardly possible for our sim. But it would be extremely important to have accurate values as we have very, very high performing engines, not just any Rotax or Lycoming that are basically ok with almost any setting (compared to the highly supercharged engines).

 

In sum, you would need a more detailed athmosphere plus you needed far, far more systems modelling. You think all that would be possible within an average of $10 per plane sales price?

[BlitzPig_EL]

Not only the price of aircraft models, but it would also reduce the numbers of units on any given map because of increased computational overhead.  We already have enough issues with the inability to have large numbers of "AI" and player units on a map, all this talk of hyper-real engine modeling is simply unrealistic given the current limitations of the game engine.

[=362nd_FS=RoflSeal]

Regarding P-47C powersettings,

Expectation of 20 min of usage of combat power in a sortie

 

Meanwhile the P-47C manual gives a 5 minute limit

 

[Talon_]

8 hours ago, RoflSeal said:

Regarding P-47C powersettings,

Expectation of 20 min of usage of combat power in a sortie

 

Meanwhile the P-47C manual gives a 5 minute limit

 

 

This should be submitted as a bug then as with current engine limit "recharge" times it is not possible to spend 20 minutes at WEP in a sortie.

[Legioneod]

1 hour ago, Talon_ said:

 

This should be submitted as a bug then as with current engine limit "recharge" times it is not possible to spend 20 minutes at WEP in a sortie.

Question is, will this convince the devs to give us longer settings? I doubt it.

 

If they can't give us longer WEP times (we should have them realistically) they should at least shorten the recharge timer for WEP and allow it to recharge in combat mode and allow combat to recharge in WEP just like the 109s.

 

With the current engine limitations I've never gotten more than one full use of WEP in a single sortie.

Edited December 9, 2018 by Legioneod

[Ehret]

20 minutes ago, Legioneod said:

If they can't give us longer WEP times (we should have them realistically) they should at least shorten the recharge timer for WEP and allow it to recharge in combat mode and allow combat to recharge in WEP just like the 109s.

 

Or better yet the 150 octane fuel; all setting would get uplift by 6", right? So the 64" would count as 15m combat power plus we would have a nice perk of 5m at 70". That is if the current flawed system would stay.

Edited December 9, 2018 by Ehret

[Legioneod]

1 minute ago, Ehret said:

 

Or better yet the 150 octane fuel; all setting would get uplift by 6", right? So the 64" would count as 15m combat power plus we would have a nice perk of 5m at 70".

Iirc combat power never changed, it remained at 52" whether you use 150 octane fuel or not. The main benefit of 150 fuel is the use of 70" and the ability to run 64" without the need of water injection.

[Ehret]

26 minutes ago, Legioneod said:

Iirc combat power never changed, it remained at 52" whether you use 150 octane fuel or not. The main benefit of 150 fuel is the use of 70" and the ability to run 64" without the need of water injection.

 

In the sim if you enable the water injection and keep MP at 58" (or lower) the combat mode 15m timer is used. If so then why not 64" for the supposed 150 octane fuel mod? The timer has the (emergency-6")+water "exception", already. It would make sense as it'd be the same pattern. Perhaps no extra changes in the timer code would be necessary, even. The 58" @ 2500rpm would get +30 minutes just like the 52" @ 2500rpm has now.

Edited December 10, 2018 by Ehret

[Legioneod]

6 minutes ago, Ehret said:

 

In the sim if you enable the water injection and keep MP at 58" (or lower) the combat mode 15m timer is used. If so then why not 64" for the supposed 150 octane fuel mod? The timer has the (emergency-6")+water "exception", already. It would make sense as it'd be the same pattern. Perhaps no extra changes in the timer code would be necessary, even. The 58" @ 2500rpm would get +30 minutes just like the 52" @ 2500rpm has now.

I'm just saying what the settings were irl, no idea how it will be implemented in-game.

[Panthera]

On 12/7/2018 at 12:40 AM, Venturi said:

From a realism standpoint, Detonation is the simple answer to these engine timer limits discussions.

 

It has been a problem for at least a decade or longer in WW2 sims.

 

IN GAME TERMS,

Pilots should not have a timer unless you run into detonation territory of manifold pressure, RPM, and mix.

 

Detonation was the true limiting factor of WW2 engine longevity IN A SINGLE SORTIE.

 

Engine wear occurred over many sorties and thus cannot be easily implemented in a game environment like IL-2 BOx, given the devs' philosophy of "new plane every time".

 

The performance limit that detonation imposes, is why intake manifold water/alcohol injection was invented in the first place... to delay the onset of detonation and thus be able to increase manifold pressure (power) higher than the fuel being used would otherwise permit.

 

The problem... implementing such a detonation system essentially requires fleshing out a large aspect of the core simulation of IL-2. So it would require a lot of work from the devs considering the expansive number of aircraft in IL-2 BOx.

 

A few factors they would need to implement for such a model to be satisfactory to the devs' own standards, I presume:

 

 

 

Advantages:

 

1. Super conservative pilot's manuals which affect some aircraft much more than others, are eliminated as a consideration. Historical comparative performances are restored without strange FM tweaking.

2. Fuels can be adjusted in aircraft options given the timeframe the map is on, as an "aircraft modification".

3. Pilot behavior becomes more historical re: engine management, without tedious and immersion-breaking "timer watcher", "gamey-ness" is reduced.

 

Problem is none of the engines ingame really suffered from this when running at cleared boost pressures. This because detonation wasn't just about the fuel used, but really more about keeping within engine temperature limits. Hence why the problem completely disappeared for the DB series once the issue with the oil cooling was solved, leading not only to 1.42ata being cleared for use, but cleared for use without any time limits what so ever. With MW50 a 10 min limit at much higher boost pressure was imposed, but with a provision for 40 min of use pr. sortie it was obviously expected to be used for a long periods of time without issue. This jives well with the 5 min limit and 20 min usage pr. sortie expected by Allied engines.

 

In general few if any of the engines ingame would suffer from detonation as long as oil & water temperatures were kept within their limits, mainly because the boost pressures available to them are the ones which they were cleared for. It only really becomes a worthwhile mechanic if you run the engine really hot and above cleared boost pressures.

 

5 hours ago, Legioneod said:

Question is, will this convince the devs to give us longer settings? I doubt it.

 

If they can't give us longer WEP times (we should have them realistically) they should at least shorten the recharge timer for WEP and allow it to recharge in combat mode and allow combat to recharge in WEP just like the 109s.

 

With the current engine limitations I've never gotten more than one full use of WEP in a single sortie.

 

Agreed, WEP should be rechargable at combat power for the Allied engines too, and the cool down period should be the same as with the 109.

 

Ideally both sides are given a 5 min limit at WEP when there's no use of water methanol (in that case it would be 10 min), a 1 min buffer and then a 5-6 min cool down period at combat power.

 

The only exception I can see would be the 109's cleared for 1.42ata which historically had no listed time limit at this boost pressure, wether or not a limit of 5 or 10 min should be given to these to keep pilots from always running around on WEP I am not sure, but it's a possibility.

Edited December 10, 2018 by Panthera

[Legioneod]

Whether or not players run around with WEP all day shouldn't even be a concern of the devs, they just need to model it realistically without any gamey limits and let the players decide on how to fly the aircraft.

 

There are only a handful of things in this game that keep it from being excellent, engine limits are one of them.

[Panthera]

49 minutes ago, Legioneod said:

Whether or not players run around with WEP all day shouldn't even be a concern of the devs, they just need to model it realistically without any gamey limits and let the players decide on how to fly the aircraft.

 

There are only a handful of things in this game that keep it from being excellent, engine limits are one of them.

 

Problem is I don't think they are ever going to remove the time limits completely, even if that would be the most realistic solution. The reason being they want to promote realistic engine usage, and thus they are going by the limits listed in the manuals. 

 

But seeing as we don't really have realistic combat scenarios either, then perhaps removing the limit for all engines might be a good idea. I'm still undecided on the issue tbh.

 

All I do know is that there's no logic behind Allied engines not being able to recharge WEP at combat power, or that it takes the P-47 a whole 20 min to recharge it.

Edited December 10, 2018 by Panthera

[ZachariasX]

6 hours ago, Legioneod said:

Iirc combat power never changed, it remained at 52" whether you use 150 octane fuel or not. The main benefit of 150 fuel is the use of 70" and the ability to run 64" without the need of water injection.

Is there a document supporting this? AFAIR it was well possible to get past 52‘‘ in earlier block Thunderbolts (they didn‘t have the same stopgaps yet), it just compensated by further enriching the rich-rich mixture, in process making the power gain at higher MAP relatively modest. The leaner mixture possible by adding water instead of fuel gives you this efficiency back and you get those horsepowers back.

 

Reading you statement makes it sound that EGT is no issue for this (turbocharged!) engine. Going past 52‘‘ with a leaner mixture (as possible with 150 octane) will drastically increase EGT at high power, calling the cooling ability of the cylinderheads into question. It is not much of a problem to melt away (with less consequences) the short exhaust stubs of an Allison. I should think the wastegate, duct and turbo are moch easier victims.

 

While water helps decreasing MAP temperature, allowing higher compression before predetonation occurs, I imagine total burn energy is a concern as well. The more heat you make, the higher the wear of the cylinder components. You can reduce that by either lowering burn temperature by unefficient rich-rich mixture or adding water as further temperature sink.

 

Now, I understand cooling of the burn is irrelevant for the 2800? Or is it just sufficient anyway?

[Legioneod]

46 minutes ago, ZachariasX said:

Is there a document supporting this? AFAIR it was well possible to get past 52‘‘ in earlier block Thunderbolts (they didn‘t have the same stopgaps yet), it just compensated by further enriching the rich-rich mixture, in process making the power gain at higher MAP relatively modest. The leaner mixture possible by adding water instead of fuel gives you this efficiency back and you get those horsepowers back.

 

Reading you statement makes it sound that EGT is no issue for this (turbocharged!) engine. Going past 52‘‘ with a leaner mixture (as possible with 150 octane) will drastically increase EGT at high power, calling the cooling ability of the cylinderheads into question. It is not much of a problem to melt away (with less consequences) the short exhaust stubs of an Allison. I should think the wastegate, duct and turbo are moch easier victims.

 

While water helps decreasing MAP temperature, allowing higher compression before predetonation occurs, I imagine total burn energy is a concern as well. The more heat you make, the higher the wear of the cylinder components. You can reduce that by either lowering burn temperature by unefficient rich-rich mixture or adding water as further temperature sink.

 

Now, I understand cooling of the burn is irrelevant for the 2800? Or is it just sufficient anyway?

Documentation for no water with 64" or for combat power never changing?

[ZachariasX]

3 hours ago, Legioneod said:

Documentation for no water with 64" or for combat power never changing?

I'll look it up. As said, all AFAIR, but that was not my main point. I don't really understand your argument, hence my question. Are you saying that there is no cooling effect (from water) required at 64'', and the limiting factor past 52'' was entirely predetonation?

 

Also, what do you think gives you more power:

 

a) 64'' MAP with 130 octane + water

-or-

b) 64'' MAP with 150 octane (no water)

-or-

c) 64'' MAP with 150 octane + water

 

Which will give most power on the shaft?

 

And question to you, do I understand correctly that in case of 150 octane, they would also re-ajust the water injection starting point from 52'' to 64''?

 

 

 

Edited December 10, 2018 by ZachariasX

[=362nd_FS=RoflSeal]

4 hours ago, ZachariasX said:

Is there a document supporting this? AFAIR it was well possible to get past 52‘‘ in earlier block Thunderbolts (they didn‘t have the same stopgaps yet), it just compensated by further enriching the rich-rich mixture, in process making the power gain at higher MAP relatively modest. The leaner mixture possible by adding water instead of fuel gives you this efficiency back and you get those horsepowers back.

 

Reading you statement makes it sound that EGT is no issue for this (turbocharged!) engine. Going past 52‘‘ with a leaner mixture (as possible with 150 octane) will drastically increase EGT at high power, calling the cooling ability of the cylinderheads into question. It is not much of a problem to melt away (with less consequences) the short exhaust stubs of an Allison. I should think the wastegate, duct and turbo are moch easier victims.

 

While water helps decreasing MAP temperature, allowing higher compression before predetonation occurs, I imagine total burn energy is a concern as well. The more heat you make, the higher the wear of the cylinder components. You can reduce that by either lowering burn temperature by unefficient rich-rich mixture or adding water as further temperature sink.

 

Now, I understand cooling of the burn is irrelevant for the 2800? Or is it just sufficient anyway?

Well performance tests of the P-47 (and P-38) give no mention of recording EGT, just Carb temperatures (which determine detonation)

Edited December 10, 2018 by RoflSeal

[Legioneod]

45 minutes ago, ZachariasX said:

I'll look it up. As said, all AFAIR, but that was not my main point. I don't really understand your argument, hence my question. Are you saying that there is no cooling effect (from water) required at 64'', and the limiting factor past 52'' was entirely predetonation?

 

Also, what do you think gives you more power:

 

a) 64'' MAP with 130 octane + water

-or-

b) 64'' MAP with 150 octane (no water)

-or-

c) 64'' MAP with 150 octane + water

 

Which will give most power on the shaft?

 

And question to you, do I understand correctly that in case of 150 octane, they would also re-ajust the water injection starting point from 52'' to 64''?

 

 

 

All I can tell you is what the document says. The whole purpose of water was to prevent detonation, 150 fuel allowed higher MAP without detonation iirc

 

With 150 octane water was not needed at 64" MAP, it was an option and would give you around a 7-8 mph increase in speed but water was not required at 64".

 

Water is also never needed at 52" so I'm not sure what your last question means, or what you're asking?

 

All I know is that with 150 fuel combat power remained at 52" and WEP was anything 64" and above (this is based off what I've read, I could be wrong if there is other documentation out there somewhere saying otherwise)

 

Edited December 10, 2018 by Legioneod

[ZachariasX]

3 minutes ago, RoflSeal said:

Well performance tests of the P-47 (and P-38) give no mention of recording EGT, just Carb temperatures (which determine detonation)

Thanks, added research is always welcome.

 

What I found here is this, an Article on Frank Walker Web, the man that made water injection for the R-2800. It has been posted here before, but they write that:

 

Water injection worked by reducing cylinder inlet temperature, thereby delaying the
onset of detonation. As the water evaporated in the induction passages of the
engine, it providing a prodigious amount of cooling to the fuel charge due to the
latent heat of vaporization of the water. Cylinder inlet temperatures went from about
350°F to about 100°F. This increased the detonation margin to the point that up to
150 inHg of manifold pressure could be used.

 

The importance of inlet cooling, something that is not achieved in the German injector engines

 

German engineers tried water injection (Wassereinspritzung) on their gasoline
engines, but with limited success. Germans, who were very good at building highprecision
pumps, had perfected direct fuel injection for their large aircraft engines.
German engineers injected water directly into the cylinders as well. Since the water
did not have time to evaporate and cool the induction air, the large cylinder inlet
temperature reduction was not achieved. Frank learned of this while reviewing a
report on a captured German aircraft engine.

 

According to that article it seems that the leaning of the mixture was important, hence they didn't use the MW50 as most alcohold would burn, enriching the mixture again to undesirable ranges.

 

So I don't really understand how the 150 octane fuel would be of any use increasing MAP when this is all done by adding water.

 

What higher octane does however is allow leaner mixture, which translates into range, not necessarily into more power. It gives you economy at higher power, not higher power per se when you have water as well.

 

In that article, I read the later paragraphs in that context:

 

Another interesting series of tests that Frank performed using X-80 (one row of an R-2800) attempted to
quantify just how lean the engine could be reliably run. Frank discovered that with
proper leaning the range of an airplane could be nearly doubled. However, the
procedure for running so lean was one so critical and difficult that Frank thought it
beyond the scope of what was to be expected of the average pilot. Years later, both
Pratt & Whitney and Wright Aeronautical used these same techniques on airline
engines to achieve ocean-hopping range. The addition of a torque meter on each
engine allowed the flight engineer to lean the engine with great accuracy and
achieve the range that Frank’s earlier experiments had predicted.

 

You can see how rich the "Auto lean" regular setting for a R-2800 at a cruise power rating actually is. Double range at the same speed means half the fuel flow, where as normal difference between the "lean" and "rich" mixture is about 20%.

 

Looking at that, I understand that predetonation.

But what I can't follow is this

12 hours ago, Legioneod said:

The main benefit of 150 fuel is the use of 70" and the ability to run 64" without the need of water injection.

1) That higher octane allowed higher MAP

2) Why would you run 64'' MAP without whater when this is already in a "timed interval" by the book that makes you have water anyway for that, plus having water I'd say even with 150 octane you could use that water to lean the mixture and get more power.

 

I'd expect the mixture being rich-rich at 64'' MAP, even with 150 octane. Or do I make a false assumption?

 

1 minute ago, Legioneod said:

With 150 octane water was not needed at 64" MAP, it was an option and would give you around a 7-8 mph increase in speed but water was not required at 64".

Ah, now I get it. Sorry, slow. Monday.

[=362nd_FS=RoflSeal]

30 minutes ago, ZachariasX said:

 

Looking at that, I understand that predetonation.

But what I can't follow is this

1) That higher octane allowed higher MAP

2) Why would you run 64'' MAP without whater when this is already in a "timed interval" by the book that makes you have water anyway for that, plus having water I'd say even with 150 octane you could use that water to lean the mixture and get more power.

  

 

1)Higher Octane fuel is more resistant to knock so higher CAT temperatures are allowed, therefore more supercharged air can be taken in.

2) The aircraft manifold settings were reset. After all, why would you run 64" with water when you could run 70" and gain even more power. Water injection is after all a limited resource

 

I am pretty certain the boost regulators were adjusted to accomodate for the higher available non-WI MAP when running 150 octane.
http://www.wwiiaircraftperformance.org/150grade/supplymemo-11july44.pdf

 

 

 

 

 

 

Edited December 10, 2018 by RoflSeal

[Ehret]

41 minutes ago, RoflSeal said:

1)Higher Octane fuel is more resistant to knock so higher CAT temperatures are allowed, therefore more supercharged air can be taken in.

 

It should be noted that Allied BOBP planes, with possible exception of the Tempest (I'm not sure) have inter-coolers and/or after-coolers (the latter in Merlin/V-1650 in the Spit and the P-51). It's actually modeled in the P-47 as you can change the MP by manipulating the inter-cooler flaps. Thus any detonation incident is unlikely if those engines are run at modest settings. In the sim I have found that the water-injection cooling effects in the virtual Thunderbolt allows to close cowl flaps completely even when slow. Just that alone increases performance by a bit.

Edited December 10, 2018 by Ehret

[=362nd_FS=RoflSeal]

Also the article above gives info on the 7 1/2 hr power test

 

The Government had specified a particular test regime to qualify an engine at “War Emergency Power”. This was a rating higher than take-off power and usually assumed anti-detonation injection. First the engine was run for five hours in five minute cycles alternating between War Emergency Power and a fast idle. Then it was run for two and one-half hours at a steady War Emergency Power rating. The Government thought this was a tough test, but Pratt & Whitney routinely ran its engines for 100 hours straight at War Emergency Power. The seven and one-half hours required by the Government was no problem whatsoever.

 

[PainGod85]

Alright, chemistry time.

 

Every instance of hydrocarbons burning is essentially initialized by a first stage of oxygen reacting with them to form peroxides. Peroxides are extremely volatile substances and will easily continue reacting in radical chain reactions (substitutions and additions) with anything that's close by. There have been too many rotating evaporators in labs worldwide whose users butchers can attest to the importance of always checking your ether for peroxides.

 

 

There are three ways to delay a runaway reaction, that is to say, the contents of the cylinder deflagrating uncontrollably:

 

1. The first is to keep the fuel mixture reasonably cool. Intercoolers, aftercoolers and ADI are your friends.

 

2. The second is to simply run the engine at a very rich mixture so these peroxides will hopefully burn themselves out before they can set the whole mixture on fire or be slow enough to react that the spark plug will still ignite the fuel at the right time. Of course, there is a very hard limit at which an engine will start choking on too much fuel for too little air and lose power. Also, soot buildup may become an issue.

 

3. The third is to smother the impending inferno. You add substances that are radical interceptors to the fuel. These are molecules that will react with peroxides more easily than the fuel itself while also absorbing the energy from that exothermic reaction.

 

 

One of these is tetraethyl lead (TEL). The other, and the one that was used in addition to TEL in high octane aviation fuel is ethylene dibromide (EDB).

 

Grade 150 fuel had around 50% more ethylene dibromide than 130 grade. This was the only quantitative difference between them, to the point that bog standard 130 grade was used to thin the troublesome 'pep' 150 grade fuel with 150% the content in EDB compared to it into the normal, already proven 150 grade fuel.

Edited December 10, 2018 by PainGod85
Typos everywhere

[=475FG=_DAWGER]

If there needs to be an unrealistic method of coercing players to treat the engines in a somewhat realistic fashion (not flying around at combat power all the time) the best way to do that is to raise fuel burn when at the power setting one is trying to limit to a level high enough to discourage the unwanted behavior.

 

This allows players use the power levels as needed and will punish those with poor planning and decision making.

 

The current method is horrendous and enough to keep many players from the title. 

[Rattlesnake]

6 minutes ago, =475FG=DAWGER said:

If there needs to be an unrealistic method of coercing players to treat the engines in a somewhat realistic fashion (not flying around at combat power all the time) the best way to do that is to raise fuel burn when at the power setting one is trying to limit to a level high enough to discourage the unwanted behavior.

 

This allows players use the power levels as needed and will punish those with poor planning and decision making.

 

The current method is horrendous and enough to keep many players from the title. 

A clever solution that also encourages toting realistic fuel loads.

[D3adCZE]

8 minutes ago, =475FG=DAWGER said:

If there needs to be an unrealistic method of coercing players to treat the engines in a somewhat realistic fashion (not flying around at combat power all the time) the best way to do that is to raise fuel burn when at the power setting one is trying to limit to a level high enough to discourage the unwanted behavior.

 

This allows players use the power levels as needed and will punish those with poor planning and decision making.

 

The current method is horrendous and enough to keep many players from the title. 

That would just exhange one unrealistic methid for another.

[Stilico]

12 minutes ago, CSAF-D3adCZE said:

That would just exhange one unrealistic methid for another.

I'm at the point where I'd take just about any change that isn't more restrictive timers. Still think they should just go with the easiest solution and do away with them all together.

[Rattlesnake]

47 minutes ago, CSAF-D3adCZE said:

That would just exhange one unrealistic methid for another.

As has been demonstrated with evidence repeatedly the most realistic option would be effectively near unlimited WEP. It is apparent that real pilots WEP’d for however long they felt they needed maximum thrust in combat situations. The only rub is that players would use it when not in combat. This would not a make a huge difference in game, EXCEPT when it comes to simulating the pilot workload involved in going from cruise to max settings when combat suddenly begins, very much simpler in a 190 than in many other planes for instance. For this reason it is desirable to incentivize people to not cruise on WEP. But the engine failing after 5 minutes of combat is also undesirable  from the standpoint of simulating a dogfight. There is no perfect system, but ~15 minutes at a go would probably remove much of the conundrum mentioned. It is short enough that no one would cruise at it long term, yet long enough that one of you would likely be down before running out of WEP becomes a fight-deciding issue.

Edited December 11, 2018 by Rattlesnake

[Ehret]

A mission designer can already limit the maximum fuel loads, right? In later planes; even in the P-39 already, anything else than nominal eats fuel quickly. I try to load no more than 70-80% but assuming my usual pattern -> take-off -> initial climb -> patrol for 50km -> bounce but extend -> climb&patrol again -> 2nd engagement -> extend and rtb because it's bingo fuel then. If I had no more than 50% fuel in the P-39 this pattern wouldn't be possible anymore; at least not at the same engine settings.

 

11 minutes ago, Rattlesnake said:

There is no perfect system, but ~15 minutes at a go would probably remove much of the conundrum mentioned. It is short enough that no one would cruise at it long term, yet long enough that one of you would likely be down before running out of WEP becomes a fight-deciding issue.

 

For distances we have in the MP 15m is enough - K4 will go +50km in just 5m; fight for the 5m and go back to the AF in the last 5m.

The problem would cease to exist if we had realistic distances to objectives, like 250-500km. Then the fuel thus endurance would be a precious commodity; not the current stuff of throwing it out as fast as possible. But, who would want to fly such matches?

Edited December 11, 2018 by Ehret

[Talon_]

7 hours ago, Ehret said:

realistic distances to objectives, like 250-500km

 

Not in the Bodenplatte scenario. I'd need to recheck my books but I'm fairly sure Tempests only had to fly 120km from Volkel to shoot at Me262s landing.

[Legioneod]

9 hours ago, CSAF-D3adCZE said:

That would just exhange one unrealistic methid for another.

Whats better, an unrealistic engine limitation set with timers? or a slightly more realistic limit of fuel?

Personally I'd take just about anything to get these timers done away with. Engine are the one thing DCS does much better than Il2.

Il2 needs to step it up imo.

Edited December 12, 2018 by Legioneod

[Guest deleted@83466]

At the risk of being Captain Obvious, I think the "problem" would be easily solved simply by reducing the chance of failure...if you run a minute over the timer and the percentage chance that the engine will blow is 50%, reduce it to something lowish like 5% or lower...and then increase that percentage chance of failure for each additional minute from there as appropriate.  I'm guessing that they are probably doing something close to that already, it's just that the percentages for exceeding the time limit start out way too high, so you're likely to blow the engine with even a little exceedance over the book values.  And what's more, is that maybe a damaged engine can have a little more nuance...maybe in some cases, if you haven't pushed it too hard for too long, it will be just start to run a little rough, a cause for concern, but not necessarily an immediate RTB moment.  Right now, when you exceed the time limit, the engine goes from healthy to either dead or very close to death at once.

Edited December 12, 2018 by SeaSerpent

[Jansgi]

 

19 minutes ago, Legioneod said:

Whats better, an unrealistic engine limitation set with timers? or a slightly more realistic limit of fuel?

Personally I'd take just about anything to get these timers done away with. Engine are the one thing DCS does much better than Il2.

Il2 needs to step it up imo.

 

I don't understand why people are even saying that DCS engine limits are better. Sure you can use higher engine settings for much longer times depending on temps, but if that engine fails it is always a 100% catastrophic failure. There is no other scenario in DCS other than a complete instant seizure of the engine if you push the engine beyond the limits. At least in IL-2 there are few different scenarios that can happen when you go over those limits even if the limitations are somewhat unrealistic. There are great many things both games could learn from each others.

 

But in the end to be honest all things considered between the games, DCS has a lot more stepping up to do than IL-2, and this is coming from someone who has played ED's games since LOMAC...

[Legioneod]

1 hour ago, SeaSerpent said:

At the risk of being Captain Obvious, I think the "problem" would be easily solved simply by reducing the chance of failure...if you run a minute over the timer and the percentage chance that the engine will blow is 50%, reduce it to something lowish like 5% or lower...and then increase that percentage chance of failure for each additional minute from there as appropriate.  I'm guessing that they are probably doing something close to that already, it's just that the percentages for exceeding the time limit start out way too high, so you're likely to blow the engine with even a little exceedance over the book values.  And what's more, is that maybe a damaged engine can have a little more nuance...maybe in some cases, if you haven't pushed it too hard for too long, it will be just start to run a little rough, a cause for concern, but not necessarily an immediate RTB moment.  Right now, when you exceed the time limit, the engine goes from healthy to either dead or very close to death at once.

I suggested this some time ago but not many players agreed with it.

I'd be willing to accept this compromise. Something like a 2% chance of failure each minute over the limit. So 2% then 4 then 6 then 8 and so on, or they could go by 5% intervals like you said. (5% first minute then 10% and so on.)

 

Even if they don't fix the system at all what they do need is to make engine recharge the same across the board. Instead of P-47s or other aircraft only being able to recharge after 20min and only at nominal power, all aircraft should have the same recharge time and at the same power settings (5min WEP recharge at combat power for example just like the current 109s)

Edited December 12, 2018 by Legioneod

[Ehret]

From my tests (not 100% sure, thought) the recharge seems to work like that for the P-47 and the P-39 at least:

 

First starts to recharge the emergency timer and it takes 10m (nominal or combat time) if you used up all emergency before. If only half then it will take 5m, 2.5m for 1/4 and so on.

If the emergency is recharged (or was fresh) then and only then the combat starts to recharge and it takes 1m of nominal to recharge 1m of combat.

 

So, in the total assuming you used all you will have to wait 25m. In practice it will be better to just land and take-off again. There is a nasty trap too - imagine you used some combat, then a lot of emergency, and you just switched back to the nominal and... engine suddenly seizes! Why?

Well, my hypothesis is: By using up the emergency the combat timer will be depleted as well. It's possible to end without any combat time left while still running on the emergency. Because the engine can not change MP/RPMs immediately it can touch the depleted combat settings for a moment. Just long enough to trigger a random failure.

 

1 hour ago, Legioneod said:

Even if they don't fix the system at all what they do need is to make engine recharge the same across the board. Instead of P-47s or other aircraft only being able to recharge after 20min and only at nominal power, all aircraft should have the same recharge time and at the same power settings (5min WEP recharge at combat power for example just like the current 109s)

 

The P-47/P-39 (P-40 probably as well) do recharge the emergency at the combat power.  The difference is the K4 has 30m of combat time instead of 15m we have in the P-47, and the recharge of 10m MW50 mode takes only 5m instead of the 10m for the P-47 5m WEP. That's why the in the K4 the emergency can be cycled with the combat mode for 3 times.

Edited December 12, 2018 by Ehret

[Legioneod]

23 minutes ago, Ehret said:

From my tests (not 100% sure, thought) the recharge seems to work like that for the P-47 and the P-39 at least:

 

First starts to recharge the emergency timer and it takes 10m (nominal or combat time) if you used up all emergency before. If only half then it will take 5m, 2.5m for 1/4 and so on.

If the emergency is recharged (or was fresh) then and only then the combat starts to recharge and it takes 1m of nominal to recharge 1m of combat.

 

So, in the total assuming you used all you will have to wait 25m. In practice it will be better to just land and take-off again. There is a nasty trap too - imagine you used some combat, then a lot of emergency, and you just switched back to the nominal and... engine suddenly seizes! Why?

Well, my hypothesis is: By using up the emergency the combat timer will be depleted as well. It's possible to end without any combat time left while still running on the emergency. Because the engine can not change MP/RPMs immediately it can touch the depleted combat settings for a moment. Just long enough to trigger a random failure.

 

 

The P-47/P-39 (P-40 probably as well) do recharge the emergency at the combat power.  The difference is the K4 has 30m of combat time instead of 15m we have in the P-47, and the recharge of 10m MW50 mode takes only 5m instead of the 10m for the P-47 5m WEP. That's why the in the K4 the emergency can be cycled with the combat mode for 3 times.

thats what I'm saying though, all recharge rates/timers should be identical for the most part. For the 109 to have 5 min recharge while the P-47 had 10min just doesn't make any sense and has no basis in reality.

 

All aircraft should have the same recharge times at the same power modes.

Edited December 12, 2018 by Legioneod