Boost vs RPM in CSP aircraft

[coolhand3011]

Hey guys just a quick question. I've been playing the 109 for quite a while and have been experimenting a bit on the RAF side, namely the Constant Speed Props (CSP) variants, and I was just curious about the modeled engine management.

In the Team Fusion patches, is there a time limit I can run full boost with a low RPM setting and actually damage the engine?

I've noticed I can seemingly fly along happy go lucky and not have to worry about it, other than making power changes in the correct order a CSP system is pretty low workload. When you want to increase power, RPM should be increased before boost/ manifold pressure, otherwise you run a serous risk of destroying the engine at high settings. Seems kind of strange that you can abuse them for so long with no ill effects, especially given the stresses that should be put on the engines running this way with the horsepower being generated under the hood. Not to mention as well how quickly over speeding a prop in the 109 causes damage.

[Haviland]

I've never had problems, though I've also never gone full boost with an RPM setting in the teens. Maybe I'll give that a shot soon.

I've done some experimenting for flat-out level speed at sea level where I've run boost cut out and an RPM setting in the 2000-2400 range for extended periods and the engine has never displayed any problems, though I know in real CSU aircraft that running very high manifold pressures at low RPMs is not the best for the engine (I'm not sure if this is something you would notice in one flight, or more of an "over time" type maintenance issue).

[coolhand3011]

I've never had problems, though I've also never gone full boost with an RPM setting in the teens. Maybe I'll give that a shot soon.

I've done some experimenting for flat-out level speed at sea level where I've run boost cut out and an RPM setting in the 2000-2400 range for extended periods and the engine has never displayed any problems, though I know in real CSU aircraft that running very high manifold pressures at low RPMs is not the best for the engine (I'm not sure if this is something you would notice in one flight, or more of an "over time" type maintenance issue).

It depends on the Horsepower the engine is producing and the amount of mismanagement, but I think a thousand horsepower engine and a mismanaged Manifold/RPM should result in a blown or at least cracked cylinder very quickly. You can only make engine components so strong to withstand the pressures so I know these weren't some super metal engines that could take that for very long. Case in point, I tested this out on DCS P51 and they definitely have it correct. If you mismanage the Manifold pressure and RPM, it doesn't take long for you to be dead sticking it back to the runway. Correct me if I am wrong but that is a Merlin engine also, a different version but still a Merlin.

If you are running full boost and not at a corresponding max RPM setting, than you should be quickly destroying your engine. Running max boost you are creating the greatest pressures in the engine and couple that with a prop that is trying to turn at an overly coarse setting you should have a recipe for a broken engine. You should normally have the prop at Max RPM and not any lower if you are going full out. You won't gain any speed by setting the RPM lower, the CSP system keeps the prop turning at max or rather the optimum pitch to develop the most power. Otherwise you are having the prop turn at a lower than optimum setting and creating less efficiency per revolution not to mention added strain on the engine from having to try and turn the prop. Additionally you can't always leave the prop maxed out all the time either, that's why there are certain time limits specified for different power settings.

The reason I noticed this is that the RPM control in the RAF aircraft seems reversed on my stick compared to the 109 and I was shocked to see that my engine wasn't blown when I was maneuvering, so I tested it out and never saw or heard a difference in the engine. Just curious to hear if TF is working on or aware of this.

[Talisman]

I have read that the following saying was given to RAF Spit and Hurry pilots to remind them how to manage the engine.

"Low revs and high boost will bring you safely home to roost".

As I understand it, the Merlin was a high performance engine designed to run at high boost levels.

Also, I believe that one of the ways to fly in combat was to have full boost and control the engine rpm with the prop pitch.

Happy landings,

[coolhand3011]

I have read that the following saying was given to RAF Spit and Hurry pilots to remind them how to manage the engine.

"Low revs and high boost will bring you safely home to roost".

As I understand it, the Merlin was a high performance engine designed to run at high boost levels.

Also, I believe that one of the ways to fly in combat was to have full boost and control the engine rpm with the prop pitch.

Happy landings,

I think you might be misunderstanding that quote.... as I have understood the high boost part is in regards to the cooling of the Merlin in a climb. High boost say +6 is better on the engine for climbout than say +2 due to the flow of air used for cooling, mainly due to the fact the engine can get up to a higher power faster and reduce the time to climb. Climbing is where the engine is getting taxed the most and has the lowest airflow and the highest power settings. High boost is also in relation to the high prop RPM. The Low RPM's bit was probably more in tuned with a lower Boost/RPM setting for cruise to decrease fuel consumption.

You are right, it is a high performance engine. Boost and RPM both affect the engine though. Think of it in a similar manner as driving a manual shift car, you have to shift gears at the appropriate RPM. There is a reason why manufacturers painstakingly test out the engine before hand to come up with Boost/Manifold and RPM ratios. See the Team Fusion wiki for these.

Sure, you fly "full boost" for the corresponding RPM setting in combat but you can't just roll back the RPM's beyond this at max boost and fly around all day. Also in a constant speed system, the pilot does not have direct control of the propeller pitch at all. All the pilot does is set the RPM, the governor adjust the prop pitch appropriately to try and maintain the desired RPM.

[coolhand3011]

Hate to reply to my own thread, but did I post this in the right spot for someone from Team Fusion to see this? :recon:

This is a pretty glaring issue. What this means as a Red pilot on a CSP model aircraft, which is probably 99% of what is ever flown in game, you really don't have to worry about CEM at all. All one really has to worry about is managing some radiators but that's on par with War Thunders CEM, you can do that in there too if you want. I'd say you can manage RPM here but like I've mentioned earlier, it doesn't matter what you seem to do with it, you can't break the engine and you can exploit it to cool your engine also while keeping max boost going and suffer no consequences. Additionally you don't have to worry about over revving it! Unless you over heat it or get a bullet in it, it's pretty much an invincible engine. Beyond a clickpit and setting a couple things up on the ground, one can pretty much just pour the coals to it with the throttle and then just vary your RPM if you need to cool down. Also over cooling/ shock cooling doesn't seem to be modeled at all either.

If you fly the 109, it's quite easy to overspeed the prop and cause engine damage and our equivalent of a CSP unit only really seems to hold the correct RPM at max power which I doubt it worked like that in real life. Also the over boosting damage seems missing there as well but at least on the early versions you do really have to manage the engine quite closely.

From the couple of people that have posted here so far, there seems to be quite a misinterpretation on how to manage an engine fitted with a CSP unit. Just looking for some official word from TF on this or that they are already looking into it or that everyone else's engines blow from mismanagement and I'm just lucky my game doesn't do it.

[RAF74_Buzzsaw]

Hello Coolhand

First of all, we do our best to replicate the aircraft as best as the game code allows... we do not dumb down aircraft such that they 'even out' in terms of difficultly.

The British constant speed props were easier to manage... that's a simple fact.

We have actually bent over backwards to acommodate Blue flyers, gone so far as not to show the problems which occurred with the earlier versions of the 109E-4's auto pitch system... in fact these didn't come into service until late in the battle, even in the 109E-4's originally did not come with the modification, and when they did arrive, there were issues with the rpm auto targeting, such that the auto system often would run at much lower rpms than optimal.

Your opinion that the British aircraft are 'bulletproof' is not borne out by the testing which we have done... in fact the 109's are much less likely to overheat than the 100 octane versions of the Spit IA or Hurri Rotol, we modeled this way because the extra horsepower generated with the higher boost used in these aircraft was being cooled by the same radiator/oil cooler system that was originally built for 87 octane horsepower levels. Horsepower equals heat.

As far as the idea that high levels of boost at low rpms is not a good idea... you would be correct, the Merlin was not recommended to be run this way... but neither was the Daimler Benz... typically this would cause heavy deposits on the plugs and resultant misfiring, hot spots and potential pre-ignition.

At this point the game engine does not model this type of engine behaviour... and although we could probably write some code to add this effect, the time required and the effort would be better allocated to other more important issues.

[coolhand3011]

Hello Coolhand

First of all, we do our best to replicate the aircraft as best as the game code allows... we do not dumb down aircraft such that they 'even out' in terms of difficultly.

The British constant speed props were easier to manage... that's a simple fact.

We have actually bent over backwards to acommodate Blue flyers, gone so far as not to show the problems which occurred with the earlier versions of the 109E-4's auto pitch system... in fact these didn't come into service until late in the battle, even in the 109E-4's originally did not come with the modification, and when they did arrive, there were issues with the rpm auto targeting, such that the auto system often would run at much lower rpms than optimal.

Your opinion that the British aircraft are 'bulletproof' is not borne out by the testing which we have done... in fact the 109's are much less likely to overheat than the 100 octane versions of the Spit IA or Hurri Rotol, we modeled this way because the extra horsepower generated with the higher boost used in these aircraft was being cooled by the same radiator/oil cooler system that was originally built for 87 octane horsepower levels. Horsepower equals heat.

As far as the idea that high levels of boost at low rpms is not a good idea... you would be correct, the Merlin was not recommended to be run this way... but neither was the Daimler Benz... typically this would cause heavy deposits on the plugs and resultant misfiring, hot spots and potential pre-ignition.

At this point the game engine does not model this type of engine behaviour... and although we could probably write some code to add this effect, the time required and the effort would be better allocated to other more important issues.

Thanks Buzzsaw for getting back up with me You answered my original question... just a shame something like that can't be modeled in the game when things like heating and overspeeding can. I sense a bit of hostility here but I never requested the aircraft be dumbed down.

I agree with you that Constant Speed props are easier to manage, there is a reason you don't see VPP systems around today. I hope you didn't read that bit about the E4s auto pitch as a bit of whinging.... I don't use it personally anyway, just seems like the implementation in game has always been off. I was also just trying to draw attention to the fact that you do actually have to manage the 109 engine in some way beyond radiator management to keep it running, not whinging about it. If I was whinging, why would I ask for more realistic engine management?

That's great, I never said that British aircraft were "bulletproof"... quite the opposite if you read what I wrote about the engine. I never really mentioned anything about overheating issues in the 109 or RAF fighters beyond the fact that you can game the game by leaving max AtA and Boost and simply roll down the RPMs to cool off or run a lower RPM at max AtA and boost and not have any overheating issues.

Just wanted to know what head way if any TF had made on this.

"As far as the idea that high levels of boost at low rpms is not a good idea... you would be correct, the Merlin was not recommended to be run this way... but neither was the Daimler Benz... typically this would cause heavy deposits on the plugs and resultant misfiring, hot spots and potential pre-ignition."

FYI deposits on the spark plugs are also known as lead deposits from the fuel and an overly rich fuel air mixture and not particularly associated with overboosting the cylinders of an engine.... Detonation is more the resultant damage that we are talking about.

I do appreciate all the hard work you guys do and I meant no disrespect but I'd never seen this issue ever raised and there does seem to be quite a few misconceptions in this community about how aircraft engines operate. That's the main reason I brought this up.

[RAF74_Buzzsaw]

FYI deposits on the spark plugs are also known as lead deposits from the fuel and an overly rich fuel air mixture and not particularly associated with overboosting the cylinders of an engine.... Detonation is more the resultant damage that we are talking about.

Actually they are associated with this type of situation, particularly with Merlin engines... later in the war the US pilots who used 150 octane fuel had problems with deposits forming on the spark plugs and compression chamber dome when running long periods of low rpms and middle level boost which were typical of escort missions... these deposits would heat up later under high boost situations and sometimes cause detonation. Pilots had to run their engines at full boost/rpm every approx. 15 minutes during the missions to clear these deposits... not best for fuel economy, but necessary.

[coolhand3011]

Actually they are associated with this type of situation, particularly with Merlin engines... later in the war the US pilots who used 150 octane fuel had problems with deposits forming on the spark plugs and compression chamber dome when running long periods of low rpms and middle level boost which were typical of escort missions... these deposits would heat up later under high boost situations and sometimes cause detonation. Pilots had to run their engines at full boost/rpm every approx. 15 minutes during the missions to clear these deposits... not best for fuel economy, but necessary.

No they are not associated with what we are talking about. I'm talking about running high Boost and low RPMs on the engine. They can lead to one another pre ignition and detonation although they are two separate occurrences in the engine. That's why most aircraft (reciprocating) use 100 LL (Low Lead) to combat this problem of lead build ups. I was specifically talking about detonation in the cylinders....doesn't matter though if the sim can't model either detonation or preignition. Then again we also aren't talking about late war Merlins and 150 octane here in this game either.

I seem to recall some talk of the sim takes into account engine wear quite a while back before TF came about. Is there any way to tweak the engine wear code to vastly accelerate the wear on the engine maybe if it is abused? Like I say, it seems like the overheat code is primarily tied to the RPM of the prop, hence the fact you can run max boost/AtA all day and just a bit lower RPM and fly around. You sacrifice a few mph but if you need it just roll the prop up to speed up...kinda defeats the whole point of the modeling engine overheat correctly.

[PFT_Endy]

The thing coolhand is talking about is nicely modelled in DCS: P51. If you try running hight boost at low rpm's then you will break the engine in several seconds. It simply grinds to a halt, broken. That's why you always need to lower boost first before lowering your rpm and the other way around, you need to rise rpm before rising the boost level. Otherwise you can kiss the engine goodbye :)

This is unfortunately not modelled at all in CoD and you don't need to think about this at all. It would be nice if this could be introduced though, unless there is some game engine limitation that prevents it. I guess the original dev team did not think it was important or they thought it was too hardcore for most players for some reason...

[vranac]

Ok, it isn't modeled.

But why would you want to run on low rpms a all ) I try to run them highest as possible if I can.
Only when saving fuel you want to fly on low rpm.

Both sides red and blue are similar but spits and hurries overheat much , much easier 15-20 k.

[Skoshi_Tiger]

I just had a flight in the Spitfire II using the Device Link raw Data program running and noticed that even though the parameter C_BoostEnabler toggles between 0 and 1, I_EngineBoostPressure contains only 0 values.

I'd assume the variable that this represents should contain the current boost pressure of the engine at any given state unless there is another parameter that holds the info? Maybe that part of the engine modeling wasn't implemented.


Also is the engine management in the P-51 comparable to the Spitfires modeled here? As far as I know the Mustang does not have a boost cut-off valve. In the Spitfire the boost pressure is limited to ~6lbs with the cut off on and ~8-12lbs with it off (depending on the model). Will running at those pressure cause pre-ignition and destructive detonation? What is the Boost equivalent experienced by the Mustang (in DCS) in these situations?
Cheers!

[RAF74_Buzzsaw]

The boost in the P-51D in DCS is 67 inchs MAP AFAIK, which is relatively equivalent to +18 boost. Should be 76 inchs MAP, but as usual in most sims the P-51's are not being rated with the 150 octane boost levels.

Coolhand:

CLIFFS OF DOVER has never been advertised as a 'Study Sim', for that type of experience, you'd best stick to DCS. The more elements required to be monitored, the more difficulty in providing a game with a large multiplayer environment. If you play DCS, you'll note they don't get +100 players online at a time.

We could implement something like what you are demanding, but it would require quite a bit of work, and we have many other elements and improvements we see as a higher priority.

If this is a game breaker for you, I'd suggest you form your own mod team, decrypt the code, re-write the .emd code and online linkages to allow your mod, and you'll be set. Shouldn't take much more than an hour or two.

[Skoshi_Tiger]

Maybe someone can tell me what I am doing wrong in DCS but I seem to be able to fly for an indefinite period with minimum RPM and throttle firewalled. As far as I can tell I am using sim game settings.


http://www.youtube.com/watch?v=GTiNOZxbh60&feature=youtu.be

In DCS under exactly what conditions should my motor die and how long should it take? To me it seems very similar to what happens in CoD.



Cheers!

[coolhand3011]

The boost in the P-51D in DCS is 67 inchs MAP AFAIK, which is relatively equivalent to +18 boost. Should be 76 inchs MAP, but as usual in most sims the P-51's are not being rated with the 150 octane boost levels.

Coolhand:

CLIFFS OF DOVER has never been advertised as a 'Study Sim', for that type of experience, you'd best stick to DCS. The more elements required to be monitored, the more difficulty in providing a game with a large multiplayer environment. If you play DCS, you'll note they don't get +100 players online at a time.

We could implement something like what you are demanding, but it would require quite a bit of work, and we have many other elements and improvements we see as a higher priority.

If this is a game breaker for you, I'd suggest you form your own mod team, decrypt the code, re-write the .emd code and online linkages to allow your mod, and you'll be set. Shouldn't take much more than an hour or two.


Buzzsaw:

"Hey guys just a quick question. I've been playing the 109 for quite a while and have been experimenting a bit on the RAF side, namely the Constant Speed Props (CSP) variants, and I was just curious about the modeled engine management.

In the Team Fusion patches, is there a time limit I can run full boost with a low RPM setting and actually damage the engine? "


Remember the original post? That's all I asked, you answered it. I don't recall mentioning "bullet proof" RAF aircraft or even "demanding" anything, if I did please show me where. I don't know why all the uncalled for hostility whenever someone raises an issue with this game. I asked a question in the Team Fusion Bug/Error Reporting forum wondering if this was in fact a bug or error in the Team Fusion patch.

Flight Sim X and others which are not truly "study sims" of any aircraft do model the engine damage we are talking about and those a pretty old titles. I thought it a logical conclusion this game would have some semblance of realistic engine management and maybe it was overlooked or something. If it doesn't and can't that's fine by me. Seeing as how the engine is the most important non living part of any aircraft, I thought this would be a pretty important subject to look at. Blowing a cylinder will kill your engine much faster than going one degree over the redline in temperature.

Surprisingly there does seem to be quite a bit of misconception about how complex high performance aircraft engines operate around here which I didn't expect. I don't know what your experience is in aviation if any, but you also brought up a completely different scenario than I was talking about.... ala pre-ignition. I did feel I needed to point you in the right direction to stay on topic. Why you brought up pre ignition at lower power settings, I have no idea, especially since in the text you quoted from me specifically said I was talking about detonation damage in the cylinders due to overboosting in post #9. This struck me as A.) Either you didn't read what you quoted from me or B.) Maybe you could use some brushing up on complex/high performance aircraft engine operation. Because we were talking about two completely different conditions there.

I'll say it again because I feel it needs reiterating. I appreciate all the work you guys put into the sim. I can't even imagine the frustrations you all must go through daily trying to figure out the codes to keep this thing running for one more patch and optimizing the minutiae for a slight performance gain. I would have no idea where to even start with a mod, your sarcasm is duly noted by the way. I know you guys are the code pros. I know we also all want the game to be as realistic as possible and want it to be going in the right direction which is why I felt the need to bring this up. Thank you for answering my question in the end.

@Vranac
One reason this was important I thought was, you can cheat the overheat system in the game as it is now by flying around at max boost/Ata all day with a lower RPM and not overheat the engine or cause any damage. You lose a little top speed but if you are just cruising around, what does it matter? If you want full out speeds, just roll the RPM back up to max and when you get too hot just roll it back down again for a little while.

@Skoshi:
The engine won't produce full Manifold Pressure with the RPM all the way back as you can see in your video. You're doing damage but if you want to really kill it fast roll up the RPMs again enough to fly around at Max Manifold Pressure...that's when the stresses are greatest. Better yet, do a 61" Take Off at a sea level airport with the RPM back, it should be a pretty short flight. You are safe as long as you fly at the manufacturer settings to your right on the canopy rail and make sure you keep up enough speed to keep from overheating.

[Gromit]

I seem to recall one of the air race stars showed the USAAF how to extend the range on their P38 Lightnings in the pacific by running at low rpm and high boost?

Can't recall his name, Howard Hughes springs to mind but I don't think that's it?

[ATAG_Snapper]

I seem to recall one of the air race stars showed the USAAF how to extend the range on their P38 Lightnings in the pacific by running at low rpm and high boost?

Can't recall his name, Howard Hughes springs to mind but I don't think that's it?

Charles Lindbergh.

EDIT: I remembered the story from a book I'd read long ago, but just did a google search and found this link that mentioned it:

http://www.ozatwar.com/ozatwar/lindbergh.htm

[Gromit]

Snapper wins a cookie!

That's the guy!

[coolhand3011]

You are right Gromit, he did manage to do this. The conventional wisdom at the time was don't run the engine over square in regards to MAP and RPM. (manifold pressure to not exceed the RPM/100)


As an observer, he quickly calculated that the combat radius of the P-38 could be extended by 30%. A standard technique at the time was to cruise at 2200- 2400 rpm’s with a fuel/air mixture set to auto-rich with the manifold pressure set to low. Lindbergh called for only 1600 rpm with a fuel/air mixture set to auto-lean and a manifold pressure set to high. This reduced fuel consumption to between 63 and 70 gallons per hour from 90 to 100 gallons per hour. The cruising speed was around 185 mph. The P-38′s used to fly a five-hour mission and come back on fumes, but after taking Lindbergh’s advice, the range of the P-38′s increased by as much as 400 miles. The missions (bomber escort and loiter) time was increased to nine hours with fuel to spare. I doubt that the pilot’s enjoyed sitting in the cockpit for nine hours!

The difference is though he is just cruising around at 185 mph with the engines not running nearly full tilt. I'm not sure what "MAP set to high" is either number wise... could just an inch or two above the published for that RPM in the AAF manual. Definitely not anywhere near full throttle /RPM.

I was always told this worked for him because it reduced the pumping loss required to maintain the engine at a lower MAP setting. He was definitely a visionary, I mean look at the changes today. It's only been really in the last 10 years or so that running a lean of peak operation on engines in cruise has come in vogue. Before that it was always thought taboo and everyone ran rich of peak.

Here is a pretty good article about running over square operations from avweb
http://www.avweb.com/news/airman/184483-1.html?redirected=1

[RAF74_Buzzsaw]

I seem to recall one of the air race stars showed the USAAF how to extend the range on their P38 Lightnings in the pacific by running at low rpm and high boost?

Can't recall his name, Howard Hughes springs to mind but I don't think that's it?

Useful find Gromit. :thumbsup:

Lindbergh's technique with the Allisons is exactly the same used by P-51 pilots over Europe, the Merlin responded the same way... except as I mentioned, that with 150 octane fuel, they had problems with deposits forming on the plugs and the dome of the compression chamber, and the engines had to be 'blown out' every 20 minutes or so.

Coolhand:

Your technique of veiled insult under platitude may appeal to your sense of entitlement, but not to me. You're on permanent ignore.

This however, is an uncensored board, so feel free to continue to post your opinions.

[Talisman]

I think you might be misunderstanding that quote.... as I have understood the high boost part is in regards to the cooling of the Merlin in a climb. High boost say +6 is better on the engine for climbout than say +2 due to the flow of air used for cooling, mainly due to the fact the engine can get up to a higher power faster and reduce the time to climb. Climbing is where the engine is getting taxed the most and has the lowest airflow and the highest power settings. High boost is also in relation to the high prop RPM. The Low RPM's bit was probably more in tuned with a lower Boost/RPM setting for cruise to decrease fuel consumption.

You are right, it is a high performance engine. Boost and RPM both affect the engine though. Think of it in a similar manner as driving a manual shift car, you have to shift gears at the appropriate RPM. There is a reason why manufacturers painstakingly test out the engine before hand to come up with Boost/Manifold and RPM ratios. See the Team Fusion wiki for these.

Sure, you fly "full boost" for the corresponding RPM setting in combat but you can't just roll back the RPM's beyond this at max boost and fly around all day. Also in a constant speed system, the pilot does not have direct control of the propeller pitch at all. All the pilot does is set the RPM, the governor adjust the prop pitch appropriately to try and maintain the desired RPM.

The quote does not say max boost, but rather high boost, nor does it say lowest rpm. I assume the quote to stand as meaning within the limits given to the pilots for settings and associated coolant and oil temps, etc. And no, I was not referring to climb and associated air flow for cooling.

This is an interesting read.

P/O David Crook, with No. 609 Squadron at Middle Wallop, published an interesting account in his book of his most successful day of the Battle of Britain, 30 September 1940:

It was now obviously a matter of moments only before we were in the thick of it. I turned my trigger on to 'Fire', increased the engine revs. to 3000 r.p.m. by slipping the constant speed control fully forward, and 'pulled the plug', i.e. pushed the small handle on the throttle quadrant that cuts out the automatic boost control thus allowing one to use emergency power.
A few seconds later, about six Me. 109s flew across right in front of us. I don't think they saw us till too late as we were coming out of the sun. Michael was leading Blue Section and I was leading Green, and immediately we swung our sections round and turned on to the tails of the enemy. They saw us - too late - and tried to escape by diving.
We all went down after them in one glorious rush and I saw Michael, who was about a hundred yards ahead of me, open fire at the last Messerschmidt in the enemy line. A few seconds later, this machine more or less fell to pieces in mid-air - some very nice shooting on Michael's part. I distinctly remember him saying on the R.T., 'That's got you, you bastard,' though he never recollects it!
The victim that I had selected for myself was about 500 yards ahead of me, and still diving hard at very high speed. God, what a dive that was! I came down on full throttle from 27,000 feet to 1,000 feet in a matter of seconds, and the speed rose with incredible swiftness - 400 m.p.h., 500, 550, 600 m.p.h. I never reached this speed before and probably never shall again. I have a dim recollection of the sea coming up towards me at an incredible rate and also feeling an awful pain in my ears, though I was not really conscious of this in the heat of the moment. I pulled out of the dive as gently as I could, but the strain was terrific and there was a sort of black mist in front of my eyes, though I did not quite 'black out'.
The Messerschmidt was now just ahead of me. I came up behind him and gave him a terrific burst of fire at very close range. The effect of a Spitfire's eight guns has to be seen to be believed. Hundreds of bullets poured into him and he rocked violently, then turned over on his back, burst into flames and dived straight down into the sea a few miles off Swanage. The pilot made no attempt to get out and was obviously dead. I watched him hit the water in a great cloud of white foam, and then turned round to see what else was going on.
A few of our Spitfires were chasing Messerschmidts all over the place and obviously a very nice little massacre was in progress, as a few seconds later I saw another Hun go into the sea. I then saw another Me. 109 going back to France as hard as he could and I chased him, caught him fairly easily, and put a good burst into him. He swerved slightly, his cockpit covering broke off the machine and flew just past my head and he then dived steeply.
I waited to see him hit the water, but he was only shamming, as he flattened out again just above the sea, and continued full speed for home, though his machine was now smoking and obviously badly hit.
For the first time in this war, I felt a certain pity for this German pilot and reluctant to finish him off. From the moment I saw him, he had no chance of escape as my Spitfire was so much faster than his Messerschmidt, and the last few moments must have been absolute hell for him. I could almost feel his desperation as he made this last attempt to get away.
But if I let him go, he would come back to England another day and possibly shoot down some of our pilots. In the few seconds during which all this was happening, I did not consciously make these reflections; my blood was up anyway and I was very excited, but distinctly remember feeling rather reluctant.
However, I caught him up again and made no mistake this time. I fired all my remaining ammunition at very close range, and he crashed into the sea, going at a terrific speed, and disappeared immediately. I circled round the spot, but there was no trace of anything. 71

[coolhand3011]

I have read that the following saying was given to RAF Spit and Hurry pilots to remind them how to manage the engine.

"Low revs and high boost will bring you safely home to roost".

As I understand it, the Merlin was a high performance engine designed to run at high boost levels.

Also, I believe that one of the ways to fly in combat was to have full boost and control the engine rpm with the prop pitch.

Happy landings,
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The quote does not say max boost, but rather high boost, nor does it say lowest rpm. I assume the quote to stand as meaning within the limits given to the pilots for settings and associated coolant and oil temps, etc. And no, I was not referring to climb and associated air flow for cooling.


I am sorry I must be being thick headed but what were you trying to say then by posting this? The whole issue I was raising was that you can't damage the engine in game when you run max boost at an incorrect RPM setting or you set the power in the incorrect way. A max power condition and detonation damage is the focus, not cruising around or anything. I'm not sure how that got shoehorned in here. Also I don't see where I said in your quote the point where I mentioned "max boost" or "lowest RPM?" Am I using these forums wrong or something because Buzzsaw was saying things that he claimed I said in his quotes as well but I couldn't find them nor did I say them? Does anyone else see them?

Nice read by the way, that's the way setting max power should be done and in the game you don't have to currently. Evidently according to Buzzsaw you don't need to worry about it in game because it can't be model it or they are too busy. This is what I was asking about, but this thread seems to have devolved quickly.

[ATAG_Snapper]

Wow, Talisman! P/O David Crook had one tough Spitfire!

600 mph in a dive!

3000 rpm "with the tit pulled" and no perforated radiator or head gasket failure!!!!!!

full throttle dive from 27,000 feet to 1,000 feet

"Spitfire so much faster than his Messerschmidt"

109's falling to pieces under the fire of 8 guns

apparent pilot kill from dead astern


...............it's enough to make you weep....... :(

:)

[RAF74_Buzzsaw]

Wow, Talisman! P/O David Crook had one tough Spitfire!

600 mph in a dive!

Pilot Air Speed Indicators are never the most accurate... Neither are pilot memories


3000 rpm "with the tit pulled" and no perforated radiator or head gasket failure!!!!!!

If you dive at full boost/rpm you won't overheat your engine... speed is the key


full throttle dive from 27,000 feet to 1,000 feet

I don't think so... Pilot is clearly embellishing his memories. If he did this, he wouldn't recover. I don't think there is an aircraft in WWII which could do this... not a P-47, not a Tempest.


"Spitfire so much faster than his Messerschmidt"

With the canopy missing, it should be... and in any instance, we don't know what type of 109, what its status was, fuel state... completely unscientific assessement.


109's falling to pieces under the fire of 8 guns

apparent pilot kill from dead astern

Again, circumstances whereby the 109 falls to pieces are unclear... was it a result of pulling out of the dive these aircraft were in, when damaged? This does happen in the game.

Our ability to replicate the effects of massed .303's firing at perfect convergence without making the .303's overly strong is not perfect. But I personally have no problem with shooting off parts of wings, setting fires, killing pilots, etc. etc.



...............it's enough to make you weep....... :(

:)

With all due respect... ;)

Maybe you should work on your accuracy? >>> :-)

[ATAG_Snapper]

Aw, just having a bit of fun, Buzz! :D

But I still want a Spit that can dive at 600 mph and not lose its wings! :devilish:

EDIT: ....and, I might add, that can pull out at 1,000 feet, to boot. Is that really asking too much? :)

[RAF74_Buzzsaw]

Aw, just having a bit of fun, Buzz! :D

But I still want a Spit that can dive at 600 mph and not lose its wings! :devilish:

EDIT: ....and, I might add, that can pull out at 1,000 feet, to boot. Is that really asking too much? :)

I set the dive speeds for the aircraft based on the recommended maximum speeds as listed in the manuals.

Could the real aircraft exceed the manual's recommended maximum speeds? > Yes... and in the game, you won't lose your wings at 450 mph IAS in the Spitfire, it happens at a higher speed. (by the way the Spit Airspeed indicator only goes to 430 mph... then stops... if you see it hit the stop, and continue to dive.. you are going faster than 430 mph IAS... you need to look at the no-cockpit view to determine your actual speed)

(ASI readings is another big ? about the above account... pilot claims 600 mph... but how does he know that when he has no means to measure that speed?)

Could the real Pilots GREATLY exceed the maximum dive speeds recommended? > Yes some pilots may have survived such a risk, but they were the ones who returned... on the other hand, the ones who didn't survive, didn't return and didn't write highly embellished accounts of their deeds. I could post RAF combat reports of pilots observing friendly planes not recovering from dives... > Was that a result of combat damage, compressibility effects, blackout, mechanical failure, oxygen starvation, etc. etc... We'll never know.

In real life there are infinite numbers of variables... maybe the Spitfire a particular pilot is flying was completed at the factory by Gracie's build team, Gracie is very conscientious, all her aircraft are beautifully constructed.... maybe the Spitfire was built by Alf and his crew of slackers, who got drunk the night before and couldn't give a toss about which missing bolt was left out...

In the game, every Spit IA 100 octane is exactly the same... yes there are built in variables as critical points are reached... > the game engine starts a random calculation as to when a failure will occur when it deals with events like radiators blowing, wings failing,etc., but generally the variables are fairly limited and most aircraft will see a result which is relatively consistent with most events of that type, with that type of aircraft.

Bottom line... > CLIFFS OF DOVER is a simulation... it is limited by computing power and our own time in its ability to replicate real life.

[9./JG52 Ziegler]

That's why you always need to lower boost first before lowering your rpm and the other way around, you need to rise rpm before rising the boost level. Otherwise you can kiss the engine goodbye :)


That is the same way one flys a civilian aircraft with a constant speed prop today.

High map, low rpm is akin to driving your car uphill in 5th gear with the pedal floored. You'd better be traveling at a very high speed or else.

[Skoshi_Tiger]

Buzzsaw:


@Skoshi:
The engine won't produce full Manifold Pressure with the RPM all the way back as you can see in your video. You're doing damage but if you want to really kill it fast roll up the RPMs again enough to fly around at Max Manifold Pressure...that's when the stresses are greatest. Better yet, do a 61" Take Off at a sea level airport with the RPM back, it should be a pretty short flight. You are safe as long as you fly at the manufacturer settings to your right on the canopy rail and make sure you keep up enough speed to keep from overheating.

I will try next time I'm in DCS.

Now Mustangs are not spitfires and as far as I know they don't have the boost cutoff control like the spitfire.

In the spitfire MKII the boost is limited to +6lbs normally or +12 when using the the modified cuttoff valve for the 100 octaine versions. +12lbs is only around 54"Mg. Is this enough to cause the immediate catestrophic damage your talking about?


Heres another discussion on how the system works

http://theairtacticalassaultgroup.com/forum/showthread.php?t=7529


Cheers!

[Roblex]

I think the most striking thing in the account that Talisman posted was the fact that the pilot went to 3000rpm and BCO before entering combat. Do that sometime on CLOD and I bet your engine blows pretty quickly no matter how fast you dive as it is the oil system that will blow. In fact *either* using 3000rpm *or* BCO will blow your engine within minutes :D

[Skoshi_Tiger]

:) I've killed more Merlin engines from over reving than just about anyone :)

From the Manual distributed with the game. Spitfire I Aeroplane Merlin II or III Engine

Section 2


1. v) The following limitations must also be observed:
At +6 1/4 lb/sq.in boost: Minimum r.p.m 2,080
Diving: Maximum r.p.m. 3,600

3,000 r.p.m. may be exceeded only for
20 seconds with throttle not less than one third open

[RAF74_Buzzsaw]

:) I've killed more Merlin engines from over reving than just about anyone :)

From the Manual distributed with the game. Spitfire I Aeroplane Merlin II or III Engine

Section 2

The constant speed British aircraft, (Spit IA, Spit IA 100 octane, Spit IIA) will not rev over 3000 due to the governor. So you can't over-rev them.

The two speed British aircraft, the Spit I, Spit I 100 octane Hurri DH5-20 and DH5-20 100 octane can be revved higher.

Due to the current limitations of the code, we are not able to allow the two speed types to rev to 3600 rpm, if we did, the aircraft would be open to an exploit, being able to climb at high rpms without any negative effect. So the maximum rpm has been limited.

Players should read the aircraft manuals on the Team Fusion Wiki page. :salute: