Aces High Bulletin Board
General Forums => Aircraft and Vehicles => Topic started by: RTHolmes on December 21, 2009, 08:33:44 AM
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I may be wrong here but, over 70" MP at WEP on the P-47M and N suggests to me that they use 150 avgas, are any other aircraft in AH modelled with 150 avgas? later spits and ponies plainly arent, not sure about the tempest or F4U-4 though.
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They did, after ww2 though.
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well plenty of aircraft used it late in ww2 too, iirc most frontline RAF spit and tempest squadrons used it from late '44, pretty sure jug, pony and 38s did too, although i'm not clear on how many of them and in which theatres.
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Absolutely.
What's out boost on the Spixteen BTW? They were doing +25 in 1944 for certain.
There is someone on the forum who has this all. Dan, or possibly Milo.
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our late spits show +18, although +21 was used for some XIVs and +25 for some IX/XVI.
our tempest shows +10.5, +11/12/13 was used with 150.
how about axis aircraft? I realise the luftwaffe had problems with getting higher rated fuel late in the war but did any units get the good stuff? how about the japanese?
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RTHolmes,
Japanese aircraft seem to be modeled with 87 octane. They did not have any high quality fuel that I have ever heard of, though they did try to find ways of getting it. Ki-84 on US 100 octane fuel in post war tests did 420mph at best altitude.
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Angus, I would have thought you would have this site bookmarked.
http://www.spitfireperformance.com/
http://www.wwiiaircraftperformance.org/150grade/150-grade-fuel.html
One thing to remember when comparing Allied and German fuels is that the German fuel was rated using the lean mixture and Allied fuel was rated using the rich mixture.
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Angus, I would have thought you would have this site bookmarked.
http://www.spitfireperformance.com/
http://www.wwiiaircraftperformance.org/150grade/150-grade-fuel.html
One thing to remember when comparing Allied and German fuels is that the German fuel was rated using the lean mixture and Allied fuel was rated using the rich mixture.
Hmmm,interesting Milo,is there a reason for the difference,rich vs lean in the ratings?
I never heard this b4 so now I'll have to look into it,man thats the best thing about the forums,you learn something everyday,in my books thats a good thing.
:salute
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RTHolmes,
Japanese aircraft seem to be modeled with 87 octane. They did not have any high quality fuel that I have ever heard of, though they did try to find ways of getting it. Ki-84 on US 100 octane fuel in post war tests did 420mph at best altitude.
Im not sure back then, but in the US you measure your octane rating slightly different, I think our 100 Ron fuel is equilent to US 93? or around that..
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The F4U-4 is modeled with the standard 100/130 grade.
If it was using what the RAF rated 150, I have some graphs that say it would have a near 5000 fpm climbrate.
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The F4U-4 is modeled with the standard 100/130 grade.
If it was using what the RAF rated 150, I have some graphs that say it would have a near 5000 fpm climbrate.
Man, imagine the whines that would ensue if the F4U-4 got 150.
I want it now just to HEAR them. :D
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Some 145 fuel was shipped to the Pacific late war. Not sure if it was used operationally. Widewing would probably know.
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They did, after ww2 though.
Not correct... All 8th AF fighters were using 150 octane fuel after July of 1944. Thus, the P-47Ms were using it.
I have a document somewhere referencing the need for 115/145 avgas for the F4U-4. I'll see if I can dig it up on my external storage drives.
My regards,
Widewing
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They did, after ww2 though.
You'd be incorrect.
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Wonder if one day the AvA could have better fuel as a perkable ord option.
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In the Aviation industry, we used to be able to get 130, which was green, but they discontinued its production years ago. Now we get 100 Low Lead, the lead helps to Lubricate and cool the engine. In the lower compression engines if you Idle for long periods it will Foul the bottom plugs, and then you have to scrape the solids out from inbetween the Barrel and the electrode. The Older engines Had high compression and did not have this problem AS bad. Plus the Barrel/ electrode set up was different. If you look at a stock Champion avaiton plug, and an older BG aviation plug the differences are really apparent. The Higher the octane the Higher compression, the better fuel useage. An aircraft designed for 100LL will run better and use less fuel if run on 100LL than it will if you were to run 87 octane, even if you do mix the Marvel Mystery Oil that you are supposed to. Plus the engine will have less of a tendency to "Detonate" at low mixture settings. The term "Detonate" means for the air/fuel mixture to combust before the piston reaches Top Dead Center. Yes 150LL was used during WW2 and for a short time afterwards. It was cost prohibitave to produce for the Civilian aircraft, and the Airfarce transfering to jets, made it un-needed and since most of the piston engine aircraft could use 130LL and 130LL was cheaper they quit producing it in any quantities. According to what I have been able to find the highest avaition fuel produced for general use is 100LL. The guys that I know that are flying the Big Iron Warbirds are using 100LL and some mix Marvel Mystery Oil 6 oz. for every 5 gals of fuel.
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Some 145 fuel was shipped to the Pacific late war. Not sure if it was used operationally. Widewing would probably know.
You can read about US avgas production in detail in this study: USAAF Study No. 65, Aviation Gasoline Production and Control.
It may be downloaded using the link below.
http://www.afhra.af.mil/shared/media/document/AFD-090601-038.pdf (http://www.afhra.af.mil/shared/media/document/AFD-090601-038.pdf)
My regards,
Widewing
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Do you recall Izzy claiming that the allies had very little of proper fuel? I can not forget that episode.
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He still does.
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Barbi gets royally pwnd over the use of 100 octane fuel during BoB in these 2 threads,
http://www.ww2aircraft.net/for...uring-bob-16305.html
http://www.ww2aircraft.net/for...af-pt-2-a-20108.html
Thanks for the link Ww.
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But what Holmes was asking in the OP was whether or not the P-47M and N in-game are modeled using 150. They are not, as that motor could pull 72" on regular AVGAS, with water. Who knows what they could pull with 150?
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I remember clearly the incredible figure of a 4.75 min. climb to 20 000 ft. for a in-service P-47M pulled from service for the test. This was from a complete article on the P-47M. Full fuel, full ammo...
To put it in perspective, the Me-109K supposedly does 4.5 min. (I heard the oil-circulation problem at nose-up angles, while using MW-50, was solved by the K model: Any clues on that? I know it wasn't solved on the G-14AS in November 1944 yet).
The best climbing in-service prop fighter of WWII? AFAIK, The Spitfire Mk IX with 150 octane pulling 80" MAP: 4.2 min. to 20 000 ft.
Worthy of note is that European theater P-38Ls used 150 fuel at 64" MAP, but the British mix of lead was poor and tended to foul spark plugs or cause other maintenance problems. There were no such problems with US-mixed 145 Av gas in the Pacific... P-47s and, to a lesser extent, the P-51s, accepted the British 150 fuel better.
I heard of engine cutting-out problems on take off for the P-51 though, killing several pilots... Erosion of the valve seats was determined as the cause, and a new mix of the 150 fuel alleviated the problem only in very late 1944, if not 1945... These cutting-out issues were initially dealt with from July '44 by much more frequent maintenance and occasionally "reving-up" the engines in flight to clean them... I even think there was a call for a return to lower octane 130 fuel for the continent-based aircrafts, were maintenance was harder, but 150 fuel remained for UK-based fighters... This is all from memory, but should give a rough idea of the issues...
Gaston
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But what Holmes was asking in the OP was whether or not the P-47M and N in-game are modeled using 150. They are not, as that motor could pull 72" on regular AVGAS, with water. Who knows what they could pull with 150?
ahh ty, must have been the earlier 2800s that could only get 70"+ by using 150 avgas.
The best climbing in-service prop fighter of WWII? AFAIK, The Spitfire Mk IX with 150 octane pulling 80" MAP: 4.2 min. to 20 000 ft.
yeah over 5000fpm in a IX :o
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Todays old warbirds may be somewhat lighter than in war-service, and perform lovely at airshows and such. I recall Mark Hanna telling about 7 boost as a standard max today. Old engines he said. You can just begin to ponder what you could do with +25 ;)
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I don't know how it equates to boost levels, but I know they're cranking 120-140" of MP out of the Merlins in Reno. Obviously that's for races and they regularly have engine failures, but it gives you an idea of the total potential of some of those engines.
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Ahh, I forgot that. They really run them like mad. There is one episode of Top Gear with that, a two-seated P51 running with some odd 2000 (or maybe 3000) hp. Jeremy Clarkson in the back seat. And I cannot find it on youtube :cry
Anyway, it is quite logical to take the careful approach on the precious old warbirds such as the Duxford ones, so one can only imagine the "tickle" of the pilot once the roaring engine brings you up.
BTW, the first Spitfire I saw flying completely baffled me with the lift. The guy really took a short run for the takeoff and went straight into a loop. I am not even sure that I could copy that in AH.
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ahh ty, must have been the earlier 2800s that could only get 70"+ by using 150 avgas.
yeah over 5000fpm in a IX :o
me wants!!! :x :banana:
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Me too.
:cool:
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Spit LF IX used 150 in mid 1944.
After ironing out a few issues all 2TAF Spits were directed to convert/use 150 in Dec 1944. (LF IX, XIV and XVI)