Aces High Bulletin Board
General Forums => Aircraft and Vehicles => Topic started by: SunTracker on November 25, 2004, 06:50:27 PM
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Someone please enlighten me here. Why was the P-80 faster than the Me262? The P-80 had straight wings, wouldn't that cause it to have more drag than the 262?
In high school I read alot of books about WW2 air combat. I can't remember which book this was from, but it talked about Richard Bong's death. One of Bong's friends said that P-38 pilots had a habit of taking off at full throttle, then as they started their climb, they would pull back on the throttle slightly. This guy went on to say that Bong did this while taking off in a P-80, it caused a flameout, and he subsequently died. Any truth to this?
So if the P-80 was superior in performance to the 262, were there any German fighters that could match it?
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Both planes weight almost the same, near 300Kg more for the 262 empty. And both planes had similar power on take off: 1800Kg for 262 and 1750Kg for the P-80. While P-80A was only 9 mph faster than 262, it had a much better climb rate and much higher ceiling. Consider also that first 262 prototype flown on march 1942 while first P-80 prototype flown on January 44.
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262 also had its engines wing-mounted (drag) where the pee-80's engine was internal (not so much drag).
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The link to the NACA drag tests on the P-80 can be found from here (http://www.hitechcreations.com/forums/showthread.php?s=&postid=1479215#post1479215).
gripen
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SL speed for the P-80A with the J33 A-11 engine was just over 60kph faster than the 262.
The J33 had better fuel consumption than the Jumo. 1.1kg/kph to 1.7kg/kph
from a chart posted by SkyChimp on the Il-2 forum
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Was the P80 engine the same princip engine as the Jumo?
The Meteors had a centrifugal engine, totally obsolete today, but a clever tradeoff at the time.
How did those engines compare to the Jumo and the P80 engine anyway.
Straight wings, btw, don't tell it all.
The starfighter, at the time probably the fastest aircraft of the world had straight wings ;)
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The axial Jumo 004B (http://www.aircraftenginedesign.com/pictures/Jumo004B.GIF)
The American J33 was based on the British engine. The Vampire testing was delayed because the Brits sent its engine to America. Using the British Whittle WB.2 turbojet as a starting point, the I-40 was developed by GE.
The J33 had a axial turbine blade.
You will get an arguement from you know who, but the British/American approach was the best.
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Well, the German Jumo used the exact same design as in todays jet engines right (?), however the materials at the time were not good enough, so the lifetime was very very short.
The British design was apparently quite reliable.
I've seen a Meteor on an airshow. It seemed remarkably maneuverable while slow, the thing did a tight slow loop right over our heads.
Most remarkable was the sound of the engine, - not just the whooosh, but there was like accoustics in it as well, a wee bit of bass. Really really cool.
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Sounds like everybody was having a lot of trouble with their jet powered aircraft.
http://www.rand.org/publications/MR/MR1596/MR1596.appb.pdf
Crumpp
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Originally posted by Angus
Well, the German Jumo used the exact same design as in todays jet engines right (?), however the materials at the time were not good enough, so the lifetime was very very short.
The British design was apparently quite reliable.
I've seen a Meteor on an airshow. It seemed remarkably maneuverable while slow, the thing did a tight slow loop right over our heads.
Most remarkable was the sound of the engine, - not just the whooosh, but there was like accoustics in it as well, a wee bit of bass. Really really cool.
Axial flow, yes. Dual-spool, high bypass turbofan, no. Most modern engines don't have variable inlet onions, although their outlet sections are variable. Safe to say, the centrifugal flow turbojet is dead.
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Axial flow, that's the word I was looking for.
I know the centrifugal is dead, but some are still running!
I've heard that obsolete centrifugal engines were used to clean snow from runways, by blowing it.
Anyway, I belive they were at their hayday, more reliable. But once proper cheramics and alloys were available, axial flow owned the day.
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Centrifugal engines are not dead. CPUs use that design.
(http://www.hal-india.com/Enginebangalore/images/garrett331.jpg)
GARRETT 331 - 5
(http://www.hal-india.com/Enginebangalore/images/artouste3b.jpg)
Turbomeca(one axial and one centrifugal compressor connected to a three stage turbine.)
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As mentioned, centrifugal flow compressors are far from dead, they've just found their niche is all. And that niche happens to not be in turbojet/fan designs.
Garrett seems to love using centrifugal compressors in their turboshaft engines, and the incredibly versatile Allison Model 250 turbo-shaft uses both an axial compressor for the 'low-pressure' side, and a centrifugal compressor for the 'high-pressure' side.
The only turbofan engine that comes to mind that uses a centrifugal compressor now-adays is a Garrett design, though the designation escapes me.
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What about the later british engines, i.e. the Goblin and such?
Were they centrifugal?
And what was the mig-15 powered with?
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Originally posted by Angus
Well, the German Jumo used the exact same design as in todays jet engines right (?), however the materials at the time were not good enough, so the lifetime was very very short.
The British design was apparently quite reliable.
I've seen a Meteor on an airshow. It seemed remarkably maneuverable while slow, the thing did a tight slow loop right over our heads.
Most remarkable was the sound of the engine, - not just the whooosh, but there was like accoustics in it as well, a wee bit of bass. Really really cool.
Most of today's jet engines are turbo-fans rather than the
Jumo turbo-jets. The difference is that turbofans do not send
all of the air ingested through the turbine, but send some
directly from the compressor section to the exhaust. This is not
only more fuel efficient, but the large mass of slower moving air
surrounding the faster exhaust through the turbine section makes
the aircraft quieter, making the neighbors happier ;)
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Originally posted by Tails
As mentioned, centrifugal flow compressors are far from dead, they've just found their niche is all. And that niche happens to not be in turbojet/fan designs.
Garrett seems to love using centrifugal compressors in their turboshaft engines, and the incredibly versatile Allison Model 250 turbo-shaft uses both an axial compressor for the 'low-pressure' side, and a centrifugal compressor for the 'high-pressure' side.
The only turbofan engine that comes to mind that uses a centrifugal compressor now-adays is a Garrett design, though the designation escapes me.
Is that the one used on the Mitsubishi Mu-2 turboprop?