Aces High Bulletin Board
General Forums => Aces High General Discussion => Topic started by: aknimitz on February 10, 2002, 09:59:13 PM
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I was watching the History Channel, and they were running a "Battle Stations" episode which primarily featured the corsair and its development and role in WWII. Of course many corsair pilots were giving their accounts, and one of them said something very interesting. They said one great thing about the corsair was that it turned so well to the left or right. The Zero could only turn to the left well, and it struggled when turning to the right. So he would just do a break turn/right and watch the zeke shoot by, and then just pull in behind and saddle up?
Any idea what this guy is talkin' about?
Nim
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I've read that the engine torque would cause the plane to only be able to turn one way coming out of a dive, dunno how true it was...
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I would guess it was a torque-to-weight problem. The old rotary engines of the WWI airplanes turned with the propellor. The rotating mass of the engine resulted in a hell of a strong gyroscopic effect. They only turned well in one direction. The Sopwith Camel comes to mind, it was notorious for its one-way gyroscopic turn performance.
All propellor aircraft exhibit this to some degree, but those with bigger props, more powerful engines, and lighter airframes should be more susceptible. The Corsair had big prop and strong engine, but was heavy. The Zero did not have a huge prop nor a powerful engine, but was light. Maybe the low wingloading/light frame was the key factor?
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A while back I read that P-38 pilots took advantage of the Zekes not being able to roll right very well. I think rolling degraded as speed increased which was compounded by the torque and so the rolling to the one direction opposite torque really suffered in the Zekes. Yeah, I'd heard of this weakness as well.
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The zeke would have very stiff controls beyond 320 mph, think of it as a compression of sorts. Add it's engine's TORQUE and you will see why it was hard, if not impossible for a zeke pilot to be able to roll the plane against its torque at those speeds.
This info was originally given to F4U pilots, then seeped to the army air corps after the F4U pilots proved it in combat.
I think that info was known and proven when they found a crashed zeke that was almost intact, repaired it and test-flew it.
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Those are the kind of things I want to see in AH, not just different turns rates and climb, and speed, but other realism things that made some planes stand out from the rest. Engine torque affect one plane at a certain speed, making it possible to use that to an advantage when flying against it. Goes every and all planes, no matter Axis or Allied.
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point of clarification: World War 1 planes commonly had rotary engines, which as pointed out above, rotate with the propeller around a stationary crankshaft. To my knowledge, no WW2 airplane used this arrangement however. Many WW2 planes did however, use radial engines which are arranged similarly, with the cylinders arranged radially around the crank, but the engine block in a radial is stationary, unlike the rotary. This greatly reduces the rotational mass. Im not sure what they were thinking when they designed the rotary engines of WW1, but it wasnt the worlds greatest idea, especially in those light planes.
Also, do not confuse, the rotary engine of WW1 with the Wankel rotary engine which has been used in recent years in automobiles, most notably by Mazda. The Wankel rotary is a completely different beast, which doesnt even have cylinders. I see people getting confused over the difference between rotary and radial all the time in here, so I thought I would clear that up.
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I believe WW1 Rotary engines produced more horsepower per pound of engine weight than did the inline engines, at least in the earlier versions of WW1 aircraft.
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I asked an old Spitfire pilot whether the engine rotary effect had any effect on turning/rolling abilities. He said that when the aircrafte was trimmed right, it didn't. However, I read somewhere that from Spitfire XIV onwards, this was noticable.
Now the Zero does not have such a big engine, but it is a very light plane, so HP to weight is a lot....a little comparison:
A6M5b 1130 Hp vs 1895 KG EW = 1,67 kg/hp
190 A8 1800 Hp vs 3180 Kg EW = 1,76 Kg/hp
F4U-4 2450 Hp vs 4180 kg EW = 1,71 Kg/Hp
Spit V 1440 Hp vs 2280 kg EW = 1,58 Kg/Hp
Spit XIV 2050 Hp vs 2970 kg EW = 1,44 Kg/Hp
The Zero has a lot of thrust to weight, however not enough to explain this.
However, Zekes were told to be unrollable at speeds above 320 miles (if my memory serves me right, or was that maybe knots...), so above 320 mph, one could possibly not counter the gyro effect.
In AH however the Zero does roll over 320, its just a bit slow
:confused:
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Hp to weight doesn't really tell the whole story...
It is a function of torque to weight, which is not quite the same as anyone who races cars should know.
But the F4U always had a very high torque to weight with its huge propellor.
Yes, the radial engines do not rotate like the WWI rotary engine, but a WWII prop was very large and turned very fast, giving it a high rotational inertia not unlike the pipsqueak rotary engines. Of course the overall weight of WWII aircraft offset this to a large extent. Apparently some aircraft at some speeds still suffered from the problem?
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Zero's engines props turned clockwise,different than most ww2 aircraft.This accounted for poor right turn performance,
According to Saki,he always turned left,and never dived into fight.
Dobe
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Those are the kind of things I want to see in AH, not just different turns rates and climb, and speed, but other realism things...
Me too. No idea if the anecdote about the Zeke is true or not. With such a light weight body pulled by that radial I could imagine it to be true. However the Zeke and F4U for two examples have popsicle cat handling in AH in direct comparison to the RL reports by test pilots that state things differently.
Westy
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Yessssssssssss.......
F4U was such a bad plane, the Navy gave it to the Marines ;)
F4U in version 1.03 seemed to handle somewhat like real-life accounts... torque would easily cause you to crash on takeoff if you didn't respond quickly and correctly.
Using lookup tables for performance data may approximate the turn and climb rates correctly, but do little to model the "feel" of an aircraft in areas such as stability. I know HTC tries their best and generally does a better job than anyone else, but not enough data was ever recorded for these planes to get it right by simply using a lookup table strategy.
Ultimately, as computers become more powerful and the equations become more accurate, the X-Planes strategy of modeling the force interaction in real-time will become superior. Of course, even if the equations are accurate, the results will only be as good as the data typed in for the aircraft's geometry, powerplant, structure, and weight distribution.
I wish there were flight sims accurate enough to use the complete wing and control surface geometry to model flight performance correctly for any aircraft in existence. It would be great to try mixing and matching technology from the different fighters to come up with the ultimate uber plane. If anyone ever makes a sim that models the F-4 Phantom and F-104 control problems correctly, I will play it exclusively. The fun is in taming the wild bronco. Air combat is just an arena to show that you have tamed your beast better than the opponent has tamed his.
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Wilbus wrote:
Those are the kind of things I want to see in AH, not just different turns rates and climb, and speed,
Actually, even though most people don't realize it, they are in AH.
Take most any plane (I haven't tested every one, but the ones I've tested work out) and do a 360 turn test to the left (its best too do 5 tests and average the results). Then repeat the tests to the right. You'll get different results. The large majority of planes turn to the left best.
This is due to engine torque, so its most noticeable down near stall speed.
Two planes that can really take advantage of this are the Yak-9U and the Typhoon. These two planes have engines that turn the opposite direction from all the other planes, so they turn best to the right. So if the Yak pilot offsets to the left (his POV) on the merge he will have a huge advantage.
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What he is most likely talking about is the yaw caused by 'P-factor' When a propeller is at a right angle to the path of flight both sides are creating equal thrust. When you raise the nose the angles the blades meet the direction of flight change. The right side creates more thrust and the nose yaws to the left. If you lower the nose the opposite happens. (This is why God gave us rudders)
I'm confused by his statement because a diving turn to the right is what a normal propeller driven aircraft does best and the Zero was a very 'normal' A/C.
More interesting, I found it strange they never discussed the Corsairs deadly habit of killing anyone that got it slow and nose
high, received a wave off and then made the mistake of firewalling that R-2800. The small tail and rudder had no chance to stop the those 2,000 horses from rolling it left and inverted with predictable results.
Both were great shows....
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"So if the Yak pilot offsets to the left (his POV) on the merge he will have a huge advantage."
IMO it's a good thing that only about 10% of the arena read these boards. :) I love (repeat LOVE) right hand turn-fighting ;)
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At speed the light zero's roll rate was slower than the corsair's who's roll rate was very fast in no small part due to the gull wings and huge ailerons. Obviously the direction of engine torque played a large role as well. At high speed the corsair pilot would break to the right, or left, depending on which way the prop spins, I dont recall off hand and by the time the zero pilot could roll his a/c he had overshot his adversary. I'm not sure but I would bet that the props in the corsair and zero probably spin in different directions. Try it in ah at about 350kn, it'll become very clear. I've been outrolled by fw's and f4's at high speed while giving chase in my mc205. I would have really been in trouble if I was flyin a zero :) The corsairs really outclassed the zero's in almost every respect.
CRASH
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There are so many factors that go into this, its not just any one of them but the cumalative effect that causes the Corsair to roll better. Boosted controls or lack of them, horsepower/torque to weight ratio, length of the wings, wing area, negative static stability, size of control surfaces, servo trim, and many other factors, most of which have been mentioned already, all combine to make an airplane have good or bad rolling capability.
By the way, the Corsairs prop spins clockwise as viewed from the pilots seat, as do almost all US made aircraft. To the best of my knowledge the Zeros prop also spins clockwise, so that isnt why.
Also, somebody incorrectly stated above that most airplanes turn best to the right. Not true, most airplanes have props that turn clockwise as viewed from the rear, causing the airplane to want to turn counterclockwise, a rolling moment to the left. This means that most prop planes turn best to the left.
The factors that cause this are:
--P-factor (one prop blade creating more thrust than other due to angle of attack causing thrust axis to be displaced from relative wind)
--slipstream swirl (the corkscrewing motion imparted to air by the propeller which swirls around and causes horizontal lifting force on the vertical stab),
--torque
--gyroscopic precession (the force created when a force is applied to the rim of a spinning object, such as a propeller)
All these act to effect the ability of aircraft to turn in certain directions. On a normal prop aircraft, (clockwise prop) all of these except gyroscopic precession cause the airplane to roll and/or yaw to the left.
My guess is that the superiority of the Corsair over the Zero in this instance has far more to do with the control surfaces than it does with the engine torque. US aircraft in general had far more control authority at higher speeds than did Japanese aircraft of WW2.
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In McGuire's "Combat Tactics in the SouthWest Pacific", the only plane he wrote that had poor right turn performance was the 'Tony'. At high speeds this plane was unable to turn or roll to the right. He also mentions that the Japanese pilots in whatever fighter would almost always break to the left.
Ack-Ack
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