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Why wasn't the P-47 used in Korea?


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#21 GregP

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Posted 23 December 2016 - 02:06 AM

Most of the guys I know who have flown Sukhoi 29/29/31, Yak 18/50/52, and Shenyang CJ-6 aerobatic aircraft say it is a bit unusual to have to use opposite rudder the first few times, but a good taildragger pilot uses whatever rudder it takes to stay straight, and they all say that while strange, it didn't take too much "getting used to it" before they flew it quite well. You don't practice that very much with a nosewheel, but conventional gear pilots do every time they taxi.

 

I'd think that if a conventional gear fighter, paritularly a high-HP one like a Griffon Spitfire, was heading for the runway edge, a good pilot would shut down and accept the rejected takeoff before crashing it. Obviously not everyone did.

 

Too bad. Another trait of the Griffon Spits was that the main gear were closer to the balance point and they are easy to nose over with moderate braking than a Merlin Spit. It's worth remembering if you land on soft turf to keep speed up until better ground is under the aircrft before slowing too much.



#22 Armand

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Posted 23 December 2016 - 02:38 AM

I have not so ever any piloting experience and however I've noticed the rudder being mentioned I have considered propellar torque to cause a roll- movement (to be countered with ailerons) and not a directional effect (to be countered with rudder)
As there is quite a difference to directional tricking whilst still rolling and an unintentional roll from the moment of lift-off as I have assumed until now, I'll be glad to be guided more closely into the torque-dynamics!?
BTW: The 'curious' phrase used by Me had the intention of leading to my steadily evolving posting 'Curious Details' !

Edited by Armand, 23 December 2016 - 02:42 AM.


#23 GregP

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Posted 23 December 2016 - 05:20 AM

Propeller torque causes you to have to use rudder when on the ground and both rudder and aileron when you lift off. You must hold in right rudder on a right--turning propeller (spins clockwise when seen from the cockpit) when climbing and it diminishes as you decrease power to cruise where the torque is generally trimmed out by fixed rudder tabs or sometimes by moveable tabs.

 

Immediately after lift-off, I have had to use both rudder and aileron on occasion, but the aileron diminishes as you accelerate to best-climb speed, after which aileron is mostly neutral. This is in 2 and 4-place light aicraft of 160 to 285 HP or so.

 

In fighters with a lot of engine, say, a P-51 Mustang, for instance, if you perform a go-around, you would generally push in a lot of right rudder and put the stick hard over into the front-right corner as you add power. When the nose starts swerving left regardless of rudder and aileron, you had better stop adding power and decrease slightly until the nose is back going straight or you'll torque-roll into the ground. Unfortunately for me, I have watched that very scenario happen in real life. The pilot was killed and the P-51 was scrap metal.

 

In high-HP pistons, you can only add power until you start to overcome the ability of the controls to counteract it. After that, you are fairly rapidly out of coutrol, usually at low altitude, with usually fatal results.

 

I have had this happen to me when flying warbird RC models with big engines. I chopped power, recovered (stopped the swing) and kept flying, without loss of altitude ... but the wing loading of the RC model was nowhere NEAR the real wing loading of the full size aircraft, and I had a LOT more control throw to use, coupled with a LOT better power-to-weight ratio.

 

When a low and slow full-scale warbird starts to depart, it can already be too late as the incipent spin may develop even if control is neutralized. It depends on the weight, the wing loading, and the stall characteristics of the warbird. The P-51 does a LOT of things quite well. Some of the not-so-nice properties of the P-51 are the stall characteristics once it departs controlled flight. If it gets into a stall break, it can require 10,000+ feet to recover. That is NOT good if you are in the landing pattern. The moral is clear, don't fool with it when low and slow. Make gradual, controlled power changes, change configurations slowly,  and stay smooth on the controls, especially the throttle. You basically push the throttle until something you don't like starts to happen, back off a bit, and continue smoothly. You can add power as speed goes up.

 

If you are straight and level somwhere near stall, say about 25 knots away, and you add a whole fistfull of power, you'll torque-roll against full stick and rudder deflection, to the left. The prop accelerates to the right, and the nose will slew left and down rapidly. Most warbird single-engine fighters will exhibit this same characteristic with right-turn props. Everything goes the other way with left-turn props.

 

Contra-props eliminate this characteristic but intruduce a whole slew of other issues all their very own.

 

Twins with counter-turning props show no torque reaction when the engine power is balanced and much worse symptoms when one engine is out or one is at high power while the other is at low power. Twins with same-turning props will always go left when you add a lot of power (right-turning props) unless a LOT of rudder is held and vice-versa, but basically don't want to roll ... just slew. A centerline twin with both engines running also will not want to roll or slew, but centerline engines also have their issues.

 

There is no perfect, high-power solution, unless you have a rocket engine. Typically they eat fuel so fast that the issues associated with them are insurmountable in a practical aircraft, assuming they don't just explode on you. That usually makes for a bad day, at least for the pilot. It DOES tend to get a shiny new rocket plane for the crew chief. The hard part comes when trying to find a new, qualified, expendable pilot.



#24 TheArtOfFlight

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Posted 27 December 2016 - 03:16 PM

That's a good question. I would have answered simply because most ww2 designed aircraft by that time were being phased out/Or had been taken out of service already. And the only ww2 aircraft that did manage to actually shoot down any Korean/Russian jets were carrier based fighters. And i believe there were only two prop driven aircraft from that period that did have Mig kill claims. The first was the F4U Corsair and the other one was the Hawker Fury. Anyone is welcome to correct me if im wrong but i have never seen any fighter kill claims by ww2 planes such as the the P51 in Korea. The P-47 M/N might have been a worthy prop fighter to deploy but by that time were there any left combat ready? And the technology had long since switched over to Jets. Good idea though.



#25 bearoutwest

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Posted 04 March 2017 - 02:19 AM

Found this link to a dissertation by Michael D. Rowland, Air Power History, Fall 2003 Issue, in another forum. (A virtual nod to Jim Oxley for the pointer.)
Research article on the use of the F-51 in Korea (or alternately the not-use of the P-47).
https://sobchak.word....he-korean-war/

 

...geoff


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