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P-51 Frozen controls


Coxy_99

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Just watched it; classic History Channel hyperbole. Taking off from Florida at any time of year introduces a great deal of humidity to the equation, so my best guess is that any water vapor inside the airframe would condense and freeze at some point, possibly affecting some moving parts. Some of my work involves working with liquid nitrogen and even in the dry air of southern California, the amount of extra frost that accumulates with just 10% more humidity is noticeable. Florida seems to me to spend 24 hours a day at 100% humidity (and parts of Georgia are even wetter--only the high art of barbecue practiced there justifies human occupancy), so I would imagine several gallons of water would have been contained in the aircraft as it reached 38,000 ft.

 

This, combined with a bit of ah, dramatic license and the extreme discomfort of an unpressurized cockpit could result in stiff controls and (speaking as a man in his sixties myself) even stiffer than usual hands and joints which could especially in front of a camera, result in the impression of very stiff or "frozen" controls.

 

cheers

 

horseback

[sIGPIC][/sIGPIC]"Here's your new Mustangs boys--you can learn to fly 'em on the way to the target!" LTCOL Don Blakeslee, late February 1944

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I worked in aerospace a few years with a engineering degrees after I left the USAF. The electronics has a plastic conformal coating on electronics, because the aircraft wrings the water out of the air each time to go up and comes down, compresses ands recycles air and water... everything where air is can get soaked in water...

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109 also had a problem with that. They changed the kind of grease used on certain points of the controls to prevent freezing. Not usual, but possible of course.

 

 

S!

"I went into the British Army believing that if you want peace you must prepare for war. I believe now that if you prepare for war, you get war."

-- Major-General Frederick B. Maurice

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I worked in aerospace a few years with a engineering degrees after I left the USAF. The electronics has a plastic conformal coating on electronics, because the aircraft wrings the water out of the air each time to go up and comes down, compresses ands recycles air and water... everything where air is can get soaked in water...

Three things:

 

The controls in the P-51, as in most aircraft of its generation, are all mechanical--every control surface was moved by muscle power. Every mechanical interface outside of the cockpit or the engine compartment would get extremely cold by the time he reached his maximum altitude, so greases and lubricants good at 25K might well have acted differently, and any water vapor inside the airframe would turn into frost or even ice somewhere. It is possible that this had some affect on the controls resistance to movement.

 

As for electronics, I would assume that the wiring in the aircraft have been replaced a few dozen times in the 60+ years since that aircraft was built. 1940s era wires were usually cloth covered over a kind of insulating putty--I ran into this sort of stuff several times while I was in the Navy in the 1970s, doing rework on early type plan position indicators (analog radar scopes). I saw conformal coating of the sort you describe arrive with solid state electronics, but I don't recall it on tube type circuitry, which would have been the original equipment on a Mustang.

 

Finally, the Mustang wasn't designed to reach and operate at that height, even assuming that the North American Aircraft design team in the LA area (was it Pasadena or Long Beach?) made allowances for that level of humidity at normal operating altitudes; I am reminded that a lot of the P-38's teething problems were due in part to its being designed and tested in Southern California, where the sorts of cold and humidity found in northern Europe are a nasty rumor and a little hard to believe while you're sipping an iced tea and savoring a guacamole dip on your tortilla chip. It's a desert here, folks, and the only reason it isn't brutally hot is that the ocean we're sitting next to is running a current down from Alaska.

 

cheers

 

horseback

[sIGPIC][/sIGPIC]"Here's your new Mustangs boys--you can learn to fly 'em on the way to the target!" LTCOL Don Blakeslee, late February 1944

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So all controls in any prop can become like that at high altitude? And by hyperbole you mean abit extreme :)

 

By hyperbole, I mean BS. Film and TV people have to be watched like a hawk and clubbed unconscious a few times before they can resist the temptation to 'improve' reality, even in so-called documentaries (and even after the requisite clubbings, you should still watch them closely).

 

cheers

 

horseback

[sIGPIC][/sIGPIC]"Here's your new Mustangs boys--you can learn to fly 'em on the way to the target!" LTCOL Don Blakeslee, late February 1944

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