PPRuNe Forums - View Single Post - Most demanding loads on aircraft landing gear
Old 22nd Jul 2016, 13:55
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Capt Quentin McHale
 
Join Date: Oct 2013
Location: McHales Island
Age: 68
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" spotted a complete u/c leg, wheels and all. All the metal parts of the lower u/c leg were blue from excess heat. I was told that this was caused by a single heavy landing and I still find it unbelievable that one single shock load could cause sufficient heating to raise the temperature of such a mass of metal to a temperature of about 500 degrees C."


Don't think so boys and girls. Yes pulse1 totally agree. Where was this 500C heat generated from? Brakes or from inside the shock strut, or both?


Brake heat at that temp would result in the fusible plugs melting on the wheel rims and resulting in flat tyres and possible wheel rim magnesium fire. Then heat transfer through wheel assemblies to landing gear trucks and associated structure AND melting the protective paint to expose "blue metal".... don't think so.


Heat generated from within the shock strut? Definately not. The strut assembly is an overgrown shockstrut just like on our cars. It is filled with a combination of oil and nitrogen and on compression through an orifice will produce next to no temp rise at all. If temps did rise to 500C (which it won't) the strut O-rings would melt and you would have a deflated strut and vast pools of oil on the ground around the gear. In my 40yr career I have never seen or heard of such a thing. Keep smiling....


McHale.
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