[ARC5] An Interesting Failure Mode

[Robert Eleazer]

I was just reading about the use of the Oboe navigation system by the RAF in WWII.  They proved the system out in Wellington bombers and then switched to using Mosquito bombers, where they kept having failures, a tube would seem to explode.  

The problem turned out to be due to the higher altitude used by the Mosquito, 20,000 ft rather than the 10,000 ft of the Wellington flights.  At the higher altitude a cooling fan, which used a Hoover vacuum cleaner motor, would turn faster due to the thinner air.  The higher RPM would reach resonance with a certain tube in the Oboe equipment, which would shatter.

Wayne
WB5WSV           
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