Hydroplaning, Air Force insight

["scott miller" <macatawa@hotmail.com>]

I also fly KC-135s full-time for the Air Force Reserves, and 
hydroplaning is a big deal for us.  We're taught dynamic hydroplaning 
begins at approximately the sq root of tire press times nine, and water 
depth exceeding tread depth.  My father learned the same when he started 
flying.  We're both mechanical engineers and car buffs, and we know it's 
not exact, but it's a pretty good wag to know when you're approching 
danger.  Our tires and most aircraft tires I've seen have just a few 
straight grooves, I've not noticed a rush to aquatreads to improve a 
very significant danger in the aviation world, so I assume tread design 
isn't a major factor in hydroplaning speed.  Killing our lift by raising 
speedbrakes on landing helps add pressure to the rubber/pavement/water.  
I'm sure my car develops some front end lift at hydroplaning speeds, how 
much I don't know.  I do know I have a lot less options when my car 
hydroplanes than my airplane.

I could go on for a while about this and other forms of hydroplaning, if 
you're really interested in more, but I have a new hobby that's 
demanding my attention.

Scott Miller
Quattro owner for five days now
'90 200q wagon

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