Re: Hot Wheels

Date:         21 Nov 99 23:56:41 
From:         "P. Wezeman" <>
Organization: The University of Iowa
References:   1 2
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On 5 Nov 1999, Robert Wright wrote:
>     I'm not sure, but I did once talk to a captain who said that on very
> heavy takeoffs, particularly out of places like Honolulu which involved some
> long taxiing, he would leave the gear down longer than normal after takeoff.
> This allowed the airflow more time to cool the brakes and also allowed the
> airplane to build up more speed before gear retraction.  (The first thing
> that happens is that the main gears doors OPEN, to allow the gear back in,
> increasing drag.)  I don't know if this is standard procedure, or just one
> captain's style.

	Why are the brakes hot at take-off? I thought it was the
tire sidewalls that overheated. As it seems to me from
watching, the plane taxis out using throttle to control speed, then
stops from taxi speed and uses brakes to hold during run-up, then
releases brakes and moves onto runway, and may stop once on runway
before starting take-off run. Brakes are used twice or so at
taxi speed, a fraction of their capacity. Is this incorrect? Do pilots
have to"ride" the brakes to control taxi speed?

                        Peter Wezeman, anti-social Darwinist

                             "Carpe Cyprinidae"