Re: RAT

From:         faurecm@halcyon.com (C. Marin Faure)
Organization: Northwest Nexus Inc.
Date:         08 Oct 96 13:00:06 
References:   1
Followups:    1
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In article <airliners.1996.1949@ohare.Chicago.COM>,
ltregear@camtech.net.au wrote:

> I've heard the A320 has a Ram Air Turbine, that automatically ejects
> into the airstream upon engine failure.
>
> My question is where is this Ram Air Turbine positioned and how big and
> how much power does it provide?

All ETOPS airplanes and some others have RATs.  They are not turbines in
the sense you may be thinking. A RAT is a small propeller mounted on a
retractable arm that pivots out of a well in the belly of the plane.
Depending on the airplane, the propeller drives a hydraulic pump or a
generator.  If there is a failure of the airplane's hydraulic system on a
fly-by-cable airplane or the electrical system on a fly-by-wire plane, the
RAT will automatically deploy into the airstream and provide sufficient
hydraulic or electrical power to operate the flight controls.  The pilots
also can deploy the RAT themselves if they want to.

It's the same concept as the little propeller-driven generator mounted on
the landing gear of small planes without battery systems like the Piper
Cub to power a radio in flight or running lights.

C. Marin Faure
   author, Flying a Floatplane