Re: Rudder control & front gear

From: (Robert Dorsett)
Organization: Netcom Online Communications Services (408-241-9760 login: guest)
Date:         08 May 95 02:09:08 
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In article <airliners.1995.531@ohare.Chicago.COM> (Robert Leong) writes:
> (Robert Dorsett) wrote:
>>The 747 is a bit different: it's controlled by the tiller on the ground, by
>>the rudder when aerodynamically active.  It has a further option of steering
>>using the center gear bogies to further assist the nose gear.
>What is a 'center gear bogies'?

The 747 main landing gear is comprised of sixteen wheels on four trucks.
The leg + truck is called a bogie.  The two center bogies are steerable.
The position of the nose wheel biases the direction of the body steering.
A maximum deflection of the nose wheel will cause the center gear bogies
to turn up to 13 degrees.

The system can be switched on and off for takeoff and landing.

>Do large jets have differential breaking of the left or right main
>landing gears


>and if yes, are they used to assist in turning as do
>light plans?

They can be.  If you turn too tightly, though, you will scrub your wheels.
But note with a tiller, you have MUCH greater authority over the direction of
the nosewheel, so differential braking is not as critical.

Robert Dorsett                         Moderator, sci.aeronautics.simulation