Re: Rudder control & front gear

From: (Robert Dorsett)
Organization: Netcom Online Communications Services (408-241-9760 login: guest)
Date:         27 Apr 95 02:53:20 
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In article <airliners.1995.451@ohare.Chicago.COM> (Wayne Dockery) writes:
>Is a commercial aircraft (e.g., B747), I understand the
>plane is controlled by the rudder for 'yaw'.  However,
>once on the ground does the pilot have to make some
>change to steer the craft with the nose gear vs. the
>rudder?  In other words, are the rudder pedals also
>used to steer the nose gear?

It depends on the airplane.  Typically the rudder pedals influence both the
nose gear and the rudder.  Beyond a certain point (40+ knots) the rudders
become aerodynamically significant, and are used to steer the airplane.
At low speeds, the rudders can bias the nose wheels to a certain extent,
but a tiller (a knob on the cockpit sidewall) is typically used to point the
wheels to a greater extent.

For instance, the rudder pedals can bias the nose gear on a 757 7 degrees,
but the tiller can bias them 65 degrees.  The 727 has similar limitations;
the tiller can bias up to 78 degrees.

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.

Robert Dorsett                         Moderator, sci.aeronautics.simulation