Nose gear steering

NOSE GEAR STEERING

Hal Stoen, June 9, 2000

12/28/99

There has been considerable discussion of late on nose wheelsteering. Perhaps this input will help- and, perhaps not. I'mgoing by memory as I don't have any reference material at hand.This pertains only to General Aviation, not to Transport Categoryaircraft..

There are exceptions, but most GA aircraft have the nose gearinterconnected with the rudder. There are some that have freecastering nose gear, but these are few in number. To my recollectionall Cessna singles and twins have interconnected rudder/nose gear,as do all Piper aircraft.

This interconnection between the nose gear and the rudder isdone with springs, although I understand some kit aircraft usebungee cords. If you are sitting still on the ground and pusha rudder pedal full in to the stops the rudder will deflect accordingly-the nose wheel will not turn. As soon as the aircraft starts toroll, the nose wheel will start turning in the appropriate direction.

On retractable gear aircraft there is a link that disengageswith the nose gear steering mechanism so that the nose gear assemblymay retract into the nose bay in a non-castered position. Whenthe gear is extended this link re-engages to allow nose gear steering.

When taking off into a cross wind the ailerons are turned intothe wind as necessary to prevent the wing on the cross wind sidefrom lifting too early in the take off roll. Let's use a takeoff with a strong cross wind from the right for example. As theaircraft rolls down the runway, the stronger flow of air fromthe right side creates more lift on that side making the wingwant to become airborne before the rest of the aircraft is ready.To counter this the pilot turns the wheel to the right as necessary.This action lowers the left aileron and raises the right one.The end effect is to place more downward pressure on the rightwing. This helps to prevent the wing from rising too early, andalso places more weight on the right gear to help the aircraftremain on the ground until a "positive" lift-off ismade.

All this time the nose gear is tracking down the center ofthe runway and the rudder is centered. Just prior to lift-off,usually at an increased speed, the ailerons are centered, thewheel is brought back a little more smartly than normal (to preventany side loading on the gear as the weight is removed), and assoon as the aircraft breaks ground a slight turn (coordinated)is made into the wind.

On landing in a crosswind, there are two basic styles: "crabbedinto the wind", and "cross-controlled, wing down intothe wind":

"Crabbed into the wind"

In this approach the aircraft is headed into the crosswindat the appropriate angle to prevent the aircraft from drifting.The aircraft arrives over the end of the runway in coordinatedflight with the rudder and ailerons in the neutral position. Theaircraft is at an angle with the runway, pointing into the crosswindas necessary to prevent drifting. While not pointing down therunway, the aircraft is _tracking_ down the runway. Just beforetouchdown the aircraft is aligned with the runway. At touchdownthe nose gear is centered. Right after touchdown the aileronsare once again rolled into the wind to keep the upwind wing fromrising.
This type of landing requires split-second timing, lest the aircraftmake surface contact in a crabbed position and heads off to theboonies, perhaps losing some landing gear fittings, tire rubber,and collecting some runway lights in the process. Personally,I could never master this type of timing.

"Cross-controlled wing downinto the wind"

In this approach the aircraft is aligned with the runway usingcross-control operation to keep the aircraft from drifting (uncoordinatedflight). With a crosswind from the right, the right wing is loweredas necessary to prevent drifting to the left. Lowering the rightwing of course makes the aircraft want to turn that way, so leftrudder is added as necessary to keep the aircraft from turning.This "cross-controlling" is adjusted as the airspeeddissipates. Also, this type of operation raises the stall speed,so a greater than normal approach speed is used. With the rightwing down, and left rudder applied, the nose gear is pointingto the left prior to touchdown. The aircraft is tracking and pointeddown the runway. Touchdown is done with the right main gear first.Then the ailerons are rolled so that the left main makes contact.Then the rudder is centered and the nose lowered more smartlythan normal. Because the rudder is centered, the nose gear iscentered and the aircraft rolls down the center of the runway.

I hope that my mind didn't develop any "memory leaks"and I that recalled all of this correctly. I mainly hope thatthis may clear things up a little bit on rudder/nose wheel steering.

This tutorial is available on a CD

This tutorial, along with additional content, is availableon a CD. Click here formore information.

Hal Stoen

rev: 8/19/2000

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