Nose gear steering
09-16-2009, 10:53 PM
Larry Brunzlick | Nose gear steering
This is my nose wheel steering adaptation to allow steering through the rudder pedals. I have included pictures. Sharon and I both want you to steer our Seawind by using the rudder pedals similar to the way we do in our Cherokee six. In addition, we will save a little weight and money by not going with the hydraulic steering. The nose wheel spindle rotates by the use of two (bicycle brake) pull cables.
I don't know yet if these cables will hold up over time but they sure will be cheap to replace. The two cables will connect directly to the right and left rudder pedals.
The cables attach to a sleeve that can couple and decouple from the nose wheel spindle when the nose gear extends and retracts. The sleeve can also be manually decoupled, when I want to make a very tight turn and let the nose gear simply castor.
In order to make a very tight turn by locking up one of the main wheels, the nose wheel has to pivot about 70Â° in order to â€œturn on a dimeâ€. If the rudder cables were allowed to turn the nose gear that much at full throw, then in a cross controlled landing such as a cross wind, the nose gear might get ripped off because of the extreme angle.
Therefore, for normal taxiing a full throw of the rudder paddles will only turn the nose gear 35 to 40Â°. When I want to make a very tight turn, I will flip a lever that decouples the steering cables from the nose wheel spindle.
I adapted my aluminum cap locking it to turn with the nose wheel spindle. I welded a 2-inch diameter aluminum tube on top of the aluminum cap. The tube is 1/4 inch thick. A bronze bushing or sleeve fits over that. The steering control cables connect to the bronze bushing. The bronze bushing couples to the aluminum tube by a thick aluminum key that fits through a slot in the bushing and the aluminum tube. There are two separate lighter weight cables (bicycle derailer cables), which control the action of the spring-loaded coupling /decoupling key. One cable is for manual use in the cockpit with a lever similar to a choke lever on an ATV, and the other cable automatically tightens and decouples the bronze bushing when the nose gear retracts.
The first picture shows the steering cables attached to the bronze sleeve, which is fitted over the aluminum tube that is welded to the spindle cap. Note the slot for the key that couples and decouples the bronze sleeve.
The second picture is a shot from above.
The third picture is a picture of the thin-walled sleeve that contains the spring-loaded key and one of the cables that controls the key. This assembly fits inside the thick aluminum sleeve.
Fourth picture is another angle of that key.
The fifth picture is the entire assembly. Note the key projecting through and filling the two slots when the nose gear is down.
The sixth picture shows the cable that pulls the key out of the slots as the nose gear retracts up. The cable for the manual coupling and decoupling is not installed here, but you can see the hole that it fits into.
Picture seven shows how the key is retracting as the cable tightens when the gear is retracting.
Picture eight shows the retracted gear. Note the steering cables going through the bulkhead above the actuator.