The overwhelming majority of tailwheel airplanes are equipped with a steerable tailwheel. The tailwheel assembly is like a caster on a shopping cart, free to turn about a pivot point. A pair of steering arms project from either side and are connected to the pivot. When the arms are connected to the rudder, usually by chains and springs, any movement of the rudder will be transmitted to the tailwheel. Thus if you push the right rudder pedal the rudder will move to yaw the airplane to the right and the tailwheel will rotate as well, causing the airplane to turn right on the ground. Pretty nifty, huh? Well, there is just one little wrinkle and that wrinkle can spoil your day. Let’s say that you are in the process of landing three point in a cross wind from the right. In order to stay over the center line, you bank the airplane to the right. To avoid turning right, you apply left rudder. You are in a typical crosswind sideslip. As long as you stay in the air everything is hunky dory. But as soon as the airplane’s tailwheel touches the ground, its canted off tailwheel causes it to swerve to the left. You feel this swerve and immediately apply lots of right rudder to stop it. That’s just what the ground loop monster has been waiting for you to do. Now the tailwheel steering to the right and the wind blowing from the right conspire to rapidly turn your plane into the wind. A ground loop has been initiated and only correct and timely applications of rudder and maybe brake will prevent the coming wreck.
I’ve always felt that the cure for this phenomenon was the correctly applied application of neutral rudder right before touchdown. I admit that it’s tricky and complicates the already complicated process of the crosswind landing. And then I talked to Bill.
Bill Duncan, who owns “Alaskan Bushwheel”, has certainly studied tailwheels as much as anyone. Bill feels that steerable tailwheels have been the reason for more ground loops than any other cause. He blames that situation that I described above. The man owns a tailwheel manufacturing company and can put anything he wants on his Maule. He can also change his mind and change his tailwheel, which he probably has. Bill’s Maule is equipped with a fully swiveling tailwheel with no steering.
I have always felt that a tailwheel airplane should have three methods of turning on the ground; rudder, brake and tailwheel steering. After talking with Bill, I may just change my thinking. But as long as I conduct tailwheel training I guess I should have tailwheel steering and teach the technique of neutralizing the rudder at the instant of touchdown in a three point landing.
Happy Swooping.
Brian
