The tailwheel lock had a pin that fell into a bracket that was attached to the actual tailwheel pivot point. Usually and on MOST of them allowed 30 degrees of swivel. The reason for this is that the tailwheels were what is termed as Free swivel, and not steerable. Aircraft such as the Beech 18 or or as it is also known the C-45 expediter had a lever in the cockpit to lock the tailwheel so that it was easier to Taxi. When the pilot needed to turn he could unlock it and turn sharper. The draw back to this system is that if you forgot to unlock it you can not turn the plane around sharp while on the ground, also if the unwary ground crew decided to push the plane with a tug, the tailwheel lock would break, or some damage would occur to the locking system or the tailwheel itself. The Beech 18 for example, the tail could be raised off the ground with the prop wash when empty. SOME pilots would "Blow the tail up" and turn it with the tail in the air, so that they did not have to unlock the tail wheel. The problem with this is that if there was a side load on the tail wheel when they set it down it could and usually did snap the tail wheel assembly off. On some of the other tail wheel aircraft the Tail wheel lock was engaged, or disengaged with the Stick, hold it back and the lock was engaged, push it forward and the lock was disengaged, this system is still in use today on aircraft that have free swivel tail wheels, such as some of the older Air-tractors and Ag-Cats, and the Emair MA-1. Many of the smaller tailwheel aircraft such as the RV-6, J-3 Cub and Aeronica Champ, and the Maul use what is called a Steerable tailwheel, they do not use a tailwheel lock the same as above. There are many manufacturers but Scott is the most popular, and the most expensive. The tailwheel is connected to the rudder using cables and springs. When the rudder is pushed the tailwheel is pulled in the desired direction. There is a "Key" that is in the tailwheel assembly that allows up to 30 degrees of steering, if more of a turn is needed the pilot can apply the break in that rudder and the key slips over center and releases, thus allowing the tail wheel to go into freeswivel. I hope this to explain a bit about tailwheels and there locking systems. As an after thought in WW1 they did not use a tailwheel they used a skid that helped stop the plane so there was no Lock.
