The woes of the Piper Tomahawk are legendary. A Camel designed by a committee. I have flown many Tomahawks of which only one flew without this continuous twisting. It is interesting reading Pilot DAR's commenst regarding the nose wheel assembly and its effect on the rudder. The nose wheel is attached to the aircraft into a collar at the leading end of the engine frame. This is subject to considerable stress and wear during take-off and landing. Distortion following heavy nose wheel landings is difficult to measure during routine servicing or during a post accident survey. The high tail plane benefits little from the propeller slipstream: its impossible to raise the nose wheel sufficiently below +/- 40kts. and also to hold off on landing below this speed. It is critically important to centralise the rudder and lower the nose to the ground whilst you have the speed. The vibration from the sideways position of the nose wheel when in contact with the ground is distinctive.