Pre-flighting my PA-18 I noticed that both of the steering arms of my Scott tailwheel were bent (the right one more severely). No recent hard landings and no off airport work. Has anyone experienced bent steering bars and do you know what caused it?
"What causes it?".. those door closer style springs that can bottom out... tire/wheel stuck in mud and/or sitting still and before progressing forward someone stomps on a rudder pedal. Time to call Wup and the boys... I wouldn't be straightening that one!
I had an original Scott "straight ear" steering arm that bent also. I replaced it with a much more robust "L" shaped arm from Bush Wheels. It is several times stronger than the original. I chalked this up to having a fairly highly loaded tail wheel and possibly trying to force a turn on the ground. Anyway, haven't bent the stronger one ... yet.
I had an original Scott "straight ear" steering arm that bent also. I replaced it with a much more robust "L" shaped arm from Bush Wheels. It is several times stronger than the original. I chalked this up to having a fairly highly loaded tail wheel and possibly trying to force a turn on the ground. Anyway, haven't bent the stronger one ... yet.
I struggled with this years ago and finally determined that on my plane it was caused by a weak leaf spring .When a landing is made [especially with heavy aft loading] it causes the spring to straighten , the steering tabs are put in a different position , rotated to a less horizontal position , where a heavy rudder input can bend them ..especially with compression type or very strong steering springs installed .....
Total removal of the springs will solve the entire issue.
There was a bid discussion about this a few years back, I think that Mauledriver might have been the proponent of that.
I must be lucky, that is one part I did not destroy back there... but anything behind the handle is a bit consumable if you work her hard... be sure the tailwheel pawl locks and releases
Get the Bushwheel Pawl. Best few dollars I ever spent!
Steve Davidson explains it in the video quite well.
[video=youtube;u3qFwzPNBgE]http://www.youtube.com/watch?feature=player_embedded&v=u3qFwzPNBgE[/video]
Tight steering springs and insufficient caster angle of the tail wheel due to loss of arch of the tail wheel spring. Use of the long pawl helps unlock the tail wheel sooner as well.
Item 11 is the pawl. AK Bushwheel has the long pawl. I would also install AN42 eye bolts on the rudder steering arms to keep from wearing where the chains/springs attach.
Replace your steering arm with a 3214T steering arm.....much more robust and better steering geometry. The new Top Cubsand Huskys come with these and ive had one on my 170 for years....MUCH better arm.
I remembered a conversation I had with bill Duncan at Alaskan Bushwheel. AK Bushwheel provides tail wheels to a lot of the aircraft manufacturers. Aviat had issues with bent steering arms and wanted them fixed as warranty items. AKBW showed them that their tail springs were losing their arch and messing up the steering geometry thus causing the steering arm bending like shown in the video above.