BC- 12D tailwheel spring

[Jim K]

I recently bought a 1946 BC-12D that obviously had the wrong tailwheel spring and replaced it with one I ordered from Univair which is supposed to be a factory copy. This spring set is about a foot shorter and is so stiff that it has no flex at all and the caster angle is towards the rear. There is not another Taylorcraft here to compare it with. Does anyone have this same spring set? Maybe this is correct.

[astjp2]

Re: BC- 12D tailwheel spring

I have the univair spring, I had to drill it out to 1/2" to get my scott 3200 to mount correctly. What tail wheel do you have? I had it with a maule also and after a few ground loops from the tailwheel failures I went with the 3200. Tim

[Jim K]

Re: BC- 12D tailwheel spring

I have a Lang D-501 A that came on the plane. Steering is sensitive but handles well and no shimmy. I am mainly concerned about the stiffness of the spring.

[astjp2]

Re: BC- 12D tailwheel spring

I have dropped my tail, hold the handle and dropped it to check the spring, It only bounced about 1", its a fairly rigid system. Do you have the spacers correct? There is a small 1.25" square block that goes through the foreward bolt, and there is a short spring that is mounted from the tailwheel and goes foreward an is in the same layer as the spacer. Hope this helps. Tim

[Jim K]

Re: BC- 12D tailwheel spring

Tim, I have a close up picture of the spring I would like for you to look at but not sure how to send a picture. Maybe you can tell me. It has the spacer but two leaves bolt to the tailwheel. Thanks for your help. Jim

[astjp2]

Re: BC- 12D tailwheel spring

Jim, you can email it to me at [email protected] or you can post it by the bottom blue button that says "reply to thread". Once there, go advanced button, then attach the file for the pic. Tim

[Pearson]

Re: BC- 12D tailwheel spring

Maybe a picture will help. Most of the set ups I have seen have a larger gap behind the spacer in the middle leaf at the forward bolt. Photo credit goes to Rob Lees.

[Jim K]

Re: BC- 12D tailwheel spring

Here is picture of my tailwheel. Springs looks same as in your picture but gap behind my spacer is about two inches and caster angle is toward rear.

[Hank Jarrett]

Re: BC- 12D tailwheel spring

I like the shackles on the steering arms. If you hook the ends of the tension springs like they did originally the springs wear groves in the steering arms.
Hank

[Jim K]

Re: BC- 12D tailwheel spring

Hank, what do you think of the angle of the shaft being shifted towards the rear from vertical?
Plane seems to handle ok with no shimmy.

Jim

[Hank Jarrett]

Re: BC- 12D tailwheel spring

Hard to see which way your tail wheel is angled from your description. What you do NOT want is negative castor. Positive castor is when the pivot shaft that the tail wheel steers around is angled FORWARD at the bottom and aft at the top. The line of the wheel steering axis should lean AFT at the top.
Even with negative castor you may not get shimmy if the pivot is stiff and the springs are tight with no play in the parts of the tail wheel, but it should be set up with positive castor so it doesn't start to shimmy when wear starts.
Hank

The wear will exceed the dampening force on the landing with the most ramp rooks watching your landing. Just tell them you needed to use the bathroom and wanted to get off the runway as fast as possible.

[3Dreaming]

Re: BC- 12D tailwheel spring

Jim, your set up looks good. In my opinion there is not a better non-pneumatic tail wheel than what you have right there. Tom

[8708]

Hi folks,
what have people used for the rubber packing around the tail wheel spring. I used a long piece of inner tube but it has not held up well. I was looking for thicker rubber but it is tough to find a long piece to do the job. Any suggestions?
Thanks! Jay

[PA1195]

Tire sidewalls can make good packing. Find a used tire with thin rubber and cut out a chunk. There's fibers imbedded in the rubber which helps it last. If too thick try some engine baffling with imbedded fibers. It's tough stuff too and thin.

[astjp2]

Contact univair and get a cub one and trim it