Problems with tailwheel... What to do ?

[PH-SCP]

Hello fellow RV-builders/flyers,

The tailwheel of my RV-9 is developing problems. It has always been hard to convince the tailwheel to turn and it required a great amount of input (and differential braking) to take it out of it's centre lock.
Today, returning from a fly-in, I landed normally and at taxi-speed I could hardly make right turns and really had to step on the rudder to turn. Whilst trying to vacate I could only steer with differential braking. At shutdown I discovered that the metal clamp that connects the rudder to the tailwheel spring had broken away completely and the rudder-cable, together with the tailwheel spring, was disconnected and dragging across the apron.

My questions are: 1. Is this a common problem to taildragger RV's and 2. How do I fix it.
My current approach would be to disassemble to tailwheel-assembly and find out why it takes so much force to take it out of the centre lock. Then try to fix that specific problem.

Your input is much appreciated. Specially hints in which direction to look.
Cheers !

 

[N941WR]

Simon,

What I don't like about the RV tail wheels is that you put those steal clamps through aluminum parts.

My solution (Stolen from an old RVator) was to put a pair of eye bolts pointing up on the tail wheel and a matching pair pointing down on the rudder horn. Then some cable shackles through those eye bolts to connect the spring. The only place I have the steal clamps is between the spring and the shackle at the rudder horn.

Check out the second 5/27/07 entry on this page of my web site for a picture and complete parts list.

BTW, since there are so few -9's flying, while I was building I would post questions specific to the tail installation over on the -7 list since those parts are identical.

 

[Pat Hatch]

Hello fellow RV-builders/flyers,

The tailwheel of my RV-9 is developing problems. It has always been hard to convince the tailwheel to turn and it required a great amount of input (and differential braking) to take it out of it's centre lock.
Today, returning from a fly-in, I landed normally and at taxi-speed I could hardly make right turns and really had to step on the rudder to turn. Whilst trying to vacate I could only steer with differential braking. At shutdown I discovered that the metal clamp that connects the rudder to the tailwheel spring had broken away completely and the rudder-cable, together with the tailwheel spring, was disconnected and dragging across the apron.

My questions are: 1. Is this a common problem to taildragger RV's and 2. How do I fix it.
My current approach would be to disassemble to tailwheel-assembly and find out why it takes so much force to take it out of the centre lock. Then try to fix that specific problem.

Your input is much appreciated. Specially hints in which direction to look.
Cheers !

Simon,

It sounds like you have an issue with your locking pin (also known as a centering cam). This can happen when there is some wear on the pin, or a burr on the pin or control arm centering slot. This will require that you disassemble your tailwheel fork and inspect the locking pin and control arm. I am including a web site that addresses this problem, part of Vince Frazier's excellent tailwheel installation instructions. This will give you an idea of how to debur and shape the locking pin. Be careful when disassembling the tailwheel fork that you don't lose the pin and spring which will come flying out of the fork shaft as you pull it apart. Here's the web site:

http://www.vincesrocket.com/products.htm

Go down towards the bottom of the page where it says 'Installation Problems.' When you put it back together, try not to get too much grease in the cam area. Just grease the shaft below the cam and put a couple of drops of oil on the locking pin instead of grease. Good luck!

P.S. Upon further reflection, you may also have a clearance problem with the fork shaft being too high or low in the housing. You may have to relieve the brass bushing at the bottom of the housing or possibly add a shim between the large nut and the housing (this only if there's too much play in the fork shaft moving up and down). If you raise the tailwheel off the ground (set the tail on a low bench or something), the fork should rotate freely, no binding at all. If it binds you have a clearance problem. When you tighten the big nut all the way down, if it binds, you may have to relieve the brass bushing a little. This could also cause your locking pin to bind up at the top end. To check this, when you re-assemble your tailwheel, do not screw the big nut on yet. First, observe the control arm and locking pin as you rotate the fork while holding the shaft up against the bottom of the housing. It should lock and unlock smoothly with moderate force and you should be able to observe the pin sliding in and out. If the locking pin is binding, you may have a clearance issue that you will have to address as I mentioned previously. Nothing that you can't fix with a Scotchbrite wheel! Although not common, this problem can occur, but once you have it right it will last a long time!

 

[PH-SCP]

Thanks Pat, sounds like a good plan..