tail wheel shimmy

[jacksel]

My RV-6 has 360 hours and for about the last 50 hours I have experienced an increasing amount of shimmy vibration on landing (I assume it's coming from the tail wheel). Also, I've noticed it's unussually difficult to get full authority tail wheel steering on the ground. The petal goes so for and stops and it's very difficult to get full authority. At the normal cam-stop point in the tailwheel, instead of breaking past, it stops hard. I have to use differential breaks to get the tail wheel to pivot over. Has anyone ever experienced this? Appreciate any advice.

 

[n5lp]

It is common to get burrs on the steering pawl that prevent it from locking in. If you remove the pawl and remove the burrs it should eliminate your problem.

 

[Mel]

You don't say which tailwheel you have, (there are several aftermarket ones), but most of them are not properly lubricated by use of the grease fitting.
If this is the case, you will need to disassemble, clean and grease the tailwheel assembly every year or so.

 

[jacksel]

It's the original tailwheel (shipped ~ 2003). Been flying since 2005 and I would say the first couple of years there were a lot of takeoffs and landings (I'm on my second set of main tires). I lube the tail wheel every year but don't disassemble and inspect. I guess it's time. Thanks for the replies.

 

[Brantel]

Also check the bolt and the holes where the tailspring is mounted in the socket built into the airplane.

These holes sometimes get sloppy allowing the tailspring to rotate in the socket.

Some people have installed tappered pins in there instead of a bolt.

 

[vfrazier]

I have a Word file that I send out with our tailwheel forks. It details how to keep your tailwheel happy and working properly. Obviously, it's meant for our Screaming Eagle tailwheel forks, but it should apply equally to Doug Bell's very fine tailwheel, or Van's tailwheel too.

Anyone who would like a copy can send a request to my email address and I'll send you a copy.

email [email protected]

Please don't PM me. I have no clue how to send attachments via that route.

Another possible cause for hard steering is a bent spring. If you whack the tail hard enough, bend the spring (often with rudder bottom damage), and cause the tailwheel pivot to lean forward enough, it gets noticeably harder to steer. Take a look at your tailwheel from the side. The main pivot axis should be reasonably vertical.

Another possible cause can be that your backseater is too heavy. If it's your wife, keep your mouth shut and simply buy one of our tailwheel forks. They handle the extra weight much better due to a superior geometry.

Thanks,
Vince

 

[Mel]

Another possible cause can be that your backseater is too heavy. If it's your wife, keep your mouth shut and simply buy one of our tailwheel forks.

If the problem is with the back seater in an RV-6, he has other problems!

 

[jetjok]

Shimmy

Also check to assure that you have no negative caster. I have not heard of this being a problem on the RV type assemblies, but it is very critical on the Scott series on larger aircraft (ask me how I know)

 

[petercavallo]

Vans Tailwheel

If you pump too much grease in it makes the tailwheel arm difficult to lock. Best maintence is to take it apart clean it and reassemble with Aeroshell #5 to lube......good for another year
Peter