Phenolic Horns
 

Tom:
I have a WH Baby Extra, which is a great aircraft. I just had the occasion to reprogram some servos, and as I was going over linkages, I found the port elevator linkage sloppy. The problem was/is that the hole in the control horn has worn enough that the screw is sloppy in the hole. All the other linkages are tight and slop free. The plane has 59 flights, probably 10-11 hours on it.

It is not a complaint, but a caution for others that the phenolic control horns may need to be viewed as a replacement item.

RE: Phenolic Horns
 

What screw?

You were supposed to put the Z bend of the pushrod into the hole in the phenolic horn. Apparently you used a different type of linkage than what we supplied.

TF

RE: Phenolic Horns
 

I used a ball link instead. I suspect it would have happened with a z-bend as well. Again, not a complaint, just an observation

RE: Phenolic Horns
 

In order for the hole to be enlarged something must have been moving inside it to wear away the surface.

Using a ball link normally would have the screw tightened securely so that any rotation occurs inside the ball link between the ball and its socket. The only way for the phenolic horn to have become worn is if the screw attaching the ball link to have come loose.

Maintenance on these planes is very important, periodic checking/tightening of screws and other fasteners helps to protect your investment.

Just an FYI, all new airplane designs from Wild Hare will be using double-truss control horns with ball links, but even with this design if the screw is not tight the inner surface can get worn.

TF

RE: Phenolic Horns
 

Thanks Tom