Control suggestions
 

I'm working on a pretty nice new plane and am not happy with the aileron control setup. The plane came with PC board servo horns to screw on to existing servo wheels. What I don't like is the amount of slop I'm finding, and would like a way to move the rod closer to the servo. The rod ends are threaded 2mm. I may have the same issue with the elevator, however the servos are much higher end and hopefully won't have the same amount of slop.

[link=http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXD910&P=7]These are my current connectors.[/link] The only issue is that drilling a hole big enough in my servo horn for the screw would interfere with the other holes and make a poor connection.

What are some suggestions to hook this up? Links and pics of some different examples would be great. Not looking to break the bank with the highest end stuff as it's only my second year flying, but want something nice. Do I just need a different kind of servo horn?

Thanks!

RE: Control suggestions
 

I use these in the 4-40 size a lot. I drill & tap the servo arm for the 4-40 screw, thread it in and then back it with a nylon lock nut. I'd do the same thing with the 2mm size also. Another thing I always do is to use a #4 flat washer on the top of the screw.

RE: Control suggestions
 

Sorry for such basic questions but I'm still new at this.

If I drill a hole in the servo horn large enough to fit the 2mm screw, it gets close to or interferes with the other holes on the servo arm - like this:

I'm hoping there's a better way to attach the swivel link or something similar to my servo horn.

RE: Control suggestions
 

http://www3.towerhobbies.com/cgi-bin...?&I=LXD916&P=M

These ball links require a smaller hole in the servo arm with almost the same size hardware.

RE: Control suggestions
 

Joe,
I would re-think your control setup if I were you. Don't use a plastic servo arm with a ball joint of any kind. Here's why: since the ball joint is mounted on top of the arm, it creates a tangential load which causes the arm to twist and eventually break. To visualize this, imagine mounting the servo arm to a servo that can't rotate while you push and pull on the linkage. It willl cause tha arm to twist. That's what happens when you fly. If you MUST use the ball joint then use either a wheel or a metal arm. These are much more resistant to this type of load. I know some guys get away with plastic arms and ball joints but I REALLY wouldn't recommend it.

I only use plastic arms with a clevis. Since the clevis transfers the load in the same plane as the arm, it doesn't create this evil twisting force. That being said, I don't like to use a clevis on anything except a pull-pull cable linkage. The typical metal-pin clevis will eventually wear the plastic arm and create slop in the linkage. This has only a small effect on the cable tension but it will be very noticeable on a rod-type linkage.

You can also use the ball-joint on a plastic throttle arm because there is very little load there since the throttle should rotate very easily.

John Pavlick
Team Black Magic, Tech-Aero Designs