throttle linkage
 

Hi,
I am using direct 2-56 metal pushrod between the servo and the engine carburator arm ( YS-110 ).
I can't use regular poshrod as i have no option to support the tube. ( the straight line between the servo arm to the engine arm is 2cm from the fuse side and also 2cm from the fuse top side )

the engine seat on hyde mount, and during operation the metal pushrod is shaking alot.... i am concern that it will
damage the servo ( and of course i guess it has affect on the engine rpm stability )
is there way to reduce the vibration affect on the throttle linkage ?

Thanks,

RE: throttle linkage
 

How about using a lighter rod than 2-56. I usually use half that diameter on my glow engines. A Z bend at the servo and quick link at the carb, or quick link at both ends for easy adjustment.
Edwin

RE: throttle linkage
 

Hi,
I usually use clevis on both sides and that's the reason for the 2-56,
what is the advantage of ligther rod ?

RE: throttle linkage
 

Hello selnekav
The 2 cm between the two arms is very short. I agree with you that the vibrations may cause a problem. Here is a possible solution: Put a Z-bend in the 2-56 rod at the servo end. Run the rod toward the carburetor and well past it, then bend the rod 180 degrees and let it come back to the carburetor arm. Put a nylon clevis on the end of the rod and connect it to the carburetor arm. Now revers the throttle servo. The rod can be bent other than 180 degrees to fit the conditions on your plane.

RE: throttle linkage
 

Hi Vila
it might be that i didn't explained it well but the rod length is about 20cm ( the distance between the rod to the fuse side is about 2cm )

RE: throttle linkage
 

Beware of metal to metal contacts here as that can and often does cause rf interference. Z bends are very bad in this respect plus will soon wear and give you lots of unwanted slop. Use a plastic clevis at least on one end, a ball link on the throttle arms is even better. Nyrods are preferable to wire as it minimizes any rf interference due to metal to metal contacts. Villa's suggestion to run the push rod past the throttle arm then 180 degree turn back works well, especially on 4 strokes where clearance is often a problem easily solved using his suggestion.

RE: throttle linkage
 

Hi,
I have no metal to metal contact and my problem is the vibrations as i can't use regular wire and tube

RE: throttle linkage
 

Is there room to wrap (loosely) some sponge around the rod and touching the sides of the fuz. this will dampen any vibration, without affecting push/pull movement.

I would also agree with comments to stay away from metal/metal arrangements and use z bend at servo and nylon clevis for adjustment at engine end.

RE: throttle linkage
 

I like the lighter rod because is flexes easily when you move the throttle. On my saito's the throttle barrel moves in and out a little bit. With a stout rod, it puts a little tension on the linkage. As long as you're clear of any metal to metal contact the steel rod works ok, but only on a glow setup. I only use nyrod on my gassers.
Edwin

RE: throttle linkage
 

selnekav:

I believe any rod will vibrate badly having 8" of span.

I recommend using one or two non-metallic slidding supports for the rod, wich could be attached to the structure with some flexible material, if the linkage deviate much from a straight line during operation.

Regards!

RE: throttle linkage
 

Thanks for the answers, i will try to build some support for a sollivan pushrod. which is more flexible then the 2-56 rod