throttle linkage end source

[N184DA]

Originally Posted by airtractor8

Regarding your solid wire mixture cable setup. If you didn't want to mess with it you could always fit a safety return spring to the control arm. That way if the cable brakes the mixture will go to full rich.
These can be had from Robinson Helicopter. They are fitted to R22 helicopter carb mixture control arms that have the solid wire setup. I dont have the part number but I'm sure any Robinson parts supplier can help you with that.
I have one on my carb'd 0320 powered 6.

I have been searching for an acceptable Mixture Return spring for my RV4, but I have been unable to come up with a "geometric solution". So your post, regarding the R22 mixture spring, got me searching and if anyone else is interested, here is what I found:

Robinson's nomenclature is a "Mixture Control Safety Spring"
Two part numbers:

A071-1 = Spring only
A071-2 = Spring and associated hardware.

I have been unable to source just the spring, and have found the price for the A071-2 assembly runs around $90.

The spring (or lack thereof), was the subject of a R22 service bulletin back in 1984, and now they are standard equipment (or so I assume)
And this Service Bulletin (SB-41), has a diagram of the spring installation, which I found helpful. Here is the link:

http://www.robinsonheli.com/service_...s/r22_sb41.pdf

I haven't ordered one yet, but just thought this info might be of use to someone. I may look for an alternative to the official "Robinson part", and the diagram gave me a new perspective to the geometry question. If I decide to get this to work, I'll post my results.

[az_gila]

Originally Posted by jrs14855

....
Regarding the mixture control end, I much prefer simply drilling the appropriate size hole in a AN4 bolt. This method eliminates the severe bend in the wire and in my opinion is far less likely to fail. The certified Pitts aircraft use the drilled bolt method.
.....

I'm not sure if the simple DIY drilled bolt is the best idea...

The certified fittings use a slightly cupped washer/fitting that clamps the single strand wire to the bolt hole. This controls the stresses at the wire bolt junction and helps reduce slippage.

This Piper fitting is an example. The cotter pin is temporarily in the wire position -