108-1 rudder return springs
During this annual, we found the rudder return springs looking a bit out of place. In a relaxed state, they measure 7 1/2 inches long. Checking with UNIVAIR, they measure the required spring to be 4 3/4 inches long.
Also, the rudder position seems to be a bit aft from what would be a normal position. Not having exact specifications, anyone have information as to the correct position of rudder pedals and the correct spring installation would be appreciated.
Attached, I hope will load, is a picture of what we have.
Rudder pedal rigging is in the Control Installation drawing as I recall. Univair can get it to you.
As I understand it, the only adjustment to the pedal location is by the cable turnbuckles (if cables are correct in length and the SB pulley done). As there is no tension posted on the cables without rudder trim and they rely on the correct return springs installed. As I see in your picture, you too may have the incorrect springs installed. If you look at the UNIVAIR parts manual pic, one of the few posted, you might see a difference in design.
What I see in yours, although a later model, is what caused me to check further for our 108-1. Sure enough, wrong installation. Since replacement and adjustment of cable turnbuckles, all is good.
Just joining the foray and not sure if this helps.
To add, the pic below was also a reason of concern. The rudder arm mounting bolt was striking the frame at the point identified when fully actuated.
What we found and hope it helps.
The correct P/N is 108-3041002. I just checked the Univair online website. It shows it for $22.65. I don't know where you came up with that $71 price?
Yes, some of the folks that have not been around Stinsons for a long time seem to think that Univair is ripping them off, but what other 70+ year old aircraft enjoys nearly 100% replacement parts availability at prices that are generally below what a similar Piper or Cezzna part would be priced at and if you really want to find rip off prices, price some Beech Bonanza parts prices.
Those of us that are Stinson lovers really appreciate the fact that Univair supports our planes so well. They, I know, have struggled to stay in business since 1946 and if we don't appreciate and use their services, they won't be around. The 22.65 seems like a lot for a "short screen door" spring but it is a legal and available exact part for our Stinsons and if not abused or lost, will last longer than we will.
Larry Wheelock, A&P/IAStinson 108 N584LW 180 LycTexas in Winter; Indiana in Summer
Yep, I looked at the wrong P/N, so $22 is much better.
This is Will Ware
Stinson 108-1 Project N97954
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Hmm. That photo looks familiar 😆
1946 Stinson 108-1, Franklin 165, at one time NX8306K