Rudder bar installation question

[8708]

Hi folks,
I am installing the rudder bars in my project.
From the original notes I have there were sometimes washers between the hold-down brackets and sometimes not!
So, are there supposed to be washers between the hold-down brackets on all 4 of the brackets?
Thanks! I hope everyone enjoyed the eclipse tonight! It was great here.
Jay

I attached three photos showing the various washer combinations on my plane. No brass shims except on the control column 'H'.
How thick are the brass shims?
Thanks!
Jay

[astjp2]

Re: Rudder bar installation question

Mine does not. Tim

[Guest]

Re: Rudder bar installation question

I have never seen washers installed in between any rudder bar hinge.

If they were there it was likely a mistake or some method to correct for a bent rudder bar (that should have been straightened).

Dave

[astjp2]

Re: Rudder bar installation question

Mine did have brass shims though that the torque tubes sat in. Tim

[Hank Jarrett]

Re: Rudder bar installation question

Are the washers under the bolts or between the tube and the brackets? There ARE supposed to be brass shims between the tube and brackets (make SURE the lube hole lines up!!!!). You could have a washer under the nut that holds the bracket in place but I can't see where else you could even put one.
Got any photos?

Hank

[Dick Smith]

Re: Rudder bar installation question

Open this link from the Rob Lees restoration site and scroll down to the bottom of the page for some visual help re: what Hank is referring to: http://www.taylorcraft.org.uk/Brey_rebuild4.htm

[Ragwing nut]

Re: Rudder bar installation question

No washers, only brass shims

[8708]

Re: Rudder bar installation question

Hi folks,
Please see images and comment I added to the start of this thread.
Thanks!
Jay

[8708]

Re: Rudder bar installation question

Hi folks,
Please see images and comment I added to the start of this thread.
Thanks!
Jay

[Ragwing nut]

Re: Rudder bar installation question

You just need to make sure that when they are tight the bar is not loose or the bar is not too tight in a bind, if washer required, no big deal

[Guest]

Re: Rudder bar installation question

The "shims" are not really shims but plain bearings made from brass shim stock.

They are shaped just like the clamps you show in picture 3 and are about .015" to .020" thick, that's my best guess.

They fit inside the clamps and oh! I just realized that since they are the same shape as the clamps the bolts go thru them and they do provide a shim at the bolt and a bearing at the tube. I suspect that when you have the "shims" in the washers will no longer be needed because the double "shim" thickness at the bolt will supplant the washer thickness.

Dave

[Hank Jarrett]

Re: Rudder bar installation question

Dave may have just hit the nail on the head! Someone left out the shims and when they tightened the bolts it bound up the "H". Put in washers to provide some clearance.
Again, put in the shims! They keep the steel parts from galling. If you have to put in a thin washer to allow clearance and the parts aren't bent,it shouldn't be a big deal.

Hank

[Mark Bowden]

Re: Rudder bar installation question

To add a bit to Dave and Hank's comments. That joint is indeed supposed to have a bearing. If you notice the clamps do not cover 180 degrees of the tube. The bearing is the two strips around the tube. The "Brass" is necessary and used as it has lower friction than steel-on-steel, doesn't corrode, can imbed debris instead of scratch up the tubes and more importantly is the sacrificial material so you don't wear out the rudder weld assembly or worse the airframe weldment. The maintenance manual as part of the periodic says to check the pedal assembly and lube the torque tube bearings.

The thickness of the brass should be the difference between the rudder tube OD and the clamp ID, minus clearance for movement and assembly tolerance. As the two sheets form the bearing surface the "tabs" take up the gap between the airframe and the clamp halves. It keeps the bolted joint stack aligned and won't distort the clamp when bolted which is why someone put the washer in. It also thus provides "360" degrees of coverage on the single tube joints and about 270 on the dual tube clamp.

The old drawings should "define" it directly or indirectly, however a guess at intended tolerance is a stock thickness of ½ to 3/4ths the difference between OD and ID measurements. The tube OD is easy to get with a caliper; the clamp ID would have to be checked with a radius gauge. It would be interesting if anyone has this drawing and see if it called out the stock thickness or defined the clearance as well as the material type. Originally it may have been a "Babbitt or White Metal" alloy vs. Brass. Don't forget to drill and deburr the lubrication hole in the part.

If you measure the parts please post back, curious to see what they are.
Mark

[Guest]

Re: Rudder bar installation question

We will never see a drawing IMHO.

Some one may have a part that they can measure though.

Will look to see if I have one.

[Guest]

Re: Rudder bar installation question

Did not find a rudder bar "shim bearing" but did find one them from the "H" frame hinge.

It is .015" brass shim stock.

Dave