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Rudder stiffeners

wirejock

wirejock

Well Known Member
I've read threads recommending a proseal dollop on the forward and aft ends of the stiffeners before assembly. Has anyone tried using a fayed application of thinned proseal on both the stiffeners and the skin before final rivet to tie them together and prevent cracking? Are the tolerances so close the proseal layer would cause a problem? I'm still a few days away from this point and reading related rudder threads. I still plan on applying the dollop of proseal, but still wonder if this idea has any merit. Any advise will be appreciated. Thanks.
 
I just went through this process a month or so ago. I don't think putting proseal between stiffeners and skin is necessary; they go on pretty snugly if you back rivet. The proseal (or RTV, which I used) is put in to damp the vibration of the skin where the stiffeners converge to damp vibration/flexing between the skin and the last rivet. A small blob between the stiffeners is all that should be needed.

Any folks out there with rudders that have an average AGL greater than than the height of my shop bench have other experiences with this?
 
When cutting the rudder stiffeners, is it better to use a cutoff wheel or bandsaw rather than snips so the ends are less likely to be deformed by the cutting?

Thanks, Mike
 
Tin snips

Followed by a deburring wheel in a drill press will produce nice smooth rounded ends.
 
I used a bandsaw, followed by a large disk sander, then a file.

I Pro-Sealed the stiffeners to the skin, and used the recommended RTV for blobs near the trailing edge, per the RV-3 manual and RV-4 drawings.

Dave
RV-3B
 
thanks

Thanks everyone. I've cut them to separate and labeled them. I will probably go with the dremel cut off wheel and use my scotch brute wheel to smooth the edge then buff with 400. I still like the idea of housing them with a thin coating of proseal (great minds David).
 
alcladrv said:
is it better to use a cutoff wheel or bandsaw rather than snips so the ends are less likely to be deformed by the cutting?
Click to expand...

Proper use of the correct snips will produce good results. Improper use and/or the wrong snips will do the deformation you mention.

Its been too long ago for me to say which I used. There are 4 options. Straight left and right and offset left and right.

I apologize if you already know this, but:

In regards to useage, keep the snips fully seated in the cut (This prevents slivers/ragged edge), and don't completely close the jaws because the tips will cause local deformation. Just slide forward while opening the jaws and repeat the partial closure.

Enjoy the journey! :)
 
snips

Thanks Bill.
I actually used the snips to make the separation cuts. I used the bandsaw for most of the delicate cuts and the dremel cutting wheel for the few that wouldn't fit it the bandsaw. All done. Life is good.
 
Any body else use a short length of drinking straw for a conduit at the trailing edge so the proseal does not dam the trailing edge?
 
Trailing edge conduit

jrs402 said:
Any body else use a short length of drinking straw for a conduit at the trailing edge so the proseal does not dam the trailing edge?
Click to expand...

I'm very close to this point.
Why would a conduit be needed there?
 
Parry
Not so much a conduit, more a drainage method.
It is to allow drainage for any water that gets in there. Otherwise a side effect of the pro seal would be to trap water in the structure.
Not sure if the straw would stop water draining as much as allow it to escape.

John
Melbourne
Australia
 
Last edited:
Drainage

rjtjrt said:
Parry
Not so much a conduit, more a drainage method.
It is to allow drainage for any water that gets in there. Otherwise a side effect of the pro seal would be to trap water in the structure.
Not sure if the straw would stop water draining as much as allow it to escape.

John
Melbourne
Australia
Click to expand...

Ahhh. So is the straw at the bottom corner or all the way down the trailing edge or a small piece where stiffeners intersect at the trailing edge?
The plans do mention a drainage hole to be drilled after the tail is mounted at the lowest point, but I like the idea of a pathway. So where did you put it?
 
Larry
Not me that did the straw.
I was just assuming that was the reason.
Have to ask JRS402 for that answer.

John
 
Larry
I did use them for drainage on the elevators and rudder. I put them at the trailing edge of the stiffeners where I put a blob of proseal so it did not make a dam. I just used short lengths where the proseal was.
 
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