Aileron spar reinforments

[TimHicks]

The 1/16" plywood reinforcements patches underneath the hinges and harware appear to be nailed on only on my prewar wing. I was prepared to glue the new replacements on.
Now I'm not sure. Should I glue or nail only?

[shipljl]

Re: Aileron spar reinforments

Mine were glued and nailed so glued and nailed when I replaced the plywood reinforcements.

[Ray]

Re: Aileron spar reinforments

I just rebuilt mine and I glued them and nailed them. One of the problems I see with just nailing them is they get ruined over time cause moisture gets behind them and damages them. I also spar varnished them and ensured the edges were sealed.

[Hank Jarrett]

Re: Aileron spar reinforments

I can't say I have seen it on the spec or drawings, but I have never heard of just nailing plywood over the spar. Accepted practice is to use the nails to apply clamping and alignment while the glue dries (on a lot of planes the nails are pulled after the glue dries). Nails alone do a terrible job of transferring shear across the joint, the GLUE does the work. That said, I have SEEN lots of doublers held on only by the nails. In EVERY case I could find evidence of the old glue that had dried out and let go. That's why we use ACCEPTED glues and seal the whole thing with good varnish. Water will rot out the surface of the wood next to the glue even if the glue survives.
Hank

[TimHicks]

Re: Aileron spar reinforments

Ok, thanks everybody for your feedback. Sorry for the spelling errors in my first post. I was trying to hurry up and post it while a New Year's Eve party was starting up all around me.

Gluing makes total sense to me. So I'll glue in the new plywood.
I think that Ray was right on. Because moisture clearly got behind my old patches and damaged the plywood. The spars look fine, though.
Tim

[Robert Lees]

Re: Aileron spar reinforments

I replied this morning, but it appears it got lost in the ether.

Hank (and others) would be able to comment upon my view thus:

The main job of the doubler is to prevent cracks in the holes of the base timber from propogating. Compression strength is not improved dramatically by the addition of doublers. Do you notice how there are no doublers where there are no holes? Nails alone would not achieve this, hence doublers should be glued.

So important is this aspect of crack prevention, that CG designed the front spar butt with a reduced base timber section to allow ply doublers to be fitted.

Just all in my opinion, of course.

Happy New Year to my American Taylorcraft friends.

[Forrest Barber]

Re: Aileron spar reinforments

The nails were for gluing pressure they could technically be removed after drying; IT has been said many times that after the "milk" glue ages, the only thing holding the ship together IS the nails.
They must be glued like a few members pointed out previously.

[TimHicks]

Re: Aileron spar reinforments

Thanks Forrest,
When I took the other aileron apart, I realized that, as y'all have pointed out, the reinforcement patches were probably glued at one time. But the glue ultimately failed such that it appeared that the nails (and the hinge bolts) were the only thing holding them together.
Tim

[swoeric]

Re: Aileron spar reinforments

I am going through the annual and found that my left aileron bracket is flexing a bit and needs to be tightened. This is the bracket that is bolted to the aileron spare in which the hinge pin goes through....the loose bracket that i found is on the center location that has the linkage. My question is how do i go about tightening this bracket? what do the bolts into the spar attach to? are they lag screws? do they have a nut? is it a captive nut?

[Guest]

Re: Aileron spar reinforments

I am going through the annual and found that my left aileron bracket is flexing a bit and needs to be tightened. This is the bracket that is bolted to the aileron spare in which the hinge pin goes through....the loose bracket that i found is on the center location that has the linkage. My question is how do i go about tightening this bracket? what do the bolts into the spar attach to? are they lag screws? do they have a nut? is it a captive nut?

I just had the same issue on both ailerons.

You have to make a slit (in the fore and aft direction) about 2-4" long in the fabric aft of the hinge/bracket.

Then reach in with a long 1/4" extention and socket to tighten it up. Make sure you have magent for picking up what you drop and a small light to peek in and see.

Afterwards you have to stitch up the slit and tape/dope it.

Do your self a favor and read the the section in ac43.13 about repairing fabric slits made for access before you do anything. You may want to adjust the size of the slit you make based on what you read here. Smaller slit=less work later. I wish I had done that I made the slits bigger than really needed and had to do more finishing work.

Then do the dope removal on the effected area before you make slit.

And you will need some dope & fabric supplies to finish up.

Dave

[Hank Jarrett]

Re: Aileron spar reinforments

It is REALLY nice if you have access to an aileron with no fabric on it. It lets you see where to put a really small hole in the fabric for the socket. If you have a clear knowledge of where everything is you can make a slot just big enough to fit the socket and extension with a swivel on it for the slight angle change to each nut. DO BE SURE TO WIRE ALL THE PARTS OF THE TOOL TOGETHER! If the socket falls off you will have to enlarge the hole to get it back out.
Another thing to consider is make SURE that wood damage isn't the reason for the loose bolts. If there is damage to the wood spar or doubler you may have to uncover and repair the aileron anyway. DON'T just keep tightening the bolts and crush the wood! A past owner may have done the same thing you are doing and the spar could be damaged from doing it too many times.
Hank

[Guest]

Re: Aileron spar reinforments

Good points about making a thorough inspection Hank.

Taping the sockets and extentions together may be more practical.

[Guest]

Re: Aileron spar reinforments

Eric,

Get with your A & P and have him work with you on this.

It will be a quite easy for him.

I had been thinking that you were an A&P and had tools and experience with this kind of thing.

My bad, legally an A&P has to do this.

Your A&P will have most if not all of the needed stuff.

This is not a preventitive maintenance item, you are getting into some complex maintenace stuff here that you will need help with as well as the legal issues involved.

Dave

[swoeric]

Re: Aileron spar reinforments

Thank you guys for the help...if somebody has a pic of an uncovered aileron that would be wonderful... can it be reached with just a closed end wrench



As far as my experience goes I have a solid background in mechanics through High School I was fortunate enough to work for a very respected corvette and hot rod restoration shop. I learned to paint, wire, and customize most everything correctly. I then went to continue work with composites, both fiber and metal based as I built control surfaces for every imaginable commercial aircraft out there.(9/11) came and I put my self through college (engineering Mech. BS, MS and in thesis for EDD in Aviation Sciences) as mechanic and manager of several local cars. I was responsible for any and all maint. of these relics so that they were ready to drive anytime the owners wished. Currently I work in the metal processing side of aviation. We handle every spar and bulkhead to the F35 and several others. I also run the assembly portion and UT here. I work next to the airport and the FBO A/P IA lets me keep my plane in his hangar and has set me up with full set of tools there. In return I turn wrenches for him mostly 421 stuff and trouble shoot his electrical problems. I get to record this towards my soon to be A/P. The 421 and Conquest owners trade me twin flight time for expediting the maint. as an extra hand.

I have posted several times on here I imagine without any real introduction. Its unfortunate that we are sparsely located as i have only met Chuck in person. I am deeply indebted to this group for the help I have received. ( stuck trim night before a needed flight, luggage and brake options, countless procedures, interpretation of FAR's and the list goes on)

I have taken many pictures of the fixes and will work to make a compilation for later submission as it seems that we have the same issues.

Please see the next thread I post.

[3Dreaming]

Re: Aileron spar reinforments

Eric, on the back side of the spar for each bolt there should be a large washer or plate and nut.