Model 90 Manuals

[Southernprop]

I am looking for a source of information for wing repair, specifically the Spar. Any info would be greatly appreciated.

Greg

[Schaeffer]

Hi Greg,

I'm hoping that one of the folks with much more experience than I have will also comment.

I've never seen a Monocoupe specific manual for wing repair. The Monococupe Service Instructions manual talks about checking the dihedral
and general rigging, but it's not going to provide the information you need.

We have some past newsletters that we'll be adding here that have valuable information. And I think there are pictures of the factory that show wings under construction in the archives. Please bear with us while we get things in order here.

In the meantime, if you haven't read 43.13-1B, you can get it online at no cost:

http://www.airweb.faa.gov/Regulatory_an ... enDocument

And The Wood Handbook from the Department of Agriculture, originally published in 1935 is an excellent source. It will come in very handy, especially as regards gluing.

http://www.fpl.fs.fed.us/documnts/fplgt ... gtr113.htm

Schaeffer

[Southernprop]

Thanks Schaeffer for the reply, I will be looking in some of the old publications. Any thing else you can think of will be greatly appreciated.

Greg

[longwing110]

Greg, it would be interesting to hear about the condition of your wing, the nature of the required repair, where along the length the spar needs repair, etc. AC 43.13 pretty much dictates what can be done and how. You'll need a 337 approved in advance describing how the repair is to be done, then do the work, then get it inspected. If you need to scarf in a new section then that will be a big job. If you can get by with maybe using reinforcing plates, then that may not be such a big deal.

On my project all I received was the front and rear spar from the right side. The rear spar included the center section. Both had been patched up a couple of times over the years. Kinda matches the logbooks and maintenance records!

The first owner, Tony Little, flew the plane for four years and there is no record of a scratch. The next owner only made it a couple of months and then the log books are a nightmare of one ground loop and repair/rebuild after another.

Dave

[monocoup]

I have done a splice on the outboard 6 or so feet of a 90A wing. The splice was just inboard of the wing strut fitting. The splice had to be done because of rotting around the plywood doubler plates on the bottom edge of the spar. There is a piece of plywood glued to the bottom edge of the spar at this point presumeably to screw the upper strut cuffs to. Our theory is that water is guided in by the control cables. We have found a number of wings with this problem.

Back to the splice...

I built a fixture that allows the scarf to be made on the new (and old spar). If anyone is interested, I can post some pictures. The splice I did was about 12" long. The center section splice is about 24" long. I believe this fixture could be made to do the 24" splice.

Best,
Frank