Top wings completed.

A forum about all aspects of the construction and maintenance of the Billy Dawson inspired modified Hatz Classic biplane. Here is the place to ask your questions and get the answers from the real experts.
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Nick
Posts: 188
Joined: Wed Mar 24, 2010 7:51 pm

Re: Top wings completed.

Post by Nick »

Yes, I would like to hear this too, since I am going to start my ailerons soon.

Nick
stearmoth
Posts: 234
Joined: Mon Apr 26, 2010 12:47 pm

Re: Top wings completed.

Post by stearmoth »

True aligning aileron trailing edge - that's what we all are looking how to achieve!
If you follow the aileron photo sequence on our website (click on the ailerons on the Hatz picture in the shop), you will find out how we tried to achieve this.
As our aluminum skins are very thin, we feared to rivet top and bottom skin as shown on the Waco pictures before. We rather made a sandwich with the angled aluminum sheet as shown on the plans and a spruce triangle stiffener. On the outer portion of the ailerons (where they are curved) we just glued in an curved aluminum sheet. We used an elastic two parts acrilic compound with better results that an epoxy glue (this is too brittle, the other is like rubber and stays elastic). The wooden triangle insert we made up to the tip (from the plans you couldn't tell where this stops).
The wooden insert was made from two parts and scarf glued flat together. We assembled then the aileron temporarily with clecos including the hinges and mounted it on the wing panel. At this stage only the top skin is accurately cut at the trailing edge. The lower skin is a bit oversize. Install a true edge (straight wooden plank) to the bottom rib flanges inboard the aileron, so that the aileron skin is supported properly (underlay some scrap between the rib flange and the edge to take care of the protruding aileron corrugations). We then put the wooden filler between the skins and shaped the triagle section of the curved wooden filler such, that there was a smooth flow up to the wing tip bow. We fixed the skins at the trailing edge with some clamps and traced the bottom skin trailing edge to follow the top skin. After this we made all the forming of the corrugation's ends (this is cosmetic and optional of course).

When all was fine we primed the inside of the skin etc. with epoxy and assembled the ailerons with this elastic compound and rivets, but no rivets yet at the trailing edge! Within the open time of the compound we installed the ailerons on the wing panel, supported it with the edge out to where the curved part of the aileron starts and attached the clamps as can be seen on the photos.
We are very happy with the result and find that way, the trailing edge is more resistant to handling (because it is as thick as the inner wooden trailing edge) , looks nicer and perfectly blends into the wing tip bow, which itself follows the wing ribs skelet line. Weight of the ailerons: top: 4.2 lbs, top: 4.4 lbs (everything installed).

We hope there is more help than confusion and good luck!

Hans & Sam, H.C. #78, Switzerland
RSouthard
Posts: 48
Joined: Tue Mar 16, 2010 9:40 pm
Location: Seaford Delaware

Re: Top wings completed.

Post by RSouthard »

Thanks guys for all the information and comments, very helpful!!

I talked with Mr. Dauhn of Dauhn aircraft yesterday and posting a link to his website. He said he would be happy to help us and supply aileron skins if we are interested. His shop is set up for rebuilding Cessna and Piper control surfaces as well as spinners and cowlings. His corrugations are based on Cessnas spacing and profile but he has all the equipment to build pretty much anything in his shop.

R J Dauhn Aircraft
352-348-7070
http://www.rjdauhnaircraft.com


Thanks again for all the help from everyone on the forum..
johnkerr
Posts: 78
Joined: Thu Mar 25, 2010 10:48 am

Re: Top wings completed.

Post by johnkerr »

The details are lost in the nether regions of my mind. I worked with a piece of stair tread with grooves routed to accept the fluted skin. With the aileron upside down and the leading edge clamped at a 90 degree angle the holes for the trailing edge rivets could then be drilled. The aileron is larger than the stair tread I had so the aileron was poisitioned forward so that tread served as backing for the drill. I went deep enough with the drill to allow cleco's to be inserted and hold everything tight all the way around the curve of the aileron. You might want to delay attaching leading edge of the underside skin from the bend out so that you can match the trailing edge flutes because that can introduce some twist if you aren't careful.

Work slow check the angles and when you are done you will have metal work to be proud of.

John
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