[mburch]

Hi all,

I am interested in hearing from anyone who has successfully done their RV-6/7 sliding canopy aft skirts in two pieces with bent tabs, as detailed in the 6/97 issue of the RVator and reprinted on page 132 of the "24 Years of the RVator" collection. Specifcially, I'm most interested in knowing how you finished off the seam between the two pieces, and whether you had any problems hiding the existence of the slots with the second piece. Any photos you have to share would be great.

For those not familiar with this idea, the author made each of the L & R halves of his canopy skirts out of two pieces of aluminum: One was a thin strip pop riveted to the rear canopy bow, and the other was a wider piece similar to the C-666 skirts but riveted only to the first strip, not to the canopy bow. The first piece has slots cut in it and tabs bent down to form the correct angle in the skirt without requiring any compound bending. Since my plexiglass sits a little high compared to the top fuselage skin, I was thinking this might be a good thing to try before I give up on metal skirts and go to fiberglass.

thanks,
mcb

 

[prporter]

Just make sure it goes with the two piece sliding canopy blouse. ;-)

OK, ok, I think I have had a bit too much catnip today. Sorry!

 

[mburch]

Haha... good one. This canopy stuff is driving me batty - I'm pretty sure I've been spending more time lately looking at skirts on the web than my wife does.

Anyway, to help satisfy my curiosity about this method, I sacrificed some scrap aluminum upon the altar of empirical research tonight and made a small mockup. Surprisingly, it didn't turn out too bad.

One piece has 1" slots cut in it, with 1/4" gaps in between: (dimensions chosen completely at random)

When the two pieces were riveted together I knew at once that I should have used a greater number of smaller tabs, to make the curve smoother. Well, this is why we test:

Underside view... it definitely is curving in two directions, just like I wanted:

Closeup view of the seam. I used an edge roller on the forward edge of the rear piece, which seems to have helped it lay down okay. I think with a tighter spacing of the tabs this might have turned out pretty good.

I do still have some unresolved questions, but this test was very informative. One open issue is what effect, if any, the more complicated shape of the canopy bow would have on the seam between the two pieces - for expediency I used a straight bend line, which is unrealistic. I'm also not sure that a rolled leading edge would want to follow a curve very well in thicker material... I used 0.020" for this test since I had some close at hand.

Probably what I'll do is first give the plans method of forming the skirts a chance. If that doesn't work I'll take those pieces and cut them down to form a row of tabs and try this method. It can't hurt, and it might just work...

Still would appreciate hearing from anyone who's actually gotten this to work, however!

cheers,
mcb

 

[JonJay]

I formed mine on an English Wheel. I got a decent fit considering my inexperience with the Wheel and am happy with it. However, I am told you do not need to do any forming or remanufacturing. The key to making the curve is to keep the edge distance of the rivets at the minimum. This allows you to "wrap" the skirt around while forming it to the arc you want without puckering between the rivets. It requires trimming the edge to keep the minimum distance as you go. I made the common mistake of having too much edge distance making it difficult to wrap the skins around to shape so I wheeled a compound curve into the skirt thinking that was the only solution. Now, I have not tried doing this, only heard from a very knowledgable experienced person that this was the way to do it. Makes sense and I would try it if I had to do over.
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