Fitting the canopy frame on a 7A slider

[sundog04]

I'm suffering through the trials and tribulations of shaping the canopy frame. It's close, but there are a couple of issues I could use some advise on.

In the plans, page 9-10, it states that the canopy frame expansion will be compensated for during the "latter stages of canopy fitting". In addition, there is a caution that emphatically states: do not try to bend or reshape the frame after the plexi is drilled to the frame! The frame will break. On the very next page under fitting the frame to the canopy, the instructions have you drill the holes through the plexi into the frame and then disassemble and adjust the frame to make the final shape. Repeat as necessary to achieve perfect fit.

Am I missing something, or do the two instructions contradict one another?

Can you safely adjust the canopy frame bows a little after you have drilled the plexi to the frame?

One other question. How critical is it that the canopy frame side bows vary by no more than 1/8" from front to back? I have beat, bent cursed and done everything I can think of, but every time I get the rear bows to fit properly, the left side bow sits about 1/4" lower at the rear than the front. Unless there is a crital reason not to, I plan to go with it that way.

Thanks,
Mike

 

[David-aviator]

I'm suffering through the trials and tribulations of shaping the canopy frame. It's close, but there are a couple of issues I could use some advise on.

In the plans, page 9-10, it states that the canopy frame expansion will be compensated for during the "latter stages of canopy fitting". In addition, there is a caution that emphatically states: do not try to bend or reshape the frame after the plexi is drilled to the frame! The frame will break. On the very next page under fitting the frame to the canopy, the instructions have you drill the holes through the plexi into the frame and then disassemble and adjust the frame to make the final shape. Repeat as necessary to achieve perfect fit.

Am I missing something, or do the two instructions contradict one another?

Can you safely adjust the canopy frame bows a little after you have drilled the plexi to the frame?

One other question. How critical is it that the canopy frame side bows vary by no more than 1/8" from front to back? I have beat, bent cursed and done everything I can think of, but every time I get the rear bows to fit properly, the left side bow sits about 1/4" lower at the rear than the front. Unless there is a crital reason not to, I plan to go with it that way.

Thanks,
Mike

Mike,

It sounds like you are very close.

The basic problem of fitting the canopy is that the frame is not a perfect match to the roll over bar. Having done 2 RV-7 slider canopies, I found the disimular match of each exactly the same, i.e., the canopy frame welding jig is consistent but not quite perfect with regard to the roll over bar. Both frames were higher on the left side relative to the roll over bar. That's why the instructions suggest shims between the glass and the bar when doing the windscreen.

To answer your questions, I would not mess with the frame after it is drilled to the glass. Any further adjustment of the frame will cause a slight mismatch with the previously drilled holes.

Once the side skirts are installed, the 1/4" will not be noticed. It would be nice to get this thing perfect, but that is very difficult. A frustrating aspect of the process is the fact that clecoes do not hold things together as tightly as rivets. Everything will change a little after it is riveted together and there isn't much you can do about it. At least I haven't figured it out.

I'd go with it as is, and get on with flying the airplane ASAP.

dd

 

[TrueAirSpeed]

For what it's worth

Mike,

For what it's worth, I did some bending on my canopy after drilling it and before installing rivets. My problem was that the canopy was too wide by about 1/2 inch on each side. I heeded the WARNING, and considered the worst possible outcome (buying a new canopy and frame), swallowed hard and bent to make a better fit. It worked out and now I am finishing the rear canopy skirts. Good luck.

Terry
RV-7, ready to hang the engine

 

[Steve A]

One other question. How critical is it that the canopy frame side bows vary by no more than 1/8" from front to back? I have beat, bent cursed and done everything I can think of, but every time I get the rear bows to fit properly, the left side bow sits about 1/4" lower at the rear than the front. Unless there is a crital reason not to, I plan to go with it that way.

I worked with my canopy for days but couldn't get the back part less than 1/4 inch lower. I ended up with my side skins C-660 at a slight angle. I cut the front part of C-660 flush with the fuselage and everything seems ok. My frame seems to clear the fuselage fine. I have everything put together with clecos so once I rivet, I guess it will tighten up.