Advice sought: Adjusting an existing tip-up canopy

Hi All,

In preparation of moving the project to the airport, the canopy was installed this afternoon. For whatever reason(s), the fit on the left side leaves a lot to be desired. Anyway, as the forward portion of the canopy comes down, the canopy frame protrudes an 1/8". In addition, there's an excess of an 1/8 gap between the forward part of the canopy and the side of fuselage; this tapers down to a nice 1/32" at the aft end. I can only imagine how much air and water this "scoop" will capture.



The fit at the hinges look good. The right side looks good, too. It looks like fluting the the left, forward C-channel of WD-716 might bring it in and lower it. Just an idea. And, i've no idea how I'd flute it with the stiffener brace in place with half of its rivets under the fiberglass windscreen fairing.

Any other ideas, suggestions, etc to adjusting this?

Thank you,

had similar problem

David,
I had similar "scoop" look on my -6A tipup, worse on pilot side but visible on both sides. Fit was good during build, after some shimming on the curved sides, until I actually attached the canopy to the frame and installed the gas struts.
I flew it that way for a little over 2 years before taking to paint shop and could often actually see bugs splatted on my canopy seal weather stripping in some spots.....

So I asked paint shop if they could do anything about it and Juan at T&P in Salinas, CA (KSNS) said there was a good sheet metal guy on the field that could fix it. With canopy pins pulled for easy removal/re-install, Juan wheeled my plane across the field to this other shop and for cost of a couple hours labor (about $180), they used hammers and shrinker to bend things down to a real nice fit that looks great now. I'm sure I couldn't have done it myself without completely rebuilding the canopy and forward skin area.

Watching it wasn't for the faint of heart though.....I went into the shop after they had finished the left side but still working on right side and it was tough to see a couple guys beating on my plane with a big hammer after my 12 and half years of construction and couple years of flying. If I couldn't see what a nice job they had already done on the side they finished, I might have been hard pressed to let them keep going!

You might check to see if there's a good aircraft sheet metal shop like that somewhere in your area. The place I went had a number of complex, compound metal parts in the shop they had worked and were building several warbird replicas (several P-51s and a P-40) so from what I saw, I had a high level of confidence in the quality of their work before they worked my plane.

Cost was well worth the improved looks, but no noticable performance difference - I can't honestly claim the traditional "gained 5 kts" from the decreased drag

Canopy nightmar

Guys,

Ken from Vans warned me that this thing is not a Swiss Watch and that if you are wanting to put it together like it has been crafted by small elves then this project is not for you.

I get that, but I am getting the impression that the Canopy is going to make me scream black and blue for months. I would like this thing to close properly and not have a draft. I am planning on flying this thing IFR at FL200. I would like to have a sealed Canopy.

Is that too ambitious a request?

Encouraging

OneCharlieKilo said:

So I asked paint shop if they could do anything about it and Juan at T&P in Salinas, CA (KSNS) said there was a good sheet metal guy on the field that could fix it. With canopy pins pulled for easy removal/re-install, Juan wheeled my plane across the field to this other shop and for cost of a couple hours labor (about $180), they used hammers and shrinker to bend things down to a real nice fit that looks great now. I'm sure I couldn't have done it myself without completely rebuilding the canopy and forward skin area.

Watching it wasn't for the faint of heart though.....I went into the shop after they had finished the left side but still working on right side and it was tough to see a couple guys beating on my plane with a big hammer after my 12 and half years of construction and couple years of flying. If I couldn't see what a nice job they had already done on the side they finished, I might have been hard pressed to let them keep going!

You might check to see if there's a good aircraft sheet metal shop like that somewhere in your area. The place I went had a number of complex, compound metal parts in the shop they had worked and were building several warbird replicas (several P-51s and a P-40) so from what I saw, I had a high level of confidence in the quality of their work before they worked my plane.

Cost was well worth the improved looks, but no noticable performance difference - I can't honestly claim the traditional "gained 5 kts" from the decreased drag

Click to expand...

Hi Chris,

Thank you for your encouraging feedback. It's reassuring to know that there are techniques that can be used w/o having to disassemble anything. This is obviously one of those areas where skill and art play are required and for the price you paid I'd consider that a steal. For the time being, I'm going to abandon the fluting idea. I don't think it's appropriate for this case. I'll keep an eye out for a talented sheet metal worker, instead.

Thanks,

I had the same issue. What I ended up doing was redrilling the left attachment to go lower, I also tried real hard to bend the canopy, real hard to do. After I was sure I did everything, I still had a raise on both sides but the left side, pilot, was the worse about 1/8. So out come the fiberglass and I put a barrier between the area in front of the canopy and the canopy and built up the area in front of the canopy and flared it to where when finished you didn't know there was a raise. Worked like a charm. It took several layers to make it right but you would never know today that I did it. Hope this helps.

The canopy is probably the hardest part of the project and seldom they come out all nice without some fancy work. Depending on how much of a gap it is, if you are going to paint the plane, then you can lay up some fiberglass and build up to match. My biggest concern about fluting or banging on the canopy is if it going to put any stress on the canopy itself which could result in a crack later on.

canopy stress with metal re-work

The canopy is probably the hardest part of the project and seldom they come out all nice without some fancy work. Depending on how much of a gap it is, if you are going to paint the plane, then you can lay up some fiberglass and build up to match. My biggest concern about fluting or banging on the canopy is if it going to put any stress on the canopy itself which could result in a crack later on.

Click to expand...

I was a little worried about that too, but it's a pretty minor amount of bending and shrinking forward of where the plexi would be stressed. In my case, the fiberglass fairing was sanded down to the skin after the metal work and re-done by the paint shop anyways (they did a much better job than what I built and flew with), so the plexi isn't really any more stressed by the rework.

When I first asked the paint shop about making it look better, I really had in mind what others have suggested - laying up build of fiberglass to match contour. I was skeptical about the bending/shrinking, but glad I had that done instead as it looks good and I don't have the extra fiberglass onboard or covering rivets should I ever have to remove the forward skin (sure hope not, but never say never). Either solution will work, and the fiberglass solution is probably easier.

I think most tippers end up with this gap. It is almost impossible to avoid it but some have managed to pull it off.

It is my opinion that the radius of the backbone of the canopy is wrong and it does not match the fuse. Some say to redrill the hinges but this does not work if the center is already flush with the top fwd skin.

I ended up fairing mine in with glass and filler. The tapper starts almost all the way fwd at the cowl line.

Hi Allbee,

allbee said:

I had the same issue. What I ended up doing was redrilling the left attachment to go lower, I also tried real hard to bend the canopy, real hard to do.

Click to expand...

I've had a couple folks suggest re-drilling the hinge. What I failed to show in the original picture was that the skin at the hinge looks great. My latest theory is that I'm dealing with a joint plate issue, C-614, back in the original construction. I recall that I needed to shim the canopy skin in order to get it to clear the forward top skin. Had the joint been a little higher, it would have raised the skin and brought in and lowered the sides a bit.



Nonetheless, I've on my todo list to remove the left side bolt and see if it drops down any more - just to be sure.

allbee said:

After I was sure I did everything, I still had a raise on both sides but the left side, pilot, was the worse about 1/8. So out come the fiberglass and I put a barrier between the area in front of the canopy and the canopy and built up the area in front of the canopy and flared it to where when finished you didn't know there was a raise. Worked like a charm. It took several layers to make it right but you would never know today that I did it. Hope this helps.

Click to expand...

If you have any, I'd sure be interested in any pictures of the process and/or results.

Thank you,

that pic shows that lowering the left hinge is not going to do anything. That pretty much looks like mine did before laying up the fiberglass. The only point to do some adjusting is the very outside edge close to where it seals to the side of the fuse, if you can bend that in and make it flush than all that's needed is to lay up the fiberglass and make everything flush, than move on. good luck.

I recommend drilling out the joint and bring in the sides. It may be extra work, but still do-able at this stage. Probably less work than a lot of fiberglassing and will ultimately look better. Your sheet metal work looks really nice. Why cover it up with a fiberglass scab?

JMHO

Roberta