Pmerems

Pmerems

Well Known Member
Advertiser
Gents,

After many years on my RV-7A project I am days away from completion. The only thing left is dressing up some wires under the cowl and final assembly at the airport. All the fiberglass is pinhole free so I am really just about complete.

However I re-installed the tip-up canopy the other day and the side fit isn't as good as I recall when I built the canopy several years ago (rather embarrassing how long this project has taken). The fit I am referring to is the match between the fuselage side contour and the canopy frame side contour. For those tip-up builders, you know what I am talking about.

The pilot side is good with a slight .020" under-lap (the canopy frame side is inboard of the side of the fuselage). But the passenger side has about .060" under-lap which I am not happy with. Just to check I removed the gas springs to see if they were contributing to the problem,they weren't


I have a few choices:

1. Leave it and live with it. However it is rather noticeable.

2. Remove the screws holding the canopy on and try to bend the canopy frame. Rather risky with questionable results and damage to the painted (interior) frame.

3. Add fiberglass and filler to the outside of the canopy side skin. Low risk. Questionable cosmetic results, future cracking problems?

I recall when building the frame I wish I had a Stretcher/Shrinker to get the bow in the frame correct but after tweaking and twisting I thought I had it rather good. But after riveting the canopy side skins, installing the plexiglass, the fit did change (obviously).


Any input would be appreciated.
 
seal?

The tip-up is magical and mysterious for shape-shifting just when you think you have perfect fit.

Have you installed a weather seal around the bottom sides? If not, do that before judging your fit. Here's what I used from McMaster Carr.

Products
Line Quantity Part Number Description Unit Price Total Price Ships
1 20
Ft. 1120A111
Edge-Grip Rubber Seal Bulb Opposite Grabber, 1/16" Edge, 3/8" Bulb Width (Same as 1120A11)
$1.36 $27.20 in the morning
 
Paul,

I assure you that once you are flying a few months (actually a couple days probably), this issue will be background noise. Unless you are trying to build a show plane....

The canopy flexes and changes with the seasons (It's Alive!!:eek:)

greg
 
Paul - as I assemble the tip up, I see similar issues. What about a guide tab mounted on the sill that pushes the tip up frame outward a little as it closes? Also, if this gap persists all the way to the back, can you add a delrin guide for the catch on the 631 bow frame that will push things out a little as the canopy closes, yet keep the catch within grasp of the canopy closing arm?
Bill - beautiful work. How many layups did you do? Can you give a brief description of your process for those of us who are glass newbies?
One of my goals is to improve the look at the bend of the forward sill, as the forward canopy frame and side skin do not meet well there and leave a little gap.
 
4 layers

of Rutan BID fiberglass were used. Each layer was staggered about 3/8 inches to obtain a smooth transition from the side canopy attach screws downward.

Apply two or three layers of blue painter's tape on the side of the fuselage, followed by a layer of shipping tape to allow the fiberglass to release after cure. The painter's tape provides the necessary clearance so the fiberglass applied to the canopy will not interfer/rub on the fuselage. Delrin guides are attached to the canopy roll bar to protect the fiberglass when opening and closing the canopy.
http://i793.photobucket.com/albums/yy216/billrv7/P2052626.jpg

The canopy was later removed to address the front area (sub panel) where the front canopy seal is attached. Two layers of fiberglass were applied to this area -- including across the area where the canopy hinge arms are located. The fiberglass was painted and an adhesive seal applied. Now, NO water gets in above the canopy hinge arms as was the case -- no pictures handy at the moment.

Best regards,

Bill
RV-7 N151WP
Barrett IO-390
Lee's Summit, MO
 
billgill said:
to the canopy side rails.

This will get rid of gap between the canopy sides and fuselage. Here are a few photos:

http://i793.photobucket.com/albums/yy216/billrv7/P2052606.jpg
http://i793.photobucket.com/albums/yy216/billrv7/P2052613.jpg
http://i793.photobucket.com/albums/yy216/billrv7/P2052614.jpg
http://i793.photobucket.com/albums/yy216/billrv7/P2052627.jpg

Bill
RV-7 N151WP
Barrett IO-390
Lee's Summit, MO
Click to expand...

Bill, that is probably the best tip-up canopy fit I have ever seen. Kudos to you. - JDP
 
Just when I thought I was done with my fiberglass

Gents,

Thanks for the inputs. After much consideration I believe the best solution is to layup some fiberglass on the canopy side skins to fix the problem. After seeing photos of Bill's work I knew I couldn't settle for my under-lap condition.

So possibly this week I will getting ready to have some fiberglass funnnnnnn.
 
Just glassed my sideskirts

I just finished last weekend putting UV smoothprime on my fiberglassed sideskirts and targa strip.

I was always going to put a targa strip on but after being frustrated with the gaps, which sound almost identical to yours, larger on passenger side, I decided to glass the whole thing. I only overlaped a 1/4" using 2 layers of 20 mil plumbers tape. So the gap on the side skirts is 40 mil whatever that equates to. I'll put felt on to seal this small gap. The frame is rigid and nothing catches at all. There is no gap on the targa strip.

IMG_0641_edited.jpg


IMG_0639_edited.jpg
 
The bottom corner of our tip up is cracked off and thought maybe doing this targa thing would work. Do you have any further pictures or instructions how you did that?
 
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