Another Tipper Canopy Question..

[Jim P]

Well the canopy has certainly generated the most questions from me so far...

Based on the lack of clear instructions in the manual, and reviewing some other sites, I have a general process question on canopy fitting. From my understanding, the basic order should go something like this (is this the right way to go?):

1) Prep fuse; tape over roll bar, mark center, get clecos out of the way as necessary, roll the side rails inboard where they mate with the tabs on the forward frame, then tape down the "ears" on the forward canopy skin.
2) Practice cutting some of the plexy, trimming off edges up to the mold lines (OK, did that front and rear only, left the sides).
3) Trim front of canopy to the point where the bubble begins. (Is there any trimming of the aft ducktail at this point?)4) Place on fuselage, mark for further trimming along the front edge. Trim a little at a time until the canopy settles within about .5" of the rollover structure.
5) Mark for the big cut.
6) Do big cut
7) When bubble sits on the rollover frame, mark and trim sides.

Jim

 

[scard]

Yeah, something like that. Although I suggest chopping most of the "ears" off to begin with and plan on front of the canopy being further back than suggested.

 

[RV_7A]

Jim-

I would recommend starting on the rear window first. There is plenty to trim from the front bubble to get the necessary fit. Heres why. If you fit the front first and then cut in half at the roll bar, it is likely you may not have enough material on the rear window to reach under the skin on the aft end. How do I know? Cause I did just opposite. Only to realize if I had trimmed just a 1/4' more from the front bubble, the rear window would not have reached far enough back. Everyone I have seen realizes this after the fact. So if you trim the rear end at the mold line and just aft of where it flares up and fit it under the skin and then trim the front so it drops down almost till it meets the roll bar, you will find that when you cut it in half you will have to do little trimming in the middle to get the rear window and bubble where they meet to fit perfectly. Once you cut them apart you can then continue trimming the front of the bubble and the aft end of it where it meets the rear window for a pefect fit. Also by doing this it ensures that the top surface of the 2 are totally level and have no change of angle where they meet. Just my 25?.

-Jeff

 

[Radomir]

Jim, many ways to skin the cat.... I would only recommend to follow the instructions.

Just to reiterate -- middle of page 9-6:

"Do not attempt to do any trimming to final size, other than around the base of the windscreen, until after you have split the canopy at the roll bar...."

 

[Jim P]

And then....

"Do not attempt to do any trimming to final size, other than around the base of the windscreen, until after you have split the canopy at the roll bar...."

But to get to the point of splitting, the canopy has to sit relatively close to the rollbar, thus additional trimming is needed on the front end?

 

[Radomir]

Correct.. but we're talking minor trimming.. roughly to where the front end starts to flatten out.. not much beyond the "lip" on the front end.. if you do that.. you'll still end up with a couple of inches to be trimmed off the back window (after canopy is split). You can't get it to sit flat on rollbar before splitting, but that's OK.. just get it close.. w/in 1/2" is fine.. I think I started with 3/4" and trimmed a little more on the front side (nothing on the back) and got it to less than 1/2 before splitting (I dont' remember, but I think it was probably close to 1/4" or so).

 

[Pmerems]

I just split my canopy yesterday

Gents,

I just made the "big" cut yesterday. What I thought would have been a big deal wasn't. My thought was that the closer I got the canopy to touch the roll frame, the less secondary trimming of the split cut would be needed. So I cut the front down progressively unit I got within ~1/8 of the roll frame. I was very concerned about cutting too much off the front which intern shortens the length of the canopy and then having problems with the "flare" at the rear of the canopy causing some problems. So far, I believe I have enough material on the rear of the canopy to work with. I also set the canopy 2" from the edge of the canopy top skin rather then the 1 3/4" mentioned in the instructions to give me a little extra in the rear.

For those who are going to start cutting their canopies, here are the dimensions I ended up cutting to:

Removed just up to the curve in the front: 5/8" gap above roll frame
Removed 3/4" along the front slope : ~1/4" gap above roll frame
Removed and additional ~3/8-1/2: 1/8 gap above roll frame
Placed canopy 2" from edge of skin

After cutting and the forward canopy laid down on the roll frame. The shift along the cut line due to the fact that the canopy was not touching the roll frame was about 1/16" max.

I hope this information helps someone.

Paul (RV-7A)

 

[JCN247DE]

suggestion to order of sequence for the tipper

I flew my -7A tipper through a heavy rain shower a few weeks back and it leaked like a screen door under the front lip of the tip-up! I thought that the seal was halfway ok from the seemingly little air leak under the panel. Imagine flying your plane through a 5 minute car wash and you have some idea of the unavoidable shower I navigated.

If I were to do it again... I would put the drip seal flange on the instrument sub panel AFTER the tip up frame and front skin was fitted to the airframe. Van's has you do it before through measuring.

I would have put the rubber seal on the fabricated drip seal angle frame and then back drilled the angle to the subframe as I held (duct taped) it in a good sealing position against the underside of the front skin.

I believe this would have helped the issue.

Jeff