RV-12 Canopy Drilling

[keny]

Hi, Haven't got to page 34-07, step 2, yet and have bad dreams about cracking the canopy? I did and didn't have a person to back up my drilling through the canopy skirt/canopy/ attach angles, so I did it differently. This way produced clean holes and no cracking: 1. Use a plexiglass drill. I bought mine from W.L.Fuller- high quality and $5 2. Drill when canopy is in the 70 to 80 degree range - may be less likely to crack 3. Prop the aft end of the canopy, attached to canopy frame, up 12" or so. 4. Clamp a 1/8" thick piece of aircraft plywood(or equivalent) to the inside of the attach angle, using "Pony" brand, or equal, spring clamps to hold skirt, canopy, and attach angle tightly together. Position the clamps very close to each side of the hole you are drilling This "backup" step is probably the most important. 5. With canopy skirt clecoed to canopy frame, use the skirt and a standard #27 drill to put a 32nd inch deep centering hole then followup drilling with a #27 Plexiglass drill, using this hole. I wanted the resulting hole to be centered within the skirt's predrilled hole. I didn't see any reason to drill 2 times in each hole(#30 then #27) so, I only drilled a #27 hole. Van's may know something that I don't about this, but the result was what I wanted. I did, however find it quite easy to enlarge the other(already drilled) canopy holes from #30 to #27 by using the plexi drill turning slowly. 3 pictures on Photobucket but haven't figured how to bring them here, yet. Hope this helps, Ken

 

[dinowal]

Hi Keny, thanks very much for that tip. Even though my kit doesn't arrive here for another two weeks, I was already having bad dreams about the canopy, mainly because I have been involved in a group that built 2 RVs before. In both cases cracks ran out from screw holes (later in the life of the aircraft) & had to be stop drilled. I did not do the drilling in either case before, & I am very keen that this doesn't happen in my 12. There are drills available here for drilling ceramic tiles, - they are bullet shaped & appear to have very little " relief" or cut, - are these what you used? Cheers, Dino..

 

[JBPILOT]

Hey guys - - -

Drill the first hole with a plexi-bit, but ONLY use a STEP-BIT to enlarge ANY hole. That will keep you out of trouble.

John Bender

 

[keny]

RV12 Canopy Drilling

Dino, I used drills ground for plexiglass. I do have a few hairline cracks in holes drilled through the aft canopy(to match holes predrilled in aft canopy bow) even though a plexi drill was used. I had to use a stepstool to drill the canopy holes nearest the center of the rear bow. This was a mistake as parallax angle issues made it difficult to drill the canopy hole to match the bow's hole. If I had to do this again, I'd take the canopy frame/canopy assembly off the airframe, put it on the floor, and drill straight down through the canopy I do know that all the holes I drilled through the canopy skirt/canopy/attach angles look good and this probably is so because I used a flexible piece of wood to backup this assembly. Also, my gut feeling is drilling a pilot hole in plexiglass and then enlarging it is a bad idea when there doesn't seem to be a reason for doing so. Maybe others will weigh in on this? KEN

 

[E. D. Eliot]

Wild thought

I am pretty sure that this is not a good idea but just a wild shot in the dark - has anyone tried burning these holes thru with a red hot pick, etc.

This must not be a worthy idea as I think that it must have been tried before and rejected.

What say you all???

 

[Geico266]

Drill the first hole with a plexi-bit, but ONLY use a STEP-BIT to enlarge ANY hole. That will keep you out of trouble.

John Bender

John has it right as usual.

 

[RFSchaller]

I haven't tried melting holes but it would probably be imprecise. Buy some lexan at Home Depot and experiment, but I wouldn't have high expectations.