About Canopy Fastening Screws: beware!

[WingedFrog]

When fastening the canopy to the rear bow, I faced a problem not mentioned in the instructions. The #30 holes in the rear bow that were punched in the factory are slightly too small for the screws. This makes the AN526C632R8 screws to act like a tap although the fastening is provided by an AN365-632 nut. This results in the screw head not being always flush to the plastic surface. After calling VANs, I was instructed to enlarge the #30 holes with a #29 drill bit... one more drilling, canopy removing, deburring, canopy mounting cycle which could be avoided with the correct instructions.

 

[gasman]

As the kits evolve to an assembly process, simple issues become an indication that the project was not engineered properly. If Van's had to stop and explain why those holes were undersize by .0075, the manual would be twice as thick. If a bolt is to be held with a nut, then the bolt should pass through the hole without much effort (excluding spar!). If the hole is too small, check the bolt size and open the hole up to fit the bolt.

Was the kit a perfect fit up to this point?

 

[WingedFrog]

As the kits evolve to an assembly process, simple issues become an indication that the project was not engineered properly. If Van's had to stop and explain why those holes were undersize by .0075, the manual would be twice as thick. If a bolt is to be held with a nut, then the bolt should pass through the hole without much effort (excluding spar!). If the hole is too small, check the bolt size and open the hole up to fit the bolt.

Was the kit a perfect fit up to this point?

I am amazed at the way any suggestion or hint to help other builders is interpreted by some (probably old timers) as attacks on VANs and responded as such.
Let's be clear, VANs is a wonderful company that has done wonders for the kit plane community for years and has produced the ultimate plane and kit with the RV-12. Is VANs perfect? No but as good as they are, builders, particularly the new kind of builders that are attracted by the RV-12 can help make them even better.
In this specific instance, the instructions specify to drill holes in the plexiglass with a #30 plastic bit. Then later these holes are enlarged with a #27 bit. Nothing about the canopy frame holes. A novice builder as I am may be puzzled by this omission and wonder if he did anything wrong. For sure , when I build my next canopy I will have no such qualms! I just thought that my post could help other novice builders avoid one more fitting-drilling-deburring cycle and I apologize to you old timers for the time you wasted reading my post

 

[Keith Williams]

Canopy Frame Holes

Jean-Pierre, as an "old time" builder (built RV6 #756 1989-99 and am still flying it) I thank you for taking the time to post this note about enlarging the holes in the canopy frame.

Every question/surprise avoided is a help.

Keith Williams
120533

(I was just starting on the canopy when the engine arrived earlier this week. Now the canopy is on hold while I get acquainted with this new piece and hunt down the latest list of items I need - 1/4 square drive metric hex head sockets, low strength thread sealer.)

 

[LifeofReiley]

As with pre-punched kits, most all holes are not to final size as they should not be. Fitting up with clecos and making necessary small adjustments is part of the final fit for a quality build.

I'm sure most will appreciate the heads up you've posted.

 

[gasman]

When fastening the canopy to the rear bow, I faced a problem not mentioned in the instructions. The #30 holes in the rear bow that were punched in the factory are slightly too small for the screws. This makes the AN526C632R8 screws to act like a tap although the fastening is provided by an AN365-632 nut. This results in the screw head not being always flush to the plastic surface. After calling VANs, I was instructed to enlarge the #30 holes with a #29 drill bit... one more drilling, canopy removing, deburring, canopy mounting cycle which could be avoided with the correct instructions.

Nothing wrong with your post. But why did you call Van's?...................

 

[MartySantic]

...........I was instructed to enlarge the #30 holes with a #29 drill bit... one more drilling, canopy removing, deburring, canopy mounting cycle which could be avoided with the correct instructions.

Try the forum search option. This subject has been previously covered a few times!! The holes on the canopy sides in the plexi can be enlarged also. The plans call for a hole in the plexi that has provides about 0.002" clearance. Not much room to allow the plexi to float with OATs varying between zero and below to 100+. Guys have suggested 0.010" minimum clearance. The unibit gives one a very nice beveled hole.

 

[DaveLS]

Why call Vans?

The holes in the 12 kit are supposed to be final size. The few holes that have to be opened up are specified in the plans. This is very different from all of the other Van kits.

E-lsa have to be made to the plans. To stay legal, varying from the plans requires authorization from Vans. This is also different from all of the other Van kits.

It is very reasonable to call Vans to insure that varying from the plans is ok.

So far, the few times I thought the plans were wrong they were not. So I have learned to be vary careful about following the plans to the letter.

Just sayin

Thanks for the heads up J-P

- Dave

 

[WingedFrog]

Thanks for your support

Very good point, Dave, about E-LSA constraints. I think that the concept will take some time to take hold among the E-AB community.

I just forgot to mention two more details:
- I did not have a #29 bit but could find a 9/64 one at a local Napa store that was close enough and worked well to remove the unwanted threads
- I had the same problem in the canopy skirts with the holes in the aluminum angle (match drilled per instructions with a #30) and applied the same solution.

 

[Reilly]

Thanks for the tip. I always look for advice and tips ahead of starting new sections.