Canopy frame

[truflite]

I am progressing slowly on my finishing kit as well as finishing up the fuselage kit. I have the canopy frame mounted to the fuse on the rollers and rails as well as the rear sliding block. My problem is that the front bow of the frame sits very high and is nowhere close to where is should orientate to the roll bar.
The horizontal square tube rises towards the front of the airframe.

My instincts tell me that I should cut the front bow tubes, where the rollers attach, to reach the proper orientation. Before I make an expensive (and stupid) mistake, has anyone else found this to be true? I did look through the manual and prints but could not find anything referencing this.

Thanks in advance for the help.

[mikehoover]

My forward bow was higher than the 3/8" pointed out in the detail, so after careful measuring and lots of head scratching, I cut approx. 1/4" off the bottoms of the the forward bow tube.

Pictures:
The forward bow clearly too high:
http://www.aclog.com/rv-9a/images/Fi...2_DSC_0841.JPG
Me taking the plunge, cutting:
http://www.aclog.com/rv-9a/images/Fi...2_DSC_0842.JPG
How it fit after trimming the bottoms of the forward bow:
http://www.aclog.com/rv-9a/images/Fi...0_DSC_0854.JPG

[Russ McCutcheon]

I?m surprised it?s not in the instructions, years ago we built these frames with the front bow at the correct length but sometimes it ended up being too short for some airplanes so Van?s (they make the bows) began leaving the front bows long and asked us (we weld/assemble the frames) to leave them long on the bottom for the builder to trim to fit, that change was made 15+ years ago. Anyway, you?re on the right track, have fun, build on

[truflite]

Mike and Russ,

Thanks for the insight on this. Mike, my tubes need to be cut about 7/16". I plan on removing about 5/16" to start and will go from there. The bow is about 5/32" out of parallel with the roll bar and the roll bar is dead on where it needs to be. Having fun and will build on, roger wilco.

[Sig600]

The bottom of the tubes will need to be cut to bring the canopy down to the called for level in the plans, but I suggest you wait until after the canopy and wind screen are on, then you can trim the tubes for a perfect fit from windscreen to canopy. I did it per the pans, but afterwards it seemed like a better idea to wait.

[ChiefPilot]

Originally Posted by Sig600

The bottom of the tubes will need to be cut to bring the canopy down to the called for level in the plans, but I suggest you wait until after the canopy and wind screen are on, then you can trim the tubes for a perfect fit from windscreen to canopy. I did it per the pans, but afterwards it seemed like a better idea to wait.

If you don't cut the tubes prior to fitting the windscreen/canopy, how do you know where to shim the windscreen/canopy to get a good fit?

[Sig600]

Originally Posted by ChiefPilot

If you don't cut the tubes prior to fitting the windscreen/canopy, how do you know where to shim the windscreen/canopy to get a good fit?

I glued my canopy to the frame (sika flex) and I cut the tubes to get the prescribed height. However I'm concerned when I do the wind screen it may sit higher than the canopy. Haven't drilled the rollers so I may be able to have them ride higher, but I digress. IMO from looking at it you could mount the wind screen, shim it, and trim the frame tubes all in one collective effort for a seamless transition from windscreen to canopy. Just an idea.

[larrynew]

If you do cut the tubes too short like I did , here's the fix I used. I used a bronze sleeve bearing from McMaster Carr pictured below. It was the closest size I could find but I did have to increase the inside diameter just a tad. I did the poor man's machine shop method of chucking a die grinder burr bit in the drill press and wrapping it with sticky backed sandpaper and reaming out the inside while I held the bearing with a drill press vise. Only took about 10 minutes. After reaming, I cut it down to length. With the screw in, it's very solid. I also ordered two quick release pins with lanyards that I might use during test flights to replace the screws. It took a while to find the right sizes so I included the invoice with part numbers.