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RV-7 / RV-9 slider canopy measurement discrepancies

alpinelakespilot2000

Well Known Member
After a few weeks of frustrating contemplation and a couple days of sometimes frustrating bending, my canopy frame is getting pretty close. However, I cannot reconcile two discrepencies with the plans. Any help would be appreciated...

1. Height of forward canopy bow vis-a-vis roll bar: One of the canopy drawings clearly indicates that the forward canopy bow should be 3/8" above the top of the roll bar. However, in the "additional notes on adjusting the canopy frame" section of my manual, it states that "The front top of the frame is about 1/8 - 3/16" higher than the rollbar." So which is it?

2. Distance between the slider tracks: The manual indicates that the slider tracks should be positioned such that the canopy frame side bows are inset 1/16" from the outside of the fuselage. "This should position the tracks approximately 40 13/16" apart when measuring between roller track inboard vertical surfaces." Problem... when my canopy bows are inset 1/16" from the outside of the fuselage, the distance I'm seeing is about 41 3/16 (or about 5/16" difference from Van's!). I know there is variation from one builder to another, but Van's measurement doesn't even seem close.

Thanks for any help!
 
Good timing on this thread! I'll be interested in the comments here. I'm just about to this point.
 
I measured mine

Hi Steve and Greg,
My -6A rails have about 1/16" inset from the INNER edge of the fuselage top longeron and they measure 40 5/8" apart at the inner vertical surfaces. In other words, a little bit of the top longeron shows....about a 1/16" and it's not critical. Just about every one you'll see is somehow different.

Keep in mind the overall picture...that the rails have to be parallel and the side skins will have to have a little clearance later on. If you can temporarily tape down the rails, mount the canopy frame with rollers and then position the canopy on top of the whole shebang (after drilling the hole for the handle), I think the picture will more easily develop. The windshield has to be shimmed to align it's trailing edge with the leading edge of the slider canopy later on.

If you get inside the cockpit and have a couple of buddies lower the canopy on, you can measure the gaps between the roll bar and canopy and also see what needs to be done....whether the slider front legs have to be raised or lowered, etc. Since the height of the rollbar is fixed, the adjusting is done on the canopy frame front vertical legs.

BTW, take some of Van's dimensions with a grain of salt and just fit it all up and take a good look.

Hope this helps somewhat,
Pierre
 
pierre smith said:
My -6A rails have about 1/16" inset from the INNER edge of the fuselage top longeron and they measure 40 5/8" apart at the inner vertical surfaces. In other words, a little bit of the top longeron shows....about a 1/16" and it's not critical. Just about every one you'll see is somehow different.
Thanks Pierre! Follow up: By "1/16" inset from the inner edge of the fuselage top longeron," do you mean from the inner edge of the aft canopy deck? (On the 7/9 there is a deck over the longeron, so you can't see the inboard edge of the longeron.) I have about 3/32" inset from the inboard edges of the canopy deck, which is what the scale of the drawings suggests I should probably have... but there are no dimensional callouts.

Still not sure why I'm measuring 41 3/16" although I think the 7/9 is wider than the 6, so that would explain why my measurement seems to be larger than yours. In fact,I wouldn't be surprised if Van's just indiscriminately copied the 6 manual for the 7/9... don't think it would be the first time. I'll try to call Van's later on and ask them this question.

Thanks again.
 
Last edited:
Yep

You're correct,
There is a canopy deck on mine too....I just looked. That's what I was talking about....mine is also around 3/32" inset there. I checked Van's specs a minute ago and the -6 and -7 share the same inside width dimensions on Van's website.

Is there a -6 or -7 near you that you can go and look at? Sure makes things plain if you could.

Regards,
Pierre
 
Canopy rail measurement

[B said:
2. Distance between the slider tracks:[/B] The manual indicates that the slider tracks should be positioned such that the canopy frame side bows are inset 1/16" from the outside of the fuselage. "This should position the tracks approximately 40 13/16" apart when measuring between roller track inboard vertical surfaces." Problem... when my canopy bows are inset 1/16" from the outside of the fuselage, the distance I'm seeing is about 41 3/16 (or about 5/16" difference from Van's!). I know there is variation from one builder to another, but Van's measurement doesn't even seem close.

Thanks for any help!

Data point:
Just measured my 7A slider tracks and they are 41-1/16" apart.
I remember this discrepancy with the drawing. I finally just assumed the drawing was wrong. The sliding part of my canopy is finished and everything looks and works good.

Mark
 
Mark Burns said:
Data point:
Just measured my 7A slider tracks and they are 41-1/16" apart.
I remember this discrepancy with the drawing. I finally just assumed the drawing was wrong. The sliding part of my canopy is finished and everything looks and works good.

Mark
Thanks Mark. I called Van's later today and Bruce said the "approximate 40-13/16" is pretty irrelevant so long as the rails are parallel and the 1/16" distance from the side tubes to side skins is maintained. Except for noting that the vertical distance from forward bow to roll bar did need to be the 3/8" noted on the drawings, he said pretty much every other dimension given on the plans was just an approximate. If everything fits and your canopy rolls back, you did it right he said, regardless of what the numbers are.

In any case, thanks for measuring yours. Actually now that I've tweaked my frame just a little more, mine is measuring at about 41-2/16", so you and I are really close!
 
The timing of this thread is great! I also am having a time interpreting the instructions for fitting the canopy frame/rail on a RV9A. I have tweaked and tweaked and now have the rear canopy frame bow matching the rear turtle deck skin. I have a 1/16th clearance between the canopy frame side rails and the skin fore and aft before I put the canopy on the frame. This is according to the manual. The manual instructions say that the canopy frame will be spread with the addition of the canopy and that this will be compensated for "later". However, I can't find the "later". In the FAQ section on Van's Aircraft, it talks about substracting a half inch from the measurements to compensate for this spread but this is not confirmed in the manual.
What do I do? :confused:
Thanks
 
I'm also at that point. A couple of notes:

1. The instructions say the plexi will cause the frame to spread approx 1/2". It was closer to a whole inch on my plane. After getting the 1/16" inset dimension, the OUTSIDE distance between the ends of the front bow was 42 1/2" so I needed to narrow the front bow to 41 1/2" before attaching the plexi.

2. The distance between my tracks is 3/8" wider than the figure in the instructions, measured after tweaking the frame for the 1/16" inset.

3. The 30 inch length dimension on the C-759 is shown in parenthesis on the print as if its already there. You'll need to shorten them approx 1 1/2" to get the 30 inch length.

If I had my ECI engine I could rivet the front skin then fit the windshield,
Steve
 
Canopy side rails

I know these are older posts, but I'm there now. I'm seeing the distance of 41 1/4. My question is the aft screw hole on the side rail is hitting the edge of the longeron. My other screw holes are all fine. Is this a problem? I have the 1/16th edge distance (mostly) on the canopy frame.

The plans show the screw no where near the longeron. Considering how the plans weren't very reliable, what have you guys seen
 
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