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canopy side weldment fit question

n567vb

Active Member
I'm working on fitting the canopy side weldment (WD-725) for a tip up, but I have a gap at one end where it meets the aft channel ribs (W-631A) that is too large to close by just clamping. I've attached a photo. No matter what I , the gap doesn't seem to improve without risking breaking the weld on the angle. Has only seen this before and how to I get this gap closed? Everything on the aft channel looks good and square. Everything else on the side weldment looks good too.

The gap on the inboard end is 3/16". On the outboard end, it is flush. The side weldment on the other side is perfect.

Here's a photo:

863652531493b24a871d8d.jpg


Thanks!
Vince
N567VB
 
I'm at about the same spot, and have noticed the same problem. For me too, the left side is nearly perfect, and the right side has about the same gap dimensions as Vince's. Apparently this is another case of Van's poorly aligned welding jigs (see other thread today about rudder pedal weldments).

I think there are basically three options here:

Option 1. Cut out and re-weld the angle in proper alignment. I don't like my odds in trying to weld aluminum, so I'll rule that one out.

Option 2. Shim the gap. Making that tapered shim could be a little tricky. I still haven't figured out a good way to do it with the tools I have available. But that would keep the aft channel square and not introduce any stress into the structure, so that would be ideal.

Option 3. Pull the aft channel forward to fill the gap. You won't break the weld. The aft channel is easily twisted in that direction, and won't put much stress into the structure. The downside is that it will be slightly twisted and out of its ideal alignment. Aesthetically, you'll have a wider gap between the aft channel and the roll bar on the inboard bottom end (see first photo). And practically, you may need to readjust the outer flange of the aft channel so that the canopy bubble still sits flush on the flange.

Both 2 and 3 seem reasonable, but I haven't committed to either one yet. I'll be curious to hear more input from others that have been there before us.
 
Yep, I had this too. I adjusted the fit of the forward end of the WD725 to the canopy frame to make the aft end meet up with the W631A. I had to adjust the drilling layout in the splice angle to retain adequate edge distance.
Steve
RV-7
UK
 
Vince,
Sorry, overlooked that your weldment is off-square. Mine was square to the W631A but came up short by about 5/32. Not sure if my actions will help you.
Steve
 
FYI- This was Van's reply to my inquiry...

First, compare the left and right side weldments to see if they are the same
length. If the right side is clearly shorter than the left side, then that's the
problem. If they are the same length, there are two solutions. If the
weldment is not riveted to the canopy frame yet, then you can move the
weldment a bit aft to close some of the gap. Then you can fill the gap with
shims. The small gap that you will create in the forward end can be filled
with bondo before you paint the plane. If the parts are already riveted, then
just fill the gap with shims. You are at the stage of the construction that
requires a little fudging to get things to fit. With all the variations that can
happen up to this point, there is no way that we can manufacture parts that
will just plop into place.
-Bruce

I think I'll try to file down the outboard edge a little to make a little more uniform gap and then try a spacer, I'll close up any remaining gap at the inboard end with a little "twist" of the W-631 Channel.
 
Thanks for posting this, Vince.
Reassuring to hear I went in roughly the right direction.
I was keen not to have shims so took out all the spacing at the foreward end.
I didn't say previously but mine were almost the same both sides so the frame itself was sitting square to the fuselage.
Steve
RV-7
UK
 
Van's also missed the point. Oh well, fudge it ;-)

It sounds like Van's also missed the point that the back angle is not square. Their recommendation only addresses the problem of overall length (what Steve had on his airplane). Oh well. The bottom line is the same: fudge it to make it work any way you see fit.

FYI- This was Van's reply to my inquiry...

First, compare the left and right side weldments to see if they are the same
length. If the right side is clearly shorter than the left side, then that's the
problem. If they are the same length, there are two solutions. If the
weldment is not riveted to the canopy frame yet, then you can move the
weldment a bit aft to close some of the gap. Then you can fill the gap with
shims. The small gap that you will create in the forward end can be filled
with bondo before you paint the plane. If the parts are already riveted, then
just fill the gap with shims. You are at the stage of the construction that
requires a little fudging to get things to fit. With all the variations that can
happen up to this point, there is no way that we can manufacture parts that
will just plop into place.
-Bruce
 
I guess that, to Van's, a shim is a shim, no matter whether it is flat or angled
(like the spacer under the splice-angle at the front of the WD725)
Steve
 
Welded wrong

I just got another email from Van's. They must have done a little more digging. They figured out that they shipped some parts out that were welded wrong. They will replaced free of charge. If you are seeing the same thing, give them a call!

Vince
RV-7
 
Mine was not square either. On the co-pilot side I had to add a shim and twist the aft frame/rib to conform to the rail.

Once it is all together, 98% of the people will never know it.
 
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