Canopy pin clearance oops...help?

WD-716 bushing edge distance

Anyone know how much edge distance is required for the hole in the WD-716 hinge? (tip-up)

Tip-up Canopy C-hinge Edge Distance Requirement

cropdusterdave said:

Anyone know how much edge distance is required for the hole in the WD-716 hinge? (tip-up)

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I noticed this did not get an answer when previously posted. But, it has been 4 years. Anybody have an answer now?

I cannot seem to locate in the plans but I seem to remember that you need at least 0.25" from the top edge and forward edge. I ended up having to replace the UHMW blocks (C-620 and its thinner counterpart) on the right side due to edge distance being too little.

Edge distance

According to AC 43.13B, edge distance restrctions oblige that holes drilled are not less than 2 hole diameters from the center of the hole to the edge of the material into which the hole is drilled. Reworking the algebra, this translates to 1.5 hole diameters from hole edge to material edge. Although, while I've never heard or read this metric to be material specific, I'm currently noting violations (by dedign) in the steel of of the cleavis halves that attach my rudder cables to the pedals. Never the less, the math of AC 43.13B remains. Good luck
Hodgson
N377CP,KWVI

I have not found a specific edge distance in the plans. It is easy to say drill them centered. There have been posts here that showed very thin distances. If you feel your hinge pin holes are too close to the edge some have recommended having them welded closed and re-drilling. That might be easier than rebuilding the frame, but I have not gone down that road. The canopy frame is retained by these two hinge pins and the canopy locks at the aft edge, so you will want to get them as close to center as possible.

I know I was very concerned about how this would turn out. Before you drill make sure you are very happy with how the frame fits the aircraft. These hinges will impact the fit and finish of the canopy frame and canopy.

If this doesn't answer your question, maybe post a picture of your results. Or call Van's; their opinion trumps mine every time.

My Canopy Hinge Edge Distance

I just finished drilling and fitting the bushing in my canopy hinge bracket and they are a little aft of center. They seem to have a 1/4" edge distance forward and on the top of each hole, with about 1/8" edge distance clearance aft.




I hope this edge distance is sufficient, but to be certain I have asked the mothership for guidance.

snoopyflys said:

I just finished drilling and fitting the bushing in my canopy hinge bracket and they are a little aft of center. They seem to have a 1/4" edge distance forward and on the top of each hole, with about 1/8" edge distance clearance aft.


I hope this edge distance is sufficient, but to be certain I have asked the mothership for guidance.

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Actually, this looks really good! You may have to make the outside more concentric to the pivot hole. Install it and look how it rotates and how close to the top skin. I had to do some trimming on mine.

I sure hope Dave hasn't been waiting 4 years for a reply.

same area

i'm working with this now and what about the aft tube that you drill into. I clecoed all the hole and then started in the middle of the aft tube and as I got to the last three holes in the skin the tube was a 1/4 inch away and if I push down the skin will dent if I take out the clecos on the bottom edge of the frame the skin will go down but the holes in the bottom edge are a 1/8 off from skin to frame. now my plan is to abandon the last two rivets holes anyone else have this problem?

Everyone has this problem!

bill v said:

i'm working with this now and what about the aft tube that you drill into. I clecoed all the hole and then started in the middle of the aft tube and as I got to the last three holes in the skin the tube was a 1/4 inch away and if I push down the skin will dent if I take out the clecos on the bottom edge of the frame the skin will go down but the holes in the bottom edge are a 1/8 off from skin to frame. now my plan is to abandon the last two rivets holes anyone else have this problem?

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Yes that is standard. There are different ways to compensate for this gap. I made some aluminum stand-offs, with a cupped end to fit the tube. Drilled a hole down the center of it, and then put it in place and drilled down to the tube. I used a long cherry max rivet to connect to the tube and added some epoxy for good measure. There are many ways.

I also made a "U" shaped set, and dimpled the holes on the tube, as the top is supposed to use counter sunk pull rivets.

Let me see if I can get some pictures if you are interested in this route.

I will get some pictures.

I center drilled the holes with a lathe, but they did not always line up well, you might think about drilling the center holes last to align with the skin. To compensate, I had to shave off the tops of the spacers that left the flat spot against the skin not perpendicular to the center hole. With the long through rivet, it was not off much and presented no problem. The challenges of a tipper.

Here is a near finished spacer.


Some spacers installed.


Two cross drilled holes in steel as a guide made two cutouts at the same time. Just stick the hardware store rod in the hole and drill it out.

Nifty spacers, Bill! I wish I'd known you when I was at the stage in the build! I used stacked small washers super-glued together ... Effective, but way crude in comparison.