Question on tipup canopy drilling....

[Brantel]

I am to the point in the directions where it tells you to drill the canopy side frame weldments/angle to the rear canopy ribs. Do I really want to do this now without the canopy on there to provide a reference for the rear ribs to ensure they are in the correct position?

Next question... I have a slight gap at this intersection where the angle of the canopy side frame weldments meet the aft canopy ribs when I have the front of the side frame weldments flush up against the main weldment in the front. I am using a 13/16 spacer and have the 1/4" space between the roll bar and the canopy ribs. Do I fill this space with a shim or do I move the canopy side frame weldments back and have a gap between them and the main weldment in the front?

 

[cjensen]

I am to the point in the directions where it tells you to drill the canopy side frame weldments/angle to the rear canopy ribs. Do I really want to do this now without the canopy on there to provide a reference for the rear ribs to ensure they are in the correct position?

Wait on drilling those Brian. If you were going to use Sika, it wouldn't matter if you have a gap. Now that I've decided to not use Sika, and I did drill my rails to the ribs when it said to, I have a gap to fill with washers, and some type of silicone.

Next question... I have a slight gap at this intersection where the angle of the canopy side frame weldments meet the aft canopy ribs when I have the front of the side frame weldments flush up against the main weldment in the front. I am using a 13/16 spacer and have the 1/4" space between the roll bar and the canopy ribs. Do I fill this space with a shim or do I move the canopy side frame weldments back and have a gap between them and the main weldment in the front?

Fill the space with a shim, but it probably doesn't matter all that much. A gap at the front shouldn't be a big deal with the way they come together with the splice plate.

 

[Greg Arehart]

I am to the point in the directions where it tells you to drill the canopy side frame weldments/angle to the rear canopy ribs. Do I really want to do this now without the canopy on there to provide a reference for the rear ribs to ensure they are in the correct position?

I just went through this over the past couple weeks. In my opinion, you are ok to drill the side weldments to the rear ribs. I did this with #40 so I could adjust a bit later if necessary when drilling out to #30 but it proved unnecessary as the fit was fine. I think the main concerns here are 1) that the joggle in the side weldment lines up properly so the canopy goes flush onto the rib from the side weldment, and 2) the side weldment is not twisted - that is it is parallel in the vertical sense to the side of the fuselage. When I did this, I clamped the ribs to the roll bar in the appropriate place, with the spacer, put the appropriate spacer under the side weldment and clamped it in place, and then drilled the holes.

Next question... I have a slight gap at this intersection where the angle of the canopy side frame weldments meet the aft canopy ribs when I have the front of the side frame weldments flush up against the main weldment in the front. I am using a 13/16 spacer and have the 1/4" space between the roll bar and the canopy ribs. Do I fill this space with a shim or do I move the canopy side frame weldments back and have a gap between them and the main weldment in the front?

I did not have this issue as mine were a bit tight if anything. However, I agree with Chad and think you could put your gap either at the front of the side weldment, or put a spacer between the side weldment and the rib. In either case, the side skirt will cover the gap. My thought structurally is that you would be better off with the shim between the side weldment and the rib rather than moving the side weldment back and counting on the splice plate. Also if you move the side weldment back, then the tabs between the front and side weldments will not overlap as much, thus not as easy to rivet together (as an aside on this, Vans tells you not to drill and rivet these tabs together until after you put the 702 skin on - once the skin is on, it is darn near impossible to get a drill/countersink into place to drill these rivet holes! Do it before you put on the 702 skin!).

(hope this was clear enough...)

cheers,
greg

 

[dhall_polo]

no, don't drill.

Clamp everything down and leave it.

After you cut the plexi in half and shape the front plexi, you will unclamp the rear ribs/frame and push the ribs into place against the canopy. Then finish drilling the center plate on the ribs/frame, then drill to the rails.

If you do any of this too early, you're very likely have fit issues.

Even if you are doing Sika, same procedure works. IMO, Sika is the only way to go.

I also would not pre-drill the two holes on the rails that eventually hold the canopy lugs. Wait till you're fitting the canopy lugs. Till then, just drill the other 4 holes.