Locating hole in slider canopy for handle ?

[petersb]

I have placed the canopy on the airframe ( with the roll bar and slider frame in place) and now have to establish the position fore and aft.


The instructions only say to make the canopy match the contour of the top frame bow, mine doesn't match the contour so I need another way to establish the fore/aft position so I can drill the handle hole.

Looking at the plans the front edge of the canopy appears to be one rivit hole forward of the front deck bulkhead. ( sorry don't know the # off hand), make sense?

I used the molding marks in the plastic to determine the centre of the canopy. I noticed manufacturer centre line marks at each end of the canopy, however the front one appears off centre.

Comments !

Peter

 

[Kyle Boatright]

I have placed the canopy on the airframe ( with the roll bar and slider frame in place) and now have to establish the position fore and aft.


The instructions only say to make the canopy match the contour of the top frame bow, mine doesn't match the contour so I need another way to establish the fore/aft position so I can drill the handle hole.


Comments !

Peter

The difficulty here is that you're into the part of the project that isn't an exact science. It is a "looks good, seems right, make it fit" process.

Look at and measure your canopy closely, trying to find the centerline. Look again and measure again. Then select a centerline to the best of your ability. Put a piece of the blue low-tack tape on the C/L, then mark the exact C/L with a fine tip marker.

With the bubble and frame off the airplane, place the fore and aft top bow of the frame along the centerline of the bubble. Shift it fore and aft to determine the best fit along that fore and aft bow. Make index marks on the bow and the canopy so you can re-establish that position later.

Now, put the frame back on the fuselage, close it, and set the bubble on top, matching up your centerline on the fore/aft bow and matching the fore and aft index marks you created earlier.

Assuming the fit looks reasonable (and this is a very subjective measure), mark where the hole goes and drill it with your tool of choice (probably a unibit).

Then, you get to work to shim the height of the slider frame and the windscreen bow so the bubble transitions appropriately between the two.

I wouldn't worry too much about any measurements or apparent dimensions given in the plans for the fore and aft placement of the bubble. Your bubble and frame are unique. They will determine the forward extent of the windscreen.

 

[LifeofReiley]

Make sure when you've located and drilled the hole that you sand, debur and sand again... very smooth or you can end up with spider cracks from the hole in a very short manner down the road.

 

[pkill]

Hello Peter,

Van’s Construction FAQs has a .pdf on Canopy Installation which might (??) help you with Frame Adjustment.
http://vansaircraft.com/pdf/canopy.pdf

As you locate your handle hole, you might consider how the rear canopy skirts will fit later. Notice that the aft edge of the canopy has a bit of a ski jump to it as the bubble flows down and out. You might want this ski jump portion just far enough behind the aft canopy bows that after you’ve trimmed that portion off, the skirts will make a nice transition from canopy glass to fuselage skin.

Good luck there.

pk