Canopy expands over time-Slider

[andrew phillips]

My canopy has been in the open position for months. Went to try to close it recently andd found that one of the pins now hits outside the hole in the delrin block. The back as expanded on one side. Thinking about the following:
1. trying to push in the one side w/o cracking the plexi
2. drilling another hole in the delrin to guide the pin back to the first hole
3. Do nothing and reach back to locate the pin each time I close the canopy
Anyone gone through this?

[Mark Burns]

Originally Posted by andrew phillips

My canopy has been in the open position for months. Went to try to close it recently andd found that one of the pins now hits outside the hole in the delrin block. The back as expanded on one side. Thinking about the following:
1. trying to push in the one side w/o cracking the plexi
2. drilling another hole in the delrin to guide the pin back to the first hole
3. Do nothing and reach back to locate the pin each time I close the canopy
Anyone gone through this?

Andrew,
Don't do #1.
You'll never be happy with #3.
#2 sounds like a good idea.

The UHMW blocks are cheap, you could make a new one also.
You can also bend the pin a little, I've done it. The angle of the pin will determine how much the rear skirt gets pulled in right at the last bit of travel.

Too much angle and it makes the canopy harder to open though.

You didn't say by how much it misses the hole. The above suggestions will work better if you are less than 1/4" off.

Mark

[Bob Axsom]

If I did any of your proposed fixes I would have to try #1 but there is another way to fix the problem that your #3 should suggest to you. Flare the hole at the entry point in the plastic block to guide the pin into position for proper alignment of the canopy and the fuselage side skin. Both of my blocks have this feature.

Bob Axsom

[DickDe]

I had problems with my RV6 slider at first. At the far aft corners of my side skirts on the canopy I have a piece of angle cut to act as a handle which I use to slide my canopy open or closed. My canopy fit sort of tight at first so I used to push it shut using those handles while actually unknowingly placing side pressure on the canopy which caused it to twist on its tracks as it moved to the fully closed position. The rear pins would miss the pin block and I bent the aluminum pin block holders by forcing the pins between the pin block and its mount. It was pretty easy to do when compounding the problem by latching the hook and twisting the "D" handle to close the canopy at this point.

To fix this problem I cut my guide holes in new pin blocks more funnel shaped and replaced the bent pin block mounts with new straight mounts. I also shimmed with thin washers the center bearing block tighter in its mounting bracket so as to limit side movement. This is the bearing block that rides on the center rail aft on the fuselage. I never had problems when I closed the canopy with the handle which is located on the centerline and I think I was forcing the canopy out of alignment as I pushed it closed. So I now push my canopy closed gently from the rear center of the canopy near the bearing block hinge point in order to limit side loads and I now longer have the problem.

This could be some of your problem as well.

Dick DeCramer
RV6 N500DD
Northfield, MN

[hgerhardt]

How about closing the canopy from the outside by pushing in (or whatever it takes) and then letting the airplane sit in the sun for a few days (or weeks) until the canopy remolds itself back to its original shape?

If you redrill your delrin blocks or even make new ones, the rear skirt will never fit again and you'll have to redo that too. You could, and should, file a bellmouth into the entrances of the holes, if you haven't done that already.

Heinrich Gerhardt
RV-6, slider

[Skyhook]

I left my -4 canopy open on the detent for cooling for about a week and found that the once-smoothly closing was darned near impossible.

This thread has indicated the 'why'.

I have closed (with difficulty) the canopy and let it sit for a few days. Hoping that does it.

[prkaye]

I wonder if this is an argument for leaving the canopy on and closed during the later phases of construction? I was planning on taking mine off to do stuff like landing gear, wiring engine, etc. But I am concerned about gradual relaxing of the bows... from this thread it seems these concerns are well-founded.