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tip up issues

R

rv72004

Well Known Member
At Oshkosh I noticed several tip up canopy issues. Several planes had the alum skin damaged where the plexi slides in behind the skin as it comes down over the roll bar.
I my case, twice the canopy slightly twisted on the way down and the plexi corners scraped the front of the roll bar.
I am thinking of cutting away the pieces of plexi that go in behind the rear/side skin as it closes. What is the take on this? Maybe someone has a better suggestion?
Thanks
 
Canopy Guide

Like a lot of good ideas on my RV-7, this isn't my idea.

A simple guide can be made from Polypropylene, Delrin or Teflon, which will prevent any canopy rash.
See pic below.

When lowering the canopy from the LEFT side the slight twist that develops in the canopy as it is lowered brings the RIGHT side of the canopy inboard, so the guide should be placed to guide the INBOARD side of the Canopy latch into the hole.

I fitted one to both sides, (before I realised only one was needed) but you only need it on the RIGHT side.
Pete.
canopyguideoj4.jpg
 
Thanks Pete,

Tried that but it doesnt really work as the guide will not guide the canopy till it is quite low in its closed position. In this low position you have already broken the corners of the plexi off if you havent been carefull. The problem is that for the canopy to engage the guide, it must be close to the roll bar , and for it to be close it must be low. I noticed damage can occur in two ways;
1] if skew on way down it will contact the roll bar with the corner that normally tucks in when fully closed.
2]If minutely skew as plexi corner enters in behind side skin it can contact the aluminium,thus bending it. The guide does help with this senario.

If the canopy lowered parallel to the roll bar the guide would be excellent.
Maybe being very carefull is the only solution.
Or getting a slider
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?
 
I've got an RV-7 tip-up that I've opened and closed, well, let's see... I'm guessing 3000 times. Here is a "damage report" after 1061 hours of flying:

The back edge of the plexi of the canopy bubble is chafed a bit where it contacts the roll bar. The paint on the roll bar has worn off in spots. I used some strips of UHMW tape in the highest wear spots.

There is some wear in the lower aft corners like you mentioned -- and the paint has worn off along the roll bar where the plexi rubs on its way down.

I have some light wear on the top of the roll bar where the steel handle rests in the "slightly ajar" position.

I have some scratches on the front face of the roll bar where, on rare occasion, I wasn't careful enough to leave the handle perpendicular when placing the canopy "ajar," and the canopy dropped closed...the steel handle end scraping the roll bar on its way down.

In general I'm very careful with the canopy. I have no cracks or broken-off pieces. The canopy corners tuck nicely into the little "slots" formed between the turtle deck skin front ends and the roll bar. I thought I might have to chop off the corners of the canopy like some builders have done, but that proved completely unnecessary. I also thought those little flaps of turtle deck skin which stick up and out would be very prone to catching on clothes or bags and getting pulled/bent out. They have not.

I do NOT have any guides of any sort. I do however have the canopy stiffener kit from Van's (3 pieces that rivet to the front of the frame).

Just wanted to give you a data point on a canopy that has been "operated" literally thousands of times with no major issues. It sounds like you're assuming your canopy will endure some kind of damage if you build it to plans. I don't think that's the case.
 
Solution #2

Jeff's guides look like a Mk II version, as the guide it from moving inboard or outboard. Nice bit of R & D. If yours are't 'Double ' Sided you could try that.

Solution #2, I used when the aircraft returned from the painter's and before the guides where refitted. It works for closing from the outside.

Lower the canopy until you can reach across to the centre of the rear canopy frame, take the weight and release the support from the canopy lift handle. The twist comes out and the canopy should close square and without interference.
Pete.
 
How do you shape the Delrin, Jeff or Pete? Just cut it with a saw and file it like wood? Jeff's guides do look really slick.
 
I need guides

My new freshly painted 7a dinged the RH ear and knocks the paint off the corner, despite the canopy stiffner.

I was probably being in a bit of a hurry during the final fit up of the plane....

Can we say ..."Not happy"

Nothing that a little touch up won't cure though.

Until i make some effective guides I am now VERY careful with the canopy.

Frank, 7a, Sam James cowl, AFP..Gorjus home made paint job! and I still don't know how to post pics
 
I cut mine using a Scroll Saw, belt sanded and then polished them using the Scotch brite wheel turning about 60rpm.

-Jeff
 
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