How to get a tipper off

I was late to the party for a previous post: "In the event of a forced landing, wood or water?", and will not hear much from a question I poisted in that thread so I wanted to re-ask a question here for your feedback.

My experience has been that it is very difficult or unlikely to be able to egress out out of a tipper canopy equipped -4 if you get flipped over on your back. The canopy sill gives you very little room to slide through even though the canopy may be shattered. I have often thought that I would like try to get the canopy off if I was forced to land in a field (I would leave it on if going into trees for some protection).

What do you all think of that idea?
How would you get the canopy off?
And now for the question that someone must have some experience with: what happens if you do open the canopy at speed (85K.)? Would it tear off and hit the vertical stab? Hang up on the hinges and beat the airplane to smithereens before landing?
Thanks

Hack said:

How would you get the canopy off?

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Me??? no idea at all.

Mythbusters would use C4

Hack said:

And now for the question that someone must have some experience with: what happens if you do open the canopy at speed (85K.)? Would it tear off and hit the vertical stab? Hang up on the hinges and beat the airplane to smithereens before landing?
Thanks

Click to expand...

I know a guy here who noticed that his RV-4 canopy was not securely latched on a flight some time back. It departed before he could get it relatched. It made a smooth departure and did not hit the tail. The wind in his face made it difficult to return to the airport and make a safe landing, but he managed it. He had noted where the incident happened, drove to the field, recovered the canopy and frame, and rebuilt the frame with a new canopy.

I don't know how fast he was going when it left but did get the impression that it was in straight and level flight.

Dave

I've read here about someone losing their canopy in a -4... Maybe it was the guy Dave knew. If I recall correctly, there's something about the piano hinge installation that is "designed" to break away. An aluminum hinge, softer rivets, something.

If so, it should "tear" free due to the aerodynamic forces of being flung open in flight. At which point you'll want to joint the debate on why some people wear a military style helmet when flying an RV... That visor would be really nice to have.

-4 canopy

I also have a friend who's canopy departed in flight. In his words it departed "explosively". The blast of wind took his hat, glasses and every loose thing in the cockpit. I don't believe it hit the tail and he landed safely. It popped open at cruise speed. Not sure how fast you need to be going for a clean break. good question for Van.

It doesn't take much force, on a -4 when the specified pop rivets are used to secure the hinge. I was working on the 1st -4 I owned, modifying the 'stop' link, & let it go just far enough to exceed the normal travel of the hinge. It instantly unzipped the 1st 3 or 4 rivets at the front of the hinge. It *is* a design feature (info from Van's at the time), but they didn't discuss the effects of using a gas strut as the stop link. I don't know, but I suspect that the back seater would get beat up pretty good before the 3/16" bolt tore out of the frame.

I also wonder about the sbs tipup models, now that gas struts are standard....

Charlie

It can even happen on the ground...

I have a friend with an RV4 who was going to do a run up, and failed to latch the canopy. He had a hybrid taxi position latch that didn't capture securely. He glanced down to power up and the canopy departed cleanly. Ripped the pop rivets right out (as they're designed to do)

The canopy missed the vertical fin, and landed in the grass behind the plane. Did nothing more than put a couple of small scratches on the canopy. He replaced the hinge and all was well...

Tom