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-   -   Poll: Do you have a canopy release/ejection mechanism? (https://vansairforce.net/community/showthread.php?t=143832)

BillL 11-18-2016 03:05 PM

Quote:

Originally Posted by ChiefPilot (Post 1127701)
On the other hand, if you *ever* want to participate in a sanctioned IAC event you need a quick release canopy. The aircraft won't pass a tech inspection without it and that means it wouldn't be eligible to fly in such an event.

Modifying a slider can be as simple as replacing two bolts with two pip pins or similar. The tip-up is designed to be jettison-able but many builders opt to leave this out for various reasons.

For a slider, I see no downsides to making it jettison-able and mine has been that way from the start. I do wear a chute when doing aerobatics.

Is there a reference to what is acceptable? i.e where it should be located? The 7 tipper could use either a linkage or a cable if the location has to be specific. If the same style linkage is used (but extended downward) a handle could be located under the throttle/prop/mix locations.

ronschreck 11-18-2016 03:57 PM

Quote:

Originally Posted by BillL (Post 1127811)
Is there a reference to what is acceptable? i.e where it should be located? The 7 tipper could use either a linkage or a cable if the location has to be specific. If the same style linkage is used (but extended downward) a handle could be located under the throttle/prop/mix locations.

IAC Official Cintest Rules:
2.2(j) If the canopy, or door for cabin-type aircraft, is hinged on the forward (leading) edge, it
must incorporate a quick-release mechanism to facilitate emergency egress.

Van's design is all you need. You may modify to relocate the handle as long as you can reach it while strapped in.

scsmith 11-18-2016 05:25 PM

Quote:

Originally Posted by Ron RV8 (Post 1127719)
A fair bit of my flying is over water...

I installed pip pins in the forward canopy attach points of the -8, primarily to jettison the canopy should I have to ditch. My feeling is that the aircraft would most likely flip inverted at touchdown, and that the canopy would most likely not be openable inverted in water due to the pressure.

Hard to say whether the airplane will be controllable after jettison, if the canopy frame hits the fin, which it most likely will on an -8.

The ideal thing for ditching would be to be able to slide it half way back and lock it. I think it might have been Jon Thocker that experimented with sliding the canopy open in flight. He found the stock fuselage construction lacks support for the track between the bulkheads and the flex of the track makes it hard to slide the canopy. Adding a partial bulkhead in the right spot may be a huge help. Search for his posts in the archives.

Bill Boyd 11-18-2016 06:42 PM

Regs are regs
 
but you will never get an unmodified -6 tipper (likely true of a -7 but I'm not sure) open enough in flight to egress the plane or to jettison the canopy. Requires slotting the forward skin over the hinges in a manner not to plans, or slowing down to maybe 15 mph.

(... so I guess you could do it in a hammerhead if you timed things perfectly.)

Since parachuting from the plane is a necessary capability for flying in sanctioned acro events, it seems to me a plans-built tipper should be excluded from entering without a demonstrated ability to accomplish this (no matter where your yellow and black handle is located). And I'd love to see how it's done, so I could shed my canopy if facing a water ditching :)

ronschreck 11-18-2016 07:24 PM

Quote:

Originally Posted by Bill Boyd (Post 1127863)
but you will never get an unmodified -6 tipper (likely true of a -7 but I'm not sure) open enough in flight to egress the plane or to jettison the canopy. Requires slotting the forward skin over the hinges in a manner not to plans, or slowing down to maybe 15 mph.

(... so I guess you could do it in a hammerhead if you timed things perfectly.)

Since parachuting from the plane is a necessary capability for flying in sanctioned acro events, it seems to me a plans-built tipper should be excluded from entering without a demonstrated ability to accomplish this (no matter where your yellow and black handle is located). And I'd love to see how it's done, so I could shed my canopy if facing a water ditching :)

All true. James Clark and I were making plans to demonstrate (on the ground) how far one needed to lift the canopy before the hinges released when we were informed by the IAC that any -6/7 with Van's canopy release mechanism would satisfy the IAC. No one knows how the 6/7 canopy will jettison in an uncontrolled situation and that can also be said for other aerobatic airplanes.

Mel 11-18-2016 07:41 PM

Original design of the RV-6 canopy was truly jettisonable.
 
Quote:

Originally Posted by Bill Boyd (Post 1127863)
but you will never get an unmodified -6 tipper (likely true of a -7 but I'm not sure) open enough in flight to egress the plane or to jettison the canopy. Requires slotting the forward skin over the hinges in a manner not to plans, or slowing down to maybe 15 mph.

Oh, but this WAS in the original plans. Mine has been this way for almost 24 years. I hope to never need this option in the air, but if I do, I have it!
The slots are covered with white tape, and no one has ever noticed unless I point it out.

vlittle 11-18-2016 07:52 PM

Quote:

Originally Posted by Ron RV8 (Post 1127719)
A fair bit of my flying is over water...

I installed pip pins in the forward canopy attach points of the -8, primarily to jettison the canopy should I have to ditch. My feeling is that the aircraft would most likely flip inverted at touchdown, and that the canopy would most likely not be openable inverted in water due to the pressure.

There is a video of an RV slider ditching in shallow water. The pilot slid the canopy back prior to touchdown, but the impact slammed it shut and he ended up inverted. He was rescued by people on the beach. Better to eject the canopy first, but it may take the tail with it.

BillL 11-18-2016 09:04 PM

Quote:

Originally Posted by ronschreck (Post 1127868)
All true. James Clark and I were making plans to demonstrate (on the ground) how far one needed to lift the canopy before the hinges released when we were informed by the IAC that any -6/7 with Van's canopy release mechanism would satisfy the IAC. No one knows how the 6/7 canopy will jettison in an uncontrolled situation and that can also be said for other aerobatic airplanes.

It might not be good to try and release a tip-up without the slot in flight. It can not go straight back. With the glare shield at head level, it would seem safer if it pivoted on the back (at the upper latch) so the front lifts and goes away leaving my head intact. I don't know any of this for a fact, but I did sit and stare at that sharp edged glare shield on day.

Is there a release procedure- like release the pins - then release the latch, then release the belts?

rmarshall234 11-18-2016 11:06 PM

Quote:

Originally Posted by scsmith (Post 1127846)
Hard to say whether the airplane will be controllable after jettison, if the canopy frame hits the fin, which it most likely will on an -8.

I wouldn't be too concerned about the canopy taking out the fin. That part of the structure is pretty stout and remember, when the canopy is jettisoned it is going the same speed as the fin. How much can it decelerate relative to the fin in that short distance? At worse, I think it would be a glancing blow.

Mel 11-19-2016 06:16 AM

Quote:

Originally Posted by rmarshall234 (Post 1127898)
I wouldn't be too concerned about the canopy taking out the fin. That part of the structure is pretty stout and remember, when the canopy is jettisoned it is going the same speed as the fin. How much can it decelerate relative to the fin in that short distance? At worse, I think it would be a glancing blow.

That canopy is like a light weight sail. Once it leaves the aircraft, it will "stop" forward motion almost immediately. The tail is secured to the airframe. It will NOT decelerate quickly. I would expect substantial damage.


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