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Canopy Jettison Handle for a tip up?

Is the Canopy Jettison "T" Handle necessary in an RV-7 tip-up?

  • Yes

    Votes: 13 22.8%
  • No

    Votes: 44 77.2%

  • Total voters
    57
  • Poll closed .

JPalese

Well Known Member
Due to a miscommunication, the instrument panel I had cut for my RV-7 tip-up does not have room for the Jettison "T" handle.

I have heard all kinds of things including - not needed - the canopy can't be jettisoned due to the new improved gas shock struts and it will take off your head if jettisoned in flight.

All comments and observations are welcome.
 
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Jettison canopy

I put my jettison Handel behind the panel
on the sub panel. I have an air gizmo for my
GPS pressure fit on the panel that can be removed
to get to the Handel. What I have read regarding
this subject is when flying with a chute, remove or dis attach
the gas struts. The tip up should easily depart the plane.
Also I have read to step on the yoke forward while ejecting
Forcing the plane into a dive. One should clear the vertical stab.
If it's still on the plane.
 
Well, I have the same thing happen, and with instruments etc there was not room for the mechanism as designed. I have extended the torsion tube down below the lower edge of the sub panel and fashioned a lower pivot for the tube and can now locate the handle . . . well . . somewhere else. Honestly, I have no clear plan for how it will end up, nor any intention of slotting the upper skin for the release of the hinge.

Except in Phase I , I am not feeling the need for a jettison capability nor chute. As a worst case, it will be able to pull the pins and service the canopy will little under panel pain.

I am eager to read the answers but in typical fashion would expect the average to be neutral with no clear conclusion.
 
I am facing the same question. Another suggestion I have heard is to use the passenger side stick to break out the canopy. Not too sure how tough that would be to bust out of in a really bad situation with very limited time. I would need an hour or two for that myself... A shotgun rather than a short metal tube would probably be a little more efficient at knocking the canopy out in a panicked hurry although I'd probably shoot myself in the process.

I'm leaning to forego the canopy jettison because as I currently see it....

A) It has not been tested/used successfully to my knowledge.

B)After phase 1 when you re-install the gas struts, the jettison handle appears as useless/impractical to me. Removing the gas struts for phase 1 also makes me wonder how easy it would be to egress during an on ground fire, etc. Can anyone discuss the handling forces involved on a canopy without the gas struts? Is this an easy one man job to get out from under it?

C) I look at the majority of issues being engine outs rather than uncontrollable flight or inflight breakup. The terrain in which I live provides a lot of landing options although I'd prefer to have several square miles of smooth manicured concrete in all directions below me. :eek:)

D) I'll perform careful weight and balance calculations, preflights, etc and do everything I can to minimize the chances for an emergency including adequate transition training in a 7A.

E) I'll say a prayer before every flight. If it goes bad after that, you know the rest of the story. :eek:)

Okay, the above is a bunch of my hot air. This is just my opinion of things as I currently see it and nothing more. I am always open to wisdom and will stand corrected if it makes sense to me.

I do have a serious follow up question because I honestly do not know the answer. Has anyone ever had to bail out of an RV-7/7A tip up while in flight? If so, were they successful in doing it?
 
Just one man's opinion...

Forgoing a release mechanism that offers a few benefits at very little weight penalty seems foolhardy. If you don't have room for the bar to come straight aft through the panel, consider making a release that instead exits vertically towards the bottom of the instrument stack, and can be operated by rotating a shaft instead of pulling on a handle.

It'll be harder to operate in flight, probably, due to the aerodynamic loads, but even if you really don't think it's going to work in flight or you don't think you'll ever need it, then at least you may have the option if the unthinkable happens.

Apart from emergencies, being able to remove the canopy can be handy if you want to work behind the panel, move the aircraft around with the cockpit open, etc. There are a few reasons you might want it. It'll be a lot easier if you have a convenient way to actuate those pins, rather than diving under the panel, and hoping you can reach back up to both sides of a couple of bolts instead.

When I bought my -6, it had the release mechanism installed, but no handle to the panel or below. The short actuator on the pins was safetied to one of the ribs behind the panel. I bought the T-handled actuator from Van's, and installed it in the panel. And then 6 months later needed it, when the canopy frame cracked due to poor aluminum welding at the factory... It was a lot easier to remove and re-install that canopy with the release handle. I even re-installed it solo.

The gas struts won't prohibit release in flight, btw... If you use the recommended cylinders, the heads are plastic, and "pop" on and off with a sharp tug. In flight, I suspect they'd release quite easily.
 
Canopy release

I too have been studying the different option to have my canopy "removable." On my instrument panel the center stack prohibited a release handle in the center. Also I don't want to secure a bracket under the dash to fumble around with in case of a "emergency". I have been thinking of a possible install of a cable type release similar to a Bowden cable. If anything happens where in need to escape from my plane in flight I don't care if it takes the tail off with the struts included. I'm on the way out anyhow. I'm not expecting to egress during flight nor do I currently own or am trained with a parachute. No other plane I have flown has problems where I thought I needed to jump...not planning on it anyhow. If I install a removable canopy (still on the fence) it will be where it would be accessible easily during flight.
 
I've been flying my -6 for almost 21 years.
Originally there were no struts. I have never installed, or had any incentive to install the struts. To me, they are in the way when entering and exiting the aircraft. Obviously I've never had to jettison the canopy in flight and hope I never do. I have, however, removed it several times during maintenance. This option is great. If I built a new SBS RV today, I would build the canopy mechanism just like the original.
 
I did not install the canopy jettison mechanism on my RV-7 but I wish I had. As Snowflake said, it gives you an additional option at very little weight penalty. No real good reason not to install it.
 
If my knowledge of earlier RV design is correct, one of the features that went along with the release mechanism was two slots in the boot cowl right above the hinges. These allow the hinges to come out vertically after release of the pins. While some may have it, I have never seen an RV with those slots since they are an obvious leak path. Mine does not.

Without this feature, I question the in-flight viability of the hinge release mechanism. The rear of the canopy would have to lift a considerable amount before the hinges would come out. With the gas springs in place, I think the front of the canopy would strike the passengers.

I did install a modified version of the hinge release for maintenance purposes. It is not the one commonly done below the panel. I brought mine rearward through the subpanel (there IS room) so I can reach it while holding the canopy.

Early construction pics of release mechanism The basics are there but at this point I had not added a short handle extension and non insulated adel and screw to fasten the handle in locked position
 
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Then you haven't seen mine. I do have the slots. They are covered with the same white tape that the glider guys use to seal wing root and other seams.
They DO NOT leak. I do have to replace the tape about every 4-5 years.
 
Nope. Some day I hope to Mel.

I thought I remembered you saying you had the slots. Was not sure if you had used sail tape or aluminum tape on them.
 
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Where to put handle

I installed the handle as stated in the Van's publication. My only thought was during Phase 1 or if I ever had to ditch I would get rid of the canopy in an emergency.

I have read a couple of ditchings in RV's and regardless of canopy design, almost impossible to break or open with the external water pressure keeping the canopy from opening. If I am in this situation... I am going down anyway... lets make it easier to exit the plane if I survive. I have hit the water at 60 mph water skiing and bounced along like a stone... abit a lot younger....
 
If my knowledge of earlier RV design is correct, one of the features that went along with the release mechanism was two slots in the boot cowl right above the hinges. These allow the hinges to come out vertically after release of the pins. While some may have it, I have never seen an RV with those slots since they are an obvious leak path. Mine does not.

I think the earlier tip-up -6's had a different shape to their hinge arms as well. They were straighter and when the canopy raises the arm needed that slot to allow the arm to move. The plans asked for a longer slot, as you say, to allow vertical departure if needed, but many didn't extend the slot any longer than needed to avoid leaks.

The newer RV's (mine is a '96 but has the newer design) have hook-shaped hinge arms that curl under the top skin and don't require any slots. There is concern that these hooks wouldn't easily extract from the fuselage in the event of an in-flight jettison. That may be a valid concern, I hope it never falls on anyone to be the first one to find out first-hand.

As for the pistons, as I mentioned they do pop off with little strength required when the canopy is open. With the adrenaline of an emergency where you need it removed, you may not have much trouble disconnecting them with a couple of sharp tugs before you release the hinge pins. That, at least, is something an owner could test on the ground. Caution: There's a lot of pressure in those pistons, and they will extend when released. Keep body parts clear.
 
I think the earlier tip-up -6's had a different shape to their hinge arms as well. They were straighter and when the canopy raises the arm needed that slot to allow the arm to move. The plans asked for a longer slot, as you say, to allow vertical departure if needed, but many didn't extend the slot any longer than needed to avoid leaks.

This is the VERY early kits. My empennage kit was bought in 1989. When I ordered my finish kit in 1991 it came with the old straight hinges, but before I got it installed, the newer "hook" style hinges came out and they were sent to me. It was still recommended to cut the slots for the jettison feature. The slots are covered with white tape to prevent leaks. Unless you know the slots are there, you will not notice them.
 
Mine have AN bolts, couldn't see the need for a jettison in a non aerobatiic rv9 and have doubts as to whether the jettisoned canopy would take out the tail. With no parachute, I can't see where it would help.
 
Jettison Handle

:)I checked with a guru or two and the consensus was that the handle was not used. I was also told that removing and replacing the canopy can be a "bear". I retained the locking pins per plan and simply relocated the release "rod" so as to ease R&R
 
IAC want jettison system for aerobatic competitions on tip up canopies.

A recent discussion from IAC tech inspectors seems to show they want a quick release mechanism for tip up canopies to be elligable to compete at IAC aerobatic competitions.
I am glad I fitted one to my RV7 but I was also disappointed with the original design that had the release lever in the middle of the radio panel.
What I did was move the standard Vans release mechanism and pull handle about 2 inches to the right so it comes out of the instrument panel 3/4 of an inch to the right of radio stack. Being able to easily remove canopy has been a great help.
 
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