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  #11  
Old 03-08-2021, 10:05 AM
Ironflight's Avatar
Ironflight Ironflight is offline
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Quote:
Originally Posted by bjdecker View Post
Imagine a scenario in flight where you decide that removing the tip-up canopy and jumping out is your only path to survival; what comes to mind? Busted through the bottom of a loop/split S and the tail came off? Wing folded up? Propeller/Engine departed the airframe?

The dynamics of and forces applied to you and the airframe in these scenarios are going to preclude any reasonable controllable actions by you. Even if you are able to get the aircraft to straight and level, just above Vs0 - what then? Does the canopy detach perfectly and pirouette end-over-end into the slip-stream (or into the tail), or do the struts hang up on one side and make the canopy do stupid things? Oh, did you remember your parachute?

Yes, I have heard of slow flight and I practice it regularly. My head stays attached at 157 MPH (inside of a SHOEI helmet on a 2009 CBR1100RR) -- until it hits or is hit by something other than air.

Ever seen a guillotine in operation? The blade moves at about 11 miles per hour from a 4 ft height...and yes its sharp, about the same thin-ness as the leading edge of the canopy frame.

So for me, the canopy stays attached, all the way to the scene of the crash.
What youíre ignoring is that there are numerous documented cases of canopies inadvertently departing RV-4ís and RV-3ís that didnít take the pilotís heads off....it certainly removed their headsets and glasses though! I donít know of any cases where a side-by-side tip-up canopy has been jettisoned, so thereís no evidence to support exactly what will happen, but in the cases where canopies departed from the other models, no one has suffered so much as a broken neck.

The question of Ēif you remembered your parachuteĒ is superfluous - I canít think of many people who are flying around so spring loaded to jettison their canopy that they would pull the handle and then realize that on that day they didnít have the chute. Putting on a chute is a pretty deliberate act, done for a deliberate reason (like flight testing or planned aerobatics), and as part of that act, you ďarmĒ your brain to jettison a canopy or not. If there is no way to get a canopy or door off, I donít wear a chute BTW.

Now I honestly think that the builder should decide if they want to have the handle installed or not, and I have no dog in that fight - but I certainly would want people making that decision to have actual information and data, and be exposed to both sides of the argument.

Full disclosure - we removed the jettison handle from our RV-6 on the last panel re-do because it was in the way, the airplane has 4,000 hours on it (so we know it is structurally sound), and we rarely if ever do anything more than a barrel roll in the plane. And....I wish we had the handle on those rare occasions where we have to pull the canopy for maintenance.....everything is a trade-off.....

Paul
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  #12  
Old 03-08-2021, 10:10 AM
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bjdecker bjdecker is online now
 
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Quote:
Originally Posted by Ironflight View Post
What you’re ignoring is that there are numerous documented cases of canopies inadvertently departing RV-4’s and RV-3’s
Paul,

Respectfully, I was not ignoring that fact. That's why I changed the subject to include "TIPUP Canopy."

Different dynamics.

Cheers!

B
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  #13  
Old 03-08-2021, 01:02 PM
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longranger longranger is offline
 
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Iím not to the point of installing the panel or canopy on my tip up -7 and havenít decided whether or not to install the jettison mechanism, but I did consciously leave it in the finish kit when I ordered. Iím not crazy about the thought of jettisoning the canopy in flight (at any speed), but I do like the idea of being able to easily remove it for maintenance. I like the idea Iíve seen elsewhere in these forums about installing the jettison handle vertically behind the panel for just that purpose.
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  #14  
Old 03-08-2021, 02:21 PM
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Janekom Janekom is offline
 
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Default It has the wrong name

Personally I think the name given to this small T handle creates the wrong perception. It should not have been called a Jettison handle but rather backup canopy opening handle or similar.

Part of my emergency procedure list on my 7A is to pull the handle as well as to release the two other latches just before landing if one is committed to an off field engine out landing. Your chances of a flip over is really good and it might help you to get out.

Also as mentioned during major work behind the panel like an avionics upgrade. Much easier than removing bolts way up there while on your back under the panel.
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  #15  
Old 03-08-2021, 03:23 PM
abwaldal@gmail.com abwaldal@gmail.com is offline
 
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All arguments aside. If you do NOT put in some sort of canopy release system you will regret it.
I bought an RV-6A that the builder just put pins in and jam nuts.
OK so I'm working on building up a new panel.
You want to know how hard it is to get to those pins and nuts to remove them to remove the canopy. Don't ask me cause you'll get an ear full. Oh wait then I built the system to make it all work. Just plain fun up under the panel with drill shavings falling in your face.
I built the supports for the system and installed a parking brake cable to lock it into place.
I did the same thing on my RV-6. Works great. NO I have never jettisoned the canopy either.
All the other concerns about this and that are mute if you need to get the canopy off so you can spend $35K on you new panel.
And to think the builder saved 1 hour and threw away the parts for WHAT???
I included the pictures of the install. The T-handle cable will be located just to the left of the Dynon HDX panel
My three cents Art
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  #16  
Old 03-08-2021, 04:48 PM
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Mel Mel is online now
 
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Default Just My Opinion......

Quote:
Originally Posted by bjdecker View Post
Yes, I have heard of slow flight and I practice it regularly. My head stays attached at 157 MPH (inside of a SHOEI helmet on a 2009 CBR1100RR) -- until it hits or is hit by something other than air.
Ever seen a guillotine in operation? The blade moves at about 11 miles per hour from a 4 ft height...and yes its sharp, about the same thin-ness as the leading edge of the canopy frame.
So for me, the canopy stays attached, all the way to the scene of the crash.
It is my, somewhat educated opinion, that if the canopy jettison is pulled and the latch opened, the front of the canopy will lift first, pushing against the roll bar, and departing upward as if hinged from the rear. I can't imagine the rear lifting first if the front is released and the especially if the rear safety latch is still latched.

I certainly understand, believe in, and respect, your freedom of not installing the release mechanism, but for me, if I built another RV-6, I would build it exactly as I did 30 years ago with the jettison handle installed.

As far as getting out when on the ground inverted, there is really no difference between the tip-up and the slider. Neither can be opened under these circumstances.
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Last edited by Mel : 03-08-2021 at 04:53 PM.
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