Paul Eastham

Paul Eastham

Well Known Member
Hi,
With regards to the center canopy handle -- the one that mounts at the top center of the canopy frame:

Is it intended to be a primary locking mechanism for the canopy in flight? The way I have it set up right now, it spins freely when the canopy is closed. It doesn't press against the roll bar like the manual implies it should. I wouldn't trust it to stay in the "locked" position on it's own -- I assumed the two side latch fingers would be sufficient to keep the canopy closed.

Do you guys use that center handle for locking anyway, or do you trust the side latches?
 
Paul Eastham said:
Hi,
With regards to the center canopy handle -- the one that mounts at the top center of the canopy frame:

Is it intended to be a primary locking mechanism for the canopy in flight? The way I have it set up right now, it spins freely when the canopy is closed. It doesn't press against the roll bar like the manual implies it should. ...
Click to expand...
I consider it a backup latch. I had the primary latch malfunction once, under high g loads, and the center latch worked to keep the canopy near closed (mine doesn't contact the rollbar either).

I wouldn't want to not have it functional and would suggest drilling a new mounting block a bit smaller.
 
n5lp said:
I consider it a backup latch. I had the primary latch malfunction once, under high g loads, and the center latch worked to keep the canopy near closed (mine doesn't contact the rollbar either).

I wouldn't want to not have it functional and would suggest drilling a new mounting block a bit smaller.
Click to expand...

It sounds like we have similar installations then -- it's functional to lock the canopy, but it spins very freely since it doesn't contact the rollbar -- so I wouldn't be shocked if it unlocked itself due to in-flight vibration or whatever.

I guess you are saying that if the hole for the handle were smaller it wouldn't rotate so freely. That's an interesting idea, though I think the bushing block came predrilled...
 
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Mine spins "freely" (the friction against the bottom of the roll bar is reduced) once the canopy is pulled down tightly by the MAIN LATCHES. If your main latches release under G, then imho they haven't been adjusted properly to go "over center."

Personally, I don't even see that center handle as a backup. Imho its only purpose is to provide something to grab when opening the canopy from inside, and to provide something to let the canopy rest on the roll bar in the ajar position.
 
Trim Block

Paul,

Excellent question...I am at the exact same point. My thought was to trim the bottom of the umhw block to "move up" the handle so that it offers some catchs on the roll frame. Mine looks like it will spin freely as well.

Scott
7A Finishing
 
I use the handle only to hold the canopy open & keep cool during taxi. Also to open & close the canopy. Works well to pull the canopy closed when you take off with it unlatched :)

BTW - I recommend you attempt flying with the tip-up canopy unlatched and let it open. It will take away any fear you may have if this happens during flight. When it opens it will come up about 4 inches. FLY THE PLANE. Get to altitude and trim for flight. Simply slow to about 100 MPH then pull it down with your right hand and latch with the left. Done, no big deal.
 
use UHMW tape

I used some UHMW tape on the latch where it touches the bottom of the rollbar to add some friction. It will also keep the paint from rubbing (as bad) as without the tape.
 
Me too.

I added a piece of UHMW like Clay, but I also added a second piece on the underside of the latch so it doesn't scratch the top of the roll bar if you use it to hold the canopy ajar.

However, I no longer use th e latch to hold the canopy ajar. Instead I carry a high density foam sanding block about 2" x 2" x 6" and put it on the canopy rail and lower the canopy on to it. For wt fanatics it weights about 2oz.
Pete.
 
I did not like the design of the safety latch either -- so I changed it. I was concerned that it could actually spin to a partial latch with me on the outside!!!! So I did the following:
1. I trashed the original attach block
2. I made a new attach block from white UHMW plastic which is wide and short vs tall and narrow like the original part.
3. I drilled it for the safety handle shaft and mounted a small compression spring (your friendly Lowe's Aircraft supply) to the top of the shaft above the attach block.

Now you must pull down on the handle and turn to latch and the spring keeps tension against the bottom surface of the roll bar. It is also impossible for the handle to spin or accidently latch when not in use since it is actually above the bottom surface due to the spring action. At this point even experienced RV builders do not notice it as looking any different.

I will post a pic if anyone is interested---100 hrs on the plane now and no spin or movement in flight.

Cheers,

db
 
I can add here, just finished this work last week.

Mine catches and locks perfectly. I put some UHMW tape on top and bottom, to protect paint in both locked and 'taxi' configuration. Mine does not spin through 360 degrees, since the cotter pin heads prevents it from a full rotation.

Looking at the assemble close up I think you can move the handle up slightly.
- The handle shaft base has welding around it preventing to sit flush on the plastic block. Remove a little material around the bottom of the plastic block base, almost like countersinking it to fit the welding.
- Then shimming the top with another washer under the existing cotter pin and washer, will move the handle a fraction higher.

I hope it works for you. Better try it before going through all the trouble of making a new block and assembly.

Regards, Rudi
 
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Change it or you will be sorry

My original installation also spun freely. I did not give in much thought until I wheeled the fuselage out of the garage and the handle rotated in the locked position and I was locked out!! :eek: Fortunately the boot cowl was not riveted and the wings were not attached, so I could get in with, you guessed it, a clothes hanger.

If the plane had been together, my best option would have been going up through the flap holes. It the flaps had been up, well I don?t want to think about it.

I hosed my UHMV block when cobbling up a mod to prevent the free spinning. The new replacement block takes a lot of rotation force to overcome the friction. In short, not all of these blocks are created equal. Good luck.
 
I suggest that you include an EXTERIOR handle (and brief user instructions) on the latch at the aft top end of the canopy. It would be nice if your externally-located rescuers could open the latch and canopy in an emergency without your interior assistance.

Also, using the latch to hold the canopy partially open during taxi appears to put a lot of twisting strain on the canopy's rear bow and latch -- particularly during a long bumpy taxi over rough surfaces -- not too good a thing in my opinion.

I've also had the wind inadvertently blow my tilt-up canopy closed from its upright position (dual gas-shock equipped) -- again, not a good thing if you have someone's fingers gripping the cockpit coaming at the time. The slamming shut canopy will also likely bend your attachment mechanism and could cause a plexiglas crack -- be careful out there.
 
I will be at the hangar tomorrow--will take a couple of pics and post tomorrow night.

BTW, the new uhmw block took all of 15 minutes to make--this is certainly not a difficult mod and it does fix a potential problem---permanently.

Cheers,

Dave B.
San Antonio, Tx
RV9a/ECI 0360/James Cowl/Catto prop-100 hrs and a permanent smile!
 
Clayton,

Attached is a pic of the tip up safety latch mod on my RV9a. The pic shows with the latch "open". Notice in the opened pic that the handle is parallel with the roll bar and slightly high--it cannot inadvertently latch.
my.php
[/URL][/IMG] You simply pull down and turn to engage the latch. As you can see the unit has a new wider and shorter mounting block (UHMW plastic), a Lowe's or Ace Hardware compression spring, and a washer/cotter pin to secure. The L shaped piece of aluminum was probably overkill but I mounted it between the block and the roll bar (bent over the top of the spring assembly) to take the hit in the unlikely event the cotter pin let go--I did not want the plexi to take the hit. The mod works as expected.

Click on the pic for a larger shot.

Hope this helps.

Cheers,

Dave B.
San Antonio
RV9a/ECI 0360/James Cowl/Catto Prop-100 hrs and a permanent smile
 
Nice, clean installation, Dave! I'm afraid I must shamelessly copy your design... :)
 
Hi Dave,

That is a good design improvement, wish I had know it a week ago, just finished mine, not wanting to go back to change now.

Regards
Rudi
 
Quick story - A friend (not me) with a tail dragger tipup had a situation where the aircraft was buffeted on the ground by winds. The freely rotating locking handle worked itself into the locked position with nobody inside. Big problem.
I drilled and tapped an 8-32 hole at right angles to the shaft, inserted a small nylon plug and screw to apply rotational friction the handle. Works great. Pics if desired.
 
Thanks to everyone for their input on this issue. I will definitely change something, though I'm not sure which of these good ideas to use/steal...
 
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