Alternate Canopy Latch / Lock Mechanism

[kmacht]

In the 9 years I have been building I have been mulling over different ways to latch / lock the canopy. Although it is probably the simplest method I just never liked sonexs the idea of cutting a slot in the canopy that leaked air and water and having a big old pad lock hanging off the side of the plane when you wanted to secure the canopy. A couple of North East Sonex gatherings ago there were a few planes that flew down from Canada that utilized a plate that slid on bushings to push the canopy latch back and forth. I liked the idea but wanted to come up with something other than bushings as it seemed like getting them adjusted just right so that they slid but didn't have excess play would be a bit of a pain. What I came up with was to use an inexpensive piece of ball bearing drawer slide from home depot as the slide mechanism. This made it so there was no adjustment necessary and the mechanism slid very easily back and forth with almost no looseness. Below is a picture of what I came up with.

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The drawer slide basically got two pieces of angle riveted on to it that capture the feet of the canopy lock bar. There are two custom made stops made out of 0.063 on either side and a set of springs to open the mechanism when it get unlocked.

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You can see from the other side that I made a pin that was bolted to one of the angles so that the pin stuck out of the fuselage and provides a means to move the mechanism back and forth.

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Here it is installed on the plane. Everything was kept nice and short so no part of the mechanism stuck out past the upper longeron. One of my concerns was if it would get in the way of my shoulder but since the mechanism is pretty narrow it seems to stay nice and clear. You can also see in that picture exactly how it grabs the lock bar. It is in the unlocked position in that picture.

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Here it is in the locked position. You can see the bar off the key lock that comes up and holds it there. I have a little more tuning to do on the arm so that it is nice and vertical when in the locked position.

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And here is the picture of what it looks like on the outside. This in in the unlocked position. To lock it you just slide the pin to the left and lock it in place with a key. It is certainly heavier and more complex than the sonex plans method but it met my criteria of being weatherproof and not requiring an additional holes or slots in the canopy.

Keith
#554

[vigilant104]

Keith,
Your design looks interesting, I'm sure it slides very smoothly. I'm not getting the "weatherproof" part--do you coverup the hole for the slide tang?

I used to own a convertible sports car, I never locked it. If someone was going to break in, I would rather buy a new stereo than buy a new stereo AND a new convertible top. I see the lock on my plane as a way to keep an honest person honest, but I know it's no deterrent to a real thief. So, if somebody is going to break in to steal my headset, I'd like them to be able to get in with very little damage to the plane. I'm hoping they cut the soft-as-butter aluminum hasp or the $1.99 padlock rather than bugger up the canopy. But, who knows--you can't count on crooks to be very smart (or considerate).

Thanks for posting your modification!

[fastj22]

The lock on the plane is required by the FAA. The level of security is not specified. Do you really think terrorists will be stopped with a simple canopy lock? And why would they choose a Sonex to deliver WMD?

I too had a convertible sports car in Boston. We used to put a sign in the windshield when parked on the street, "No Radio, car unlocked" just to keep them from cutting the top.

Other than that, I like the proposed latch. Looks better than the hole in the canopy and meets FAA requirements.

[kmacht]

See, thats what happens when you polish somethign on a non-polished plane. The lock mechanism is weather proof. What you see in the picture is a metal plate that slides back and forth with the pin and keeps the slot covered no matter where the pin is in the slot.. It is polished to a shine so in the picture it sort of looks like a giant slotted hole.

As said above, the lock is there just to keep honest people honest or at least to keep a lazy thief out. A few seconds with a drill going into the key lock would have the plane open in no time. Fortunatly I have less than $500 in my panel so there isn't much in there to steal anyways. My intent was just to have something that didn't require another hole cut in the canopy, didn't require a pad lock that can get banged around and chip up the paint and wouldn't leak air or water when flying or tied down. There is nothing wrong with the factory method but this is an experimental aircraft so it lets you put your own touches on things.

Keith

[vigilant104]

See, thats what happens when you polish somethign on a non-polished plane. The lock mechanism is weather proof. What you see in the picture is a metal plate that slides back and forth with the pin and keeps the slot covered no matter where the pin is in the slot.. It is polished to a shine so in the picture it sort of looks like a giant slotted hole.

Ah, got it. Thanks.