Thorp Air Command - T18.net

What do you think about this latching system? There are one of these latches on both sides of the canopy. Do yall think this is a sufficient latching system, or is a latch at the top of the canopy absolutely necessary? Its not finished to look nice just yet, so forgive the rough look.

You only need one latch at the top of the canopy. Other latches will only serve to trap you in in the event of a mishap. A horizontal pin at the front of each canopy rail fitting into the rollover bar will keep the canopy from lifting. My canopy has six hold downs and one latch at the top for a total of seven points holding the canopy down when closed. One quick release of the top latch and sliding the canopy back 1" releases all.

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Bob Highley
N711SH
SN 835
KLAL

I agree with Bob . A single latch at the top is all you need . I did the Thorp latch as it has a handle on the outside should "Squad 51" need to pull my sorry ass out of the AC . With the single latch and the canopy frame "pins" that slide under the fus. deck rails , the canopy is not going anywhere . Other folks use a single inside over center type latch on the top of the canopy , but then again there is no way to open the canopy from the outside with it latched . The Thorp latch is not that hard to make and works very well .

RB

I agree with you both, but my airplane doesnt have a latch at the top, so I am trying to come up with an extremely simple latching system where I will not need to fabricate the standard Thorp latch. I think if I install the standard Thorp latch, I will have to drill through my canopy, and I dont want to do that if I can help it.

You can get an over center latch from McMasterCarr (or other vendors) that will attach to the canopy frame and then to the windshield frame with no drilling of the glass . Probably less than $10.00 for the latch . There are many examples of this type latch in the NL's . You need to keep the escape plan simple with regard to the latch/latches . A single release fits the bill .

RB

Hi Ryan, I hate working with Plexy also, The single latch at the top I agree is probably the wisest choice, but I too opted for the latches on each side. Gotem from McMaster Carr about 5bucks apiece, they will hold 400#. Just a bit overkill but they are very functional. It is a very simple install and all but weightless. Tom Hunter had a slick canopy latch that opens from the outside with a Allen wrench, but then Toms bird was like Riches bird, exceptional to say the least.............Dan

Yes, the single latch at the top is the best, but the roll bar and canopy frame are 2 different diameters and creates an angle that puts a twisting stress on any latch I install there. So, thats why I started looking at the canopy latches on the sides.

Go WAY back to some early posts about the latch . I think Lee uses the Coleman cooler latch ? I think that's the latch CSA sells ? In fact I think it is in Phil Tuckers catalog ? If you are worried about differences in tube dia. shim up the low side on the canopy frame . Most over center latches can be adjusted to compensate for the difference .

RB

I think I got my latch issue resolved. Gonna go to the hangar today for a test fit. Rich, I never thought of CSA for a latch. Good idea. But, I haven't heard of a catalog put out by Phil Tucker. Is it on the Internet, or do you subscribe?

Phil Tucker and Ken Knowles were T18/S-18 vendors which is now CSA . Sorry for the confusion .

RB

OK, so here are two pictures of my unfinished latch. I have an AN3 bolt on both the roll bar and the canopy rail. I believe the canopy rail is too thin for only a bolt (I think the bolt would pull out), so I will put a rivnut in there. If the rivnut were to be pulled out of the canopy rail during flight, I think I would have exceeded Vne. Thoughts and comments?

The rivnuts in the photo are something the previous owner installed.

Not sure if you are getting a positive closing of the canopy . By that I mean a tight seal to keep out the rain/wind . I still think an over center latch like John Kerr uses would be a better option . I know others have used a similar type over center latch from the NL write ups . The over center will pull the canopy forward against the canopy seal . The latch does not need to big as wind forces tend to push the canopy forward and down .

RB

You only need one over center latch at the center of the canopy where it mates with the wind shield it's almost impossible to open the canopy in flight, go with the over center latch it's easy to install .
Tom Carnett 393TC

I guess I should just go with an over the center latch

Ryan: I can ask John Kerr what type of over center latch he has ? It is simple and "Sweet !" He thinks I am sweet , but that's another topic ! Bada Bing , Bada Boom !

RB