81JM has had cheap suitcase latches, like these but not as good, and a side hinged canopy for thirty years. Never a problem except when I forgot to latch. The canopy lifted a few inches at beginning of takeoff roll. I aborted, latched the canopy, and resumed takeoff. Most remarkably, my passenger was still game.
On Fri, Jan 27, 2023, 7:29 AM Mark Langford <[email protected]> wrote: > John Gotschal wrote: > >>All planes I have own and flown has this happen, the hatch, door, > latch finds a way to open on it's own. 2 certified, 1 experimental. I > have often carried a bungee to hold it from unlatching.<< > -------------- > John, > On N56ML, I installed simple "suitcase latches", one on each side of > the front hinged canopy, midway along the canopy frame. N891JF had > some installed by Jim Faughn, and I later added some similar ones to > N891CJ. Enclosed is a photo of the ones I used on N56ML, as well as a > source, Pegasus Racing. The ones on N56ML are from McMaster Carr and > "not rated" for strength, but I suspect that's only because people > building suitcases are not terribly concerned about the force needed to > pry one open, as the suitcase would fail first. The Pegasus folks do > rate theirs at 350 pounds (each!), given the lift on racing car hoods > are other removable panels. Both are steel and of substantial > construction. Note that there is a a "secondary" catch, a button that > you have to slide up in order to flip the release lever down. This > prevents inadvertent opening of the latch. This sounds obnoxious, but > it quickly becomes second nature once you've operated it a few times. > > These are easily retrofitted to most KRs, but the key is to ensure that > you are fastening the latch to something substantial inside, which is > pretty easy....a wooden block epoxied below the top longeron, with > countersunk screws all the way from the outside to the inside of the > plane through the block, with a nut on the inside of the block. > > Obviously, the hook's connection to the canopy has to be strong as > well, so multiple layers of fiberglass or carbon fiber spread over a > significant area both inside and outside will get you there, assuming > your canopy frame is reasonably strong to start with....and again, with > screws all the way from outside to inside. > > Another option is the "draw latch", available from McMaster Carr. Joe > Horton used something similar on N357CJ, but I wasn't physically strong > enough to tighten them up fully, so I swapped in the easier version that > I used on N56ML. That option is enclosed also....often used on windows > as locks. They go "over center", but no secondary latch. The McMaster > version is rated "light duty", so again, not rated for pull strength. > > See enclosed photo and sources..... > > Mark Langford > [email protected] > http://www.n56ml.com > Huntsville, AL > > -- > KRnet mailing list > [email protected] > https://list.krnet.org/mailman/listinfo/krnet >
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