While I mostly agree with Mark and also feel the canopy should be hinged at the front: if you have one already hinged at the side there may be hope and a safer method. I just build a Drongonfly canopy latch that is virtually identical to the Long EZ latch for N47MG. I have a lot of time in Long EZ’s and haven’t ever heard of a canopy opening in flight on one that was latched. There is a safety catch just in case it does come open. If you are still building then for sure go with the forward hinge but if you already have a flying airplane and don’t like what you have look at the Long EZ / Dragonfly type latch.
Victor Taylor Irvington, AL > On Jan 24, 2023, at 9:02 PM, Mark Langford <[email protected]> wrote: > > > On 1/24/2023 7:34 PM, John Gotschall via KRnet wrote: > > Is there a vacuum above a kr canopy in flight that makes it pop up? > ----------------------- > > I've talked to two KR pilots in the last few days who both said they'd > forgotten to latch the canopy and it only opened a few inches in flight. > This is with a forward hinged canopy, so yes there's down pressure on the > front, but the lift at the rear is stronger, at least that's been my > experience. I've forgotten to latch one side of the canopy on two different > KRs, and the unlatched side rises a couple of inches, and other side stays > put. This happens on takeoff, so the speeds are low, and I'm sure it gets > worse with more speed. Problem is, the force is so high that I couldn't > pull it shut to latch it, so I did one circuit at super slow speed and landed > to latch it. > > Joe Horton told me last night that he has deliberately opened his canopy in > flight (also probably at low speed) when a blown oil seal blew so much smoke > into the cockpit he couldn't see where he was going, and again, it only rises > a few inches. > > A side hinged canopy WILL blow off, even on the ground. The first time I > started N891JF without adult supervision, the canopy (which was shut but not > latches) opened so quickly that it broke the limiting strap. was lucky to > catch the cross-brace in time to keep it from being ripped off the plane, and > that was just on startup, not on run-up! I had to fly it home from Omaha > with a C-clamp on that side. That's what happened to John Schaffer (if I > remember correctly), but I'm not sure why the canopy departed in the first > place, as it was latched and he was flying at 8000' or so, is my > recollection. Maybe he'll chime in on that. > > I do recall that Alan Buzza at Perth had his side-hinged canopy open ion > takeoff (don't know if it was unlatched or not) and that it immediately > killed the lift on one side and he crashed near the end of the runway. > > Moral of these stories is don't fly a side-hinged canopy. Directions on how > to fix that are at > > http://www.n56ml.com/n891jf/canopyhinge/ > > Don't worry....you don't need a lathe to build your hinge points. I've got a > lot of hours this thing, so it works. I recently hit 200 mph in it (in a > three second dive) and wasn't worried about the canopy at all. > > Mark Langford > [email protected] > http://www.n56ml.com > Huntsville, AL > > -- > KRnet mailing list > [email protected] > https://list.krnet.org/mailman/listinfo/krnet -- KRnet mailing list [email protected] https://list.krnet.org/mailman/listinfo/krnet
