Yes, look at your canopy. The top is the shape of your wing top
airfoil surface, and it produces lift. Vibration is what caused mine
to open, but I now have an entirely different latch mechanism. The
aircraft structure did not fail, nor did my latch, it just vibrated to
the unlock position.
-----------------------------------------From: "Mark Langford"
To: krnet@list.krnet.org
Cc:
Sent: Tuesday January 24 2023 9:02:15PM
Subject: Re: KRnet> Canopy failure question
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
m...@n56ml.com
http://www.n56ml.com [1]
Huntsville, AL
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Links:
------
[1] http://www.n56ml.com
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