"Questions for the latch designers:
Will the secondary latch engage automatically on
closing the canopy?
If not then you're adding to the checklist.
"How far will you have to close the canopy for the
secondary latch to engage?
I see limited efficacy if you have to close it farther
than the point
People prop open their canopy for ground ventilation.
""Will the secondary latch be operated by the
primary lock handle?
This would be ideal.
Can the secondary latch be released from outside
the cockpit and will its
Operation be obvious?
In my mind, the answers to these questions are
critical. I won't use a
Latch that doesn't allow immediate and obvious ingress
in an emergency."
These requirements and more were on the initial
requirements list. Working with a small team, John
Smith has compiled about 25 different ideas and
variants. Most focus on requirements first, then
simplicity, then means of attachment. General
approach:
- Latch is on top of canopy with simple striker
plate on fuselage arch
- It latches while the canopy is still open
a bit but latches into place when you release canopy
you are holding open with your hand.
- Pilot or copilot applies single upward motion to
lift canopy at center with upward facing palm of
hand applied to a small forward facing lever that
disengages latch when you push up. So getting out is
1) release main latch and 2) reach up, push up on
canopy at center which means your palm will push up
on the internal lever, and canopy opens.
- A penetration through the arch to the outside
engages a flush or nearly flush lever outside on
top that can be pulled up from outside. Rescuer
approaches plane, side latch is released, canopy can
be raised an inch or two, hits secondary latch, but
external lever is clearly visible to untrained
outsider who can immediately detect what is still
holding the canopy from further motion, sees the
lever, pulls up on lever, canopy does its final
release and swings upward. Think of it as similar
to a hood latch that has its release on the top
surface of the hood.
Other requirements (must haves) and desires (nice
to have) welcome. John is a very busy boy, on the
road a lot, so I am providing first response, but he
is the leader of the team working this problem in
Australia. Current questions focus on attachment
methods to canopy and fuselage arch, and have been
submitted to Lancair. With some guidance on approved
attachment methods and locations, we can narrow the
options and present to this group for review.
Fred Moreno