I was a partner in a 2001 Duo that came with the canopy
latch mod already fitted. The canopy never came open
spontaneously and I never found any tendency for the
latch to gradually open itself. BUT - several times
I found that in the front cockpit my left hand would
catch on the latch - the distal end of which projects
a bit - and several times I found that I slightly caught
the latch in the open part behind the button of long
sleeved cotton shirts. I was surprised how easily
the latch would move in flight with a gentle catch
and on one ocasion I accidentally pulled the latch
open on my shirt but was able to shut it quickly before
the canopy moved.

I would doubt that the latch of our glider would have
opened by vibration on the ground run. I do think
that the shape of the Duo latches makes them particularly
liable to be accidentally caught. It would be better
if the latch was shaped like LS latches - curved in
from the canopy frame and then back towards it so that
it is easy to get hold of but has no projecting forward
facing end.


John Galloway



At 07:54 20 June 2004, David Starer wrote:
I recently had the alarming experience of the canopy
coming nearly fully
open on a Duo Discus shortly after take-off on aerotow.
Both my student (who
was flying the glider at the time) and I grabbed the
handles when the canopy
was about 45 degrees open and managed to close it.
However all efforts to
lock it failed, probably because the airflow was distorting
the Perspex and
preventing the frame from seating correctly, so we
resorted to holding it
closed. The canopy catch has had a SH mod. kit fitted
which is supposed to
apply some spring pressure to keep the catch in the
closed position.

The takeoff in question was a relight after landing
at another airfield, and
after discussion with my student, we decided to continue
the launch and had
an otherwise uneventful glide home, holding the canopy
shut till we landed.

Both my student and I clearly recalled doing our pre-takeoff
checks,
including confirming that the canopy was locked closed.
The most likely
cause of the incident seems to be vibration during
the slightly bumpy
takeoff run, which probably caused the catch to move
towards the open
position.

I subsequently discovered that this has happened before.
The mod. kit is
pretty ineffective as the spring isn't even strong
enough to pull the catch
into the closed position when the canopy is open, let
alone when the
mechanism has to engage at three points along the canopy's
length.

The following day I wrapped a single turn of PVC wing
tape around the catch;
enough to hold it closed, but easy to break if the
canopy needed to be
opened in an emergency. The worst aspect of the whole
incident was losing my
favourite gliding hat which blew off my head when the
canopy opened!

Has anyone had a similar experience or advice on improving
the Duo's canopy
catch?

David Starer