Whilst I haven't done anything to increase mechanical security, I did install two micro switches in series – one on the canopy closing mechanism (behind the seat back panel and at the bottom of the canopy handle slot), and another just forward of one of the canopy alignment plates (this sits within the hull / canopy joggle so its hidden, but is closed by a small adjustable "pin" mounted to the canopy itself – so hardly noticeable). So, unless the both the latch mechanism is in the closed position and the canopy is pulled down properly to the closed position, the canopy open alarm is triggered.
I'd like to think it unlikely that the internal canopy latch handle could be accidentally / inadvertently opened in flight if an inflatable canopy seal is installed (and it is inflated) as this does significantly increase the resistance to moving the handle. But…interested in other views.
John
VH-XTZ
John N G Smith
Tel / fax: +61-8-9385-8891
Mobile: +61-409-372-975
Email: john@jjts.net.au
I am not sure a secondary latch is needed if you modify the latch stricker plate. The latch fingers will have greater overlap. I added an extra plate with the hole enlarge to accept the delran piece - see attached. I used countersunk screws for clearance. As a way to deal with pilot error, I added a canopy latch switch which illuminates when the latch is open and if open and airspeed is above 30 kts, I get an aural warning.
Dan Ballin
N386DM