Although I have not yet made the first flight, I believe that having the canopy open inflight might mess up my hair.... and my underwear. I therefore set about scheming on how I could tether the canopy so that it either could not move at all or at least not lift very far if it unlatched. Noise I can handle, but turning the cabin into a wind tunnel test is not my idea of a good time.
I wanted the following features:
(1) Easy to find parts.
(2) Cheap as possible.
(3) Simple to design and install.
(4) Very strong to resist canopy lift.
(5) Provide a handhold to assist in latching the canopy.
(6) Minimum interferrence with my hands, arms and shoulders inflight.
What I settled on was a pair of plain, 2" wide seatbelts (available from a host of online sources). I cut the metal anchor parts off of the female ends to allow me to make my own brackets for them.
I fabricated the brackets from 1/8" aluminum angle, drilled them to rivet to the inside of the canopy frame where they could be grasped while I sat inside.
Once the brackets were deburred, primed and painted, I got my lovely and talented wife (racking up those brownie points fellas) to sew the female ends to the brackets. I then rivetted them in place with six A5 rivets each.
It is important to sew the female ends onto the brackets as short as possible. That prevents them from dangling any farther down into your way than they have to. It also makes it as easy as possible to draw the male ends tight once you have buckled them to the female end. The male end with its factory sewn-on bracket attaches where the outboard end of the lap harness bolts to the main gear upright.
I had intended to cut the extra length from the male end of the seatbelt to minimize the amount of extra web strap dangling inside the cabin. I realized after installation however, that they can be left buckled and extended to their full length to limit the canopy opening. Unrestrained, my canopy opens so far that the front weatherstrip gets mashed against the cowling. With the tether left buckled and fully extended, it holds the canopy just short of doing that. The tether is somewhat obstructive in this mode but even my 81 year old dad can manage to work around it. For those who can't maneuver around the tether, one side can hold the canopy while the first person enters from the opposite side. That person then buckles the tether on his side and releases the other one so the second person can enter. It's very easy to do.
The finished tethers satisfy all of my design criteria without busting my brain or my budget. While I sincerely hope that they never have to actually hold my unlatched canopy inflight, I am confident that they have more than enough strength to do so.
If any of you have questions or comments feel free to contact me for discussion, additional info or fabrication techniques.