Since I am 600 miles from home, simple solutions are needed until I am able to fabricate a more robust system for restraining the canopy in the unlikely ;-) event that it opens in flight. Here are a few pictures.


I use the bungee cord as my second set of hands while installing the lower cowl and had been looking for a storage solution. The ends go through the seat belt bracket and I purchased a hook at the hardware store for $1.50. The bungee is stretched fairly tight. The hook has been modified, ground down the tip, just need enough to keep the bungee in place and it is easily pulled off.



Not a perfect solution, but the canopy will not open in flight. Mission Accomplished!

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Comment by Dr. Edward M. Moody II on October 4, 2010 at 3:18pm
It'll work. If the primary latch is forgotten or incompletely latched, the bungee will prevent it from rising very far. That's all that is needed to allow you to get back on the ground. Nice simple expedient solution until a gee-whizz device can be designed and installed.

Ed
Comment by Jake Reyna on October 3, 2010 at 4:40pm
Gary, there are better ideas, but I needed a simple solution. The key to this solution is that the canopy will be latched first, then the bungee will be stretched tightly to engage the hook.

The incident I experienced was due to Pilot error, I didn't latch the canopy and the root cause was the lack of a written checklist. I've created a checklist and it has 2 entries dealing with the canopy. Latch the canopy. Attach bungee cord. Will the bungee restrain the canopy if I forget to latch the canopy first, I'm not sure, but I am confident that the canopy will not open if I latch it before flight regardless if I have the bungee.

In most certified aircraft, there is a second door latch, why shouldn't we have something similar in our airplanes.

Other solutions, besides those already posted, would be to use cowl latches as the secondary system.

Adding a tab to inside of the canopy frame that would extend through a slot in the top rail and using a 1/4" hitch pin through a hole in the tab and fuselage side skin would eliminate the possibility the canopy would open in flight, but it would only work if you used the pin.

My point is that the first step is to latch the canopy.
Comment by Gary Ray on October 3, 2010 at 9:40am
Jake, my experience with partial latched canopy episodes would lead me to conclude that
a bungee cord is much too elastic to do the job. In flight the canopy has enough lift that a 200 lb pilot can not pull it down even on one side. Also, the location for maximum mechanical advantage would have to be much further rearward. For me this is most likely to happen on very hot days where you leave the canopy partially unlatched for additional ventilation then get your clearance to take off without engaging the full latch. It is spooky, windy, and embarassing to admit to the tower that you need an immediate return to remedy a canopy latch. So far I have not experienced a fully unlatched canopy which would be much worse. It is now the largest, boldest entry on the pre-takeoff list and probably warrants an instrument panel graphic reminder.
Comment by Richard Rost on October 2, 2010 at 10:29pm
Hey they always told me K.I.S.S. (keep it simple stupid) Looks like one of those things that will work great for a buck fifty investment.
RIch

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