I attempted to open my -7 slider canopy while rolling out on landing at Logan KLGU.
It was HOT outside, so as soon as the wheels touched, I popped the canopy release, trying to get a little fresh air in the cockpit. The tail was still flying (indicating that I was still rolling about 45+ mph) when I attempted to slide the canopy back. I was able to get it open with about 1/2" gap, but it wouldn't open any further until the tail quit flying.
This is the only time I've ever tried to open the canopy with anything greater than taxi speed, and I proved to myself that the canopy just ain't gonna open in flight...
Caveat - I was still flying the plane, so I didn't really, really, try to push the canopy open. I simply opened it until it stopped, and then I continued to fly the plane. Perhaps with some adrenaline rush, I probably could have gotten it to open further???