Don't ask me how I know this. If you were to take off with the canopy closed but unlocked, the noise level gets louder with airspeed increases. if you miss that sutle clue, and if you have a carbon monoxide detector, it will start making even more noise. Why you might ask, well my friends, it seems that the cockpit inflight becomes a low pressure area, therefore it tends suck the canopy down with some amount of force. That force combined with the up sloping T-rail the back of the canopy has to climb to move aft is beyond the strength of most mere mortals. How did I determine this? I am a college graduate with a History degree. That degree and the smell of exhaust and the aforementioned carbon monoxide detector going off were clues not lost on me. Now the important part, ignore the unlocked canopy, it anin't going nowhere, nohow (history degree). Fly the aircraft to a safe altitude, trim for level flight a reasonable power setting, then use both hands, one on the handle and the other to push up and forward on the canopy. You probably won't get into the full locked position on the first try, but turn the handle if it partially catches to mechanically move the canopy slightly forward, The next try will most likely be sucessful. Dan from Reno