I have the Legacy canopy latch modification that props the canopy open about 1.5" as shown on Don Barne's website.  The canopy latch must be locked for the canopy to be fully closed.  One time I started my take-off roll with the canopy unlatched and because the canopy was propped open the noise and wind made me immediately aware the canopy was not closed.  There was plenty of time to pull the power and abort the take-off.  Now I believe that this mod not only helps ventilate the cabin on the ground, but it may have also saved my life. http://www.lancairlegacy.com/tips_canopy_fixes.html Jim Thomas Legacy, 180 hrs