http://www.avweb.com/avwebflash/news..._197685-1.html
"Pilots familiar with Lancair designs speculate that an unlatched canopy
introduces a significant distraction to the pilot but should not in and
of itself result in complete loss of controlled flight for the Lancair
Legacy."
I could imagine that there might be some degree of disruption to the
airflow. Maybe this would affect the rudder and/or elevator response?