I did the flight test with the strakes taped on with only "100 mph tape", so I elected to do the tests at very low power settings in order to keep the airspeed down. I figured the effects would be similar to those at normal cruise speeds. The indicated airspeed was about 135 (150 kts true as I recall) at about 8,000 ft density altitude. Problem was in doing two consecutive flight tests at exactly the same conditions. The temperature was different and I'm not 100% sure the power setting matched exactly. As long as I kept my rose-colored glasses on I was able to convince myself that the conditions favored the "no-strake" condition and therefore the speed loss wasn't that much. I haven't flown it enough since to get a good feel for the speed loss under normal cruise conditions. If the numbers are accurate the 1.5% speed loss represents an increased power requirement of almost 5%, which I don't think is the case. As I posted earlier, the strakes are 25 degrees from vertical and are parallel. I doubt very much that the natural streamlines at that position are parallel - If I had done a more rigorous job I would have verified the streamlines before installing the part.