I got the Summitlink 10" prop guards, installed and they are snug and fine. But they are sizable, and I'm wondering if others observe loss of battery/flight time with these installed? Seems there would be some modest impact, but I wonder if it could be more than that - e.g., 20%? http://www.amazon.com/Summitlink®-Guards-Phantom-Versions-Release/dp/B00RFX2L6G Seems to me they affect windage, weight, and the thrust of the props (by interfering with that thrust), but that last point tests the limits of my physics understanding. Thoughts?