I had been flying my Tarot 650 Sport quad with 13"props and decided that since I have T-Motor MN3520 motors, I'd go with 15" x 5 props. I ordered then a LONG time ago and they finally arrived from China. Here is how it looks now: The aircraft weighs 3.1 KG AUP (6000 mAH 6S lipo and a small 450 mAh 3s for powering the gimbal and vtx); so given the motor specs, I can expect around 14 minutes endurance, if I maintain around 57% throttle, I should draw 26.4 A and produce 5.58KG thrust. But since I'm in Colorado, at 5K ft elevation, I'm not sure what to expect. A concern I have is clearance between the prop and the GPS mast (Sorry about the photo orientation - it looks okay in photobucket): There is hardly any clearance, but the boom and GPS mast are both stiff, so flex shouldn't be an issue. Still, it's worrisome for me... I'm looking forward to a test flight where I exercise all functions - landing gear retract, gimbal horizon adjustment and tilt. Later, if everything goes okay, I will attempt some longer endurance flights.