Thread: Build Log 2.4m UAV build log for AP, GIS, Photogrammetry View Single Post
 Jul 31, 2012, 08:21 AM Registered User Cardiff, UK Joined Aug 2008 357 Posts Update - After looking around, I have found some guidelines for motor sizing, eFlite recommend 70-90 Watts per lb. If my model will weigh 4.5 - 5kg, thats around 10-11lb (as BMatthews has stated previously), Therefore 10 lb x 90 watts = 900 watts required. This is a lot. Thinking of using eFlites power 46 motor. With a 4s battery - 14.8v x 40amps continuous current = 592watts. I think i've got that right. If anyone could recommend one of the eflite motors that would be great... Also, is my following calculation correct, ... If i wish for 900 watts of power, and i know my battery voltage, Can I divide 900watts by 14.8v to work out the amps? 900 / 14.8 = 60.81Amps - does this mean that I need a motor that can give 60 amps? Where does prop size come into it? Does a motor generate a different number of watts depending on prop size? Cheers