The proper way to size a motor to an electric plane is by watts per pound. So if you have a plane that you expect to be 6 pounds all up flying weight then a 600 watt motor would give you 100 watts/pound.
More info with deeper explanations can be found here:
EVERYTHING YOU WANTED TO KNOW ABOUT ELECTRIC POWERED FLIGHT
Thank you for the reference. I had in mind a pusher delta winged plane about 450 sqin wing area, 6lb weight. It seems I should be OK if I stay below 8lb. Ill use your reference again to select battery, ESC, prop etc. Thanks again.
http://www.maxxprod.com/pdf/CR3516.pdf.... this document suggests that this motor is only the equivalent of a .30 engine. Reading the specs it seems that 35A/motor on 3s might be getting you 700W max. A decent .46 equates to around 900W.