Ok joeosborn Im going to try to explane how to choose a moter and prop for your rc planes, so stick with me , here we go. There is 3 basic things you need to know to figuer this out,
1, The total weight of the plane ready to fly as it would sit for take off.
2, The amount of ground clearance for the prop.
3,The wingspan and wing area of your planes wing.
Thats it in a nut shell,since one and two is self explanatory, I'll walk you through the third one.
There is three things that the wing can tell you,
1,The stall speed of your plane
2,Prop diameter
3,How fast to prop the plane for (How fast the plane will fly)
So lets figure out your wing loading (How much weight your wing can carry or lift,
when we talk about wing loading we use terms (Weight per squar foot of wing area)
so measure the wingspan wingtip to wingtip, then measure the chord(Average wing width is your chord)
1, multiply the wingspan by wing chord
this will give you your wing square inches.
2,convert to square feet by dividing the answer by 144.
3,To find your wing loading divided the plane weight by wing area in square feet this answer will be your wing loading.
so every square foot of your wing can carry that much weight.
Now with this info we can figuer out the stall speed of your plane(the slowest speed possible with out falling out of th sky) To do this find the square root of your wing loading anwser.To do this just google it, put this in google,square root of blank is( the blank is your wing loading anwser. Take that anwser and multiply it by 5, and then you have your stall speed.Now you want you top speed to be 2.5 to 3 times your stall speed you can even go up to 4 to 4.5 times for some planes. then you want about 75% of your planes weight in thrust.pick the bigest diametet prop as possible (up to 25% wingspan) now sipn it fast enough to get your speed you went .So look at the spec for moter and mach up prop size with KV and on back through your power system it all should just fall into place for you just take you time. to figuer out the watts of a moter just take max amps multiply by the volts from your battery to get the watts for that moter, (a 3s lipo is 11.1 v)
I know alot of info take your time a you will get it. Hope this helps out...... .