Selecting the best propeller and electric motor for scratch builds


New member
I've seen several comments/posts on the subject, but I am NOT made of money, and don't choose to smoke my ESCs, motors and such by experimentation.

Certainly there's tons of material out there. But who has time to sit and surf and surf on the internet for answers. Would like to see FT's take on this.

I would like to see more about props greater than 2 blade (3, 4 or more!) Also, having discussion on prop/motor efficiencies, and show the amp draw from variations. (ex: static motor specification, then varied prop dia with same pitch, then perhaps static motor, static prop size, varied pitch. Then, static prop size, pitch, varied motor sizes) Or something of this sort.

If I am asking to recreate the wheel here, please point me in the right direction. I'm looking to begin developing my own scratch builds but the thing that holds me back is choosing the right electronics for the particular model I am designing.


New member
I think picking up one of the power packs from flitetest will be a step in the right direction. Most of their planes, new and old, will fly great with the power packs they have for sale. If you're designing your own planes then there are a lot of factors that come into play. I've always gone by the Watt per Pound rule. I think I usually stick around 100W per pound (All Up Weight) and it has done me well. I'm by far no expert in the many different aspects of electronics, but this has worked for me.


I build things that fly (sometimes)
There are a few options I use. In the end there really isn't any replacement for hooking up a watt meter and doing a bench test of the setup installed in the model but you can get close.

The first tool I use is motocalc ( This lets you play with various setups and get an idea of stats. is another WONDERFUL resource. This has tons of motor/prop combos with test data.

With either of these tools if you can't find the exact motor you have try something similar... it should give you an idea.

Some motor manufacturers also have their own calculators (I know scorpion does). It is worth checking the manufacturer's site.

Googling for similar models (size, weight, performance) and looking at their proven setups has also worked for me.

Hope that helps!


I also really like the eCalc site ( They have an easy to use calculator that I have found to be pretty accurate and includes all the motors I've got so far. Free to use (but you only get 25% of the motor database, and it changes randomly), otherwise like $3 a month or something.
Oooh good info here! This is exactly something I'm struggling with too. Do you guys also like the 10% rule for spying power to escs and servos?