Matching props to motor?

sprzout

Knower of useless information
Mentor
Anyone know of a tool to size props to motors? I'm trying to find something that I can use that will allow me to take and input say, 1200kv, 3s/25c battery, and have it spit out what size prop I need for

I've gotten stuck on the Power Packs and like them, but I also have some motors that I picked up at an R/C swap meet. I'd like to utilize them if I can, especially since I see the packs going in and out of stock fairly quickly; I know that there are certain efficiencies with certain props, I just don't know how to figure out which prop with which battery with which kv output motor, if that makes sense.
 

rockyboy

Skill Collector
Mentor
I'm also a frequent buyer of swap meet motors. :)

My approach is to do a google image search of the motor name and number and look for charts that show the power requirements with different props. This has worked for me with at least a dozen motors, and only failed me two or three times. And that was what prompted me to build a test stand and buy a watt/amp meter. :)
 

sprzout

Knower of useless information
Mentor
I'm also a frequent buyer of swap meet motors. :)

My approach is to do a google image search of the motor name and number and look for charts that show the power requirements with different props. This has worked for me with at least a dozen motors, and only failed me two or three times. And that was what prompted me to build a test stand and buy a watt/amp meter. :)

The test stand/watt/amp meter sounds like something that would benefit both me and my father...he's trying to find a combination for his Mister Mulligan and a little park flyer that he had to replace the motor on (he bought it complete at a swap meet; the ESC went belly up, and he figured he could just replace it and have it working - turns out it's hard to find a brushed ESC that will work with the requirements of the motor).

Any suggestions on a particular watt/amp meter that I should look at?
 

rockyboy

Skill Collector
Mentor
I have the El Cheapo turnigy one from hobby King but the best one I hear about is the Watts Up
 

ViperTech

Member
The test stand/watt/amp meter sounds like something that would benefit both me and my father...he's trying to find a combination for his Mister Mulligan and a little park flyer that he had to replace the motor on (he bought it complete at a swap meet; the ESC went belly up, and he figured he could just replace it and have it working - turns out it's hard to find a brushed ESC that will work with the requirements of the motor.


Do you know the manufacturer of the Mister Mulligan? I found a great planes model that has a 52" wingspan and it calls for a 42-50-800kV motor and a 12x8E prop on a 45 amp esc and a 4s battery.

What size is the park flier? I look around to find comparable size planes to get a sense of the motor and prop size needed.

Might just want to go brushless on the park flier.