What is your expected weight and line length?  E-Flite 32 or Cobra 3520 14 would be a good starting point.  The next motor size down is similar to those on the Crist Rigotti over heating thread, with a smaller plane.  But, no, I am not flying one so may not have the answer that you are looking for.

The main difference I can see is the 25 has 870kv and the 32 has 770kv. Does that mean the Eflite 25 would have less torque and need to run at higher rpm, more current, is this why they get hot?

The way you're thinking about it does not take into consideration that you're going to stick a prop on it that's right for your airframe, and set the ESC and timer up so that it turns at the speed that's right for the prop.  At that point the 25 will consume as much current and voltage as it needs to do the job, as will the 32.  The 25 will need less voltage and more current, yes, but that's not necessarily a good reflection of "why it gets hot".

It's more that the Eflight 25 is just a smaller motor with a smaller power rating.  So with both motors providing the same power to the prop, the 25 will (probably) be a bit less efficient, thereby generating more heat, and it's smaller, so it'll be less able to dissipate the heat that it does generate.

A really good, quick & dirty way to check to see if your motor will work for control line stunt (I think this came from Dean -- I know I didn't cook it up) is to look at what it's rated for on a 3D airplane.  If it'll fly a 2-pound 3D airplane, it'll fly a 2-pound stunt ship.  Etc.  You're talking a hair less than 4 pounds, and the 25 is rated up to 3.5 pounds -- so you're pushing it with that motor.  The 32 is rated for 4.5 pounds -- so that looks like the way to go.

Use a Cobra!

Thanks Eric, do you know about what a Thunder Gazer would weigh all up?


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Ok so, 64 oz = 4 Lbs x 150 = 600 watts. Cobra 3520/14 with 5 cell is 850 watts?

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