The Spectrum AR6400 ultra microlite reciever is a fantistic development in ultra small set up's-the instructions indicate that it is both brushed and brushless compatable-- Horizon Hobby tech people tell me they havent developed the brushless yet and advised me to find out what the boys are using in RC Groups So what are you using in a brushless set up?

A few people have used a 1S brushless setup, but the results are not fantastic since you get pretty much the same power as the brushed motor. Sure enough, your motor will last forever, but it's not the greatest.

If you want to go brushless, then a 2S system really shine! Keep in mind that you have to operate the AR6400 at 4.2V though, so ideally, you want to use a small ESC that has a 5V BEC. You can then simply use a 1N4004 diode between the ouput of the BEC and the AR6400 which will lower the voltage close enough for your AR6400.

So from there, it's only a question of picking a decent ESC (3 to 5 amps), a decent brushless motor, and a suitable propeller.

Read the instruction manual for the AR6400 to see how to switch the connector to external ESC and have fun. In 2S, you can take pretty much any ultra-micro and make it go warp speed.

Good luck

i have used a AP-05 motor on 2s in the UM SU-26 and it was a rocket with a 4.5x4 gws prop
i did the above diode mod to keep the rx from croaking.
here is the motor i used: link

Have a look in the micro and indoor forum, there a lot of info there about setups and planes the 6400 works good with.