I just got a plane with a 380 size brushed motor that runs on a 8.4V nimh battery. I have a bunch of 11 V lipo batteries that I have just hanging around. What kind of brushless motor and esc can I use in it. he plane is a sd piper j3 cub three channel.
Go see Jeff at heads up RC,, bubsteve 2408-21 Outrunner Brushless Electric Motor & 18A ESC
The very popular 2408-21 is a 1.6 oz, 1400KV, 400 class direct drive outrunner brushless motor designed for medium to high speed park flyers. Best performance is obtained with the GWS EP8040 prop and a 3 cell Lipo battery, such as the Power Up 11.1v 1300 20C. This combination is often used on the GWS Formosa, Mustang, Zero, Spitfire and many sport planes weighing up to about 30 ounces. Producing up to 22 ounces of thrust, it far outclasses the 300 to 400 speed brushed motors it replaces. It is both lighter and more powerful than the typical 400 speed brushed motor. And with the included stick mount, it is often a simple drop in replacement.
The 2408-21 works very well as a pusher motor on delta models, flying wings and profile jets. I suggest using the TP 7x6E prop for some very nice speed. The Power Up 11.1v 1000 20C Lipo battery can be used to keep the weight low on these types of models.
The 2408-21 can also be used with 2 cell Lipo batteries such as the Power Up 7.4v 1300 20C. It will provide up to 15 ounces of thrust with the GWS EP1060 prop, and it is sometimes used in profile combat plane competitions with the GWS EP9070 prop. MOUNTING OPTIONS: An aluminum stick mount with heat sink is included, along with two prop nuts and a washer. A firewall mount is available in our store. Always check the tightness of all motor set screws and motor mount screws when installing motors. The motor set screws require a 1.5mm Allen wrench. Rotating propellers are dangerous. Please stay clear of prop and wear eye protection. Propeller test data using a 3 cell Lipo battery: GWS and TP props fit the 3mm shaft on this motor perfectly - no adapter is needed. APC and Master Airscrew props require a prop adapterorprop saverfor a 3mm shaft. The GWS EP8040 is the most commonly used prop with this motor. It will produce about 22 ounces of thrust at 14 amps with a pitch speed of 43 mph.
Depending on what size prop you need - an ARC 28-37-4 would be good for direct drive, with 6" prop, and of course any larger size if geared. It is hard (if not impossible) to find a 28mm inrunner with low enough Kv for direct drive of, say, 9"-10" props.