FT Racer, new build more motor question


New member
I have built quite a few FT planes from both plans and speed build kits and my favorite plane has been the FT Racer (Slinger?) design. It has a wonderful speed envelope and is such a beautiful plane in the air. Unfortunately this past weekend it met its end, it flew a great 1.5hr session on Saturday but on Sunday first launch lost RC (dang jacket messed my antennas up) and it fell into a permanent dirt nap. It had seen many many crashes as it is one of my oldest planes so I wasn't too tore up about it.
Though my heart was with the old bird I immediately bought a new speed build for it and I am excited to match all the old birds charm with wing patches etc.

My question is, I recently received a bunch of motors and props from a friend and want to use them. What I have are Tmotor MN3520 400kV motors. I am wondering if this is a good idea? They came with the carbon fiber 15x5 props. The original motors that came in the power pack are 70g and these new motors are 150g. I would need to balance the CG a lot more, perhaps move forward the wing? What other things should I keep in mind on this build? Good idea? bad idea? How would the flight characteristics change?


Eternal Student
That motor is huge for this plane, and a very low Kv rating meaning you'd probably run it at 6S - further increasing the weight. Assuming yo got it all balanced you'd probably rip the wings off ;)