Jason,

My Delro is running on a Plettenberg 25-12 which was shown with a 20 x 13 as a maximum prop size as well, but handled the 20.5 x 14 with no trouble. I have a thread, [link=http://www.rcuniverse.com/forum/m_9271587/mpage_2/key_/tm.htm]Plettenberg 25-12 is it enough?[/link], running in which I discuss my experience with this 520g motor.

BUT . . .

I'm genuinely interested in hearing some more input on the Spark as I'm always on the lookout for the next plane and the Spark is one of the few e-machines that comes in complete ARF format. Plus I'm fascinated by your choice of motor as it is a fraction of the cost of the Plettenberg and if it is flying your Spark well on a 20 x 13 at 50 amps, it may be a more efficient choice than the monster 30-10.

Don't forget to let us know how you like the RASA 20.5 x 14 as well!


Joe