I have tried a 11x9 last sunday, which gave me a promising 14600 on the ground, but already during take off the engine started to make problems, being to fast for aborting the take off I made one round and landed, put the engine more rich and flew again....speed was the same like with the 12x10...so I guess I will stay with the 12x10 which has proven to be a reliable setup...
these plane is anyhow not really made for SPEED...look forward to fly my Jackal with Jett engine 0.56 in two weeks and hopefully soon the Nemesis NXT
rgds
Gordon