Q40 and Q500 (428) are using Nelsons and Jetts. Profi is only making a Q500 other than the MB Profi F3D engine. The Q500 Profi is not is not quite as fast as the new Long stroke Nelson and Jett Q500 motors. You do not see it at races much. There is a new class of Q500 (426). It uses a sport Jett motor and is about 15 to 20 mph slower than 428 but the motors are only $250. MB in the Netherlands is developing a new Q500 and Q40 motor with Profi but it will probably not be released in the US.

Denis

You are in Saugus. Have you been to our field in Castaic??
I would guess not or you would know there are several of us who race 424, 426, 428 and 422.
There is also a large heli contingent.
There is a race at Whittier narrows this coming week end.

Denis