Instead of the .18 or .15, I'd go for the .21 and use the Kress fan. Although it's quite expensive for the fan ($140). For another 1/2" in diameter, you get a lot more power (4lb thrust w/ 30K rpm using an OS buggy engine). You can buy the impellor and rig up your own fan (which I've seen done and works very well).

Check out the following thread:
http://www.rcuniverse.com/showthread...hreadid=209749

Scroll down and check out my .21 Mirage with a Kress fan.

What are you planning on putting it in?

Russ
[email protected]]