To overcome this problem on our engine dyno at work, a steel clutch system was used--problem solved. I can't take credit for it as I had nothing to do with it, but as far as I can tell the steel clutch works like a charm. I'll get more info when I get back to the office next week. The other main concern with nitro crawlers is heat. The problem is also the same on our dyno. Two (I believe) inecpensive brushless cooling fans (look like computer fans to me) solved that problem. That's just some food for thought. Even with those two issued addressed, I don't think (and have never said) a nitro crawler could compete with an electric crawler. I'm not sure why it keeps coming back to that. It would nice if we could keep this civil since it appears this topic is here to stay on this forum.