There are some YouTube videos on pulse jets. I think they are flown on 80' lines doing around 100 mph. One was stunting it as though it were a stunter. Thing weighed 6 lbs. I can't find that video, but here is one doing 211 mph.

[youtube]http://www.youtube.com/watch?v=U2DZtFvd6Ho[/youtube]

That .51 powered one should be a really nice one.