Out of the 4 Regal Eagles I have built, the one that flew off of grass the best, was one powered by an OS.91 and Dynamax fax. It would get off of grass in about 150' and climb out with authority (for a DF). It had Spring Air retracts, Robart struts and Compact Unibrake wheel brakes. It also had a self made bifurcated thrust tube. Pic of it in my gallery.

The lightest one I built was OS.77 / Byron fan powered. It took about 450 - 500 feet to get off of grass if there was a head wind. If the wind was cross or completely calm, it might not get off at all. It would get off of pavement in about 150'