Hi all, concerning speed records: The main criteria is a measured course, 1 km long etc, then at least two runs over this course, one in both directions , the average speed is your max. This is to cancel out the wind factor. Things like the Bloodhound SSC , have to turn around and complete a second run within one hour. for them a wind of say 30km/h, is nothing for they could do 1000km/h etc ! For a small hovercraft, going much much slower, a return run within minutes would return a truer average. The true ground speed is what you want, not what your aircraft type speedo says. Francois Malan