The problem is, most pilots have never seen a gyroplane specifically designed for ultralight service. The usual approach is to simply strip down an Experimental machine until it makes weight. The result will be an under-powered machine ( power loading or gross weight/horsepower will typically be as much as twice that of an Experimental single-seater) trying to fly at essentially the same disc loading (rotor disc area/gross weight). This may work after a fashion for light pilots, but those of us of a heavier persuasion will not be happy with the result!

There are several ways to go about designing a legal machine that will perform. For example, by careful weight management, Ken Brock gets reasonable performance out the KB-3 by using a larger engine (65 hp). The blades are not super-efficient, so the only real price paid with this approach is a relatively high minimum flying speed.

Martin Holman's Bumble Bee flies with a modest engine (40 hp) and a 1.2 psf disc loading by virtue of very efficient custom rotor blades. In contrast, the Gyrobee uses relatively inefficient Rotordyne blades but gets good performance on 40 hp by using a larger rotor disc to bring the disc loading down to 1.0 psf. At this low disc loading almost any blades will give decent performance.

You wouldn't design a fixed-wing ultralight by simply leaving things off a Cessna 150 and that approach doesn't work any better with gyroplanes. In contrast, if you start with a clean slate and design for the limits of Part 103, you can end up with a machine that performs quite well.