[1][2] The KB-3 was derived from the 1970 KB-2 and specifically designed to comply with the US FAR 103 Ultralight Vehicles rules, including the category's maximum empty weight of 254 lb (115 kg).

The aircraft has a standard empty weight of 250 lb (113 kg).

It features a single main rotor, a single-seat open cockpit without a windshield, tricycle landing gear and a twin cylinder, liquid-cooled, two-stroke, dual-ignition 64 hp (48 kW) Rotax 582 engine in pusher configuration.

Fuel capacity is 5 U.S. gallons (19 L; 4.2 imp gal) and is housed in a combination pilot seat/fuel tank.

[1] Due to its small size and light weight the KB-3 is easy to transport by trailer and can be set up to fly in ten minutes.