Mike, I do need to remind you that regulation of ultralight aircraft in the United States is covered by the Code of Federal Regulations, Title 14 (Federal Aviation Regulations), Part 103, or 14 CFR Part 103, which defines an "ultralight" as a vehicle that:
has only one seat
Is used only for recreational or sport flying
Does not have a U.S. or foreign airworthiness certificate
If unpowered, weighs less than 155 pounds
If powered:
Weighs less than 254 pounds (115 kg) empty weight, excluding floats and safety devices
Has a maximum fuel capacity of 5 U.S. gallons (19 L)
Has a top speed of 55 knots (102 km/h; 63 mph) calibrated airspeed at full power in level flight
And
Has a power-off stall speed of 24 knots (45 km/h; 28 mph) calibrated airspeed or less
In Europe, the sporting (FAI) definition limits the maximum take-off weight to 450 kg (992 lb) (472.5 kg (1,042 lb) if a ballistic parachute is installed) and a maximum stalling speed of 65 km/h (40 mph).
You would have to check the specifics for your country to ensure legal operational limits.
James