[1][2][3] The aircraft was designed before the US FAR 103 Ultralight Vehicles rules, but later versions were intended to specifically fit the category.
The Hummingbird features a high wing, a V-tail, an open cockpit, tricycle landing gear and twin, wing-mounted engines in tractor configuration.
Its 70% double-surface, 36 ft (11.0 m) span wing is cable-braced from an inverted "V" kingpost on early models and is strut-braced on later versions.
The pilot is accommodated in a web sling seat that allows for foot-launching, an unwritten requirement for ultralights in the USA prior to FAR 103.
[citation needed] In 2009, Sweeney was experimenting with electric motors on one of his Hummingbirds, but no test flights were conducted.