The AVX Aircraft Company has come up with a pretty slick design for a roadable helicopter in response to the DARPA RFP for a “flying Hummer.” It’s a conveniently cubical boxy shape, with a fair deal of internal volume, with two ducted fans for forward thrust and foldable coaxial rotors.
I’ve always prefered the idea of a “roadable helicopter” to a “roadable airplane.” As well as providing more convenient folding of the lifting surfaces – the Terrafugia folds up into something of a mess… serviceable, but large and exposed, and vision-blocking – a roadable helicopter provides better operational versatility. Whether you’re a civilian trying to get home from the office or soldiers trying to get the hell out of Dodge, if you find yourself stuck on a highway, a roadable airplane won’t help much. But a roadable helicopter can, in principle, just pull off the road, fire up the rotors and lift off vertically.
AVX is also proposing to convert old OH-58D Kiowa airframes into coaxial/ducted pusher configurations. If their estimates are accurate, it would be a relatively cheap way to turn these old bitrds into new, fast battlefield tools.