The "Whisper II" roadable airplane,
envisioned by the team of Precision Design and University of Oklahoma, OK, is the culmination of several years work in this field. It is a two-place, three-wheeled road vehicle that can be licensed as a motorcycle when used on the ground, but has outboard folding wing panels on the sides that can be lowered into position for flight. A DC motor supplies power to the rear wheels when the vehicle is on the road for both forward and reverse movement at slow speed. An engine supplies power to a ducted pusher prop when the vehicle is operating at high speed on the ground and aloft. Innovative thrust augmentation is implemented to the duct, which contributes to higher thrust and lower noise levels. Our approach is innovative in that it applies the latest research in duel-mode, personal air vehicle transportation systems using rapid prototyping techniques to generate full-scale systems.
Above
is a three-view drawing of the conceptual Whisper II aircraft with the wings in
the folded lower position. Several studies have been conducted to access
the feasibility of dual-mode, personal air vehicles. In good aircraft design,
the mission defines the configuration. The constraints, which drive such a
design, have evolved into some common elements. The first is the volume the
vehicle must fit into. This is a box with a dimension of 7’ ´ 7’ ´ 20’. This
places severe constraints on wingspan. A unique highly efficient wing design
is required, which either has a low aspect-ratio wing or some type of wing
deployment system. In the event of wing deployment it must be designed (idiot
proof) so that there is no chance of flight attempts with wings partially locked
into position. The second is weight. If a vehicle is below a weight of 1500
pounds and has three wheels it will be classified as a motorcycle by the
Department of Transportation (DOT). Vehicles above this weight or having four
wheels have different classifications and, as such by DOT, have safety
requirements, which must be met in order to operate on highways. The DOT
requirements, such as safety glass and crashworthiness, drive the vehicle weight
up substantially. It is important to design a vehicle, which can both fit into
present DOT requirements and also be able to fly. A third requirement is that it
must be able have a ground and flight power system that is light in weight and
is able to reverse directions. A fourth constraint has to do with CG shift. If
the wings are folded or retracted in to any position other than along the cord
line, the shift of CG has to be accounted for in some manner. Folded wings must
not interfere with visibility or access to the cabin. Fifthly, during landing,
the amount of energy, which must be dissipated goes up by the square of the
speed. The ability to take off and land at slow speeds will contribute to the
overall safety of the vehicle.
For this years round of funding with NASA we made some design improvements (not shown) and renamed the vehicle "Safe I".
Below is the letter we received for our efforts
