At Krossblade Aerospace of Tempe/Mesa, Arizona, a group of six young men have developed the concept for a hybrid 5-seat transformer airplane called “SkyCruiser,” and a prototype called “SkyProwler,” a VTOL transformer unmanned aerial vehicle (UAV) or drone. SkyCruiser takes off and lands vertically (VTOL), cruises at more than 500 kph/300 mph, and also has road drive capability.
The patent pending switchblade mechanism forms the basis of the transformation of SkyCruiser and SkyProwler. Airplanes need to fly fast, and to fly fast, an aircraft needs to be as aerodynamically clean as possible. That’s why airplanes are long and narrow, somewhat drop-shaped, with as few of ‘things’ sticking out as possible.
For vertical take-off and landing on the other hand, an aircraft needs to be the opposite of aerodynamic. The more things you have sticking out producing lift (think of the extreme of a parachute, for example), the easier it is to hover. This is one of the main reasons that helicopters, which are great at hovering, are not very good at forward flight, being slow, as well as needing a lot of fuel.
The switchblade mechanism transforms an aircraft from the aerodynamically clean airplane configuration to the VTOL configuration, which features a number of rotors that together have a large rotor disc area that is ideal for hovering at low power.
The switchblade mechanism is of similar technical complexity as a gear retraction mechanism and in itself adds very little weight to SkyCruiser and SkyProwler.
SkyCruiser has four rotors, but is designed to be able to land safely with only three rotors (using some thrust vectoring with the thrusters at the tail to counteract yaw). For a controlled crash landing, all the SkyCruiser needs are two rotors, but it has to have one rotor operating on each side. The movable arms can be used for this purpose to slightly reconfigure the position of the large VTOL rotors. Also, each arm carries two rotors, a big one carrying most of the weight and a small one, carrying some weight, but being mainly used for control and stabilization (www.krossblade.com).
