UrbaPlane
UrbaPlane
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The UrbaPlane is a more aggressive engineering design towards a roadable aircraft. The UrbaPlane is fundamentally different from the CyclePlane. Whereas the CyclePlane is a minimalist approach towards a proof of concept roadable design, the UrbaPlane features folding wings, a variable wheelbase landing gear, and a ducted propeller. The flight controls are located in the slipstream of the propeller. Consequently flight controls must be actively positioned with regard to the commanded inputs by the pilot vs. the aerodynamic control power available at that moment. UrbaPlane will require fly by wire control positioning. Aerodynamic Approach Additionally UrbaPlane utilizes an aerodynamic approach pioneered by the Custer Channelwing. The Channelwing used propeller suction to provide accelerated flow over the wing which produced additional lift. This lift developed was beyond the normal amount of lift produced by the airspeed from the aircraft's forward motion in conventional aircraft. As roadable aircraft are nearly all wingspan-challenged, this design takes the maximum advantage of the available techniques to produce a better flying aircraft.
Variable Wheelbase One of the problems facing roadable aircraft is the differing stability requirements for a multifunction vehicle. Most road vehicle designs tend to place wheels as far as possible toward the edges of the body envelope for stability. Aircraft however, generally produce additional lift in the transition to takeoff through rotation. The longer wheelbase of a road vehicle may well preclude or prevent rotation if no allowance is made for the differing operational modes. The UrbaPlane's rear landing gear therefore swing an arc for and aft dependent on operational mode of the vehicle. Twin Engine With Counter Rotating Propellers The UrbaPlane also features dual counter rotating propellers and twin engines. This is one feature of the downloadable UrbaPlane model that may not be practical to include in the fielded design. Providing twin engines would provide an additional margin of safety during high angle attack take off and landings. The counter rotating propellers remove the adverse yaw produced by propeller bite when operating with synchronized engines. When modeled as a single engine design, significant rudder trim was required through the operational speed range of the aircraft. Degraded Modes Both the CyclePlane and UrbaPlane will operate in flight regimes that raise flying qualities issues to the pilot in degraded mode operation. The aerodynamic qualities of the channel in the UrbaPlane will allow very short takeoff and landing approaches. During these times the aircraft is operating at a relatively high angle of attack for light aircraft. The fact that the channel allows these types of approaches and departures shows the strength of the concept. If the aircraft were to become un-powered however, the positive aerodynamic effects of the channel will be immediately lost. At a high angle of attack it's probably possible for the aircraft to transition almost immediately to a stalled condition. The UrbaPlane downloadable model therefore offers a ballistic parachute which is manually deployed for emergency recovery of the aircraft.
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Copyright 2004 CyclePlane
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