VTOL aircraft using fixed forward canted rotors
A vertical take-off and landing aircraft and method which uses fixed rotors for both VTOL and forward flight operations. The rotors are positioned to achieve a high span efficiency. The rotors are positioned to even out the lift across the span of the wing. The wing may also have narrow front and rear airfoils which may provide structural support as well as providing lift during forward flight, or may have a single center wing. The wing rotors are tilted forward and provide some forward propulsion during horizontal flight.
1. An aerial vehicle adapted for vertical takeoff and horizontal flight, said aerial vehicle comprising:
a main vehicle body;
a right side wing assembly, said right side wing assembly comprising:
a right side wing coupled to said main vehicle body;
a right side span support coupled to said right side wing;
a plurality of right side wing rotor assemblies wherein the spin axis of each of said right side wing rotor assemblies is tilted forward from vertical in a fixed position relative to the aircraft structure in the range of 5-20 degrees, said plurality of right side wing rotor assemblies adapted to remain under power during forward flight, said plurality of right side wing rotor assemblies comprising:
a right side forward inboard rotor assembly forward of said right side wing, said right side forward inboard rotor assembly coupled to a forward end of the right side span support;
a right side rearward inboard rotor assembly rearward of said right side wing, said right side rearward inboard rotor assembly coupled to a rearward end of the right side span support, wherein when in a forward flight configuration said right side rearward inboard rotor assembly is higher than said right side forward inboard rotor assembly; and
a right side outboard rotor assembly coupled to a tip of said right side wing, wherein said right side rotor assemblies further comprise:
an electric motor;
a top central hub coupled to a rotating portion of said electric motor; and
a plurality of blades coupled to said central hub; and
a left side wing assembly, said left side wing assembly comprising:
a left side wing coupled to said main vehicle body;
a left side span support coupled to said left side wing;
a plurality of left side wing rotor assemblies wherein the spin axis of each of said left side wing rotor assemblies is tilted forward from vertical in a fixed position relative to the aircraft structure in the range of 5-20 degrees, said plurality of left side wing rotor assemblies adapted to remain under power during forward flight, said plurality of left side wing rotor assemblies comprising:
a left side forward inboard rotor assembly forward of said left side wing, said left side forward inboard rotor assembly coupled to a forward end of the left side span support;
a left side rearward inboard rotor assembly rearward of said left side wing, said left side rearward inboard rotor assembly coupled to a rearward end of said left side span support, wherein when in a forward flight configuration said left side rearward inboard rotor assembly is higher than said left side forward inboard rotor assembly; and
a left side outboard rotor assembly coupled to a tip of said left side wing; wherein said left side rotor assemblies comprise:
an electric motor;
a top central hub coupled to a rotating portion of said electric motor; and
a plurality of blades coupled to said central hub; and
a horizontal thrusting rear rotor assembly adapted to provide horizontal thrust during regular flight, wherein said aerial vehicle does not have controllable control surfaces.
2. The aerial vehicle of claim 1 wherein the spin axis of said right side wing rotor assemblies is tilted forward at an angle to the normal of the horizontal flight line of the aerial vehicle in nominal forward flight in the range of 8-12 degrees, and wherein the spin axis of said left side wing rotor assemblies is tilted forward at an angle to the normal of the horizontal flight line of the aerial vehicle in nominal forward flight in the range of 8-12 degrees.
3. The aerial vehicle of claim 1 wherein the spin axis of said right side wing rotor assemblies is tilted forward at an angle to the normal of the horizontal flight line of the aerial vehicle in nominal forward flight in the range of 5-15 degrees, and wherein the spin axis of said left side wing rotor assemblies is tilted forward at an angle to the normal of the horizontal flight line of the aerial vehicle in nominal forward flight in the range of 5-15 degrees.
4. The aerial vehicle of claim 1 wherein said top central hub is a flattened hub.
5. The aerial vehicle of claim 1 wherein the ratio of the diameter of said top central hub to the diameter of a sweep of said plurality of blades is greater than 0.25.
6. The aerial vehicle of claim 5 wherein said right side span support and said left side span support comprise airfoils extending downwards from the rear of said right side span support and said left side span support.
7. The aerial vehicle of claim 1 wherein the ratio of the diameter of said top central hub to the diameter of a sweep of said plurality of blades is greater than 0.30.
8. The aerial vehicle of claim 7 wherein said right side rotor assemblies and said left side rotor assemblies further comprise an undercowling extended rearward of said top central hub.
9. The aerial vehicle of claim 1 wherein said right side rotor assemblies and said left side rotor assemblies further comprise an undercowling extended rearward of said top central hub.
10. The aerial vehicle of claim 1 wherein each of said plurality of right side rotor assemblies has a mating left side rotor assembly approximately equidistant from a center line of said aircraft on a line through the approximate center of mass of said aerial vehicle.
11. The aerial vehicle of claim 1 wherein said right side span support and said left side span support comprise airfoils extending downwards from the rear of said right side span support and said left side span support.
12. The aerial vehicle of claim 1 wherein said left side wing and said right side wing are partially forward swept wings such that the aerodynamic center of the wings is rearward of the center of mass of the aerial vehicle.
13. The aerial vehicle of claim 1 wherein said left side wing and said right side wing are coupled to the top of said main vehicle body.