Voting Result: 3.2191433159
Overview for Manta ray (CUBE Wing)
The concept of Cube Wing is based on Y6 copter.
Considering the air resistance, I think that the most efficient cargo flight is the flying wing shape.
The main design consideration of CUBE Wing is as follows:
To have the same flight performance regardless of cargo, CUBE Wing has same CG position with/without cargo.
The front of the vertical motor, by using two propellers turn in a coaxial form, In a small space, so get a higher payload.
When CUBE Wing transits to horizontal flight after vertical take off,
CUBE Wing maintains forward wings closed with straight flight which is advantageous in the initial low speed.
As the speed of flight is increased, CUBE Wing is changed to swept-wing for the efficiency of the high speed and the rear vertical motors stop. Wing is moved to there was a vertical motor position.
The CG of CUBE Wing during swept-wing flight is same with it of vertical take off.
When CUBE Wing reaches a steady flight, the front vertical motor is stopped and covered with canopy in order to minimize the air resistance.
The two propellers for forward flight eliminate the anti-torque and guarantee stable flight during not only the transition from vertical take off to horizontal flight but the rapid throttle change.