Large-sized aerial vehicles can take off and land vertically, and hover horizontally. All flight motions depend mainly on changing the direction of the rotor stub wing, which enables aerial vehicles to lift and land vertically and cruise horizontally. However, applying such a function to unmanned aerial vehicle can result in problems. Unmanned aerial vehicle have much higher Horse power to weight ratio than crewed airplanes. Applying the construction of large-sized aircraft to unmanned aerial vehicle, which are much smaller and lighter, may cause unmanned aerial vehicle to deflect and thus lose balance. Speedier gyroscope and computing processor are therefore applied to speed up computing. As a consequence, unmanned aerial vehicle can become heavier and incur more production cost. To cope with this defect, this paper proposes a different design, the key point of which is forming a 60 degree to 90 degree angle between the propeller rotating axis and moving direction. The two power-plants constitute an isosceles triangle, therefore solving the long-existing problem.