1. Unit 2 Unmanned Aircraft
Module 1 The UAS Component
1.2 – Airframe and Wing Design

2. Airframe and Wing Design
Forces of Flight
Lift
Weight
Thrust
Drag
107.3 Definitions
The following definitions apply to this part. If there is a conflict between the definitions specified in §1.1 of the chapter, the definitions in this part control for purposes of this part:
Control station means an interface used by the remote pilot to control the flight path of the small unmanned aircraft.
Corrective lenses means spectacles or contact lenses.

3. Airframe and Wing Design
Lift
Opposes the downward force of weight
Produced by the dynamic effect of air acting on the airfoil
Acts perpendicular to the flight path through the center of lift
Weight
The combined load of the aircraft, crew, fuel, and cargo
Pulls downward due to gravity
Opposes lift acting vertically downward through the center of gravity (CG)

4. Airframe and Wing Design
Thrust
The forward force produced by the power plant/propeller or rotor
Opposes the force of drag
Generally acts parallel to the longitudinal axis
Drag
The rearward force caused by the disruption of airflow by the wing, rotor, fuselage, or other protruding object
Opposes thrust acts rearward parallel to relative wind

5. Airframe and Wing Design
Bernoulli's Principle
Describes basic principle of pressure differential
As the velocity of air increases the pressure of the air decreases

6. Airframe and Wing Design
Airfoils
Any surface that provides an aerodynamic force when interacted by a stream of air
Typical airfoils
air moves over the top and accelerates creating lower pressure
Air moving below slows down creating higher pressure and lift
Upwash is the deflection of oncoming air as it moves up and over the wing’s leading edge
Downwash is the deflection of the air down past the trailing edge of the wing

7. Airframe and Wing Design
Chord line is a line that connects the leading and trailing edges of a wing cross-section
Camber is the curvature of the surface of the upper and lower halves of the wing
Angle of attack is the angle between the cord line and the relative wind
Relative wind is wind parallel and opposite to the flight path

8. Airframe and Wing Design
107.3 Definitions
The following definitions apply to this part. If there is a conflict between the definitions specified in §1.1 of the chapter, the definitions in this part control for purposes of this part:
Small Unmanned Aircraft means an unmanned aircraft weighing less than 55 pounds on takeoff, including everything that is on board or otherwise attached to the aircraft.
Small unmanned aircraft system (small UAS) means a small unmanned aircraft and its associated elements (including communication links and components that control the small unmanned aircraft) that are required for the safe and efficient operation of the small unmanned aircraft in the national airspace system.

9. Airframe and Wing Design
Stall
Dangerous condition that results from the separation of air from the upper surface of an airfoil resulting in loss of lift
Velocity of air over the airfoil does not effect stall by is affected by angle of attack
The angle at which separation occurs is called the critical angle of attack
Separation starts at the trailing edge and works forward as the angle of attack increases

10. Airframe and Wing Design
Wing design factors
Wing design will affect the performance of the wing
Major wing characteristics include
Camber
Wing
Planform
Aspect ratio
Total wing area

11. Airframe and Wing Design
Aspect Ratio
The ratio between length and width of the wing
Higher aspect ratios give less drag for the same amount of lift

12. Airframe and Wing Design
Planform
The overall shape of the wing when seen from above or below
Elliptical
Have minimum drag but has a much more significant stall characteristic
Rectangular
Less efficient then elliptical
Stalls start at the wing root and work outwards, allowing ailerons to still be effective in a stall

13. Airframe and Wing Design
Tapering
Less drag then rectangular and more effective at higher speeds
Stalls start slightly inboard of the wing tips
Allows for higher aspect ratio and reduction of weight
Sweptback
Found in commercial airline jets
Provides better efficiency at higher speeds and decreases drag

14. Airframe and Wing Design
Wing types
Affect stability of the aircraft
Dihedral will produces a smaller movement
Anhedral reduces stability of the craft