Aerospace

Stability: Static and dynamic stability 

Cessna: stable but not very maneuverable 

F16: Unstable but more maneuverable 

Stability: Static and dynamic stability can be described as positive, negative, or neutral 

Positive stability: moves away from area of disturbance 

Negative stability: moves toward area of disturbance 

Neutral: No movement 

Negative oscillation: increase over time

Positive: decrease 

Neutral: no increase or decrease 

Positive stability easier to control 

Stability all around the aircraft 

Roll stability: aircraft’s movement around longitudinal axis 

Roll stability depends on wing placement 

Engine placement affects pitch stability 

Asymmetric thrust causes problems 

Horizontal stabilizer: provides downforce to keep nose up in flight 

Vertical stabilizer: keeps airplane straight 

Short wings: Less stable, more maneuverable 

Long wings: More stable, less maneuverable 

CG affects maneuverability, as does airframe design 

Unstable aircraft: B-2 and F-117 

Helicopters are highly dynamic 

Parts of rotor: Hub, root, rotor blades, and the mast. 

Relative wind and induced flow 

Induced Flow: air the rotors push down 

Collective changes the pitch of the rotor blades. 

*Swash plate related to this 

Rotors produce gyroscopic motion 

Dissymmetry of lift: sometimes asymmetrical lift regarding the rotor blades. 

The advancing blade gets more lift, the retreating blade gets less lift. 

Blades need to “flap” to combat this 

Pitch changes throughout rotation 

Sometimes the retreating blade can stall 

Coriolis effect: Angular momentum is the moment of inertia represented by multiplied 

First helicopter blades made from aluminum (allows flapping) 

Semi-rigid: had a flapping hinge (allows feathering and flapping) 

Fully articulated: lets each blade flap by themselves (allows feathering, flapping, and hunting) 

Fuselage is suspended, so it oscillates. 

Weathercock stability refers to the helicopter’s tendency to weathervane into the relative wind. If tailwind is present, an uncommanded and rapidly accelerating yaw can occur. 

Stability: static or dynamic 

Elevator: controls pitch 

Ailerons: controls roll 

Rudder: controls yaw 

T-tail: elevator on top of vertical stabilizer 

Stabilator: entire horizontal stabilizer moves 

Front elevator called a canard 

Elevons: combine elevator and ailerons 

Flaperons: combination of flaps and ailerons 

Spoilerons: combination of spoilers and ailerons 

Cyclic: controls helicopter in any horizontal direction 

Anti-torque pedals: yaw 

Collective: increases or decreases lift 

Cable and pulley: used in most small airplanes 

Hydraulic: pilot inputs boosted by hydraulic pressure generated by hydraulic pumps 

Fly-by-wire: control surfaces are moved through electronic signals transmitted through wires to actuators 

A coordinated turn is one in which the relative wind is aligned with the aircraft’s fuselage 

Skidding: The airplane slides outside the arc of the turn 

Slipping turn: The airplane slides inside of the arc of the turn 

Secondary flight controls: improve an aircraft’s performance and can reduce pilot workload: 

-wing flaps 

-leading edge devices 

-trim systems 

-spoilers 

Types of flaps: plain, split, slotted, and fowler 

Fixed wing uas and single rotor have control surfaces similar to manned aircraft 

Multi rotor typically involve a different control method 

Quadcopter can hover, climb, descend, yaw, pitch, and roll 

To yaw on a drone, opposite motors increase lift 

Rate of turn formula is: 1,091 x tangent of the bank angle / airspeed in knots = degrees per second 

Radius of turn formula: v^2 / 11.26 x tangent of bank angle = feet 

Planes can handle up to a certain amount of Gs 

ISS: 0 g 

Earth: 1 g 

Roller coaster: 3.5-6.3 g 

Aerobatic plane / fighter jet: 9-12 g 

Missile: 100 g 

Negative Gs make you feel weightless and push you away 

Load factor is measured in Gs, the amount of force applied to an aircraft to deflect its flight from a straight line 

Normal, utility, acrobatic 

Aircraft have EG diagram 

Maneuvering speed: V(a) 

Pilot can fly between structural cruise speed and never-exceed speed in smooth air only