The Test Flashcards
Three ways of decelerating an aircraft once it has landed?
Full flap Brakes Thrust Reverse Spoilers Parachutes
What is flutter?
Causes wings and or stabilisers to oscillate
Name the types of aerodynamic balance
Horn balance Insert hinges Balance tabs Spring tabs Servo tabs
Elevators attached to the horizontal stabiliser control what?
Pitch about the lateral axis
Three types of drag?
Friction
Lift
Total
Methods of improving directional stability
Add dorsal fin
Add a ventral fin
Extending the length of the fuselage
Increase the size of the fin
Aircraft generally fly in?
Stratosphere
Troposphere
Methods of boundary layer control?
Suction
Blowing
Vortex generators
Air jets
Explain the function of vortex generators
Energise the boundary layer
Allows laminar air flow and transition point to extend back along aerofoil
Increasing lift and reducing drag
Stagnation/total pressure
Static pressure + Dynamic pressure
Sea level ISA values
Temp- 15*
Pressure- 1013 millibar
Density- 1.226 kg/m3
Why is the Isa required?
Compare aircraft
Calibrate instruments
ISA
International Standard Atmosphere
Purpose of flaps
Change camber & AOA without changing wing angle or it’s attitude
What angle of incidence is a wing attached to give the best L/D ratio
4*
Normal cambered wing stalls at?
15-16* AOA
Most effective combination of leading and trailing edge devices?
Slats & thrills slotted Fowler flaps
Total reaction of an aerofoil in an air stream is affected by? 6
Density (p) Velocity (v) of airflow Wing area(s) Angle of Attack(&) Surface finish Aerofoil shape
Benefits of a Fowler flap
Increase camber
Increase Alpha @ same attitude
Increase surface area
Energise boundary layer if slotted
Ways in which roll stability can be achieved
High vertical tail fin
Sweep back
High wing or low CG
Dihedral
Explain the purpose of
Anhedral wings?
Dihedral wings?
They both increase stability.
A- used to reduce +ve static lateral stability
Define aspect ratio
Span/chord
The ratio of span to chord
Rudders attached to the fin, control what?
Yaw, normal axis
Ailerons attached to the wings, control what?
Roll about longitudinal axis
Converging duct/ Venturi?
Dynamic pressure & velocity increasesincreases,
The distance between the tips of the wings?
Span
Wash out
The reduction in angle of incidence towards the tip.
As angle of attack increases…
Total reaction increases together with lift and drag
What is the boundary layer?
Thin layer next to surface, slowed by surface friction & viscosity
How does boundary layer flow?
Laminar and becomes turbulent at the transition point
Point at which air separates from the wing?
Separation point. No lift lots of drag
How thick laminar layer
0.1-0.2
Stall?
No further increased lift with increased AOA
Negligible movement of CP with AOA on…
Symmetrical aerofoil
Total reaction is
Lift & drag
