Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
33 Cards in this Set
- Front
- Back
Explain all 3 lines on the L over D chart -
|
CL - measure of the aerofoil ability to produce lift (critical 16 deg)
CD - measure of the aerofoil ability to produce drag (parasite + induced) L/D - aerofoil efficiency max at 4 deg - min L/D is best endurance (min power = best range) |
|
Using an aircraft model, explain Dutch Roll -
|
- lateral stability (roll) stronger than directional stability (yaw)
- stability is the tendency to return to original position after disturbance 1. A/C rolls left 2. A/C sideslips left (due L&W not directly opposed) 3. RAF from the left, A/C yaws left 4. Wings level right (strong lateral) 5. A/C sideslips right etc. |
|
Lateral stability increased by -
|
-dihedral wings (increase A/A on downgoing wing = increase lift)
- sweepback wing (downgoing wing more lift due more span +aspect ratio to RAF) - high keel (high fin, T-tail or high wing), low CG |
|
Directional stability increased by -
|
- large fin area and keel
- long moment arm (from CG) |
|
What can cause Dutch Roll?
|
- use of rudder at high subsonic Mach
- turbulence |
|
Explain yaw dampers and why a/c would have more than 1 -
|
- small control surface driven by rate gyro (on rudder)
- prevent/min unwanted yaw - 2; one for upper, one for lower surface. Seperate couple for redundancy - usually limited movement to prevent full rudder deflection in malfunction - autopilot requires 1 before can be engaged |
|
IAS vs. TAS in a climb - bigger, lesser or same?
|
- climb at fixed IAS, Mach + TAS increase
-climb at fixed Mach, IAS + TAS decrease - SoS slower in cold air (climb) - SoS constant in troposhere (36,000ft) |
|
What do vortex generators do at low airspeed? How do they help?
|
- energize boundary layer, cause turbulent layer
- produces more drag, less lift but remains attached at high A/A - good for a/c that cruise at low IAS so moderate A/A |
|
What happens to Mach if you climb at a constant IAS?
|
- altitude increases, TAS increases due less density
- as alt increases SoS decreases due cold air - Mach INCREASES |
|
What are the advantages of aft CG?
|
- less L+W nose down couple
- less downforce needed by stabilizer - less A/A, less drag = increase range, speed, endurance |
|
What type of engines does the CX B747 have?
|
RB211-524G/H-T
|
|
Tell us about the RB211 and RB211-524 -
|
- RR 1st 3 spool engine
- 524G/H more thrust - G = 58,000lb - H = 60,600lb - redesigned fan and IP compressor - 1st to feature Full Authority Digital Engine Control - Trent = better HP compressor, lighter, fuel effecient, less emissions so -T series |
|
What is Hong Kong's location?
|
22 deg 20 min N
114 deg 11 min E |
|
Explain the benefits and attributes of horizontal stab fuel tanks -
|
- Airbus: trim fuel
- decrease cruise drag by moving CG (disadvantage = weight + complex in failure) - in climb fuel aft = nose up attitude, less downforce - in descent fuel forward = slow speeds, nose down, easier to manouevre (stall recovery) - Pros: manipulate CG directlly, change CG with little mass movement, CG close to optimum |
|
Explain why swept wings -
|
- delay effects of compressibility (shockwaves, drag)
- allows cruise at higher Mach - increases lateral stab - less lift, higher max A/A so lower drag |
|
Limitations of swept wings -
|
- change in tip flow direction = reduce effective angle
- flow compression at wing root = more drag than theoritical |
|
Disadvantages of swept wings -
|
- lower increase in lift, higher stall angle
- high drag at high A/A, boundary layer seperation (control: slats/slots, vortex gen, saw tooth) - high min drag (speed brake) - tip stalling (wash out, boundary layer control) - deep stall (pusher/shakers) |
|
Why do wing tips stall first on swept wing?
|
- all aerofoil have tendency to stall tip 1st
- swept wing lateral and LONGITUDINAL controls difficult - CP moves up wing (towards root) = smaller moment between CP and CG, less manourverable |
|
What kind of flaps does the B747 have?
|
- Triple slotted trailing edge (fowler??): increases chord then camber
- slots directs HP from under wing to remain attached to flap = lift - Krueger flap; hinged at LE from UNDER surface wing. Increase camber and max CL |
|
What types of flaps are there?
|
Plain, slotted, split, fowler, zap, krueger
|
|
What a/c do we use from JFK to HKG?
|
B777-300ER to North America (New York)
|
|
Where are JFK, O'Hare, LAX and SFO international airports?
|
New York, Chicago, LA, San Francisco
|
|
Explain ETOPS -
|
- Extended-range Twin-engine Operational Performance Standards
- allows twin airliners (A330, A350, B777) to fly long distance routes. - refers to SE flight times between diversion airfields (if more than 60 min) - now 180 max at entry to service - extended to 240min case by case (+probation 24 mths etc.) - A350 plan on 350min, B777 330min - 2 stages: 1. type approval, 2. Operational certification (based on operator) |
|
Explain the fuel system on the A330 -
|
- A330/A340 fuel transfer between wing+centre tanks and fuel tank in horizontal stab (by FADEC)
- optimize a/c CG for cruise - CG trimmed with fuel weight, rather than drag inducing aerodynamic trims in elevators |
|
Population of HK?
|
7 million
|
|
Where does CX fly in North America?
|
Vancouver, Toronto, New York, Chicago, LA, San Francisco
|
|
What's the name of CX first a/c?
|
'Betsy'- retired in 1955, found 30 years later in Aus.
- HK science museum |
|
When is CX anniversary?
|
24 September 1946 (66 years old this year)
|
|
Who were the founding members of CX?
|
- American: Roy C Farrell
- Australian: Sydney de Kantzow |
|
How many days a month would you expect to fly?
|
SO = 12 rostered days a month
- 21 days annual leave |
|
CX is not really a global airline, what continent don't we fly to?
|
Antartica!
- Others: Asia, Europe, Australia, Africa, North America, South America |
|
What percentage of HK is chinese?
|
95%
- Other: Filipino, Indo, Westerners, Indian, Nepalese, Japanese, Thai, Pakastani |
|
What is Fly-by-wire?
|
- movements of flight controls converted to electronic signals by wires
- flight computers determine how to move actuators to provide ordered response - auto stability (gyros with sensors) - quadruplex for redundancy - weight saving, smaller stabilizers - Airbus A320 1st all digital airliner - B777 1st boeing. Yoke visual feel. Will operate outside limits in emerg. |