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21 Cards in this Set
- Front
- Back
In supersonic flight, unlike subsonic flight, supersonic flow has fixed or variable density?
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Variable.
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In supersonic flow through a convergent duct, what happens to velocity / pressure / density?
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Decrease Velocity
Increase Pressure Increase Density |
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In supersonic flow through a divergent duct, what happens to velocity / pressure / density?
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Increase Velocity
Decrease Pressure Decrease Density |
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What does Mach Number represent?
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The percentage of the current speed of sound.
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What is the formula for calculating the TAS for a given Mach Number?
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TAS = 39 x √K
0 degress C = 273K |
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Define the following terms:
M (fs) Local Mach Number M (crit) |
1. Free stream mach number - the mach number of the whole aircraft thru the air.
2. The mach number of the flow at a particular aircraft point. 3. The mach number that produces the first evidence of local sonic flow. |
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M (cdr)
M (det) M (mo) |
1. Slightly above M (crit) where significant shockwave drag problems develop.
2. The number at which the bow wave attaches to the leading edge of the aerofoil or A/C nose. 3. Maximum Operating Mach Number. |
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What are the speed ranges for the following phases of flight;
Subsonic Transonic Supersonic |
Subsonic = 0 - 0.75M
Transonic = 0.75 - 1.20M Supersonic = 1.20 - 5.00M |
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Mach Tuck is a result of what moving rearwards as the aircraft accelerates?
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Center of Pressure
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How does a swept wing reduce the onset of compressibility effects?
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A swept wing is presented to the airflow at a less than perpendicular angle. More perpendicular = quicker onset of effects.
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List 5 advantages of a sweep back design.
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1. Delayed onset of compressibility effects.
2. Increased M (crit) & M (cdr) 3. Increased Force Divergent Number. 4. Reduced magnitude of CL changes. 5. Improved lateral stability and slight improvement in directional stability. |
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List 6 disadvantages of a sweep back design.
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1. Increased chance of tip stall.
2. Reduced CL Max. 3. Reduced trailing edge effectiveness. 4. Structural complexity. 5. Possible dutch roll tendencies. 6. High induced drag at high AoA. |
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Explain Dutch Roll.
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The increasing dominance of lateral stability over directional stability.
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Describe the 2 types of Yaw Dampers.
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1. Parallel - moves rudder pedals and must be off for T/O & LDG.
2. Series - doesn't move pedals and can be on for all stages of flight. |
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What happens to the stalling EAS & IAS as altitude increases?
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They both increase, but IAS increases by the greater margin.
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What does the speed V imd represent?
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Speed of minimum total drag.
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V imd is also representative of what scenarios?
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1. Best Lift/Drag ratio
2. Best Endurance (Minimum Fuel Flow) 3. Max Excess Thrust, ie Best Angle of Climb |
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Maximum still air range occurs at what speed?
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1.32 x V imd
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In a strong headwind, fly _______than V imd to achieve max range.
In a strong tailwind, fly _______than V imd to achieve max range. |
Faster................Slower.
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Best Endurance is flown at what speed?
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V imd
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As fuel is burnt during the cruise, the drag curve moves which direction?
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Down and to the Left.
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