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29 Cards in this Set
- Front
- Back
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Describe positive static stability |
The disrupted body will move back to its original position (ball in a bowl) |
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Describe negative static stability |
Object continues to move away from original position post-disruption (ball pushed down a hill) |
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Describe neutral static stability |
Object moved from original position will stay in its new position once disrupted (ball on a table) |
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Describe dynamic positive stability |
A body continuously returning to (and through) its original position. E.g a pendulum |
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What name is given to waves that demonstrate dynamic positive stability with damping? |
Damped phugoid oscillation |
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Can positive dynamic stability occur if the body never reaches its original position/reaches it once? |
Yes. If the inside of a bowl is sticky and a ball still rolls slowly to the centre, it’s still classified as positive dynamic stability. |
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Describe neutral dynamic stability |
A perfect sine wave of motion with no damping or amplification. Also known as simple harmonic motion. |
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What five factors affect dynamic stability? |
-Momentum -Static stability in roll, pitch, and yaw -Angular velocity about the three axes -Moments of inertia about the three axes -Aerodynamic damping |
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Describe a longitudinal dihedral |
The tail plane is set at a lower angle of incidence than the main plane, providing a stabilising influence to the airframe, and making the aircraft “rest” slightly nose up |
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Describe a lateral dihedral and its advantages |
Wing tips are higher than the wing root. This produces a stable rolling moment whenever sideslip is present, or when the aircraft is flying with one wing higher than the other |
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What are the four factors that impact a lateral dihedral? |
Dihedral angle, slope of the lift curve, aspect ratio, and wing taper |
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What is damping in roll? |
AoA (and therefore the CL) of the down-going wing is higher than that of the up-going. This resists rolling movement, and the effect is proportional to roll rate. |
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When flying for endurance, the goal is to minimise what factor (and how do we find this)? |
Gross fuel consumption (GFC). Found by multiplying specific fuel consumption by time. |
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When flying for endurance, what speed do we want to fly at? |
Vmp with an added 10kts buffer |
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What is the advantage of flying low (for engines)? |
Less power is required |
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What is the advantage of flying high (for engines)? |
Engines are more efficient in cold temperatures |
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What is specific air range, and how do we calculate it? |
A measure of an aircraft’s efficiency in a given mode. SAR = distance travelled / fuel used |
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What six forces acting on a prop do you need to know, and how are they drawn? |
Back (Definition) |
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What do we need to know for the spinning graph? |
Back (Definition) |
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What are the four yaw effects we may experience at takeoff? |
Gyroscopic effect; Asymmetric blade effect (P effect); Slipstream effect; Torque reaction |
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What six forces acting on a prop do you need to know, and how are they drawn? |
Back (Definition) |
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Define Mach local |
Speed of air at a specific location around the aircraft. |
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Define EAS |
Equivalent airspeed, which is IAS corrected for pressure errors and instrument errors. |
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What four factors affect engine power? |
RPM Altitude Temperature Velocity |
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What is the center of gravity margin? |
the distance of CG movement until neutrally stable. This is an indicator of the degree of longitudinal stability. |
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What does the graph of TAS (ground speed) with varying wind vs power required show? |
Back (Definition) |
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What are the sonic speed ranges? |
Back (Definition) |
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What are the stages of spin and what do they involve? |
Back (Definition) |
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How does a swept wing affect lateral stability, and what effects the magnitude of effect? |
It improves it. Angle of the sweep, aspect ratio of the wing, and the taper ratio |
