Aerodynamics 2 COPY Flashcards
DESCRIBE the performance characteristics and purpose of the best climb profile for the T-6B,
Best climb speed will meet or exceed any obstacle clearance requirements while providing a greater safety margin than slower airspeeds.
DEFINE absolute ceiling, service ceiling, cruise ceiling, combat ceiling, and maximum operating ceiling
Combat ceiling: Altitude where max power excess allows only 500 fpm ROC.
Cruise ceiling: altitude at which an airplane can maintain only a 300 fpm ROC.
Service ceiling: altitude at which an airplane can maintain only a 100 fpm ROC.
Absolute ceiling: The altitude at which an airplane can no longer perform a steady climb since maximum thrust excess is zero.
Operational ceiling: 31,000 ft for the T-6B
DESCRIBE the locations of the regions of normal and reverse command on the turboprop power curve
The region of normal command for a turboprop occur at velocities greater than maximum endurance airspeed (the lowest point on the power required curve).
The region of reverse command for a turboprop occurs at velocities less than maximum endurance airspeed.
EXPLAIN the relationship between power required and airspeed in the regions of normal and reverse command
In the region of normal command, more power is required for the airplane to go faster while maintaining altitude.
In the region of reverse command, more power is required for the airplane to fly at slower airspeeds and maintain altitude.
DEFINE nosewheel liftoff/touchdown speed
The lowest speed that a heading and course along the runway can be maintained with full rudder and ailerons deflected when the nosewheel is off the runway; The minimum safe airspeed that the noswheel may leave the runway during takeoff, or the minimum airspeed at which the nosewheel must return to the runway during landing.
STATE the pilot speed and attitude inputs necessary to control the airplane during a crosswind landing
The pilot must approach at a speed above NWLO/TD. He will maintian directional control with the rudder and apply ailerons to overcome the lateral stability that is trying to roll the airplane away from the crosswind.
STATE the crosswind limits for the T-6B
Maximum crosswind component for takeoff or landing in the T-6B is 25 knots.
DEFINE hydroplaning
When the airplane’s tires skim atop a thin layer of water on a runway.
DESCRIBE the effects of propeller slipstream swirl, P-factor, torque, and gyroscopic precession as they apply to the T-6B
- Torque will tend to roll the airplane’s fuselage counter-clockwise. Rudder and the automatic Trim Aid Device (TAD) are the primary means of compensating for engine torque.
- Propeller Factor (P-factor) is the yawing moment caused by one prop blade creating more thrust than another. It will cause the airplane to yaw right at high speeds and yaw left at low airspeeds.
- Slipstream Swirl is the corkscrew motion that the propeller imparts to the air. It causes the airplane to yaw left when at high power settings and low speeds.
- Gyroscopic Precession is a consequence of the properties of spinning objects. When a force is applied to the rim of a spinning object, a resultan force is created 90° ahead in the direction of rotation. Pitching the nose of the T-6B down causes the airplane to yaw left.
DESCRIBE what the pilot must do to compensate for propeller slipstream swirl, P-factor, torque, and gyroscopic precession as they apply to the T-6B
- To compensate for torque, the pilot must apply right rudder at high power settings
- To compensate for P-factor, the pilot must apply right rudder when at high power and low airspeeds and left rudder when at high power and high airspeeds.
- To compensate for slipstream swirl, the pilot must apply right rudder when at high power and low airspeeds.
- To compensate for gyroscopic precession, the pilot must apply right rudder while pitching down, and left rudder when pitching upt
DESCRIBE the effect of lift on turn performance
An increase in lift will result in greater turn performance by allowing an increased angle of bank.
DESCRIBE the effect of weight on turn performance
Turn rate and radius are independent of weight.
DESCRIBE the effect of thrust on turn performance
An airplanes thrust may limit turn performance since you must have sufficient thrust to overcome the induced drag created at high load factors.
DESCRIBE the effect of drag on turn performance
An increase in drag will limit speed, thereby increasing turn rate and decreasing turn radius.
DEFINE turn radius and turn rate
Turn radius (r) is a measure of the radius of the circle the flight bath scribes.
Turn rate (ω) is the rate of heading change measured in degrees per second.
DESCRIBE the effects of changes in bank angle on turn performance
Increasing bank angle will increase the turn rate and decreas the turn radius (increased turn performance)
DESCRIBE the effects of changes in airspeed on turn performance
Increasing airspeed (same bank angle) would decrease the turn rate and increase turn radius (decreased turn performance)
DESCRIBE the effects of aileron and rudder forces during turns
Aileron is used to set the angle of bank while rudder is used to coordinate the turn. Too much rudder in the direction of the turn will result in a skid. Opposite, or insufficient rudder the direction of the turn will result in a slip.
EXPLAIN the aerodynamic principle that requires two G’s of backstick pressure to maintain level, constant airspeed flight, at 60 degrees angle of bank
In a turn, the lift vector is divided into two components, the horizontal component of lift which turns the airplane and the vertical component of lift which opposes gravity. In a level turn, the vertical component of lift must be equal to weight, therefore as bank increases, total lift must increase. at 60 degrees of bank, lift must be double weight. Load factor is equal to lift over weight (2 G).
DESCRIBE the relationship between load factor and angle of bank for level, constant-airspeed-flight
Load factor increases gradually at low angles of bank, but exponentially at angles greater than 60°
DEFINE load, load factor, limit load factor, and ultimate load factor
Load is a stress-producing force that is imposed upon an airplane or component.
Load factor (n) is the ratio of total lift to the airplane’s weight.
Limit Load Factor is the greatest load factor an airplane can sustain without any risk of permanent deformation.
Ultimate Load Factor is the maximum load factor that the airplane can withstand without structural failure.
DEFINE static strength, static failure, fatigue strength, fatigue failure, service life, creep, and overstress/over-G
Static strength is a measure of a material’s resistance to a single application of a steadily increasing load or force.
Static failure is the breaking or serious permanent deformation of a material due to a single application of a steadily increasing load or force.
Fatigue strength is a measure of a material’s ability to withstand a cyclic application of load or force.
Fatigue failure is the breaking of a material due to a cyclic application of load or force.
Service life is the number of applications of load or force that a component can withstand before it has the probability of failing.
Creep is when a metal is subjected to high stress and temperature and it tends to stretch or elongate.
Overstress/Over-G is the condition of possible permanent deformation or damage that results from exceeding the limit load factor.
DEFINE maneuvering speed, cornering velocity, redline airspeed, accelerated stall lines, and the safe flight envelope
Maneuvering speed (Va) or cornering velocity is the indicated airspeed that an airplane can achieve its maximum turn rate and minimum turn radius. The slowest velocity that an airplane can generate its limit load. It is usually the recommended turbulent air penetration airspeed.
Redline airspeed (VNE) is the maximum permissible airspeed for an airplane. Beyond the redline airspeed, a pilot may experience control problems and structural damage to the aircraft due to aeroelastic effects.
Accelerated stall line: a curved line describing the number of g’s that can be generated at a given indicated airspeed as a function of CLMAX angle of attack for a particular airfoil. Also called maximum lift.
Safe flight envelope: The portion of the V-n diagram that is bounded on the left by the accelerated stall lines, on the top and bottom by the positive and negative limit loads, and on the right by redline airspeed. An aircraft may operate in its safe flight envelope without exceeding its structural or aerodynamic limits.
DESCRIBE the boundaries of the safe flight envelope, including accelerated stall lines, limit load factor, ultimate load factor, maneuver point, and redline airspeed
The safe flight envelope is bounded on the left by the accelerated stall lines, on the top and bottom by the positive and negative limit loads, and on the right by redline airspeed. An aircraft may operate in its safe flight envelope without exceeding its structural or aerodynamic limits. load factor is the vertical scale, while airspeed is the horizontal scale. maneuver point is the point where the accelerated stall line and the limit load factor line intersect.
