M17 HELICES PART I

How does propeller produce thrust? (1.2). By increasing the air pressure behind the propeller rotating plane. By accelerating large mass of air rearwards. By decelerating large mass of air rearwards.

What is the usual power setting pitch (max pitch) of a propeller? (1.2). 10° to 12°. 85° to 90°. 20° to 35°.

A fixed pitch propeller is normally more efficient at: (1.6). medium to high speeds at high altitudes. low to high speeds at high altitude. low to medium speeds at low altitudes.

Angle of attack on propeller is the angle: (1.3). between propeller chord line and direction of flight. between propeller chord line and relative wind direction. between propeller chord line axis of propeller.

Pitch or blade angle is the angle between (1.5). between propeller chord line and relative wind direction. between propeller chord line axis of propeller. propeller chord line and rotation plane of propeller.

There is (1.6). less pitch at the shank of propeller blade than at blade tip. less pitch at the tip of propeller blade than at blade shank. larger pitch at the end of propeller blade than at blade shank.

Characteristic positions of the propeller blade angle (blade station) in most cases is measured from: (1.5). 2 inches from the blade root. centerline of the engine. root of the blade.

The centrifugal force is acting on a propeller blade in the following manner: (1.9). It tends to pull out the blade and increase the blade pitch. It tends to pull out the blade and decrease the blade pitch. It tends to pull out the blade, without affect on the blade pitch.

Thrust bending force (1.9). bends propeller blades backward. bends propeller blades forward. pulls propeller blades out of hub.

For aircraft cruise, the following propeller pitch angle is mostly used: (1.9). Low pitch. Medium pitch. Feather.

The chord line of a propeller is: (1.6). a line joining the leading and trailing edge of a blade. a line joining tip and root of a blade. a line joining blade trailing edge and propeller hub axis.

The primary purpose of propeller is to (1.2). change engine horsepower to thrust. provide static and dynamic stability to aircraft. create lift on the fixed aerofoils of an aircraft.

Reverse blade pitch is (1.2). from -2° to -8°. from 2° to 8°. from -2° to 0°.

What is effective pitch stands for? (1.4). It is same as geometric pitch. It is geometric pitch minus slip. It is geometric pitch plus slip.

What is the "P-Effect" on a propeller aircraft? (1.10). It is the propeller assimetric disk loading which occurrs only during climb or descent. It is the propeller assimetric disk loading which occurrs only in cruise. It is the propeller assimetric disk loading which occurrs only during the thrust reverse application.

Torque on an aircraft with propeller engine acts (1.11). opposite the direction of propeller pitch. the same direction as it is the direction of propeller rotation. opposite the direction of propeller rotation.

Feather position of the fan blade is at (1.2). 80° to 85°. 85° to 90°. exactly at 90°.

What is the variable pitch propeller? (1.3). It is a propeller where blade pitch angle can be adjusted by maintenance crew before flight depending on the type of flight operation. It is a propeller where blade angle can be changed automatically during the operation, depending on command levers position. It is a propeller where the pitch is changing by using the basic propeller forces: mainly centrifugal and torque forces which change blade angle as required.

The actual distance a propeller moves forward through the air during one revolution is known as the: (1.4). relative pitch. effective pitch. geometric pitch.

A constant speed propeller provides maximum efficiency by: (1.2). increasing blade pitch as the aircraft speed decreases. increasing the lift coefficient of the blade. adjusting blade angle for most conditions encountered in flight.

What operational force tends to bend the propeller blades forward at the tip? (1.9). Thrust bending force. Torque bending force. Centrifugal twisting force.

A fiberglass composite blade (2.6). could not be struck by lighting, since fibreglass is not an electricity conductor. could not be struck by lighting due fast turning of the blades. requires lightning strike protection.

Centrifugal latches are fitted to lock the propeller (2.9). in feathered position in case of engine failure. in feathered position in case of propeller failure. in fine pitch position (usually before the engine shutdown).

During normal propeller operation, oil pressure for propeller operation is provided by: (2.8). the oil pump in the propeller governor. the oil pump in the propeller hub. the engine oil pressure pump.

The constant-speed control unit is also called: (2.8). propeller governor. propeller synchrophase control unit. propeller accumulator.

The following materials are mostly used for manufacture of modern propellers: (2.6). Wooden. Steel (hollow steel blades), composites (with or without metal spar) and aluminum blades. Composites (with or without metal spar) only.

The wood most often used today for propeller construction is (2.2). Balsa. Spruce. Birch.

What are the advantages of aluminium propellers? (2.5). Low cost of maintenance and the low weight. The resistance to acid and caustic solutions. Quick removal and installation and good resistance to the foreign object damage.

What is the benefit of contra-rotating propellers? (2.10). Less noise produced. Eliminates single propeller torque which acts on the aircraft. Decreased pitch of each propeller.

Propeller bolts when tightening propeller hub should be tightened using: (2.4). any tightening method. circle pattern. star pattern.

Propeller back is the side with: (2.7). Lower camber. Higher camber. Depends on the type of propeller (pusher or puller).

Ground-adjustable propellers (2.8). pitch can be changed while propeller is rotating. pitch can not be changed at all. pitch can be changed while propeller is not rotating.

What is the meaning of propeller blade "back" and "face"? (2.7). Both of them are blade areas away from the engine. The back faces away from the engine and is the cambered side. The face is in the direction of the engine and is the flat side. The face faces away from the engine and is the cambered side. The back is in the direction of the engine and is the flat side.

Tractor propeller is mounted (2.10). In front of the engine. At the back of the engine. In front or at the back of the engine.

While installing propeller mechanic should: (2.12). align index marks on spinner bulkhead and engine cowl. align index marks on spinner and engine cowl. align index marks on spinner bulkhead and spinner.

Oil pressure increase in governor means (2.8). no propeller pitch change. lower propeller pitch. higher propeller pitch.

What will happen if the CSU on twin engine turboprop aircraft leaks oil? (3.22). Propeller blades will go to higher pitch and RPM will fall. Propeller blades will go to lower pitch and RPM will fall. Propeller will go to higher pitch and RPM will increase.

When does the aerodynamic imbalance appear? (3.4). It is the imbalance which occurs when the center of gravity of the propeller does not coincide with the axis of rotation. When the thrust (or pull) of the blades is unequal. It is imbalance of the propeller when the centers of gravity of propeller elements (for example: counterweights or blades) do not follow the same plane of rotation.

During the operation in beta range, the propeller pitch is controlled (3.18). by power lever. by condition lever. by overspeed governor lever.

Which acts on a blade in direction of blade pitch decrease? (3.4). Centrifugal twisting moment (CTM). Thrust and torque force. Drag and lift force.

Why is feathering necessary on multi-engine aircraft? (3.8). To prevent the engine rotation, since its oil system is not functioning, the engine and propeller bearings could be damaged. To prevent the propeller turning and decrease of drag in case of engine failure. To enable the engine further operation in case of propeller failure.

Why, on some engines, the propeller is normally positioned to low pitch before the engine is stopped? (3.19). to prevent the moisture to enter in the propeller cylinder. to enable oil to remain in the propeller cylinder. to prevent overheating of the engine starter during next start.

Electrically controlled propeller use DC power and rotation: (3.26). to turn the propeller. electrically controled propellers do not exists. to control propeller blade pitch.

Which of these statements applies to a propeller that has been “feathered”? (3.15). Its leading edges are facing forwards in the direction of flight. It is operating at its maximum rotational speed. Its leading edges are facing 90 degrees to the direction of flight.

What device push propeller against the hydraulic pressure to high pitch? (3.4). Low pitch stop. Governor pilot valve. propeller counterweights.

If propeller blade angle is decreased and engine power remains the same, the RPM will: (3.2). Decrease. remain the same. increase.

If the engine power increases, the CSU (Propeller Governor) will retain the same RPM by : (3.2). increasing the blade angles. keeping constant blade angles. decreasing the blade angles.

Propeller auto feathering function is disarmed by pilot: (3.11). during landing. during T/O. in cruise.

How does the crew change the propeller RPM on a constant speed propeller? (3.3). Propeller RPMs are constantly changing during the flight (automatically). By moving the condition lever which changes the CSU speeder spring tension. By moving the power lever which changes the CSU speeder spring tension.

On most single acting propellers (on multi-engine aircraft) the following is correct: (3.4). Oil pressure moves the blades in direction of low pitch, spring in the direction of high pitch. Oil pressure moves the blades in direction of high pitch, spring in the direction of low pitch. Oil pressure moves the blades in direction of high pitch, pressurized nitrogen in the direction of low pitch.

Reduction gearbox allows the (3.19). blade tips to operate below the speed of sound. blade tips to operate above the speed of sound. In beta range the propeller pitch.

blade tips to rotate slower than the root of the propeller blade (3.18). not changing at all. not changed by governor but by fuel mixing lever. not changed by governor but by power lever position.

The governor oil pressure is approximately: (3.22). 200 psi. 300 psi. 40 psi.

54) As over speed protection the governor - when RPM becomes to high: (3.25). bleed off propeller servo oil into reduction gearbox sump and decrease the blade pitch. bleed off propeller servo oil into reduction gearbox sump and increase the blade pitch. increase servo oil pressure in reduction gearbox and increase the blade pitch.

55) The most efficient AOA varying from: (3.2). 10° to 12°. 5° to 7°. 2° to 4°.

What is the purpose of pilot valve within the CSU. (3.22). to receive the inputs from the pilot through the power lever in the cockpit. to receive the inputs from the pilot through the power lever in the cockpit auto feather the propeller in case of it's failure. it supplies the oil to the blade change mechanism, allows the oil to flow back into the scavenge oil system or it locks the system to keep the blade pitch constant.