Propellers Flashcards
How the fuck is aircraft electrical power for propeller deicer systems transferred from the engine to the propeller hub assembly?
By slip rings and brushes.
How is anti-icing fluid ejected from the slinger ring on a propeller?
By centrifugal force.
On most reciprocating multiengine aircraft, automatic propeller synchronization is accomplished through the actuation of the what?
propellers governors.
Propellers fluid anti-icing systems generally use which of the following?
Isopropyl alcohol.
What is a function of the automatic propeller synchronizing system on multiengine aircraft?
To control engine RPM and reduce vibration.
Ice formation on a propeller blade will…
produce unbalance and vibration.
What unit in the propeller anti-icing system controls the output of the pump?
Rheostat.
Proper operation of electric deicing boots on individual propeller blades may best be determined by what?
feeling the sequence of boot heating and have an assistant observe the load meter indications.
A propeller synchrophasing system allows a pilot to reduce noise and vibration by what?
adjusting the phase angle between the propellers on an aircraft’s engines.
Which of the following determines oil and grease specifications for lubrication of propellers?
Propellers manufacturer’s instructions.
Grease used in aircraft propellers reduces the frictional resistance of moving parts and is easily molded into any form under pressure. This statement defines what?
antifriction and plasticity characteristics of grease.
What type of imbalance will cause a two-blade propeller to have a persistent tendency to come to rest in a horizontal position (with the blades parallel to the ground) while being checked on a propeller balancing beam?
Vertical.
What is the purpose of an arbor used in balancing a propeller?
To support the propeller on the balance knives.
If a blade of a particular metal propeller is shortened because of damage to the tip, the remaining blade(s) must be what?
reduced to conform with the shortened blade.
The application of more protective coating on one blade than the other when refinishing a wood propeller…
may be necessary to achieve final balancing.
Apparent engine roughness is often a result of propellers unbalance. The effect of an unbalanced propeller will usually be what?
greater at high RPM.
Which of the following is used to correct horizontal unbalance of a wood propeller?
Solder.
Propellers aerodynamic (thrust) imbalance can be largely eliminated by what?
correct blade contouring and angle setting.
A powerplant using hydraulic controlled constant-speed propeller is operating within the propeller’s constant-speed range at a fixed throttle setting. If the tension of the propeller governor control spring (speeder spring) is reduced by movement of the cockpit propeller control, the propellers blade angle will what?
increase, engine manifold pressure will increase, and engine RPM will decrease.
Why is the pulley stop screw on a propeller governor adjustable?
To limit the maximum engine speed during takeoff.
During engine operation at speeds lower than those for which the constant speed propeller control can govern in the INCREASE RPM position, the propellers will what?
remain in the full LOW PITCH position.
When engine power is increased, the constant-speed propeller tries to function so that it will what?
maintain the RPM, increase the blade angle, and maintain a low angle of attack.
The propellers governor controls the what?
oil to and from the pitch changing mechanism.
During the on-speed condition of a propeller, the…
centrifugal force of the governor flyweights is equal to the speeder spring force.
What actuates the pilot valve in the governor of a constant-speed propeller?
Governor flyweights.
What action takes place when the cockpit control lever for a hydromatic, constant-speed propeller is actuated?
Compression of the speeder spring is changed.
What will happen to the propellers blade angle and the engine RPM if the tension on the propellers governor control spring (speed spring) is increased?
Blade angle will decrease and RPM will increase.
How does the propellers over speed governor on a turboprop engine decrease propeller RPM?
As oil pressure increases, the servo piston is pushed forward, and the feather spring is compressed.
How is the speed of a constant-speed propeller changed in flight?
By changing the load tension against the flyweights in the governor.
When the centrifugal force acting on the propellers governor flyweights overcomes the tension on the speeder spring, a propeller is in what speed condition?
Over speed.
What operational force causes the greatest stress on a propeller?
Centrifugal force.
What operational force tends to increase propeller blades angle?
Aerodynamic twisting force.
How is a propeller controlled in a large aircraft with a turboprop installation?
By the engine power lever.
How does the aerodynamic twisting force affect operating propeller blades?
It tends to turn the blades to a high blade angle.
Which of the following best describes the blade movement of a propeller that is in the high RPM position when reversing action is begun?
Low pitch directly to reverse pitch.
Propellers exposed to salt spray should be flushed with what?
Fresh water.
How can a steel propeller hub be tested for cracks?
By magnetic particle inspection.
Which of the following functions requires that use of a propeller blades station?
Measuring blade angle.
The propellers blade angle is defined as the acute angle between the airfoil section chord line (at the blade reference station) and which of the following?
The plane of rotation.
During which of the following conditions of flight will the blade pitch angle of a constant-speed propeller be the greatest?
High-speed, high-altitude cruising flight.
The actual distance a propeller moves forward through the air during one revolution is known as the what?
effective pitch.
The pitch-changing mechanism of the hydromatic propeller is lubricated by what?
the pitch-changing oil.
What is the result of moving the throttle on a reciprocating engine when the propeller is in the constant-speed range with the engine developing cruise power?
Opening the throttle will cause an increase in blade angle.
Propellers blade stations are measured from the what?
hub centerline.
The thrust produced by a rotating propeller is a result of what?
an area of decreased pressure immediately in front of the propeller blades.
Why is constant-speed counterweight propeller normally placed in full HIGH PITCH position before the engine is stopped?
To prevent exposure and corrosion of the pitch changing mechanism.
The low pitch stop on a constant-speed propeller is usually set so that what?
the engine will turn at its rated takeoff RPM at sea level when the throttle is opened to allowable takeoff manifold pressure.