Last Updated on 4 years by teboo
081 07 01 00 Conversion of engine torque to thrust
081 07 01 01 Explain conversion of aerodynamic force on a propeller blade
081 07 01 02 Relevant propeller parameters
(01) Describe the geometry of a typical propeller blade element at the reference section:— blade chord line;
— propeller rotational velocity vector;
— true airspeed vector;
— blade angle of attack;
— pitch or blade angle;
— advance or helix angle.
Define ‘geometric pitch’, ‘effective pitch’, and ‘propeller slip’. Remark: For theoretical knowledge examination purposes, the following definition is used for geometric pitch: the theoretical distance a propeller would advance in one revolution at zero blade angle of attack. (02) Describe how the terms ‘fine pitch’ and ‘coarse pitch’ can be used to express blade angle.
081 07 01 03 Blade twist
(01) X Define ‘blade twist’. (02) Explain why blade twist is necessary.081 07 01 04 Fixed pitch and variable pitch/constant speed
(01) X List the different types of propellers:— fixed pitch;
— adjustable pitch or variable pitch (non-governing);
— variable pitch (governing)/constant speed. (02) Discuss the advantages and disadvantages of fixed-pitch and constant-speed propellers. (03) Discuss climb and cruise propellers. (04) Explain the relationship between blade angle, blade angle of attack, and airspeed for fixed and variable pitch propellers. (05) Describe and explain the forces that act on a rotating blade element in normal, feathered, windmilling, and reverse operation. (06) Explain the effects of changing propeller pitch at constant IAS.
081 07 01 05 Propeller efficiency versus speed
(01) Define ‘propeller efficiency’. (02) Explain and describe the relationship between propeller efficiency and speed (TAS) for different types of propellers. (03) Explain the relationship between blade angle and thrust.081 07 01 06 Effects of ice on propeller
(01) Describe the effects and hazards of ice on a propeller.081 07 02 00 Engine failure
081 07 02 01 Windmilling drag
(01) Describe the effects of an inoperative engine on the performance and controllability of an aeroplane:— thrust loss/drag increase;
— influence on yaw moment during asymmetric power.
081 07 02 02 Feathering
(01) Explain the reasons for feathering a propeller, including the effect on the yaw moment, performance and controllability.081 07 03 00 Design features for power absorption
081 07 03 01 Propeller design characteristics that increase power absorption
(01) X Name the propeller design characteristics that increase power absorption.081 07 03 02 Diameter of propeller
(01) Explain the reasons for restricting propeller diameter.081 07 03 03 Number of blades
(01) X Define ‘solidity’. (02) Describe the advantages and disadvantages of increasing the number of blades.081 07 03 04 Propeller noise
(01) X Describe how propeller noise can be minimised.081 07 04 00 Secondary effects of propellers
081 07 04 01 Torque reaction
— counter-rotating propellers;
— contra-rotating propellers.
081 07 04 02 Gyroscopic precession
(01) X Describe what causes gyroscopic precession. (02) X Describe the effect on the aeroplane due to the gyroscopic effect.081 07 04 03 Slipstream effect
(01) Describe the possible effects of the rotating propeller slipstream.081 07 04 04 Asymmetric blade effect
(01) Explain the asymmetric blade effect (also called P factor). (02) Explain the influence of direction of rotation on the critical engine on twin-engine aeroplanes.081 07 04 05 Hazards and management of propeller effects
(01) Describe, given direction of propeller rotation, the propeller effects during take-off run, rotation and initial climb, and their consequence on controllability. (02) Describe, given the direction of propeller rotation, the propeller effects during a go-around and their consequence on controllability. (03) Explain how the hazards associated with propeller effects during go-around can be aggravated by:— high engine performance conditions and their effect on the VMC speeds;
— loss of the critical engine;
— crosswind;
— high flap setting;
— engine failure at the moment of the go-around.