Aerodynamics Of The Propeller

Classical aerodynamics is a compulsory study subject for pilots at all levels of experience. Propeller Aerodynamics is a subset of this fascinating subject. Propellers have their unique aerodynamic terminology, forces and handling requirements, knowledge of which all pilots must be aware of to safely handle the aircraft they are flying. Incorrect propeller handling can cause damage to the aircraft and reduce performance efficiency. Most aerodynamic text books only give a brief view of propeller aerodynamics; however this book Propeller Aerodynamics delves more deeply into this subject. The book covers the history and operation of aircraft propellers, prop pitch, thrust, efficiency, aircraft stability, prop forces, constant-speed units and more. This is all essential reading for the pilot progressing to more advanced high-performance aircraft.

Classical aerodynamics is a compulsory study subject for pilots at all levels of experience. Propeller Aerodynamics is a subset of this fascinating subject. Propellers have their unique aerodynamic terminology, forces and handling requirements, knowledge of which all pilots must be aware of to safely handle the aircraft they are flying. Incorrect propeller handling can cause damage to the aircraft and reduce performance efficiency. Most aerodynamic text books only give a brief view of propeller aerodynamics; however this book Propeller Aerodynamics delves more deeply into this subject. The book covers the history and operation of aircraft propellers, prop pitch, thrust, efficiency, aircraft stability, prop forces, constant-speed units and more. This is all essential reading for the pilot progressing to more advanced high-performance aircraft.

This report presents the results of an investigation conducted in the Langley 300 mph 7- 10-foot wind tunnel for the purpose of determining the aerodynamic characteristics of a model wing-propeller combination, and of the wing and propeller separately at angles of attack up to 90 degrees. The tests covered thrust coefficients corresponding to free-stream velocities from zero forward speed to the normal range of cruising speeds. The results indicate that increasing the thrust coefficient increases the angle of attack for maximum lift and greatly diminishes the usual reduction in lift above the angle of attack for maximum lift.

Introduction: The tests described in this report were made on a 1/8-full-size model of a large, long-range, twin-engine flying boat in NACA tank no. 1. The airplane had a wing loading of 43.9 pounds per square foot and a power loading of 11.5 pounds per horsepower. Its arrangement was such that 34.2 percent of the wing area and 56.1 percent of the horizontal tail area were included within the fore-and-aft projection of the propeller disks. The model was fitted with leading-edge slats to make the angle of attack for maximum lift coefficient correspond with that of the airplane at the low Reynolds number associated with the tank tests (3.28 x 105 based on the mean aerodynamic chord and the get-away speed of the model). The model was equipped with two three-blade metal propellers of scale diameter and form, power for which was furnished by two variable-frequency alternating-current motors. Sufficient power was available to develop scale thrust with the propellers. The tests were divided into two parts: (1) aerodynamic tests to determine the effect of the slipstream and thrust from the powered propellers on the lift and trimming-moment characteristics, and (2) hydrodynamic tests to determine the effect of the powered propellers on the range of stable locations of the center of gravity.