07-07-2012, 12:08 PM
Optical Computing
Optical Computing.ppt (Size: 713.5 KB / Downloads: 42)
PROPELLER MATERIAL
Composite and plastic propellers
Aluminum propellers
Stainless steel propellers
Fibreglass-reinforced Nylon
Fibreglass
Carbon Fibre
TYPES OF AIRCRAFT PROPELLERS
Fixed pitch
Wooden Propellers
Metal Propellers
Ground adjustable pitch
Two-position
Controllable pitch
Constant speed
Full Feathering
Reversing
PROPELLER FUNCTION
The propeller consist
of two or more blades
connected together
by a hub.
The hub serves to attach the blades to the engine shaft.
The blades are made in the
shape of an airfoil like wing
of an aircraft.
DESCRIPTION OF PROPELLERS
A propeller generates an aerodynamic force.
The propeller is rotated by the engine and this creates thrust and moves the aircraft forward.
Diameter is the width of the circle described by the rotating blades.
Leading Edge of the airfoil is the cutting edge that slices into the air.
As the leading edge
cuts the air,
air flows over the
blade face and
the camber side.
FORCES ACTING ON A PROPELLER
Five forces act on the blades of an aircraft propeller in motion:
Thrust bending force- thrust loads on the blades act to bend them forward.
Centrifugal twisting force- acts to twist the blades to a low or fine pitch angle.
Aerodynamic twisting force- the blade is twisted towards a coarse pitch position.
Centrifugal force- the force felt by the blades acting to pull them away from the hub when turning.
Torque bending force- propeller blades bend away from the direction of rotation.
Optical Computing.ppt (Size: 713.5 KB / Downloads: 42)
PROPELLER MATERIAL
Composite and plastic propellers
Aluminum propellers
Stainless steel propellers
Fibreglass-reinforced Nylon
Fibreglass
Carbon Fibre
TYPES OF AIRCRAFT PROPELLERS
Fixed pitch
Wooden Propellers
Metal Propellers
Ground adjustable pitch
Two-position
Controllable pitch
Constant speed
Full Feathering
Reversing
PROPELLER FUNCTION
The propeller consist
of two or more blades
connected together
by a hub.
The hub serves to attach the blades to the engine shaft.
The blades are made in the
shape of an airfoil like wing
of an aircraft.
DESCRIPTION OF PROPELLERS
A propeller generates an aerodynamic force.
The propeller is rotated by the engine and this creates thrust and moves the aircraft forward.
Diameter is the width of the circle described by the rotating blades.
Leading Edge of the airfoil is the cutting edge that slices into the air.
As the leading edge
cuts the air,
air flows over the
blade face and
the camber side.
FORCES ACTING ON A PROPELLER
Five forces act on the blades of an aircraft propeller in motion:
Thrust bending force- thrust loads on the blades act to bend them forward.
Centrifugal twisting force- acts to twist the blades to a low or fine pitch angle.
Aerodynamic twisting force- the blade is twisted towards a coarse pitch position.
Centrifugal force- the force felt by the blades acting to pull them away from the hub when turning.
Torque bending force- propeller blades bend away from the direction of rotation.