aircraft propeller Flashcards
what was the first version of the propeller
rotating screw design
who invented the rotating screw design and when
Archimedes 200BC
introduced to aviation to distinguish between the aeronautical and marine type propellers
airscrew
introduced the idea of using two propellers on airships
jp paucton
what are the two propellers on airships for
propel the craft forward and lift it upward
who used the first airborne propeller on his hot air balloon and when
Jeanne Pierre Blanchard, October 16 1784
who invented the first full-size powered airship and when
Jules Henri Giffard, 1852
what are the components of the first full-sized powered airship
three-bladed propeller paired with a 3-horsepower steam engine
aviation pioneer who successfully built steerable aluminum airships powered by large wooden propellers and when
alberto santos-dumont, 1873
what was the firs successful controlled and sustained flight and when
Wright Flyer I December 17 1903
modern propellers are made from what materials + range of number of blades
aluminum or composite materials with two to six blades
converts the power output of the engine into forward thrust to move the aircraft through the air.
propeller
what is a propeller essentially is
rotating wing or airfoil
converts rotational energy into propulsive force creating thrust which is approximately perpendicular to its plane of rotation.
propeller
rotational energy can be produced by what
piston or gas turbine engine
two or more blades of propeller is connected by what
hub
It is the force that moves the aircraft through the air and it is generated by the propulsion system of an aircraft.
thrust
basic nomenclature of propeller
blade, blade back, blade face, shank, tip, hub, leading edge, trailing edge, blade station, blade angle, blade pitch
One arm of a propeller from the butt to the tip.
blade
The thickened portion of the blade near the hub of the propeller. sometimes referred to as the root. it is usually thick to give strengthand it’s cylindrical where it fits the hub barrel
shank
The surface of the blade as seen by standing in front of the propeller.
blade back
The surface of the blade as seen by
standing directly behind the propeller. is the surface of the propeller blade that corresponds to the lower surface of an airfoil or flat side.
blade face
The portion of the blade farthest from the hub.
tip
The central portion of the propeller that is fitted to the propeller shaft,
securing the blades by their roots.
hub
The forward or “cutting edge” of the blade that leads in the direction the propeller is turning.
leading edge
The edge of the propeller adjacent to the aft end of the hub. it is the rear edge of the airfoil, where the airflow separated by the leading edge rejoins.
trailing edge
These are reference lines, usually designed as measurements, made from the hub. These lines are numbered and locate positions on the propeller blade. They are usually designated at 6-inch intervals. The first station is normally 12 inches from the hub.
blade station
angle formed between the
propeller’s plane of rotation and the chord line of its airfoil section.is an angular measurement and is expressed in degrees.
blade angle
is the distance in inches that a propeller section will advance in one revolution.
blade pitch
a part of an airfoil that hits the air particle first.
leading edge
portion of the airfoil where the airflow over the upper surface rejoins the lower surface airflow
trailing edge
straight line joining the leading and trailing edges of an airfoil
chord line
imaginary line drawn halfway between the upper and lower surface of the airfoil. denotes the amount of curvature of an airfoil
mean camber line
upper surface of an airfoil
upper camber
lower surface of an airfoil
lower camber
in early development of propeller the first used materials in constructing propeller is this
wood
preferred for its greater homogeneity and material reliability
steel
most commonly used materials in constructing aircraft propeller in modern time
aluminum alloy
made from high strength fibers and resin that forms a durable and lightweight plastic
composite
forces acting on the propeller
centrifugal force, torque bending, thrust bending force, aerodynamic twisting force, centrifugal twisting force
greatest force acting upon the propeller blade. tends to pull the blade of a spinning propeller out of its hub.
centrifugal force
tendency for a blade to bend backwards, through its length in a direction opposite reaction. created by the density of air
torque bending
causes a rotating propeller to try to pull away from the aircraft.
thrust bending force
tries to rotate the blades in the hub to an increased blade angle.
aerodynamic twisting force
the point at which this force is exerted most strongly on the chord of the airfoil
center of pressure
blades tends to twist them to a lower pitch angle. This occurs because all parts of the propeller try to remain in a plane parallel to the plane of rotation.
centrifugal twisting force
has the blade pitch, or blade
angle, built into the propeller.
fixed-pitch propeller
types of propeller
fixed-pitch, ground adjustable, controllable, constant, feathering, reverse
blade angle cannot be changed after the propeller is built
fixed-pitch propeller
what are fixed-pitch propellers designed for
best efficiency at one rotational and forward speed
fixed-pitch propeller are used on what kind of aircraft
light single engine aircraft
can be changed only when the propeller is not turning
ground adjustable propeller
permits a change of blade pitch, or angle, while the propeller is rotating. allows the propeller to assume a blade angle that gives the best performance for particular flight conditions.
controllable pitch propeller
The propeller has a natural tendency to slow down as the aircraft climbs and to speed up as the aircraft dives because the load on the engine varies. the speed is kept as constant as possible. By using propeller governors to increase or decrease propeller pitch, the engine speed is held constant.
constant speed propeller
Constant speed propeller is also known as what
automatic-pitch propeller
A propeller which changes to the operational forces and is not controlled from the cockpit.
constant speed propeller
is a constant-speed propeller used on multi-engine aircraft that has a mechanism to change the pitch to an angle of approximately 90°.
feathering propeller
are controllable propellers whose blade angles may be changed to a negative value in-flight. is to create a
negative blade angle to produce thrust in the opposite direction.
reverse pitch propeller
blade element theory was evolved when and by who
1909 by Dryewieki
This theory assumes that the propeller blade from the end of the hub barrel to tip is divided into various small, rudimentary airfoil sections.
blade element theory
Are designated distances along the blade as measured from the center of the hub or from some reference line marked near the tip.
blade station
perks of division of sections separated by stations
provides a convenient means of
discussing the performance of the propeller blade, locating blade markings, finding the proper point for measuring the blade angle, and locating antiglare areas.
is the difference between the geometric pitch of the propeller and its effective pitch.
propeller slip
distance a propeller should advance in one revolution with no slippage
geometric pitch
is the distance it actually advances.
effective pitch
recognizes propeller slippage in the air.
actual, or effective, pitch
relationship of slip
geometric pitch - effective pitch = slip
