SIFT Study Guide with Accurate
Solutions
Thrust, drag, weight, lift - ANS-The four forces acting on helicopter in forward flight
are...?
As air flows over upper surface of airfoil, camber (curvature) of airfoil causes increase in
speed of airflow which decreased pressure. Pressure is increased on bottom and this
gives lift. - ANS-Bernoulli's Principle or the "venturi effect"
"for every action there is an equal and opposite reaction"
*small amount of lift is provided by the rotor blades lower surface deflecting air
downward, thus having a small force upward - ANS-Newtons Third Law of Motion and
how it applies to helicopters
thrust;
pitch angle - ANS-Weight is overcome by ______ and this is accomplished by
increasing the ____ _____ of the main rotor blades.
yaw - ANS-The tail rotor produces thrust and is variable through use of antitorque
pedals which control the helicopters _______.
wind
profile, induced, parasite - ANS-Drag always acts parallel to the relative _______.
Total drag is composed of three types of drag....
any "parasite" on the aircraft that creates a drag.
Ex: low air pressure in tires, skin friction (rough surface that creates resistance) - ANS-
What is Parasite drag?
drag produced by shape of the aircraft - ANS-What is profile drag?
when at the back of the wing, air flowing fast over the top meets air flowing slowly
underneath. - ANS-What is induced drag?
, an object at rest will stay at rest, and in motion will remain in motion at constant velocity
unless acted upon by an unbalanced force - ANS-Newtons First Law of Motion states
that....
1. Sliding/Kinetic Friction
2. Fluid Friction (through air or water)
3. Rolling Friction: when object rolls instead of slides across surface
4.Static Friction - ANS-Four Types of Friction:
When object is acted upon by constant force, its resulting acceleration is inversely
proportional to the mass and directly proportional to the applied force
F=ma - ANS-Newtons Second Law of Motion states that...
Fg=(Gm1m2)/d^2
G=gravitational constant=6.67x10^-11 - ANS-Newtons Law of Universal Gravitation
equation
You decrease the force by a factor of 16 - ANS-Two objects a distance of "d" apart.
What happens to force b/w the two objects if you increase d by a factor of 4?
1. Manufacturers Empty Weight: total weight of aircraft as it was built and meant to fly,
and does not include fuel or fluids, passengers or other things
2. Operating Empty Weight: the MEW + weight of crew, fluids, unusable fuel, and
equipment required for flight. Does not include baggage, passengers or usable fuel
3. All Up Weight: (aircrafts gross weight)total aircraft weight at any given moment during
a flight. Decreases as flight time proceeds (fuel is depleted)
4. Maximum landing weight: weight limit for landing. exceeding may harm landing gear
5. Maximum Zero Fuel Weight: limit weight of an aircraft with its contents and includes
unusable fuel...excludes weight of usable fuel and consumable liquids on board
6. Max Takeoff Weight: weight limit for takeoff. Exceeding this limit increases power
required for takeoff
7. Maximum Ramp Weight: weight limit for an aircraft to taxi or be towed on the ground -
ANS-Aircraft weight and balance: what does each acronym stand for and mean?
1. MEW
2.OEW
3. AUW
4. MLW
Solutions
Thrust, drag, weight, lift - ANS-The four forces acting on helicopter in forward flight
are...?
As air flows over upper surface of airfoil, camber (curvature) of airfoil causes increase in
speed of airflow which decreased pressure. Pressure is increased on bottom and this
gives lift. - ANS-Bernoulli's Principle or the "venturi effect"
"for every action there is an equal and opposite reaction"
*small amount of lift is provided by the rotor blades lower surface deflecting air
downward, thus having a small force upward - ANS-Newtons Third Law of Motion and
how it applies to helicopters
thrust;
pitch angle - ANS-Weight is overcome by ______ and this is accomplished by
increasing the ____ _____ of the main rotor blades.
yaw - ANS-The tail rotor produces thrust and is variable through use of antitorque
pedals which control the helicopters _______.
wind
profile, induced, parasite - ANS-Drag always acts parallel to the relative _______.
Total drag is composed of three types of drag....
any "parasite" on the aircraft that creates a drag.
Ex: low air pressure in tires, skin friction (rough surface that creates resistance) - ANS-
What is Parasite drag?
drag produced by shape of the aircraft - ANS-What is profile drag?
when at the back of the wing, air flowing fast over the top meets air flowing slowly
underneath. - ANS-What is induced drag?
, an object at rest will stay at rest, and in motion will remain in motion at constant velocity
unless acted upon by an unbalanced force - ANS-Newtons First Law of Motion states
that....
1. Sliding/Kinetic Friction
2. Fluid Friction (through air or water)
3. Rolling Friction: when object rolls instead of slides across surface
4.Static Friction - ANS-Four Types of Friction:
When object is acted upon by constant force, its resulting acceleration is inversely
proportional to the mass and directly proportional to the applied force
F=ma - ANS-Newtons Second Law of Motion states that...
Fg=(Gm1m2)/d^2
G=gravitational constant=6.67x10^-11 - ANS-Newtons Law of Universal Gravitation
equation
You decrease the force by a factor of 16 - ANS-Two objects a distance of "d" apart.
What happens to force b/w the two objects if you increase d by a factor of 4?
1. Manufacturers Empty Weight: total weight of aircraft as it was built and meant to fly,
and does not include fuel or fluids, passengers or other things
2. Operating Empty Weight: the MEW + weight of crew, fluids, unusable fuel, and
equipment required for flight. Does not include baggage, passengers or usable fuel
3. All Up Weight: (aircrafts gross weight)total aircraft weight at any given moment during
a flight. Decreases as flight time proceeds (fuel is depleted)
4. Maximum landing weight: weight limit for landing. exceeding may harm landing gear
5. Maximum Zero Fuel Weight: limit weight of an aircraft with its contents and includes
unusable fuel...excludes weight of usable fuel and consumable liquids on board
6. Max Takeoff Weight: weight limit for takeoff. Exceeding this limit increases power
required for takeoff
7. Maximum Ramp Weight: weight limit for an aircraft to taxi or be towed on the ground -
ANS-Aircraft weight and balance: what does each acronym stand for and mean?
1. MEW
2.OEW
3. AUW
4. MLW
