SIFT study guide Exam/93 Complete
Accurate Questions and Answers
The four forces acting on helicopter in forward flight are...? - -Thrust, drag,
weight, lift
-Bernoulli's Principle or the "venturi effect" - -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.
-Newtons Third Law of Motion and how it applies to helicopters - -"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
-Weight is overcome by ______ and this is accomplished by increasing the
____ _____ of the main rotor blades. - -thrust;
pitch angle
-The tail rotor produces thrust and is variable through use of antitorque
pedals which control the helicopters _______. - -yaw
-Drag always acts parallel to the relative _______.
Total drag is composed of three types of drag.... - -wind
profile, induced, parasite
-What is Parasite drag? - -any "parasite" on the aircraft that creates a drag.
Ex: low air pressure in tires, skin friction (rough surface that creates
resistance)
-What is profile drag? - -drag produced by shape of the aircraft
-What is induced drag? - -when at the back of the wing, air flowing fast over
the top meets air flowing slowly underneath.
-Newtons First Law of Motion states that.... - -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
, -Four Types of Friction: - -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
-Newtons Second Law of Motion states that... - -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
-Newtons Law of Universal Gravitation equation - -Fg=(Gm1m2)/d^2
G=gravitational constant=6.67x10^-11
-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? - -You decrease the force by a
factor of 16
-Aircraft weight and balance: what does each acronym stand for and mean?
1. MEW
2.OEW
3. AUW
4. MLW
5. MZFW
6. MTOW
7. MRW - -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
Accurate Questions and Answers
The four forces acting on helicopter in forward flight are...? - -Thrust, drag,
weight, lift
-Bernoulli's Principle or the "venturi effect" - -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.
-Newtons Third Law of Motion and how it applies to helicopters - -"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
-Weight is overcome by ______ and this is accomplished by increasing the
____ _____ of the main rotor blades. - -thrust;
pitch angle
-The tail rotor produces thrust and is variable through use of antitorque
pedals which control the helicopters _______. - -yaw
-Drag always acts parallel to the relative _______.
Total drag is composed of three types of drag.... - -wind
profile, induced, parasite
-What is Parasite drag? - -any "parasite" on the aircraft that creates a drag.
Ex: low air pressure in tires, skin friction (rough surface that creates
resistance)
-What is profile drag? - -drag produced by shape of the aircraft
-What is induced drag? - -when at the back of the wing, air flowing fast over
the top meets air flowing slowly underneath.
-Newtons First Law of Motion states that.... - -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
, -Four Types of Friction: - -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
-Newtons Second Law of Motion states that... - -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
-Newtons Law of Universal Gravitation equation - -Fg=(Gm1m2)/d^2
G=gravitational constant=6.67x10^-11
-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? - -You decrease the force by a
factor of 16
-Aircraft weight and balance: what does each acronym stand for and mean?
1. MEW
2.OEW
3. AUW
4. MLW
5. MZFW
6. MTOW
7. MRW - -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
