Test Bank Solution Manual for Helicopter Private Pilot Rated 100%

Test Bank Solution Manual for Helicopter Private Pilot Rated 100% What is an airfoil? - Answers Is any surface producing more lift than drag when passing through the air ar a suitable angle. Describe the leading edge of an airfoil? - Answers It lead the airfoil through the air. Rounded shape on a helicopter. Describe the trailing edge of an airfoil? - Answers It trails behind the leading edge. Small tipped shape on a helicopter. What are the two types of rotor blades? - Answers Symmetrical and asymmetrical. Describe the upper and lower cambers of each rotor blade type. - Answers Symmetrical- upper and lower cambers are the same shape. Asymmetrical- upper and lower cambers are not the same. What is the cord line on an airfoil? - Answers It is an imaginary line from the leading edge to the trailing edge of an airfoil. What is the plane of rotation on an airfoil? - Answers The actual plane the rotor blade is moving through the air. Define relative wind. - Answers It is airflow relative to an airfoil. What is angle of attack? - Answers It is the angle between the airfoil cord line and the resultant relative wind. What is induced flow (downwash)? - Answers Downward flow of air. Most pronounced at a hover with no wind. Describe the mechanical angle AKA pitch angle or angle of incident. - Answers It is the angle between the cord line of a main or tail rotor blade and it's rotor disk. Describe how an airfoil produced lift. Venturi and Bernoulli's - Answers Venturi - velocity is increased as static pressure is decreases. Bernoulli's - as air speed increases pressure decreases. (Low pressure on top of airfoil and high pressure on bottom of airfoil). What percentage of lift is achieved from Bernoulli's principle? - Answers 70%. The rest is from Newton's third law. Describe Newton's third law of motion. - Answers For every action there is an equal and opposite reaction. What percentage of lift comes from Newton's third law? - Answers 30% Describe parasite drag. - Answers Is the non lifting components of the helicopter. (Cabin, rotor mast, tail, landing gear). It is present any time the helicopter is moving through the air. Describe induced drag. - Answers It is generated by airflow circulation around the rotor blade as it creates lift. AKA a by product of lift. What are the two types of profile drag? - Answers Form drag Skin friction Describe form drag. - Answers It results from the turbulent wake caused by separation of airflow from the surface of a structure. AKA the design of the airfoil, or object. Describe skin friction. - Answers It is caused by surface roughness. How do you get your total drag curve? - Answers Average all drags together. The best rate do climb for an R-22 is? - Answers 53 knots. How is drag considered by the manufacturer when determining the best rate of climb and autorotative decent speeds? - Answers By averaging all of the drags and determining the total drag curve. What are the 4 forces acting upon an aircraft? - Answers Lift Weight Thrust Drag Describe lift? - Answers Lift is the force that acts upward on the helicopter. Opposes weight. Describe weight. - Answers Weight is the force of gravity that pulls down on the helicopter. It opposes lift. Describe thrust. - Answers It is the force that propels the aircraft in a particular direction. It opposes drag. Describe drag. - Answers It is the force that resists movement in any direction. It opposes thrust. What is translating tendency? - Answers tendency of a single rotor helicopter to drift laterally while hovering. Also called tail rotor drift. What are the three elements of blade coning? - Answers Weight Centrifugal force Lift What is centrifugal force? - Answers The movement of the blades at operating rate. Blades move directly out. What is the relationship between RPM and centrifugal force? - Answers As RPMs increase the centrifugal force brings the blade up and out. At what speed does transverse flow occur? - Answers Between 10 and 20 kts. How does transverse flow affect helicopter flight? - Answers It causes the helicopter to shutter, the nose to pitch up, yaw left, and roll right due to gyroscopic procession. What is the relationship between transverse flow and gyroscopic precession? - Answers As the front is the rotor is producing lift, gyroscopic procession kicks in moving the lift over to the left causing a right roll. What is effective translational lift (ETL)? - Answers ETL occurs when the main rotor system completely outruns the recirculation of old vortexes and begins to work in relatively clean and undisturbed air. ETL occurs at about 16-24 knots depending on blade size, area and RPM of the rotor system The rotor system becomes more efficient and this increased efficiency continues as airspeed increases until the best rate of climb airspeed is reached. How does ETL improve performance? - Answers The flow of air through the rotor disk is more horizontal, which reduces the induced flow and drag with a corresponding increase in angle of attack and lift. What control inputs will a pilot need to make as the helicopter enters ETL? - Answers Apply forward and left lateral cyclic input. At what speed is ETL lost? - Answers Approximately 24 kts. What is felt when the helicopter leaves ETL? - Answers The nose of the helicopter pitches up and the helicopter rolls to the right. What is gyroscopic precession? - Answers It is the resultant action or deflection of a spinning object when a force is applied to this object. Occurs approximately 90 degrees in the direction