Torquiness
What law of physics explains the concept of torque in helicopter dynamics? What does this law state?
Newton's 3rd law. Every action has an equal and opposite reaction.
What is the definition of relative wind in the context of helicopter aerodynamics? Is this the same as or different from relative wind for fixed wing aircraft?
What part of the helicopter does the cyclic control, and how does it move?
The main rotor - it changes the pitch.
Name the controls of a helicopter and where they are located in the flight deck.
Collective – on the outside of the pilot’s seat.
Cyclic – in the center in front of the pilot’s seat, attached at the floor.
Throttle – on the handle of the collective.
What are the three main types of rotors?
Rigid
Semi rigid
Fully articulated
The primary purpose of the tail rotor on a single main rotor helicopter is
To counteract the torque of the main rotor.
Describe how the lift generation mechanism of rotary-wing aircraft differs from that of fixed-wing aircraft.
Rotary-wing aircraft generate lift through rotating blades, enabling vertical takeoff and landing, while fixed-wing aircraft rely on forward motion and fixed wings for lift.
What part of the helicopter does the collective pitch control move, and how does it move?
Controls the angle of the rotor blades simultaneously.
What is the primary function of the swash plate in helicopter flight controls?
Transfers control inputs from stationary to rotating movements.
This type of helicopter powerplant does not need a clutch.
Free turbine.
Describe how a dual main rotor system achieves stability without a tail rotor
.A dual rotor system achieves stability by having two rotors that spin in opposite directions, which counteract each other's torque.
Horizontally, thrust
horizontally, travel
What control can change the pitch angle of the entire helicopter?
The cyclic
How does increasing the collective pitch angle affect lift?
It increases lift.
What part of the powerplant power train allows for auto rotation?
The freewheeling unit.
Name 3 styles of dual rotor helicopters
Tandem
Intermeshing
Coaxial
Side by side
Describe how rotor blades function as airfoils to create lift in helicopters.
Rotor blades act as spinning airfoils that create lift by changing the pressure of the air above and below them.
For a helicopter with external cargo loading and release: The release mechanism must allow ______________________ to pass through _____________________________.
the center of action
the center of gravity.
Describe how gyroscopic precession is accounted for in helicopter design.
Describe a fully articulated rotor.
Will have the ability to feather (collective), each blade can flap independently (flapping hinge), and will also have a drag hinge that allows the blade to move chordwise.
What can the tail rotor do besides counteract the torque of the main rotor?
Turn the helicopter around the yaw axis.
What is the equation for dissymmetry of lift. How it it applied for advancing versus retreating blades?
Rotor rotation speed +/– ground speed = dissymmetry of Lift
On the collective lever.
What is the Coriolis effect? What blade design reduces Coriolis effect?
It is the effect that happens with the center of mass gets closer to or farther from the axis of rotation. Closer causes spinning speed to increase, farther causes it to decrease.
Underslung rotor on seesaw blades; drag hinge on flapping blades.
What causes coning and why is it uneven?
It's caused by centrifugal force and dissymmetry of lift. The dissymmetry of lift and tendency of liftier blades to rise and less lifty blades to sink makes it uneven.