Lecture 11 Flashcards
In a hover, what are the four forces doing?
Acting vertically.
In directional flight, what are the four forces doing?
They seperate. Thrust and drag go diagonal, weight and lift still vertical.
Collective stick is what and located where?
Helicopter goes up and down with it. Left of pilot. up=up
What increases the lift of the helicopter?
The increase in AOA of all the main rotor blades
Cyclic stick does what and located where?
Moves helicopter forward by changing pitch of a rotor blade, tips rotor disk forward.
located in front of pilot. Forward=forward
Why is it called the cyclic stick?
It changes the pitch on a rotor blade at only one part of the rotating cycle
Why is rearward flight and rapid deceleration dangerous?
The rotor blades can hit the tail boom of the aircraft or cause the tail rotor to hit the ground
When you move cyclic angle how does that change blade angle?
Inputs from pilot raise, lower, or tilt the non-rotating swash plate
By raising, lowering, or tilting the non-rotating swash plate,
the rotating swash plate is correspondingly raised, lowered, or tilted
As the swash plate is moved, the pitch change links that spin with the rotor blades
are also raised or lowered= changing pitch of blades
Why does the helicopter run at a constant RPM?
- increasing rotor speed to get more lift takes too long
- the rotor blades need centrifugal force to hold them out straight or else the lift forces will fold up and break the blades
Main rotor blades are what?
Flexible
With no centrifugal force, what happens to main rotor blades?
the rotors will DROOP when they are not spinning
What happens to the blades when they are spinning and put under a lift load?
Blades pull up, or “cone”
How do you translate aircraft left or right?
Cyclic stick
What do tail rotors control?
The direction the helicopter is facing
What controls the tail rotors?
Foot pedals called anti-torque pedals
The tail rotors also counteract the ______ of the spinning main rotor blade
torque
Main rotor spins ______ meaning the fuselage turns _____
counterclockwise
clockwise
What does the tail rotor do to keep the aircraft flying straight?
Provides thrust in the opposite direction that the fuselage is trying to turn
Moving the foot pedals does what?
Changes the pitch of the tail rotor
Tail rotors runs at a _____ RPM
constant
More pitch = ?
More thrust
Turns helicopter against the torque force
Less pitch = ?
Less thrust
Turns helicopter in the same direction as torque force
What if the tail rotor quits?
Helicopter spins around in a circle opposite the direction of the main rotor
What does the vertical stablizer do?
Provides the sideways force so tail rotor can have neutral position
Reduces power needed from engine and increases fuel efficiency
What does enclosing the Fenestron (tail rotor) do?
Decreasing injuries from tail rotor and reduces strike accidents
No tail rotor aircraft
Increases safety and reduces noise. Only works on small aircraft
Torque changes as main rotor blade changes, but RPM stays constant, sooooo
A fan with variable pitch blades is put in front of the tail boom to force air into the boom
As more main rotor pitch is used, and more anti-torque is needed,
the fan changes pitch
automatically increasing the flow of air out
through the slot in the starboard side of the tail boom.
