Recap 12.3

What is the definition of vibration?

• 
  A motion characterized by linear movement

• A motion characterized by random jumps

• A motion characterized by repeated oscillations about an average position

• A motion characterized by constant speed

1. When the rotor head and blades are balanced as a separate unit….

• Chordwise balance must be established first

• Spanwise balance must be established first

• Chordwise/Spanwise balance can be achieved first

• None of the answers are correct

What are the causes of helicopter vibrations?

• Correct blade(s) alignment and tracking

• Unbalanced components and aerodynamic forces

• Proper maintenance

• Passenger discomfort and crew fatigue

How are helicopter vibrations classified?

• 
  Primary, secondary, and tertiary vibrations

• Slow, moderate, and fast vibrations

• Simple, complicated, and steady vibrations

• 
  Low frequency, medium frequency, and high frequency

Static balance in a helicopter is achieved when…

• Centre of gravity of entire rotor system aligns with rotor mast’s axis of rotation

• Excessive vibration is reduced to an acceptable figure

• Centre of pressure of entire rotor system aligns with centre of gravity

• When blades are statically and dynamically balanced

How is vibration sensed when it comes to electronic balancing?

• Interrupter and Magnetic Pickup

• Piezoelectric type accelerometer

• Strobex lights

• Fuselage Anti-vibration

What are the three general areas of high-frequency vibration?

• The main rotor, tail rotor, and engine

• The main rotor, engine, and drive train systems

• The tail rotor, engine, and drive train systems

• The main rotor, tail rotor, and transmission

Excessive vibrations can lead to ease in controlling the aircraft, making it easy for the pilot to maintain a stable and precise flight path.

• True

• False

• Not Sure

Prolonged exposure to high vibration can contribute to?

• longevity components life

• Wear of mechanical, electronic, and airframe components

• Improved component durability

• Enhanced performance of the machine

When is dynamic balancing to be done?

• Once static balancing and blade tracking is done

• Once blade alignment and blade tracking is done

• Once blade alignment, static balancing and blade tracking is done

• Not all of the answers are correct