Flight Mechanics - II Mid - I, September - 2014

1.If the forces and moments on the body caused by a disturbance tend initially to return the body toward its equilibrium position ,the body is ________________
  • Statically stable
  • Statically unstable
  • Dynamically stabe
  • Neutrally stable
Answer: A
2.Equilibrium demands that the summation of moments equal to ________
  • One
  • zero
  • two
  • none
Answer: B
3.An ______________ angle is reached when the “floating tendency” chα is just opposed by the “restoring tendency “ chδ
  • Elevator gearing
  • Side slip angle
  • Bank angle
  • Equilibrium floating
Answer: D
4.The gearing between the stick and the elevator may be obtained by equating the work done at the top of the stick to the work done at the ________
  • Elevator
  • Rudder
  • Ailerons
  • Stabilizer
Answer: A
5.As C.G moves forward aircraft becomes
  • Un Stable
  • Neutral point
  • More stable
  • No effect
Answer: C
6.Lateral – directional trim requirements can be simply stated as achieving a total aircraft rolling moment and yawing moment of zero. In coefficient terms trim equates to _________
  • Cl and Cn = 0 for trim
  • Cl and Cm = 0 for trim
  • Cm and Cn = 0 for trim
  • None of these
Answer: A
7.The lateral stability and control , deal with the equilibrium and its maintainability about the _________
  • Z-axis
  • Y-axis
  • X-axis
  • XY- axis
Answer: C
8.The derivative Clδa defines the change in rolling moment that results from aileron deflection .It is also called the _________
  • Elevator hinge moment
  • Dihedral effect
  • Elevator angle per g
  • Aileron control power
Answer: D
9.The ratio qt/q is called the ------------------
  • elevator gearing G
  • stick force
  • tail efficiency ηt
  • Aileran efficiency
Answer: C
10.___________ stability deals with the time history of the vehicle’s motion after it initially responds to its static stability
  • Positive static stability
  • Negative static stability
  • Dynamic stability
  • Longitudinal Stability
Answer: C
11.The hinge moment coefficients can be expressed in terms of partial derivatives as ___________
Answer: Ch = (∂ Ch/∂α)∂ α + (∂ Ch/∂∂)α ∂
12.Cmα, Clβ, and Cnβ are referred to as _____________
Answer: Stability derivatives
13.For the airplane to be stable the slope of the Cm versus Cl curve must be ______
Answer: Negative
14.The parameter affected by the elevator deflection is _________
Answer: Tail AOA
15.Side slip angle causes increase of the airplane’s _______
Answer: Drag
16.____________ is the angle between the plane of the wing and a horizontal plane ,positive if the wing tip is above the wing root
Answer: Dihedral angle
17.Aircraft rolling moment acts about the x-axis and may be expressed using the rolling moment coefficient as _______
Answer: La = CL q sb
18.One of the most frequently used methods of aerodynamic balancing control surfaces is the __________
Answer: Set back hinge
19.__________________ is a measure of the aircrafts ability to realign itself along the direction of the resultant wind so that the disturbance in sideslip is effectively eliminated
Answer: Static directional stability
20.The ______________ aerodynamic defined as the angle between the velocity vector and the airplane’s plane of symmetry
Answer: Angle of sideslip