List of top Flight Mechanics Questions

During landing, an airplane experiences a net vertical ground reaction of $15{,}000\ \text{N}$. The weight of the airplane is $10{,}000\ \text{N}$. The landing vertical load factor, defined as the ratio of inertial load to the weight of the aircraft, is __________ (rounded off to 1 decimal place).

Which of the following statements about absolute ceiling and service ceiling for a piston–propeller aircraft is/are correct?

For an airplane having directional (weathercock) static stability, which of the following options is/are correct?

For an aircraft moving at 4 km altitude above mean sea level at a Mach number of 0.2, the ratio of equivalent air speed to true air speed is ............ (rounded off to 2 decimal places). The density of air at mean sea level is $1.225 \,\text{kg/m}^3$ and at 4 km altitude is
$0.819 \,\text{kg/m}^3$.

For a general aviation airplane, one of the complex conjugate pair of eigenvalues for longitudinal dynamics is given by $\lambda = -0.039 \pm 0.0567 i$ (in SI units). If the system is disturbed to excite only this mode, the time taken for the amplitude of response to become half in magnitude is ............ s (rounded off to 1 decimal place).

An airplane with wing planform area $S=20\,\text{m}^2$ and weight $W=8\,\text{kN}$ is flying straight and level with a speed of $V=100\,\text{m/s}$. The total drag coefficient is $C_D=0.026$ and the air density is $\rho=0.7\,\text{kg/m}^3$. The total thrust required to introduce a steady climb at angle $\gamma=0.1$ radians is ............. N. (round off to the nearest integer)

The maximum permissible load factor and the maximum lift coefficient for an airplane are $n_{\max}=7$ and $C_{L,\max}=2$, respectively. For a wing loading $W/S=6500\ \text{N/m}^2$ and air density $\rho=1.23\ \text{kg/m}^3$, the speed yielding the highest possible turn rate in the vertical plane is .............. m/s. (round off to the nearest integer)

An airplane weighing $40\ \text{kN}$ is landing on a horizontal runway and is retarded by an arresting cable. The tension in the arresting cable at a given instant is $100\ \text{kN}$, and the cable makes $10^\circ$ with the runway as shown. Assume engine thrust continues to balance airplane drag. The magnitude of the horizontal load factor is \underline{\hspace{1cm}}. \;(round off to one decimal place) \begin{center} \includegraphics[width=0.5\textwidth]{09.jpeg} \end{center}

For a longitudinally statically stable aircraft, which one of the following represents the relationship between the coefficient of pitching moment about the center of gravity $C_{m_{cg}}$ and absolute angle of attack $\alpha_a$? (Note: nose–up moment is positive.)

Consider a thin symmetric airfoil at a 2 degree angle of attack in a uniform flow at 50 m/s. The pitching moment coefficient about its leading edge is _________ (rounded off to three decimal places).

For a conventional airplane in straight, level, constant velocity flight condition, which of the following condition(s) is/are possible on Euler angles ($\phi, \theta, \psi$), angle of attack ($\alpha$) and the sideslip angle ($\beta$)?

An unpowered glider is flying at a glide angle of 10 degrees. Its lift-to-drag ratio is _________ (round off to two decimal places).

For International Standard Atmosphere (ISA) up to 11 km, which of the following statement(s) is/are true?

The service ceiling of an airplane is the altitude

Regarding the horizontal tail of a conventional airplane, which one of the following statements is true?

An airplane (5500 kg) initiates a pull-up at 225 m/s with curvature radius 775 m. CG, CP, and tail point T are shown. Thrust and drag cancel. Tail force is vertical. Find the tail force (round to one decimal place).

Which of the following statement(s) is/are true?

A conventional fixed-wing aircraft, with a horizontal tail and vertical fin, in steady and level flight is subjected to small perturbations. Which of the following statement(s) is/are true?

An aircraft with twin jet engines has:
Thrust per engine = 8000 N
Spanwise distance between engines = 10 m
Wing area = 50 m$^2$, Wing span = 10 m
Rudder effectiveness: $ C_{n_{\delta r}} = -0.002/\text{deg} $
Air density at sea level: $ \rho = 1.225 \, \text{kg/m}^3 $
The rudder deflection, in degrees, required to maintain zero sideslip at 100 m/s in steady and level flight at sea level with a non-functional right engine is ________ (round off to two decimal places).

$C_m - \alpha$ variation for a certain aircraft is shown in the figure. Which one of the following statements is true for this aircraft?

Let $V_{TAS}$ be the true airspeed of an aircraft flying at a certain altitude where the density of air is $\rho$, and $V_{EAS}$ be the equivalent airspeed. If $\rho_0$ is the density of air at sea-level, what is the ratio $\frac{V_{TAS}}{V_{EAS}}$ equal to?

A jet transport airplane has the following data:
Lift-curve slope of wing-body: $\frac{\partial C_{Lwb}}{\partial \alpha_{wb}} = 0.1/\deg$
Lift-curve slope of tail: $\frac{\partial C_{Lt}}{\partial \alpha_t} = 0.068/\deg$
Tail area $S_t = 80\ \text{m}^2$, wing area $S = 350\ \text{m}^2$
Tail moment arm $\ell_t = 28\ \text{m}$
Mean aerodynamic chord $\bar{c} = 9\ \text{m}$
Downwash: $\epsilon = 0.4\alpha$
Wing-body aerodynamic center: $x_{ac}/\bar{c} = 0.25$
CG location: $x_{cg}/\bar{c} = 0.3$
Determine the pitching-moment coefficient slope $C_{m_\alpha}$ (round off to three decimals).

A jet aircraft weighs 10,000 kg, has an elliptic wing of span 10 m and area 30 m$^2$. The zero-lift drag coefficient is $C_{D0} = 0.025$. The maximum steady level-flight speed at sea level is 100 m/s. Density of air is 1.225 kg/m$^3$, and $g = 10\ \text{m/s}^2$. Determine the maximum thrust developed by the engine (round off to two decimals).

For a conventional fixed-wing aircraft, which of the following statements are true?

For a conventional fixed-wing aircraft in a 360$^\circ$ inverted vertical loop maneuver, what is the load factor ($n$) at the topmost point of the loop? Assume the flight to be steady at the topmost point.