JNTU B.Tech II AIRCRAFT PERFORMANCE Previous Question Paper (August/September - 2022 - R16)

The functional performance characteristics of a fixed-wing aircraft define its operational capabilities and limitations across different flight phases. These are primarily categorized into steady-state performance and maneuvering performance.

Key characteristics include:

• Take-off and Landing Performance: Defines the ground roll distance, transition to climb, and flare distance, which are critical for runway requirements.
• Climb Performance: Measured by the rate of climb and climb angle, determined by the excess power or thrust available over the power or thrust required for level flight.
• Cruise Performance: Focuses on range and endurance, governed by the lift-to-drag ratio and specific fuel consumption (SFC). It involves optimizing speed and altitude for fuel efficiency.
• Ceiling: The maximum altitude at which an aircraft can maintain steady horizontal flight, including absolute ceiling (rate of climb is zero) and service ceiling (rate of climb is 100 ft/min).
• Maneuverability and Controllability: The ability to change flight path and attitude, often represented by the V-n diagram (load factor vs. velocity) to define structural and aerodynamic limits.

Given: Altitude h = 3000 ft, Velocity V = 100 m/s, Condition = ISA + 15°C.

First, determine the ambient temperature. Standard temperature at 3000 ft (914.4 m) is T = 288.15 - (0.0065 * 914.4) = 282.21 K. With ISA + 15, T = 282.21 + 15 = 297.21 K.

i) Mach Number (M):

ii) Static and Dynamic Pressure:

Standard pressure at sea level P₀ = 101325 Pa. Using the pressure ratio for 3000 ft (approx 90.5% of sea level pressure):

Density ρ = P / (R * T) = 90800 / (287 * 297.21) ≈ 1.064 kg/m³.