Cruise Flight Performance for Jet and Propeller Aircrafts V2

by admin in on April 23, 2019

This is the second version of ‘Cruise Flight Performance for Jet and Propeller Aircrafts’ and is about a GUI program that calculates the cruise flight Range and Endurance (Flight Time) performance for both Jet-Engine and Propeller-Engine aircrafts:

For Propeller Aircraft:

  • Endurance (Flight Time) for Fixed Altitude
  • Endurance (Flight Time) for Fixed Speed
  • Flight Velocity that forces the Endurance at Fixed Altitude
  • Flight Velocity that forces the Endurance at Fixed Speed
  • Flight Range

For Jet Aircraft:

  • Range for Fixed Altitude
  • Range for Fixed Velocity
  • Flight-Velocity that force Fixed Altitude Range
  • Flight-Velocity that force Fixed Speed Range
  • Endurance (Flight Time)

In addition to the usual cruise flight performance characteristics that includes:

  • Maximum Level Flight Speed
  • Minimum Level Flight Speed
  • Stall Speed
  • Speed Corresponding to Minimum Power and Minimum Drag
  • Lift to Drag Ratio for Minimum Power and Minimum Drag
  • Lift Coefficient for Minimum Drag and Minimum Power
  • Chart presents:
  • Induced Power and Induced Drag
  • Zero-Lift Power and Zero-Lift Drag
  • Total Power and Total Drag, and position of Vmin, Vmax, VDmin, and VPmin.

Input Requirements:

To run the program you need to insert the following values:

  • Flight Altitude
  • Reference Area
  • Airplane Weight
  • Fuel Weight
  • Specific Fuel Consumption
  • Engine Power or Thrust
  • Zero-Lift Drag Coefficient CDo
  • K constant of CL^2 in the drag polar equation
  • Maximum Lift Coefficient
  • Propulsive efficiency.

The code based on Pamadi[1] and Saarlas[2] equations of performance of jet engine aircraft in cruise flight.

Examples you can try with this program:

[1] A propeller airplane weighs 45000 N, fuel weight 10000 N, and has a reference area S of 31 m2. The drag polar is given by CD = 0.014 + 0.038CL^2, CLmax = 1.5, and the engine power P = 921 KW and propulsive efficiency (Eta) 0.85 with specific fuel consumption 2 N/KW/H . Determine the maximum and minimum speeds in level flight at sea level and at an altitude of 10 Km, and what is the Speed and Minimum Power at the maximum height.

[2] A jet-engine airplane weighs 51 KN, fuel weight 12000 N, and has a reference area S of 26 m2. The drag polar is given by CD = 0.009 + 0.06CL^2, CLmax = 2.05, and the engine thrust T = 31,900 N with specific fuel consumption 30 N/N/h. Determine the maximum and minimum speeds in level flight at sea level and at an altitude of 9000 m. What is the absolute ceiling of this airplane?

Used Terms:

  • L: Lift
  • D: Drag
  • Em: Maximum E(L/D)
  • mp: Minimum power
  • Emp: E for Minimum Required Power
  • CD0: Zero-Lift Drag Coefficient
  • K: Weight of CL^2 in Drag Polar (CD = CD0 + K*CL^2)
  • Vmp: Velocity at Minimum Required Power
  • CLmp: Lift Coefficient for Minimum Required Power
  • eta: Propulsive Efficiency

Program Interfaces:

The Program has three GUIs, as presented in the down pictures, the main interface gives you a Choice to select either Jet-Engine Aircraft or Propeller-Engine Aircraft Performance Analyzer. The second and third interfaces are the Jet-Engine Aircraft analyzer window and Propeller-Engine Aircraft Performance analyzer window themselves.

 

 

References:

[1] Bandu N. Pamadi, Performance, Stability, Dynamics, and Control of Airplanes, Second Edition,  at NASA Langley Research Center, Hampton, Virginia.

[2] Maido Saarlas, Aircraft Performance, Department of Aeronautics Engineering at U.S. Naval Academy.

 

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