Calculating Cruise Flight Performance of Jet-Engine Aircrafts V2.0

This is the second version of ‘Flight Cruise Performance Calculator for Jet Aircraft’ and also is about a GUI program that calculates Range and Endurance (Flight-Time):

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

in addition to the other cruise flight performance in the past version, includes:

• Maximum Level Flight Speed
• Minimum Level Flight Speed
• Stall Speed
• Speed Corresponding to Minimum Drag
• Maximum Lift to Drag Ratio
• Absolute Ceiling (Maximum Flight Hight corresponding to Minimum Drag)
• Chart presents: Induced Drag, Zero-Lift Drag, Total Drag and position of Vmin, Vmax and VDmin.

Required Inputs:

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

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

The program gives you the maximum hight, Velocity, Range and Endurance of a given airplane characteristics and the minimum required thrust for this altitude. 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:

A jet-engine airplane weighs 45000 N, hold fuels 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 thrust T = 20,000 N, and Engine 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)
• CD0: Zero-Lift Drag Coefficient
• K: Weight of CL^2 in Drag Polar (CD = CD0 + K*CL^2)
• c: Specific Fuel Consumption

Program Interface:

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.