Climb Flight Performance Characteristics For Jet and Propeller Aircrafts

by admin in , , on April 15, 2019

This GUI program calculates all the Climb flight performance and characteristics for Jet-Engine and Propeller Aircrafts, the performance characteristics (Outputs) for both aircrafts includes:

  • Maximum Rate of Climb
  • Climb angle at Maximum Rate of Climb
  • Flight Velocity at Maximum Rate of Climb
  • Lift Coefficient at Maximum Rate of Climb
  • Climb Time at Maximum Rate of Climb
  • Maximum Climb Angle
  • Rate of Climb Climb at Maximum Climb Angle
  • Flight Velocity at Maximum Climb Angle
  • Lift Coefficient at Maximum Climb Angle
  • Climb Time at Maximum Climb Angle
  • Absolute Ceiling
  • Service Ceiling
  • Hodograph of Climb flight
  • Rate of Climb Graph with Height
  • Inverse of Specific Excess Power with Height

Required Inputs are:

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

  • Altitude of Airport from Sea Level
  • Reference Area
  • Airplane Weight
  • Engine Power
  • Propulsive Efficiency (Eta)
  • Zero-Lift Drag Coefficient CDo
  • K: constant of CL^2 in the drag polar equation (CD = CDO + K*CL^2)
  • Maximum Lift Coefficient
  • Initial Climb Height
  • Final Climb Height

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

Example you can try with this program:

[1] A jet-engine airplane weighs 51 KN and has a reference area S of 31 m2. The drag polar is given by CD = 0.009 + 0.06CL^2, CLmax = 2.05, and the engine thrust T = 31,900 N, initial climb height is 100 m and final is 10 km. Determine the maximum climb characteristics (Maximum Rate of Climb and Maximum Climb Angle) with the proper conditions where they occur, at sea level. What is the absolute and service ceilings of this airplane?

[2] A Propeller airplane weighs 50 KN and has a reference area S of 30 m2. The drag polar is given by CD = 0.01 + 0.06CL^2, CLmax = 1.98, and the engine power P = 840 KW and propulsive efficiency 0.85, initial climb height is 100 m and final is 10 km. Determine the maximum climb characteristics (Maximum Rate of Climb and Maximum Climb Angle) with the proper conditions where they occur, at sea level. What is the absolute and service ceilings of this airplane?

Used Terms:

  • L: Lift
  • D: Drag
  • CD0: Zero-Lift Drag Coefficient
  • K: Weight of CL^2 in Drag Polar (CD = CD0 + K*CL^2)
  • CL: Lift Coefficient
  • Eta: Propulsive Efficiency
  • R/C : Rate of Climb
  • Gamma_max: Maximum Climb Angle

Program Interface:

The Program has three interfaces, the first one [1] Main Interface gives you access to both Jet and Propeller analyzers, as presented in the down pictures, the first interface [2] For Jet Aircraft gives you a Choice to select one of three graphs (Hodograph of Climb Flight, Rate of Climb with Altitude and Inverse of Specific Excess Power with altitude) the calculated results are presented also on these charts, the third interface [3] For Propeller Aircraft gives the same results of the second one but for a propeller aircrafts.

1. Main Interface:

 

2. For Propeller Aircraft:

Figure 1. Rate of Climb with Altitude

Figure 2. Hodograph of Climb Flight,

Figure 3. Inverse of Specific Excess Power with altitude

     

2. For Jet Aircraft:

Figure 1. Rate of Climb with Altitude

Figure 2. Hodograph of Climb Flight,

Figure 3. Inverse of Specific Excess Power with altitude

 

Definitions:

  • Absolute Ceiling: The altitude where the maximum rate of climb equal to zero (R/C)max = 0.
  • Service Ceiling: The altitude where the maximum rate of climb drops to 100 ft/min (30.5 m/min).

 

Notes:

  1. The altitude of Airport from Sea Level parameter works in this code within the range 0 and 9km.
  2. If some results are negatives then there are an error in your inputs. The program has been tested on various ranges of airplanes characteristics and the results were accepted and logical.

 

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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