# Climb Flight Performance Calculation for Jet-Engine Aircrafts

by admin in Aerospace , Control Systems & Aerospace , MATLAB Family on April 15, 2019This GUI program calculates all the Climb flight performance and characteristics for Jet-Engine aircrafts, the performance characteristics (**Outputs**) 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 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 Thrust
- 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:**

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?

**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
- R/C : Rate of Climb
- Gamma_max: Maximum Climb Angle

**Program Interface:**

The Program has one interface, as presented in the down pictures, the interface 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.

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:**

- The altitude of Airport from Sea Level parameter works in this code within the range 0 and 9km.
- 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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