Table of Contents

Aerodynamics Series

2020년 7월 26일 일요일

Flight-SIM : Initial Version of the Flight-SIM w/ Demo

Previous Work Status

Missile-SIM : Performance Evaluation for Iskander / Kh-47M2 Kinzhal & ATACMS+Booster

The new topic for My page : Optimization of Supersonic aerodynamic aircraft


Flight-SIM : Trajectory & Performance Analysis for Jet Aircraft

Flight-SIM : Generic DB of single-aisle Airliner : Part 2

Flight-SIM : W.I.P of the SIM II


1. Demo-Test for Flight-SIM w/ single-aisle Airliner

 Configuration of the code is shown in the Previous work status. After the works for debugging and DB generation, I could show you the flight trajectory or range performance of the aircraft with specified DB. This test is not based on the realistic data but generic or typical data of the single-aisle airliner. Please enjoy it. 

 1) Input : Trajectory set up

 Flight-SIM has several options for the trajectory prediction as described in the previous WIP articles; On/Off of SID/STAR, Optimization or Manual Climb/Descend can be selected from the input excel file. Example is shown in Fig. 1 with this demonstration case. Cfg and Cfg_eng numbers mean that the Flight-SIM could simulate trajectory simulation with variable geometry or multi-mode engine if the DB were available. 

Fig. 1 Trajectory input table for the Flight-SIM

 2) Input : Airliner / Engine DB

 Aerodynamic characteristics and weight specification are provided in the Airliner DB while Engine has own separated DB. Weight specification is shown in Fig. 2 which is similar to typical single-aisle airliner; aerodynamic characteristics varied by Mach number, Reynolds number, and AoA are recorded in table with breakpoints. Flight-SIM uses 4th order polynomial fitting to calculate the aerodynamic force with proper input.  

Fig. 2 Aircraft DB

 DB structure of the engine is similar to that of aircraft however, more breakpoints should be provided for the throttle change. 0% for flame out, 70% for idle, 85% for middle, 100% for climb or military thrust, and 110% for TOGA or Afterburner. In Flight-SIM, non-throttle specified step like Cruise, SID/STAR automatically find the proper thrust for its trim while Climb, Descend, TO/LD will use specified breakpoints like 70%, 100%, or 110%. 
More detailed structure of the simulation or input DB is available at previous articles. 

Fig. 3 Engine DB

 3) Output : Demo RUN

 Execution of the Python code for the Flight-SIM is done for two cases of demonstration; 
 (1) Uniform Cruise Altitude with 6t of fuel
 (2) Two Cruise Altitude with 12t of fuel 

 Idle execution screen is shown in Fig. 4. Whole trajectory data is recorded by specified excel file; each step provides finish status report. Optimized cruise Mach number and altitude is shown in Fig. 4; Figure shows progress of the running code. 

Fig. 4 Idle Screen for run of Flight-SIM

 Result of (1) is shown in Fig. 5; Raw result summarized flying status of each time step. 

Fig. 5 Raw result of Case (1); part of them are only shown

 Result of (1) is shown at Fig. 6; flying distance, altitude, speed, and AoA change during the flight are calculated. Corresponding change of engine, atmosphere, and fuel are also shown. 


Fig. 6 Few graph of Single-Airliner Trajectory

  Result of (2) is shown at Fig. 7; flying distance, altitude, speed, and AoA change during the flight are calculated. Corresponding change of engine, atmosphere, and fuel are also shown. 



Fig. 7 Few graph of Single-Airliner Trajectory with more fuel and step climb

 4) Conclusion

  Flight-SIM is completed and tested for typical single-aisle airliner DB. Although flying range is too exaggerated, the code itself provides proper reasonable flying trajectory based on the DB. Tool will be developed for not only aircraft also aerospace plane or space-craft. My next aircraft design will be evaluated based on this simulation.