Assistance with Understanding MachUp 6 Parameters

[Shubham Bedke]

Hello Everyone,

I have found MachUp 6 to be very helpful for UAV design. However, I need some assistance in understanding a few aspects of the software. Specifically, I am trying to understand the meaning of CD,L and CD,L^2. Where can I find the values for these parameters, and how are they calculated?

Additionally, I would like to know how to set the units for parameters in MachUp 6.

I appreciate any guidance you can provide to help me better understand MachUp 6.

Thank you.

Best regards,  
Shubham Bedke.

[Mathiyazhagan RJ]

You can go through this video for the CD,L and CD,L^2.

MachUp 6 is dimensionless. For the dimensional analysis, you can use MachUp 5

[Shubham Bedke]

  Thank you for your guidance @Mathiyazhagan RJ.

 

 Does MachUp 5 or 6 support Eppler Airfoil?  

[Mathiyazhagan RJ]

It seems the airfoil cannot be directly imported. You need to run the analysis for the Eppler airfoil in X-foil and then import those values into the spreadsheet shown in the video. From that spreadsheet, you can obtain the airfoil coefficients to apply directly to MachUp. However, I noticed significant deviations between the XFLR5 results and MachUp when predicting the airfoil coefficients using the spreadsheet.

[Shubham Bedke]

Thank you for your support. Could you suggest resources with accuracy to do complete Fixed Wing UAV Aerodynamic Sizing, Stability, and Control Checks? I am interested in comprehensive FW UAV Design, including Sizing, Stability and Control, Trimming, Performance Optimization, and more. I hope you will help me to learn.

[Mathiyazhagan RJ]

For aerodynamic sizing, refer to the book Aircraft Design: A Systems Engineering Approach. This spreadsheet will help you properly size your plane. For stability analysis, you can use the XFLR5 software. Although the learning curve is a bit steep, there are numerous tutorials on YouTube that can guide you through the stability analysis process. For subsonic UAV stability analysis, XFLR5 values are close to real-world conditions. If you’re looking for CFD analysis, consider using OpenFOAM. If you’re not familiar with the command line approach of OpenFOAM, you can use the FreeCAD add-on called CfdOF. There are also YouTube videos available to help with the installation.

Cheers,

Happy flying.

[Shubham Bedke]

I am currently reading "Aircraft Design: A System Engineering Approach" by Mohammad H. Sadraey and have completed the first six units, with the stability and control section remaining. Is XFLR5 suitable for stability analysis? I am asking because XFLR5 does not account for fuselage drag. For my UAV, which is a twin-boom with an inverted U-tail configuration and a fixed-wing type, I have selected the Eppler 214 airfoil for the wing and the NACA 0009 for the tail. The maximum takeoff weight (MTOW) is 15 kg. Could you provide any suggestions for this UAV configuration?

[Mathiyazhagan RJ]

You can determine the pitching moment of your fuselage using either CFD or hand calculations. For steady-state trim calculations, xflr5 is a useful tool, especially since the wing generates most of the moment during cruise conditions. After calculating your trim state with the lifting surfaces in xflr5, you can verify stability by creating a subscale prototype. xflr5 provides an initial estimation of your plane’s stability. Once you have a prototype, you can cross-verify the stability conditions and trim values using the flight logs.

[Shubham Bedke]

Thank you for guidance.