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FlightStream - Incorrect Moment Coefficients
Hi, I am working on a student project using FlightStream to obtain a full set of stability derivatives for a light GA aircraft, similar in configuration to a Cessna 172. I have been able to produce good results for lift, drag, and side force derivatives, but the pitching, rolling and yawing moments and their associated…
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FlightStream License checkout failed
I'm getting a license error every time I open FlightStream. Please find the attached image. I have tried reinstalling FlightStream, and it did not help. Altair says my license key is still active. Can you please help me fix this error?
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Question about Mesh Convergence for Rotor Geometry
According to the manual, it is recommended to run the analysis with a non-zero angle of attack. For rotors, would it be appropriate to use geometries with varying collective pitch angles for this purpose? Also, in OpenVSP’s detailed settings, the manual mentions setting the clustering values for the leading edge and…
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FlightStream - CCS Wing Meshing Growth Controls Being Ignored
Hi, I have been using the CCS wing meshing tool in FlightStream to create the wings and horizontal/vertical stabiliser for a light aircraft. The mesher works fine without control surfaces, but the moment I specify a control surface it seems to ignore any growth scheme settings. For example, this wing has 160 chordwise…
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Axial Mesh refinement on a fuselage component
I am having problems to refine the mesh on a fuselage component in the axial direction, in the user manual it seems to be possible to do it but the mesh refinement zone tool is only available in the CCS wing tool. Furthermore, i saw that it is possible to use the wrapper tool to refine mesh but it deteriorates the global…
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Inquiry Regarding Tessellation Control in OpenVSP
According to the FlightStream manual, when exporting a rotor from OpenVSP, the values for LE Clustering and TE Clustering should be set to 1. However, there is no specific guidance on how to set the Root Cluster and Tip Cluster values. I would like to inquire about the recommended settings for these parameters.
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FlightStream Publications
This discussion is a running list of FlightStream publications. Our team will routinely update this thread. If you are unsure whether an investigation of interest is available, please reach out to our team directly. Little, D. S., Majdalani, J., Hartfield, R. J., & Ahuja, V. (2025). Improved prediction of propeller tonal…
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Community Champion of the Month - July, 2025
The Community Team would like to introduce the July Champion of the Month, Dr. Luca Cavagna @Luca Cavagna who has vast experience as an aerospace engineer in the field of aeroelasticity , flight/ground loads and simulation. Luca Cavagna graduated in 1998 from Politecnico di Milano in Aerospace Engineering with a thesis on…
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Can I use reliably Altair products to simulate CFD on extreme flight conditions?
Description: Usage and limitations of Hypermesh and FlightStream for specific flight conditions in CFD analysis Product/Topic Name : Hypermesh, Hypermesh CFD, Hyperworks, FlightStream Hi everyone! My team is having difficulties evaluating the options with Altair softwares on CFD analysis on specific flight conditions. We…
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flight stream에서 로터의 FM 관련 문의
현재 openvsp에서 모델링을 한 로터를 이용하여 .p3d 파일로 flightstream의 solver를 이용해서 로터의 FM을 계산해보고 있습니다. 그런데 메뉴얼에 나와있는 대로 mesh를 구성하였지만, 원하는 FM의 값에 다가가지 못하고있습니다. 다양한 mesh를 이용하여 계산해본 결과, 모멘트의 값이 너무 크게 나오는 결과가 지속적으로 나타나고있습니다. 그리고 mesh에 따라 모멘트(Moment_Z)와 추력(Force_Z)의 값이 너무 큰 변동이 있는것을 알았습니다. 파워를 계산함에 있어, 모멘트와 각속도를 곱하면서 계산하고 있는데, 모멘트의 값을 설정하는 변수가…
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FlightStream License Error – GlobalZoneAM Feature Not Found (Error Code 9)
Hi, I’m getting the following license error when launching FlightStream: The Altair License Manager is running, and the license file is in the expected location. I also tried restarting the service, but the error still shows up. Does this mean the license doesn’t include the GlobalZoneAM feature, or is there something else…
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M2Cn distribution 질문
안녕하세요 충남대학교 석사과정 박기정입니다. 몇 가지 질문이 있습니다. 1 . 1 time step run한 후 Export 했을 때 지정한 블레이드 단면들에 대한 X, Y, Z, nx, ny, nz, L, Cp, Mach, vx, vy, vz, vtot, Cp_ref 값이 여러 개 (Edges = 60, 이때 데이터 60개 추출) 나오는데 어떠한 값을 사용해야 근거 있는 데이터값을 얻을 수 있을까요? surface cross section에서 section plane : XZ, Plot direction : X를 사용했습니다. 2. 지정한 블레이드 단면들에 대한 X, Y,…
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[Flightstream] 무차원화된 M2CN을 로터 디스크에 뽑는 방법
충남대학교 석사과정 박기정입니다. 이전 질문으로 non-dimensional normal force M2Cn을 프롭로터에 대해서 디스크에 contour를 그리는 것에 대한 답변을 받을 수 있어 감사했습니다. 이전에 공유해주신 파일을 이용하여 로터 블레이드가 한 바퀴 회전할 때의 전체 데이터가 blade section별로 나오는 과정은 확인 했으나 제가 원하는 데이터는 로터 블레이드가 한 바퀴 회전할 때 azimuth angle 별로 원하는 blade section의 데이터를 뽑을 수 있는 방법이 궁금합니다. 예를 아래의 사진 자료 통해 공유하겠습니다. SPAN…
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Doubt regarding flightstream, why are my Cl values this unrealistic?
Hey everyone, I tried to simulate flow around a 777 generated from VSP, I did all the steps properly, like uniting, removing all degenerate faces, marking all trailing edges and wake termination nodes, but my simulation still isnt working. I also did proper meshing according to this vide - FlightStream Tutorial: OpenVSP to…
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Applying the Polhamus Vortex Lift Correction to Altair FlightStream
Background In aerodynamic design, particularly for aircraft with delta or highly swept wings, accurate lift prediction is not just a convenience; it’s a necessity. At high angles of attack, traditional linear lift models fail to capture a critical phenomenon: vortex lift. This blog post explores vortex lift correction,…
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FlightStream Self Paced Training Presentation
The FlightStream Self-Paced Training Presentation is a comprehensive resource designed to help users of all experience levels master aerodynamic simulation at their own pace. This training covers everything from the basics of FlightStream, including its interface and physics theory, to advanced topics like multi-body…
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FlightStream Tutorial Models and Files
Overview: These are a set of files available for use to explore and understand the capabilities of Altair FlightStream. There are help Youtube videos that go along with these models. Included in the zip file are: Files: 777ER.vsp3 Blunt_TE_original.p3d Boeing 757S.STL…
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FlightStream: Mesh Convergence Study
Mesh convergence studies are crucial for verifying the reliability and accuracy of analysis results. By systematically refining the mesh and observing the convergence of key aerodynamic parameters, such as lift and drag, you can establish confidence in the validity of your simulations. This guide will walk you through the…
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Main FlightStream Tutorial Discussion
This discussion thread is designed to provide easy access to all existing tutorial files and videos in one convenient location. Whether you're just getting started or looking to deepen your understanding, these resources are here to guide you every step of the way. Feel free to explore the linked tutorials, and don’t…
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How to make Flightstream recognize my active student license?
I have completed all the steps to download Flightstream and to activate my student license in the system, according to a video tutorial. However, as I launch the app, I come across this error: License checkout…not found. Any idea how to solve it?
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Discrepancy between FlightStream 2023 and FlightStream 2025 results
I have plots between the two versions where the drag is close to doubled in 2025 compared to the 2023 results.
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Getting License error for FlightStream
After launching the FlightStream Application i am getting license not found error , but i have installed the license and authenticated it still im getting such error. I have attached error screenshot and license screenshot. Kindly help me out
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FlightStream, student license issue
Hello, I have an issue regarding the student licensing of the FlightStream program. After reading the installation documentation, I understand that there is a need for a license file which I currently don't have. Could you tell me how can I get a student license file? I attached a photo of the installation process where…
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Why is my Flightstream ground-plane unsteady simulation not converging?
Hello, I'm trying to model a vehicle in hover and cannot get the solution to converge. If you could shed some light on why the solution is not converging, it would help a lot. What I have tried: Tried a single propeller without ground (viscous and inviscid) and it works. Tried two propellers and without ground, and it…
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FlightStream 2025 (Windows) crashing on all unsteady simulations
Hello, I have an issue where FlightStream 2025 crashes every time I run an unsteady simulation. I did not have this issue with the 2023 version. I have a Windows machine with 64gb of RAM and 32 parallel threads. I have tried running the same simulation on a Linux machine and it works fine. I have tried uninstalling and…
