I'm playing with XFLR5 to get some tables of steady-state aerodynamic forces and moments for a small scale plane, that I then plug in my own rigid-body 3D simulation to get close to realistic behaviors. I am familiar basic principles of flight, but not with aerodynamic theories/methods. I have a couple of questions about LLT analysis option - hope they make sense.
From the guidelines, I can see that LLT is for wing-only analysis. However, the LLT option remains active also when the plane definition includes more than the main wing. I am using a main wing + elevator (+ fin) configuration. Are the LLT results in this case for the main wing alone ? Or is the elevator also analyzed and included in the overall lift, drag and moments results - and if this is the case, is then the downwash effect / change in angle of attack on the elevator panel geometry due to the main wing included ?
And the second question is about sideslip. I can see that sidesliped position can be analyzed either with a Type 1 - in which beta is set to a fixed value, or as a Type 5 analysis, as a beta range. In both cases, the LLT option is available. But the guidelines say that the "(sidesliped) resuling geometry is analyzed using the conventional VLM and panel methods".
I am also wondering how/if the viscous part is included in general in the lateral analysis, given that the airfoil analysis is 2D, for lateral wind the 2D section would be different - in any case this is my simple understanding.
Thanks.
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Even if you define the elevator and fin, in the case of an LLT analysis, these will be ignored and the results wll be related to the wing only.
In the case of LLT, the slideslip is ignored.
Yes, the viscous part is included. It is calculated by interpolating the foil data using the local lift coefficient. Very clearly an approximation, at the limit of what can be asked of xflr5's simple model.
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Hi everyone,
I'm playing with XFLR5 to get some tables of steady-state aerodynamic forces and moments for a small scale plane, that I then plug in my own rigid-body 3D simulation to get close to realistic behaviors. I am familiar basic principles of flight, but not with aerodynamic theories/methods. I have a couple of questions about LLT analysis option - hope they make sense.
From the guidelines, I can see that LLT is for wing-only analysis. However, the LLT option remains active also when the plane definition includes more than the main wing. I am using a main wing + elevator (+ fin) configuration. Are the LLT results in this case for the main wing alone ? Or is the elevator also analyzed and included in the overall lift, drag and moments results - and if this is the case, is then the downwash effect / change in angle of attack on the elevator panel geometry due to the main wing included ?
And the second question is about sideslip. I can see that sidesliped position can be analyzed either with a Type 1 - in which beta is set to a fixed value, or as a Type 5 analysis, as a beta range. In both cases, the LLT option is available. But the guidelines say that the "(sidesliped) resuling geometry is analyzed using the conventional VLM and panel methods".
I am also wondering how/if the viscous part is included in general in the lateral analysis, given that the airfoil analysis is 2D, for lateral wind the 2D section would be different - in any case this is my simple understanding.
Thanks.
Thanks!