Aerowerx
WellKnown Member
I have been doing some virtual experiments, with changing sweep angle.
This is a tandem configuration with the pilot at 5 feet from the nose and the passenger at 8 feet. A picture of the configuration is in the previous post in this thread.
Here is a tabulation of the results, from an Excel spreadsheet...
Any one of these sweep angles would probably work, but 23 degrees puts the CG closest to the passenger.
What I did not record here was the "efficiency". I do not know how XFLR5 calculates this but I would guess that higher is better.
What I did was to change the sweep angle, and then adjust the wing position to get a zero pitching moment with both the pilot and passenger at 200 pounds each. Next removed the passenger and tried various pilot weights. It might be possible to have a lower pilot weight for some sweep angles, but I used the same weights for consistency. A 160 pound pilot works for all sweeps. Anything less (like 150 pounds) and the analysis model gives up with the wing in stall (model is tail heavy). This was all done with no trim control, by the way.
You can see how the sweep angle affects the NP position and the static margin.
Don't take these results as design guidance, since I will have to do this all over again after I get a better number for the structure weight. At this time I only have a reasonable guesstimate of the pod and wing weights.
Ooops! Somehow got that lift distribution attachment. Didn't mean to.
This is a tandem configuration with the pilot at 5 feet from the nose and the passenger at 8 feet. A picture of the configuration is in the previous post in this thread.
Here is a tabulation of the results, from an Excel spreadsheet...
Any one of these sweep angles would probably work, but 23 degrees puts the CG closest to the passenger.
What I did not record here was the "efficiency". I do not know how XFLR5 calculates this but I would guess that higher is better.
What I did was to change the sweep angle, and then adjust the wing position to get a zero pitching moment with both the pilot and passenger at 200 pounds each. Next removed the passenger and tried various pilot weights. It might be possible to have a lower pilot weight for some sweep angles, but I used the same weights for consistency. A 160 pound pilot works for all sweeps. Anything less (like 150 pounds) and the analysis model gives up with the wing in stall (model is tail heavy). This was all done with no trim control, by the way.
You can see how the sweep angle affects the NP position and the static margin.
Don't take these results as design guidance, since I will have to do this all over again after I get a better number for the structure weight. At this time I only have a reasonable guesstimate of the pod and wing weights.
Ooops! Somehow got that lift distribution attachment. Didn't mean to.
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