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I have a MAV and I need to find out the lift and drag coefficients for the wing and tail. I am not available with a wind tunnel so I will be using a load cell along with a separate wind source. Now I can measure forces on the MAV, airspeed at the wing and tail surfaces.

If I just use the angle of attack at the centre of mass then I can find the corresponding lift and drag coefficients (since there are two unknowns and two equations for forces along x and z axis). Now if I want to find separate lift and drag coefficients for wing and tail, for the corresponding angle of attacks, how am I going to do that? Once again I have force on the MAV in the x and z axis, angle of attacks for wing and tail, air speed, two equations of forces but four unknowns.

Please guide me resolve this issue.

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  • $\begingroup$ You'd need to test the wing separately from the tail, one might think. Doing this outside a wind tunnel seems like a lot of opportunity to introduce errors into your numbers... wind tunnels are used instead of load cells for some pretty good reasons, even though they're expensive to build & to maintain. Also, what is a MAV? Only thing I come up with is Mark Watney's "Mars Ascent Vehicle" but I don't think that's what you're testing. $\endgroup$ – Ralph J Sep 17 '18 at 16:01
  • $\begingroup$ Thanks for your reply. I don't have access to a wind tunnel and a load cell is the next best thing available to me. MAV stands for micro aerial vehicle. $\endgroup$ – Mani Sep 18 '18 at 4:25
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I guess your design is a conventional one.

One approach could be integrating two load cells in between the tail and wing sections.

You can measure drag force and moment. And the moment may help you estimate the tail lift (with some serious assumptions though).

If space is a concern, you can try building a scaled model (2:1?) to test a larger model. The resulting forces and moments must be corrected for Reynolds effects.

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