Drag and Lift Sensors for a Subsonic Wind Tunnel

[PorridgeAlmanac]

Hey everyone,

I'm a student working on building a wind tunnel with some classmates. I'm in charge of figuring out the drag and lift force sensors. I'm currently looking these two components:

http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_2128260_-1
http://www.jameco.com/webapp/wcs/st...1&productId=2136471&catalogId=10001&CID=MERCH

I don't really have any experience with either of these, and am not sure if these are suitable for measuring drag and lift (I'd order two, one for each of the types of forces). I'm looking to do something like this setup:

http://www.grc.nasa.gov/WWW/k-12/airplane/tunbalint.html

I'm also considering this setup from Science Buddies, as shown below. It consists of two Vernier force sensors attached to a vertical pole that mounts a test object in the testing chamber. It seems like a fairly easy and reliable setup, however. I think it requires use of Logger Pro. That will work, but it's not the most flexible--the other types of sensors could be easily programmed with an arduino nano to do whatever we need.

Any thoughts or comments are appreciated!

 

[HuskyNamedNala]

I think this might be a good solution. The alternative is a force balance, which requires calibration and can be very inaccurate. Given the size of your tunnel your measurements will probably be small, requiring high quality precision devices to make accurate readings. You can forgo pitch measurements and using pitot tubes measure the velocity around the control volume to estimate lift and drag. I have only heard of one tunnel doing a control volume calculation.

 

[jim hardy]

Doubtless you've gone back to the source - Wright Brothers wind tunnel balances?

http://quest.arc.nasa.gov/aero/wright/team/fjournals/hange/balance.html
i think there's an arithmetic or wording mistake in that one, but it's obvious where they flipped a sign

http://www.wright-brothers.org/Adventure_Wing/Hangar/1901_Wind_Tunnel/1901_Wind_Tunnel.htm

if your force sensors don't work out
here's a cool angular measurement gizmo
http://www.sensitec.com/upload/SENSITEC/PDF_Downloads/Datenblatt/Sensitec_AA747_DSE_04.pdf
(disclaimer - i never used one, just looks like an alternate approach that'd lend itself to a Wright balance)
and a "how to use it" from a solid industrial equipment manufacturer

http://www.analog.com/en/design-cen...circuits-from-the-lab/CN0323.html#rd-overview

good luck guys, keep us posted ?