Wing Project Images

Image 1: Our wind tunnel is a PVC pipe 4 feet long and 2 feet in diameter. The inside of the pipe looks uneven, but it is actually rather smooth. The fan at the other end of the pipe in the photo is blowing away from the camera, so air enters the tunnel at the near end. For our preliminary tests we have run the fan at full speed, giving an air speed of about 4.5 meters per second according to a hand-held anemometer. The power supply on the left allows us to vary the speed of the air from 0 to 4.5 m/s.

 Image 2: The above photo shows how we are currently attaching the wing to the Vernier Dual Range Force Sensor. This is the first thing we tried, and I imagine it will change. A 2-inch screw attaches an aluminum paint guard to the force sensor. The wing is currently held to the paint guard by rubber bands. We have discussed various possible methods for configuring the wing and force sensors, but we are having difficulty devising a way to measure the true lift and drag on the wing (not affected by any torque the wing may experience). See also Images 3 and 4 below.

Image 3: Here is another view of the wing-sensor assembly.

Image 4: Here is yet another view of the wing-sensor assembly. (This is an early picture. For the data shown later on this page the wing was actually repositioned so that it was perpendicular to the screw holding it, and the point of attachment was closer to the center of mass.)

Image 5: This is the student-designed wing profile. The wing is about 45 cm broad, constructed of a balsa skeleton and a poster board skin wrapped with plastic wrap. The wing and mounting assembly (screw, paint shield, and rubber bands) weigh a total of 1.07 N.

Image 6: The Vernier Dual-Range Force Sensor connects to a Vernier Iniversal Lab Interface which, in turn, connects to a MacIntosh laptop computer running Vernier Logger Pro data collection software.

Image 7: This is a graph of data collected with the wing held horizontally and the force sensor (screw) held vertically. The sensor sees downward forces as negative and upward forces as positive. The sensor was zeroed before data collection. The fan was turned on at approximately t = 6 seconds, and the air speed reached 4.5 m/s at about t = 10 seconds. The average force for the period after t = 10 seconds is 0.160 newtons. It is assumed that this was the lift force of the wing for this air speed. The graph shows the presence of vibrations/oscillations of the wing, but this might not be as bad as it looks and is accounted for by determining the mean force over a longer time interval.

Image 8: This is a graph of data collected with the whole assembly tilted 15 degrees. The sensor was not zeroed before data collection this time or any time after. The mean force reading when the air was not moving was 0.075 N (reflecting the fact that the force sensor is reading less than the weight due to the angle of tilt of the assembly). The average force for the period after t = 15 seconds is 0.365 newtons. It is assumed that this resulted from both lift and drag on the wing.

Image 9: This is a graph of data collected with the whole assembly tilted 25 degrees. The mean force reading when the air was not moving was 0.122 N. The average force for the period after t = 15 seconds is 0.688 newtons.

Image 10: This is a graph of data collected with the whole assembly tilted 45 degrees. The mean force reading when the air was not moving was 0.420 N. The average force for the period after t = 15 seconds is 0.937 newtons.