When doing the preliminary design for the plane, we wanted to be able to sense airspeed. When a pilot is bringing the aircraft in for a landing airspeed is important. The pilot will have to keep that plane above its stall speed, so that the plane can keep up lift an stay in the air. We wanted a sensor that would provide an accurate reading of relative airspeed.


The relative airspeed measurement was implemented using a SenSym, SCX004D, 4" water column pressure sensor. The sensor was mounted on an SCX-E1 evaluation board. The gain of the board was modified, and the sensor was calibrated in the windtunnel in the Mechanical engineering lab.
The sensym SCX evaluation board was used for the circuit board. After the sensor was mounted on the board, the gain needed to be changed. By using the equations in the handbook, we set the gain so that when the airspeed was at maximum, 70 mph, then the output would be 5 volts.

Picture of the Pitot Tube in the wing:

Diagram of pitot tube:

Circuit digram:


This sensor was the easiest to calibrate. The pitot tube was mounted in a wind tunnel, and the sensor output was set. When the airspeed was 70mph, the output of the sensor was set to 5 volts. This allowed the plane to reach speeds of 70mph with the sensor being able to read it. The airspeed was then decreased at 10mph increments and the voltages were recorded. The plot of the Voltage versus Airspeed can be referenced below.

Calibration Plot:

Design Considerations and Problems:

There were no problems with designing the circuit for this airspeed. The only design consideration that we faced was to set the airspeed high enough so that the speed of the plane could be read. The sensor was very accurate and posed no problems when tested. Be careful if you use this sensor for anything it is extremely sensitive to shocks. If you drop it, you could possibly break the silicon diaphram and ruin the sensor.



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Bill Glenn 
Pat Malloy 
Greg Norton 
AFTS Project Group