Flush Airdata Sensing (FADS) System
@Machinebird
Bearfoil, not a bad question at all.
The tympanum (diaphragm) concept has some limitations but could work under limited conditions.
You might find this of interest:
http://www.nasa.gov/centers/dryden/p...ain_H-2379.pdf
http://www.spaceagecontrol.com/nasa-tm-104316.pdf