Sometimes technological change is dramatic — think pistons to jets — but sometimes the subtle advances are just as revolutionary. One greatly appreciated part of an airplane that could one day be changing is the venerable pitot-static system. While doing away with a projecting pitot tube would also do away with a tiny bit of drag, the product of the probe’s efforts offer an upside few of us would choose to turn down for less than a knot’s gain. Still, the system can be inaccurate, especially at slow speeds, and is especially inadequate for helicopters. The Laser Air Speed Sensor Instrument project (LASSI) now in the works aims to develop optical sensors and ditch the tubes, replacing them with ultraviolet laser systems that would be more accurate, easier to maintain (that’s the goal, anyway) … and drag-free. The project, which started last year, is being worked on by BAE Systems, Advanced Optical Technology Ltd., Spectrum Technologies and the Department of Physics at Hull University in the U.K. For helicopters, LASSI will greatly improve the information provided to pilots during low-speed activities, BAE said. For fixed-wing aircraft, the reduction in drag achieved with the removal of pitot tubes will save fuel. The ability to “steer” the sensor will enable accurate vector measurements to be taken, which should improve the control of flight. For military aircraft, LASSI will enable a reduction in the radar cross-section of the aircraft, improving its survivability in enemy territory. LASSI could also be used for alternative applications such as mapping the airflow around buildings and structures, BAE said.
