Supersonic Aircraft Get Quieter
One of the many reasons the concord was grounded was because of the massive amount of noise pollution generated as the aircraft continually broke the sound-barrier. But recent research and development efforts seem to be targeted towards getting supersonic aircraft back in the air on a commercial level. What has changed?
Aircraft research and development is always being improved on, with the result that NASA has now been able to conduct a series of flight tests designed to measure the shockwaves generated by an F-15 fighter jet so that they can see if it is possible to design quieter supersonic aircraft. The LANCETS (Lift And Nozzle Change Effects on Tail Shock) project is aimed at assisting with the development of commercial aircraft. The goal is to design supersonic commercial aircraft that can fly without generating any of the loud and annoying sonic booms that generally prohibit them from flying over land. Research shows that the boom loudness is directly related to the strength of the shock waves. Since these shock waves are created from on the front and rear of the aircraft and the way that the wings generate lift, it seems plausible that a sharp change in design should enable the booms to become much quieter. This is not the first time NASA has been involved with this sort of research. They have previously teamed with private companies with a similar goal of trying to establish how the aircraft’s shape may affect the strength of shock waves. In that case, a spike was added to the nose of the aircraft for the purpose of the experiment.
NASA will be using a NASA F-15B for the LANCETS experiments and research projects. The aircraft has adjustable airfoils (canards) in the front of the wing which make it possible to adjust the aircraft for the sake of the experiments. It engine nozzles can also be adjusted in flight. Two of these aircraft are flown one behind the other, the first making the necessary changes mid-air while the second, the probing aircraft fitted with purpose-designed equipment, monitors the shock strength of the first aircraft. Using these easily modified aircraft means that a lot of time and money is saved and invaluable research is conducted quickly and efficiently. The resulting data will be used to improve aft-shockwaves effects and will be made available to interested university and industry partners, so benefiting all in the aeronautics industry.