US patent is part of design work for quiet business jet
Gulfstream has patented a telescoping nose or tail spike for a supersonic aircraft that is expected to reduce sonic boom significantly. The US patent is part of Gulfstream's continuing conceptual design work on a quiet supersonic business jet.
The spike extends in supersonic flight to reduce the sonic-boom amplitude by distributing the pressure disturbance over a greater length. The tip of the spike, being smaller in cross-section than the nose of the aircraft, also generates a weaker initial shockwave.
Further weak shocks are generated by the cross-section transitions between adjacent telescoping sections. The position and shape of these transition regions are selected to reduce the coalescence of the weak shocks into a strong sonic boom at the ground.
The patent also applies to a unique way of shaping the aircraft and spike to create an asymmetrical pressure distribution, so that shockwaves propagate towards the ground with less intensity than in other directions. In this design, the nose and tail lie on a line defining the flat bottom of the fuselage.
Gulfstream says reducing sonic boom to the level where supersonic flight over land becomes acceptable is crucial to the commercial viability of its supersonic business jet. The company believes a large-scale demonstrator will be required before it can launch development of its proposed Quiet Supersonic Jet.
GRAHAM WARWICK / WASHINGTON DC
Source: Flight International
