Page 70 - AA 2018_09

on the ground. As Peter Coen, NASA’s
supersonic project manager explains,
the goal is to reduce the boom to a
thump.
As far back as when the Concorde
was retiring in 2003, NASA was
flying a Northrop F-5E fighter with a
modified nose and fuselage to research
whether aircraft design can reshape its
shock wave and therefore reduce the
sonic boom.
More recently, it has been The X-59 resembles a long
investigating the sonic boom using an dart with aft-mounted
F/A-18 Hornet. By having the Hornet delta-shaped wings and
dive at supersonic speed towards a tailplane. nasa
specific point on the ground, NASA
has been able to measure the noise
level a few miles away from where the
boom is focused and where the shock
waves have spread out and weakened.
The result is more of a ‘sonic
thump’ than a sonic boom and is
likened to the sound of a car door
closing.
Later this year, NASA will take the
tests away from the flight research
facility to the Gulf of Mexico. There
it will aim the boom at the Gulf and
measure the resultant thump on the
city of Galveston using a combination
of sensors and 500 human
volunteers. Armed with this data, they
will have a greater appreciation of The Spike S-512 is designed
what noise level people on the ground to carry 22 passengers
will accept. and cruise at Mach 1.6. spike
However, the Hornet only has the aerospace
capacity to simulate a sonic thump
over a limited area and supersonic initiating two rulemaking activities on the previous Achilles heels of cost and
travel in the future will call for the civil supersonic aircraft noise. environmental impact are also being
loud sonic boom to be eliminated, “The first activity is a proposed addressed.
rather than merely directed away from rule for noise certification of In addition to the development
the populous. supersonic aircraft, and the second of the X-59, Lockheed Martin is also
To this end NASA, earlier this year, is a proposed rule to streamline and involved in a commercial supersonic
awarded Lockheed Martin’s Skunk clarify the procedures to obtain special project with Aerion Supersonic and
Works a US$247.5 million contract flight authorisation for conducting GE Aviation through the development
to design, build and flight test a Low supersonic flight testing in the United of the three-engined Aerion AS2
Boom Flight Demonstrator (LBFD). States.” business jet. Characteristic of all
Named the X-59 QueSST and It would seem that the sonic boom airframes in the SST realm, the AS2
just under 30 metres in length, its is on the verge of being replaced by a is needle-like, although in place of
futuristic form resembles a long dart dull double-thump, signalling a new a delta wing is a thin tapered wing,
with aft-mounted delta-shaped wings heartbeat in air transport. somewhat reminiscent of the F-104
and tailplane. The specially designed Starfighter’s, as is the T-Tail. Seating
airframe accepts that shock waves A new boom between eight and 11 passengers,
will form on the various surfaces of When the Concorde came to a halt and with a ‘boomless’ cruise speed
an aircraft but aims to prevent them for the final time, there were those of Mach 1.1, it has already garnered
shock wave. As a consequence of the ‘The X-59 will who shed a tear at the passing of an the attention of the Flexjet fractional
from combining into a single intense
aircraft ownership program, which has
era. However, the aviation landscape
reduced intensity, the noise heard on fly a series has changed greatly since the 1960s placed a US$2.4 billion order for 20
the ground will be far less. when this supersconic pioneer was AS2s to be delivered in 2023.
On completion of flight testing, of flights first conceived. Along with sonic On a slightly larger scale, the
the X-59 will fly a series of flights boom research, the evolution of Boston-based Spike Aerospace is
to validate their results. To facilitate over selected materials, increased computing power, developing the S-512 with the goal
over selected communities in 2022
to efficiently carry 22 passengers at a
developments in engine design and
this and other aspects of research, communities improved dynamic modelling are just speed of Mach 1.6 without creating a
the FAA announced in May that it some of the advancements that have sonic boom. 37 metres in length, the
development of supersonic flight by in 2022.’ the potential to open up a new dawn S-512 has a modified delta wing and
would be taking steps to advance the
aims to reduce the flight time between
in supersconic transport. In doing so,
70 AUSTRALIAN AVIATION