At the 2010 NBAA Convention, we took the time to get some peace
and quiet... by visiting some folks that are breathing new life
into elder bizjets. The FAA awarded Quiet Technology Aerospace a
Supplemental Type Certificate back in January of 2003, that
authorizes the installation QTA’s Stage 3 Hush Kit on all
Spey-powered Gulfstream aircraft. The QTA Hush Kit is unique in its
design, integrating the aircraft’s existing thrust reverser
system with advanced noise suppression, without affecting aircraft
handling or range.
The QTA Hush Kit uses a unique translating mechanism to enable
integration of the acoustic system with the existing thrust
reversers, requiring no additional controls. The ejector is mounted
on two carriage assemblies, one on each side, and slides on
low-friction linear bearings.
The ejector is mechanically linked to the Thrust Reverser
System, such that when it is deployed, two "translating" links push
the ejector aft and the thrust reversers’ doors deploy. Upon
stowing the thrust reversers, the ejector is automatically pulled
forward into the stow position.
Forward radiated fan noise is a contributor to both take off and
approach noise levels. It is also the largest contributor to cabin
noise. The high-pitched whine of the Spey engine is tamed by the
QTA Hush Kit, which incorporates acoustic treatment to the Inlet
Bullet to reduce the sound level of the fan. The QTA Hush Kit
retains the original GulfstreamTM acoustically treated tailpipe,
the original 5 lobe mixer nozzle is removed and replaced with a 12
lobe "fluted" mixer nozzle.
The 12 lobe nozzle works with the ejector in promoting the
mixing of the ambient air stream with the jet exhaust. The major
reduction in outside aircraft noise levels is achieved through this