Funded Through Program Launch, Wing Test Planned In NM
Aero-News has received an update from Aerion, the company that
aims to fly corporate executives at supersonic velocities aboard a
business jet that will also offer operating costs comparable to
conventional long range jets. After receiving continued funding
from the company board through program launch, the company plans to
test the aircraft's innovative laminar-flow wing this summer by
using a rocket-sled.
That test wouldn't be possible without the funding for it.
Aerion's board approved the funds in March, and as of now the
project is funded right up to the point where production design and
prototype development would begin.
"All of our activities to this point have shown that the
aircraft is technically and economically viable," said Aerion Vice
Chairman Brian Barents. "This has given us the confidence to enter
into discussions with OEMs and first-tier suppliers who would
become consortium partners."
Barents added that the program is "on schedule and on plan,"
with ongoing efforts to further refine the design and to confirm
supersonic performance. Active discussions with potential partners
Rocket Sled Testing Slated For June-July
With money in hand, Aerion next plans a test of supersonic
natural laminar flow at high Reynolds number using a rocket sled in
the June-July period at Sandia National Laboratories near
Albuquerque, NM. The purpose of the test is to demonstrate natural
laminar flow at Reynolds numbers approximating those on a
full-scale wing at supersonic cruise conditions.
(The Reynolds number is used to characterize aerodynamic effects
such as skin friction drag and the location of boundary layer
transition from laminar to turbulent air flow.)
Company officials added the test should also serve as another
validation point for Aerion’s unique transition prediction
and design software, which predicts the transition from low-drag
laminar flow to high-drag turbulent air flow.
To test the wing design, a cluster of 5-inch-diameter rocket
motors will accelerate a half-wing model at 30g’s to a speed
of Mach 1.5. The test article will maintain that speed for about
1.7 seconds, before hitting a water brake at the far end of the
track. The water brake consists of a snow-plow-like scoop on the
sled which is lowered into a trough of water that is lifted up and
thrown forward, thus slowing the sled. The track is 10,000 feet
Aerion expects to record several types of data during this test.
As in previous tests using a supersonic laminar flow test article
attached to a NASA F-15, the test wing will be observed with IR
thermography. This is a technique utilizing infrared cameras to
observe the different heating rates of the laminar and turbulent
Two IR cameras will track the model from stations near the
track. Boundary layer total pressure probes mounted at the trailing
edge of the wing will directly measure the thickness of the
boundary layer. In addition, accelerometers on the non-imaged side
of the wing will characterize the vibration of the wing.
The rocket-sled test is not without technical risk. Many factors
associated with the test equipment could contribute to reduction or
loss of laminar flow, including that the high unit Reynolds number
makes airflow much more sensitive to surface roughness than it
would be at full scale. Any vibration of the sled on its track
could also cause the laminar flow transition to occur sooner than
it would in flight, as could reflections of the sled’s
leading edge shock off the ground and track. The rapid changes in
speed and short duration of the test also might not heat the
surface enough for the IR thermography to be effective.
Despite those risks, Aerion engineers maintain the rocket sled
represents the best chance to validate their data for the company's
patented supersonic natural laminar flow technology, that
substantially reduces drag at supersonic as well as high-subsonic
cruise speeds. Aerion hopes the design will allow the development
of an aircraft that can use existing powerplant technology (from
Pratt & Whitney) to propel the aircraft above Mach 1.
Since announcing the project at the 2004 NBAA
Conference, Aerion engineers report gains in range,
performance and cabin size beyond original goals as a result of
continued subtle aerodynamic changes. As the company has reported
previously, NBAA IFR range at supersonic speed is beyond 4,000
nautical miles. Latest refinements appear to add a comfortable
margin to that figure.
The aircraft will be fuel efficient at cruise speeds just below
the speed of sound, allowing it to perform short and long-haul
overland missions with the same economies as today’s large
business jets. Range is roughly the same at both subsonic and
supersonic speeds -- exceeding 4,000 nautical miles. The aircraft
also has a low boom signature, and boomless cruise up to Mach 1.1.
Its maximum cruise speed will be Mach 1.6.
philosophy is to utilize demonstrated technologies and to minimize
complexity. The Aerion SBJ therefore is designed to cruise
efficiently up to 51,000 feet, its certification limit.
Aerion is an aeronautical engineering organization based in
Reno, NV. The crucial work of developing and patenting the
supersonic natural laminar flow wing was conducted over more than a
decade by a predecessor company, ASSET Group (Affordable Supersonic
Executive Transport), led by Dr. Richard R. Tracy.
In late 1999 and early 2000, ASSET performed supersonic flight
tests in collaboration with NASA’s Dryden Flight Research
Center, confirming predicted levels of natural laminar flow.