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 are ongoing.

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 long.

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 boundary layers.

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.

Aerion’s design 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.

FMI: www.aerioncorp.com