flying deep.(Technology Information)

INTEGRATED DESIGN AND ANALYSIS TOOLS DRIVE SUBMERSIBLE VEHICLE TECHNOLOGY TO NEW DEPTHS

Hold on to your seats, we're going down." These are not words passengers want to hear from their pilot when in flight over the ocean. Yet the ominous phrase takes on anew meaning when it comes from the mouth of engineer Graham Hawkes, a trailblazer in the development of submersible vehicles for underwater viewing. Hawkes is the visionary behind the design of more than 70 percent of all piloted underwater vehicles ever built for research or industrial uses and more than 300 research remotely operated vehicles (ROVs). In addition, one of his crafts, the Deep Rover submersible, holds the record for enabling the deepest solo ocean dive at 300 feet.

The most recent incarnation of Hawkes' vision is a first-of-its-kind, untethered two-person submersible craft that will allow scientists to "fly" deep into the ocean and explore the domain in a way not possible using existing submersible technologies. Scheduled for completion early next year, the DeepFlight Aviator, as the new vehicle is called, will be able to maneuver with a speed and ease unmatched by existing submersible vehicles. Crucial to the development of the new sub has been the engineering team's reliance on a well intergrated suite of automated design and analysis tools.

DeepFlight Aviator evolved from an earlier award-winning Hawkes design called DeepFlight I. Introduced in 1996, DeepFlight I was the first underwater craft to employ the lift principle of airplanes. The vehicle was designed with stubby, inverted wings that provide a "negative" lift to counteract the slightly buoyant characteristics of the sub and pull the craft down. At cruising speeds, DeepFlight is neutrally buoyant and depends on its thrusters to drive it up or down. This principle, along with the vehicle's small size, allows the pilot to descend at a very fast rate to maximize bottom time.

In contrast, conventional submersibles and submarines reach depth slowly, typically using a negative buoyancy ballast system to control dive and accent. The ballasts are continually loaded until the craft is slightly heavier than the water it displaces. To return to the surface, the ballast is jettisoned. Often, using this mechanism, the submersible will spend 90 percent of its underwater time getting to and returning from the underwater research site.

Getting Down

The DeepFlight Aviator takes the airplane principle to a new level. It uses inverted airfoils and positive buoyancy to "fly" underwater with a freedom of movement approaching that of scuba diving. The vehicle offers the depth and underwater-viewing capabilities of a conventional submersible (minus the noisy mechanisms and bright lights that cause those underwater organisms capable of fleeing to do so) and the mobility of a submarine. Unlike conventional submersibles, which require a specially equipped mother ship to accommodate their size and crew, DeepFlight Aviator is designed to operate independently under on-board pilot control.