SEAPOWER Magazine The Official Publication of the Navy League of the United States VOL. 49, NUMBER 2 February 2006

17 …And Into the Sky

Easy-to-assemble, disposable aircraft may be launched from carrier ship to resupply future combat units ashore

By RICHARD R. BURGESS, Managing Editor

Some time in the future, U.S. expeditionary or Special Operations Forces moving inland, awaiting vital logistical support, may find their supplies crash-landing in a nearby field. The supplies would be delivered to their precise position by a disposable unmanned glider with inflatable wings that is assembled on a ship 50 miles away and launched from a giant electromagnetic tube.

Such a scenario is only a concept at present but indicative of the ideas being explored to address the technological and affordability challenges of the Navy’s sea basing initiative to enhance mobility and reduce its reliance on ports and harbors controlled by other nations.

The essence of sea basing is that U.S. military forces of the future will do their logistical support and troop-staging operations at sea rather than on land, diminishing the need to rely on other nations’ air space or overland routes for access to the battlespace. Beachheads, “iron mountains” of materiel and headquarters ashore would be relegated to the nation’s military museums. To make that concept a reality, the military needs new ways of moving troops and materiel to world hot spots.

The Advanced Logistics Delivery System (ALDS) is an approach to providing logistics that does not rely on manned aircraft, landing craft, accessible ports or overland access inland.

The glider would be launched by a specially designed 7,000-8,000-ton high-speed vessel, a 550-600-foot trimaran fitted with a launch tube based on a rail assembly more than 360 feet long and curved upward from the halfway mark. It would be capable of launching a 1,500-pound glider at a speed of 500 knots.

Initially conceived by the Naval Surface Warfare Center’s Carderock Division (NSWCCD) in Bethesda, Md., the ALDS concept is being further developed by the Center for Innovative Ship Design, a joint team of the Office of Naval Research and the Naval Sea Systems Command that includes members from industry, academia and the Navy.

The unmanned glider features a stingray-shaped flat center section containing a cargo bay and avionics bay. The wingless body would be flung by the launcher into the air. After leaving the launch tube, compressed gas would be activated to inflate wings attached to body, producing a flying wing airframe that would provide additional lift. The craft would glide to a controlled crash at its destination, likely guided by a Global Positioning System device.

Inflatable wings are an advantage, according to the craft’s designers, because they would not be subject to launch forces and would make the gliders easier to handle aboard ship.

The gliders would have a 50-mile range, which could be extended up to 160 miles with the addition of rockets that would fall away as the glider reached its apogee.

Geoff Hope, an aerospace engineer with the U.K. Ministry of Defence, and Colen Kennell, a naval architect with the NSWCCD and considered one of the world’s experts on innovative naval ship design, are members of the concept development team that last year described the ALDS idea at the Joint Sea Basing Conference sponsored by the American Society of Naval Engineers.

Hope and Kennell maintain the unmanned glider designed for the ALDS offers numerous advantages over manned aircraft. The airframe would feature a small radar cross section, making it difficult to detect on air-defense radars.

Without an engine, it would be quiet and produce no heat subject to detection by infrared sensors. Without a crew, its loss would pose no risk to personnel. Its disposability would simplify the landing at the point of delivery.

However, the designers say there are technological barriers to their success, mainly from the huge volume of supplies that must be delivered. Their operational parameters are to provide 100 percent of the dry cargo needs for the 6,800 troops of a Marine Expeditionary Brigade, approximately 75 short tons per day. The ALDS also would provide 10 percent of the wet cargo needs of troops further inland or in areas too hazardous for V-22 Osprey tiltrotor aircraft. That would require 233 gliders per day, with launch rates up to two per minute.

That scenario is daunting, but the designers came up with an innovative solution. Instead of devoting shipboard hangars to the onboard storage of gliders, the glider structures would be molded onboard from blocks of plastic and “snapped together like a big plastic toy,” said Patrick McGinnis, the ALDS Launch Concepts team leader at the Naval Surface Warfare Center’s detachment in Philadelphia.

They would be fitted with modular avionics and inflatable wing kits. “It would be like an assembly-line process, where you build it, pack it [and] shoot it,” he said. “Build on demand.”

Although the ALDS ship would be highly specialized, it would not be a single-purpose ship. Its deck also would be available as a resupplying and refueling pad for V-22s and helicopters transiting to and from the battlespace.

Hope and Kennell said a trimaran design is ideal for the ALDS craft because it would provide best balance of speed, volume and stability requisite for the long, narrow center hull which would house the glider launch tube. Power for the launch would be supplied by a linear induction motor, similar to the Electro-magnetic Aircraft Launching System (EMALS) being developed by General Atomics for the Navy’s next-generation aircraft carrier.

As with EMALS, the ALDS launching system is made possible by the greater amounts of electrical power available to future ships with advanced electrical motors and integrated power systems.

“We’re using EMALS as a baseline for the system,” McGinnis said. “We were able to get the equipment to about half [the size of EMALS].”

Because the cargo glider is envisioned to be smaller and lighter than a typical carrier-based aircraft, a scaled-down version of EMALS is adequate, although the launch velocity of the ALDS glider would be much greater than that of a carrier aircraft because the glider would lack its own thrust.

According to Chris Hatch, spokesman for the Naval Surface Warfare Center’s Philadelphia detachment, the ALDS concept is still young and subject to further innovation. He said that engineering students from Virginia Tech are giving the concept a fresh look.