Unmanned air logistics vehicle projects continue to receive funding - but will future pilotless passenger aircraft be accepted by the public?

Lightweight military unmanned air logistics vehicles (UALVs) may become widespread within the decade if current developments continue to receive funding. USAir Force interest in medium- and heavy- lift military UALVs is also re-emerging, almost two decades after it first studied the concept of what was then known as a "modular airlifter".

At the Unmanned Systems 2003 conference in Baltimore, Maryland, in July, the US Air Force unveiled a concept for fleets of UALVs with payload capacities of 45,000-72,600kg (100,000-160,000lb) guided by a Boeing C-17 mothership as a solution to ongoing shortfalls in the US military airlift fleet.

At the same conference, the US Navy's Carderock Surface Warfare Centre unveiled a concept for inflatable-wing, autonomous cargo gliders that would be used to resupply small forces ashore. The idea grew out of an even more ambitious proposal, since shelved, for dedicated logistics "carrier" ships able to resupply an entire battalion 370km (230 miles) away.

Interest in civilian UALVs is also re-emerging. One concept, conceived within the US Federal Aviation Administration, proposes automated freight airlift operations at local industrial parks.

National network

At the International Air and Space Symposium in Dayton, Ohio, last month, Herman Redless, director of the FAA Office of Aviation Research, argued that a national UALV network has the potential to speed up the US domestic air-freight system and could pave the way for the introduction of fully automated light passenger aircraft.

While Redless' paper remains his own view and not FAA policy, he proposes that the concept could extend to providing private-aircraft access to individual shopping malls across the USA.

The introduction of pilotless passenger aircraft remains debatable, however. Most UAV industry leaders are sceptical about public acceptance, despite a general agreement that the technology is already available for what Northrop Grumman's veteran UAV developer Norm Sakamoto refers to as "inhabited unmanned air vehicles". He says: "The bottom line is that if you don't get the public to accept being transported in a UAV you will never sell the idea." Large UALVs could be under development within 10 years, he argues.

Lockheed Martin continues to look at unmanned and optionally piloted aircraft as part of its advanced airlifter studies. "We look at every possible opportunity," says chief technical officer Malcolm O'Neill. He is sceptical about unpiloted C-17-sized airlifters, however. "The issue is 'what is the added advantage?'."

The more likely near-term application for UALVs, particularly passenger-carrying versions, is support of special forces operations. O'Neill says Lockheed Martin is studying wholly autonomous and optionally piloted troop-carrying versions of its proposed MACK special forces aircraft, originally conceived for the US Air Force Special Operations Command's (SOCOM) long-term AC-X gunship and MC-X transport requirements.

Lockheed Martin first unveiled proposals for the MACK aircraft late in 2002. O'Neill says that as a Special Operations Forces (SOF) transport, an unmanned or optionally piloted variant would make extensive use of low observables to protect personnel on board. "It is something that would have a low signature and which could fly in low and then pop up and drop the troops, or it could fly in low and auto-rotate or land vertically."

Work is continuing on the potential costs, capabilities and advantages of the unmanned version and Lockheed Martin is discussing the concept with both the USAF and the SOCOM.

Northrop Grumman has also discussed with SOCOM the issue of special forces insertion and recovery using UALVs, including potential use of the more capable MQ-8 Fire Scout UAV to deploy individual SOF personnel. The company says that one concept is based on a Fire Scout lifting and carrying an SOF operative already strapped into a hang glider to a pre-defined insertion point. On arrival, the SOF operative would be released from the UAV while at altitude and fly down to a landing point of his choice.

The RQ-8A Fire Scout has a lifting capacity of 90kg. The uprated MQ-8, which will feature a three-bladed rotor and other improvements, is expected to be able to lift 270kg. Modification of the UAV's ordnance racks - designed to carry Lockheed Martin Hellfire and 70mm (2.75in) rocket pods - would allow a single medical evacuation litter to be carried on either side of the aircraft.

The heavier lift capacity is also being considered by Northrop Grumman as opening the door to the use of UAVs to carry slung stores for resupply missions ashore or at sea. Similarly, the US Navy is openly touting Fire Scout as a potential transport and delivery system for a range of airborne mine warfare payloads, including autonomous underwater mine hunting vehicles.

Stepping stone

Fire Scout may only be a stepping stone to the development of more capable vertical take-off and landing (VTOL) UAVs.

The most likely driver, O'Neill argues, is the US Army's Future Combat Systems project. This programme envisages a broad family of UAV and unmanned ground vehicles operating autonomously on the future battlefield within the decade. UALVs and their ground-based equivalents would be used to haul supplies, as well as acting as delivery systems for smaller robotic systems.

Gutherie says the concept is likely to significantly influence USN and Marine Corps thinking about what missions a UALV could perform. "I think when you talk about logistics and the army, the focus will be on things that are very difficult to do right now - deliver payloads in the middle of the night, in the middle of bad weather, in hot sun."

The USMC has previously experimented with using UAVs as a deployment system for a variety of loads, including ground-based sensors, automated fire support weapons and as a general haulage system for ship-to-shore supply requirements.

The most notable of those experiments, carried out in 2001, used an optionally piloted Kaman K-MAX helicopter, the "Burro", as a surrogate UALV.

Kaman says it is continuing to develop the concept and sees potential for optionally piloted helicopters in military and civilian roles, the latter including airborne firefighting missions in high-risk areas. USMC demonstrations using the aircraft were not continued after 2001 because of changes in US UAV acquisition policy that restricted single-service acquisitions. The policy has recently been set aside, and Kaman is now carrying out surrogate UALV demonstrations with the Burro for the US Army's Aviation Applied Technology Directorate at Fort Eustis, Virginia.

The army is also watching ongoing development by Aerovironment and the US Air Force Research Laboratory of the SkyTote VTOL UAV, which is intended to form the basis of a scaleable family of battlefield transports. Explicit US Army requirements for a UALV capability are still several years from definition, however.

As well as Burro, it has been toying with the idea of a UALV variant of the A160 Hummingbird VTOL UAV now being developed by the US Defense Advanced Research Projects Agency (DARPA).

Multirole possibility

Speaking at the Unmanned Systems 2003 conference, John Sundberg, deputy project manager for the US Army's UAV Systems Project Office, said that if technical problems with the A160 powerplant were overcome, the air vehicle could form the basis of a new type of multirole UAV family. "This could turn into a cargo carrying UAV," he says.

The US Army's nearest UAV-based transport requirement is for a delivery system for urgently needed medical stores. Sundberg says one of the lessons from the campaign in Afghanistan during 2002 was that it "had situations where troops got pinned down. They were surrounded, some were wounded and couldn't get out or get help."

The Quickmeds project has now been approved by the US Army surgeon general, and is based on the concept of equipping AAI Shadow 200 UAVs already in US Army service with twin 9kg capacity stores pods. These would be loaded with medical supplies and flown to a predetermined waypoint above the isolated soldiers, then dropped. Each pod would be fitted with a tail kit controlled by a low-cost GPS satellite guidance system to ensure it landed close to friendly personnel. The pods would have a crushable nose to prevent the supplies being damaged on impact.

A related stores carriage concept has already been developed by Northrop Grumman Integrated Systems for its BQM-34 Firebee UAV. Northrop says the pod could be used to carry medical supplies, food, ammunition or leaflets for use in psychological warfare campaigns. Unlike Quickmed, however, the pod is designed to eject stores, rather than being released from UAVs.

Psychological warfare requirements are also driving SOCOM's acquisition of an operational UALV capability based on the SnowGoose, developed by Canadian company Mist Mobility Integrated Systems Technology (MMIST). A derivative of MMIST's SHERPA parafoil airdrop system, the SnowGoose is fitted with an engine, standardised payload bus and multi-waypoint navigation suite.

Prototype system

SOCOM commissioned development of a prototype system in 2001, initially for use as a wide area leaflet distribution system. Five production units have since been ordered, with the first of these publicly displayed for the first time at the Weber Field UAV demonstration in Maryland on 14 June. The unit has been undergoing acceptance testing at the US Army Yuma Proving Grounds since the beginning of August.

Purchase of the same SnowGoose variant is being considered by the Australian Defence Force as part of its semi-classified Joint Project 2076 Psychological Operations requirement, approved in this year's national defence budget.

Further SOCOM orders are also being explored, with a fleet of up to 74 air vehicles for use in a wider variety of special force logistics roles.

Source: Flight International