In recent years, major aerospace companies such as BAE Systems, Boeing and EADS have all expressed interest in lighter-than-air and hybrid air vehicles, for ISR and remote heavy airlift applications. But apart from HAV, only Lockheed Martin (LM) has progressed beyond the drawing board.
In the 1990s, prompted by Fred Smith of Federal Express, the renowned Skunk Works in Palmdale, California, studied concepts for a huge cargo-carrying hybrid named the Aerocraft.
After a design review, the Skunk Works team led by Bruce Wright sought outside expertise. A system design and engineering contract was awarded to Airship Technologies Ltd., led by Roger Munk. But Fred Smith lost interest in the Aerocraft when he realized that it could not meet his cost targets. Bruce Wright retired–and later came to the UK to work as a consultant to Munk.
Meanwhile, LM briefed the Aerocraft to the Pentagon. It had obvious military potential. At Palmdale, the team now led by Dr. Robert Boyd continued work on hybrids, in typical Skunk Works secrecy. The U.S. Defense Advanced Projects Research Agency (DARPA) eventually launched the Walrus project to develop a hybrid airship capable of transporting up to 1,000 tons over intercontinental distances. The vision was to carry an entire Army brigade “from the fort to the fight.”
On Jan. 31, 2006, the Skunk Works flew a demonstrator designated P791 at Palmdale (pictured). The P791 was about 125 feet long–much larger than the SkyKitten hybrid demonstrator that Munk’s next company, ATG, had flown six years earlier.
The first flight of the P791 was unannounced but was observed by outsiders. No further flights were acknowledged by the Skunk Works. Earlier this year, however, Boyd told Airship magazine that the P791 flew six times. The flights were not without incident, although LM claimed that all the flight test objectives were successfully completed. DARPA’s Walrus project was subsequently canceled.
There were some differences, but also some similarities, between the P791 and the SkyCat hybrid designs that ATG was developing. In 2007, LM took legal action against Roger Munk, ATG and SkyCat Ltd. for infringement of patents. The claims against ATG and SkyCat were dismissed and the claim against Munk was settled in 2008 before trial, with each side ordered to pay its own costs.
LM competed against Northrop Grumman for the U.S. Army’s LEMV contract–and lost. At Palmdale, Bob Boyd’s team refocused on commercial applications. Details of the P791 were eventually made public in 2010. In March 2011, Aviation Capital Enterprises (ACE) of Canada announced an exclusive agreement with LM to develop a large hybrid airship to help the developers of natural resources to reach remote areas. Nothing more has been said since (by either party) about this relationship.
Earlier this year, Boyd made a presentation entitled “The Road Not Needed” to the Solve For X forum sponsored by Google. He said: “This technology is ready to go...the issue is ‘growing’ the world of transportation to expect such a big change.” –C.P.