Return of the Airship
By Mike McLeodGeneral Aerospace Aerospace Discovery Air
Long ignored buoyant aircraft are making a comeback as the need to ship cargo to remote locations intensifies.
Except for the occasional sighting at a Super Bowl half-time, buoyant aircraft (better known as blimps) have been out of sight and out of vogue in aerospace circles for nearly a century. Images of the Hindenburg crash of 1937 grounded future airship development and continue to haunt those who strive to commercialize the flying machines.
Now, after a decade of steadily rising fuel costs and the hunt for high-priced resources moves inexorably farther into remote, hard-to-reach locations, interest in airships has experienced a renaissance. While still considered somewhat of a “fringe” mode of transport, proponents say the economic tipping point in favor of modern heavy-lift airships—capable of ferrying 50 tons or more—is only few years away.
“We have more demand for more things moving by air than ever before,” says Dr. Barry Prentice, professor of supply chain management at the I.H. Asper School of Business, University of Manitoba. “But we also have more places in the world we want to get to that don’t have infrastructure; 70 percent of Canada’s land mass, for example, has no roads.”
Where the Roads End
An outspoken supporter of airships for more than a decade, Prentice points to the fact that approximately 30,000 Manitobans in remote communities depend on the annual construction of 2,200 kilometers of winter ice roads for critical supplies. If that construction is delayed, due to a short winter, supplies have to flown in, driving the cost of goods to two or three times their market price. At the same time, the expense of permanent roads, he says, is enormous and is money better spent elsewhere.
“Building all-weather gravel roads in northern Manitoba costs $1 million per kilometer,” Prentice says. “It can be done, but when you have Muskeg, permafrost, rock outcrops and so on, it just isn’t economic. So what’s left?”
More than an advocate, Dr. Prentice is also president and CEO of Buoyant Aircraft Systems International (BASI) with partner and BASI Chief Science Officer Dale George. In December 2011, the pair unveiled their 24-metre long Giizhigo-Misameg (which means Sky Whale in Oji-Cree) airship at the University of Manitoba.
The relatively small-scale blimp will be used for research to test the vessel’s ballast exchange, electrical propulsion and fuel cells under cold weather conditions. Once proven, the intent is to build much larger airships to service resource operations in Northern Canada as well as remote communities.
“Mining will be the first big markets for airships,” says Prentice. “The problem with this type of transport, given the value of the equipment and the number of cycles you have to make during a year to pay for it, is that your market length is in the 250 to 300 mile range. We have many markets like that in Canada. All you have to do is look at a map and see where the roads and rail lines end.”
Combat to Cargo
As with many advances in aerospace technology, interest in modern airship initially took off with the military. In fact, in last six years, the various branches of the U.S. armed forces have invested more than $1.13 billion in four airship programs.
The largest deal has been the $517-million contract signed by the U.S. Army with Northrop Grumman in June 2010 to buy at least three airships. Destined for surveillance duty in Afghanistan, the US Army’s long-endurance multi-intelligence vehicle (LEMV) will be designed and built by Northrop partner, Hybrid Air Vehicles (HAV) of the U.K.Like BASI, the Bedfordshire-based airship company is also eyeing the cargo transport market. In August 2011, HAV signed a preliminary agreement with Yellowknife’s Discovery Air—Canada’s second largest aircraft operator—to design and develop a potential fleet of commercial hybrid airships to transport supplies to Canada’s north.
Both companies hope to reach a final design soon and see delivery of the first of several 50-ton capacity HAV 366 hybrid airships begin by 2015. For Stephen “Fig” Newton, B.Eng., director of business development at Discovery Air, the business case for airships is an obvious one.
“You can pretty much do anything with these vehicles,” he says. “You can land on water, snow or ice. You can turn it inside its own body length; you can take off fully loaded within four body lengths; and you can pick up vertically 40 percent of its maximum payload. So it has all the benefits of a helicopter or fixed-wing with very few of the downsides of any of them.”
Rise of the Hybrid
Still, many are sceptical of airships. One of the main reasons is that the airship’s biggest advantage (i.e. “free” vertical lift) is also its biggest design headache, especially for heavy cargo applications. After all, what happens when a huge airship, filled with enough helium to equalize the weight of 50-tons, loses its cargo? Traditionally, dealing with buoyancy has required ground crews, mooring lines and the delicate balance of ballast management.
Yet Prentice says, modern airships are a world away from their predecessors. BASI’s Sky Whale handles the buoyancy problem by compressing the helium during landing and cargo unloading. The dense gas then acts as ballast while atmospheric air is pumped into ballonets to retain the envelope’s shape. After unloading, the helium is pumped back in for the trip back.
Hybrid Air Vehicles tackles the problem from a different approach. It’s HAV 366 vehicle is a hybrid airship and not subject to many of the same challenges of a traditional blimp, say its creators. Heavier than air, hybrids gain lift by a combination of three forces. Helium assists with take-off and flight, but nearly half the vessel’s lift comes from the aerodynamic shape of its envelope.
In addition, lift off, landing and sustained hover are further assisted by vectored thrust nacelles at the envelope’s aft and front quarters. As a result, heavier-than-air hybrids require less volume to lift heavy loads than a comparable dirigible.
“The other crucial element is HAV’s air cushion landing system that blows air toward the ground,” says Andy Barton, HAV’s chief designer for heavy cargo airships. “The air cushion system, paired with the vectored thrust, makes sure you have a gentle landing.”
“That airflow is also reversible,” he adds. “So once you have landed, the direction of the air flow is sucking you to the ground and can cope with significant unevenness. That also allows 30 tons to be removed immediately, while the ship is refueling. Once that’s done, the rest of the cargo can be taken off.”
While relatively slow, Barton says the HAV 366’s 2400-hp Pratt & Whitney Canada gas turbine engines will produce a typical cruising speed 80 knots fully loaded with bursts up to 110 knots. In addition, the vessel’s considerable size (109m x 55.7m x 32.7m) and shape bolster its stability in rough weather.
“We’re okay in winds up to 80 knots, and we can do ground handling in winds up to 50 knots without masting up,” Barton says. “Due to the airship’s cross section, the impact of cross winds is less than for the traditional blimp shape. And since we are heavier and we have some aerodynamic trim on the design, we have better handling properties.”
Many of the design challenges have been overcome, but the real obstacles holding airship development back aren’t technical but economic, says Jay Godsall, founder and CEO of Toronto-based Solar Ship. The problem, he says, is that the cost to develop a heavy-lift airship hovers around $1 million per ton of lift, making it difficult to find investors willing to fund a vessel large enough (20 or more tons of lift) to be economically viable—especially when a technology has yet to be proven. Of course, the only way to prove it is to make the initial investment.
“With airships, there is no entrepreneurial first step where you raise a bit of money, get a little first customer and then incrementally grow. This is an immediate big play,” he says. “The only way around that, is if you figure how to make a smaller airship and make it useful to a customer.”
That’s where Solar Ship is looking to position itself. The company is currently developing a unique hybrid concept designed to ferry medical supplies and other cargo to remote locations and areas in need of disaster relief.
“If you trying to get to a place like Haiti after the earthquake, when you couldn’t get emergency supplies in for eight and a half days, then you don’t need carry 20 tons,” he says. “A ton of critical cargo into Haiti in eight and half hours would have saved a lot of lives.”
Like the HAV hybrid, Solar Ships’ aircraft is heavier-than-air and, as such, gains 60 percent of its lift from its delta-wing design. This allows the airship to take off, land and pilot more like a conventional plane and is therefore more manoeuvrable and resistant to wind conditions.
At the same time, helium increases cargo carrying capacity and cuts the space needed to take-off and land down to 50 to 100 meters. Most strikingly, the hybrid’s large, inflated wing provides ample surface area for the solar panels that power its engines.
“Not having to burn fossil fuels, in certain parts of the world, is really valuable thing,” Godsall says. “For Canada, it makes sense for us to run a hybrid fuel system. But in regions of the Congo, the Amazon or Indonesia, they don’t have fuel at any price.”
Although the need for cargo transport to remote locations is growing, the fact remains that many have tried to commercialize airships before without success. Still, proponents say economic pressures and technological advancements have reached a point that the age of the airship is inevitable.
“Technology without demand is just a curiosity, but the demand is there,” says Prentice. “Soon, we are going to see airships flying in the U.S. military. Once that happens, people will see opportunities for profit, and the flood gates will open.”