Futuristic designs of airships are not just the stuff of science fiction. New aerodynamics and structural design, as well as advanced materials technology and engine architecture, have made for more durable airships capable of longer, more autonomous flights, with large capacity for cargo. This, in turn, has led to companies investing in the next generation of airships which are safer and more efficient.
One British company that has been working in this area is Hybrid Air Vehicles (HAV). Its airship, the Airlander 10, is due to make its maiden flight in the coming months after tests last year showed that it was capable of getting off the ground. The Airlander is part airship, part plane and the size of a football pitch. It doesn’t require a runway, is 70% greener than a jet aircraft, and could be used to transport cargo to inaccessible regions around the world.
“Certain tasks Airlander will be able to do more sustainably and cheaper,” explains Chris Daniels, the company’s head of partnerships. Daniels maintains that it is difficult to compare Airlander to other airships “as there is nothing currently available in its class of endurance or cargo-carrying capacity”.
According to HAV, the Airlander has many benefits over other types of cargo aircraft. For example, the narrow window of weather conditions that a traditional airship can fly in, coupled with the large ground crew needed, mean that the economics and operating models are very different.
“Both Airlander and other airships benefit from ‘free’ lift due to the lifting gas, helium, so are basically only using energy to lift the cargo and move it forward, rather than needing to lift the dead weight of the aeroplane or helicopter,” says Daniels.
Lockheed Martin is another company that is developing a hybrid airship. It is working on launching a 21-tonne airship in 2018 as a way to deliver heavy cargo and personnel to remote locations that may be inaccessible to trucks and other transport.
The company flew its P-791, a fully functional, manned flight demonstrator, in 2006. This demonstrated the technologies required for operational hybrid airships. Lockheed Martin says its new airship will be able to carry up to 21 tonnes of cargo and will burn less fuel than conventional aircraft.
Bob Boyd, hybrid airships programme manager at Lockheed Martin, explains that the craft’s sustainability benefits come from a variety of factors, including burning significantly less fuel than conventional aircraft, and producing 0.4kg of carbon emissions compared with 1.2kg from the average jet aircraft. He says: “They also produce significantly less noise pollution with low-speed propellers and small diesel engines, and they require little to no infrastructure, which eliminates the need to create roads to access remote areas.”
Compared with aeroplanes and even lighter-than-air (LTA) airships, which are inherently efficient due to the lifting gas, Boyd explains that the company’s hybrid approach offers significant utility, and the fuel used per tonne carried is also much less. “The hybrid airship is engineered to provide the most cost-effective solution and the sustainability benefits are inherent,” he says. “Our design features a multi-lobe structure, which applies a careful balance between weight, performance and aerodynamics.”
However, legislating for the use of hybrid airships has not been easy. Given that non-rigid hybrid airships did not fit within existing US Federal Aviation Administration (FAA) regulations, Lockheed Martin has been working with the agency for a decade to create a new set of criteria to allow the craft to operate safely. “The nature of the hybrid airship did not fit well with any regulations, explains Boyd. “It was instead a blend of several different guidelines from airships, airplanes and helicopters.”
After a decade’s work, the criteria to certify hybrid airships for the Transport Category were finally approved by the FAA in April 2013. Following that approval, the team has been developing the project-specific certification plan over the past two years, which details how it will accomplish everything outlined in the Hybrid Certification Criteria.
“The approval of the certification plan represents an important risk-reduction milestone for our customers,” says Boyd. “Completing this step took dedication from both the Lockheed Martin system experts and the FAA, who worked meticulously through thousands of detailed items to achieve consistent and accurate verification statements covering the entire aircraft.
“The company has had to work through the capabilities, intended use, and natural characteristics of the airship with the FAA to create a set of criteria and verification detail that will maintain a safe and operable hybrid airship in the commercial world.”
New aspects of the certification include the air-cushion landing system, which is hovercraft-type landing gear that permits take-off, landing and manoeuvrability in unimproved areas on land or water. The physical size is another differentiator, given that the 20-tonne hybrid airship is the size of a football field. An advantage of the hybrid airship is that it is more controllable than a lighter-than-air vehicle.
Boyd says: “We received the FAA’s approval of the hybrid airship Certification Plan for our initial 20-tonne airship, the LMH1. Approval of the plan is important for our potential customers because they cannot offer services with the hybrid airship until certification is achieved.”
The next step in the regulatory framework is developing the operating rules, in concert with the production of the hybrid airships. “We will begin production of the operational vehicle using internal funds once we have confirmed buyers,” says Boyd. “Additionally, we have built a full-scale prototype of the entire 20-tonne cargo system. You can’t overstate how important, from a real commercial perspective, having regulatory approval is.”
But analysts believe that the market for such airships is uncertain. “Air cargo numbers have been low for years, and there is a lot of capacity in the air freight business,” says Richard Aboulafia, aviation analyst and vice-president at the Teal Group, an aerospace and defence research firm. “The idea of building hybrid airships is irresistible to inventors and engineers and has been for a long time. A commercially successful airship will likely have to depend on transporting exotic cargo to exotic locations which in theory sounds like a great idea,” he says. “It’s when you get to the details that things get problematic. There could be some kind of niche – it’s just proved elusive so far.”
The problem, explains Aboulafia, is going to be determining whether there is a viable market for hybrid airships in the future. “There are big challenges facing the hybrid air vehicle market, despite recent developments from companies looking to produce them,” he says.
Eventually, Lockheed Martin expects to scale up its hybrid airship to 500 tonnes, which would allow for the creation of inland ports. “By using the curvature of the earth and eliminating the need to use multiple modes of transport (truck to train to ship to truck), a 500-tonne hybrid airship could move cargo from central China to the central part of the US at a cost approaching ocean freight and in much less time – a couple of days versus weeks,” says the company
As for HAV, the Airlander 10 is the prototype and is likely to be smallest version in a range of airships in the future. “The first development trend Airlander sees after the launch of the Airlander 10 will be to make an already green aircraft even greener,” says Daniels. “We envisage electric engines. We will start with just the forward two and keep the rear two conventional as a safety aid and to give extra power on take-off and landing. But we foresee that we will go to four or more electric engines at some point, with large batteries powering them.”
Eventually, Daniels explains that airships are likely to be solar powered, “giving a truly capable zero-carbon aircraft with almost unlimited endurance”. And the company expects them to be bigger. “We have designed both an Airlander 50 and Airlander 200, carrying 50 and 200 tonnes respectively. These will have more powerful engines and will have much more volume of lifting gas but will work on the same principle.”
While HAV and Lockheed Martin expect their airships to be game changers for the market, whether the craft will take-off in a big way in the industry is another matter. Despite the doubts, Boyd believes that hybrid airships “will introduce the next revolution in affordable transportation”.