February 16, 2012 by Dan Swinhoe
The AEROS 40D Sky Dragon , MAV6 M1400-I, Hybrid Air Vehicle HAV 304, and the Lockheed Martin P-791. On paper they don’t sound like very much, but in reality they are part of a new wave of Airships being designed both in the UK and US.
Airships, also known as Dirigibles or Lighter Than Air (LTA) Vehicles, are some of the biggest of aircrafts in the world, but they make up the smallest branch of aeronautics. Why? “A combination of bad luck and widespread misunderstanding of their true nature and complexity,” says Peter Ward, Chairman of the Airship Association.
“Traditional airships have had several barriers to wider acceptance, that have not been addressed due to lack of investment over 70 years. Primary among these barriers were perception of safety; ground handling and load exchange.” History has had its part to play as well. “The second world war had seen massive advances in aircraft technology, funded by the need for national survival, with little corresponding investment in LTA Technology. LTA technology had played a small, important, but often overlooked role in both the UK and US war effort, with little development effort since 1918.”
“After the Second World War, with a vast number of surplus transport aircraft and ships being disposed of cheaply, with hundreds of ex military airfields across the world, commercial ventures naturally used the ex-military equipment and facilities until newer and faster alternatives were made available by industry. With the advent of the Cold War; the continuation of the Arms Race, and commercial spin-offs; cheap fuel; no environmental concerns and rising standards of living, the business case for developing an alternative to aircraft was non-existent.”
Airships have been around for over 150 years. First developed in the late 1850s, they reach their hey-day was in the 1930s. At the time they were still miles ahead of heavier aircraft and were pushing the boundaries of flight.
Crossing the oceans, reaching the poles, they were giants of the sky. But by the late 30s they had fallen out of favour. Speed, cost, vulnerability to weather and the rise of aeroplanes had swept the airships aside. Since then there has always been just enough interest to keep the myth alive. Various companies have built smaller airships, mostly for advertising or tourists, and as time goes on more new concepts and big projects have brought the iconic blimp into the 21st century.
For the novice, airships are cigar-shaped balloons, filled with light gas to make them float. Most have a carriage underneath for the crew and rudders to steer. Generally airships can be broken down into three groups: Non-rigid, Semi-rigid, and Rigid. Non-rigids are your average advertising blimp like you seen above stadiums, a big balloon with air. Semi-rigids have some support, mainly to hold the carriage, Rigids have a metal framework that keep their shape with or without gas; these are the kind that spawned the world-travelling giant Zeppelins.
“Currently there are no intercontinental airships in production. Existing airships are small blimps,” Peter says. “There are several R&D programmes in progress which will produce large airships. Two of the major R&D programmes (Lockheed Martin, Hybrid Air Vehicles) are based on bi-lobal and tri-lobal designs.”
It’s these new designs which could prove successful. “Different types of Airships are being constructed, with a different purpose to the familiar blimp. The US Military has been fighting asymmetrical wars for over a decade. During the campaigns in Iraq and Afghanistan, they have re-discovered the Aerostat, and re-learned that a tethered aerostat gives a wider horizon for surveillance purposes for longer periods and at lower operational cost than most conventional Remotely Piloted Vehicles (RPVs). By increasing the area around a Vital Point that can be kept under surveillance, the perimeter security teams improve their chances of detecting and preventing hostile activity.”
While it’s good to see interest, the industry itself is still virtually non-existent. “Several small underfunded companies have kept the technology alive over the last few years, with occasional efforts to fund major projects. Market research into size of potential market has been done, but not shared with the Association as it is expensive & valuable data.” As with many technologies, if anyone will lead the way to widespread LTA use, it will be the military. “Once the technology has been accepted by the Military, then industry will benefit from the spin-offs.”
While recessions normally kill-off big plans and research, it seems that these tough times could be a boon for the airship industry. “Fuel costs in the US Military are huge, and any way that could produce a saving in fuel, while maintaining operational tempo, is welcome,” Peter says. “LTA has the potential to offer reduced operational cost, with some significant improvements in aspects of operational efficiency. This has been one of the drivers for the US Military’s renewed interest in LTA for surveillance and, possibly, for heavy lift transport.”
There certainly has been interest from the military. Aeros’ Aeroscraft was looked into by DARPA as a battalion transport. Nicknamed ‘Walrus‘, it would carry men, vehicles and all their equipment directly to where they would be needed, and should fly by 2013. DARPA also has ISIS in the pipeline, a giant unmanned surveillance blimp that sits six miles up in the Earth’s stratosphere.
The US military also has HALE, which had an unfortunate accident during testing. But it’s not just military that are taking an interest. Funded by the EU through the 7th Framework Programme, the Multibody Advanced Airship for Transport (MAAT) project dreams of having a giant, 350 metre disc-shaped airship. Cruising high in the clouds on a permanent route, it would have smaller feeder pods bringing passengers to and fro. The AHAs (Airship Hub Airport) would be two tall towers, saving on space and runways and in theory it would be cheap and almost completely green, running mainly from solar power.
So there’s plenty going on in the concept and development areas. There’s also a small but growing group of groups looking to promote and educate.
“The Airship Association was formed in 1971 by a group of individuals who firmly believed that Lighter than Air (LTA) vehicles had been overshadowed as a form of transport, by the more glamorous, and adrenaline inducing world of aircraft. To them, the clear benefits of LTA vehicles in terms of Large Payloads, small operational infrastructure requirements, lower fuel consumption per ton/mile (compared to aircraft), lower intermodal transfer costs were important issues that needed to be bought to a wider audience.”
It’s main goals are simple: promote the science, practice and consideration of all matters relating to airships, circulate information on all matters affecting airships and to publish books and papers connected with airships, promote research and experimental work on airships.
“We believe that the Airship Association has made a small but significant impact. By publishing the quarterly journal, we have kept the subject of Airships alive, and provided a virtual meeting place for both enthusiasts and entrepreneurs.”
One of the council’s members, Professor Gabriel Khoury, is the author of a major book on current airship technology, and the Association played a significant part in the drafting of the Transport Airship Requirements (TAR) in the early 2000s, which has been adopted by both EASA and FAA as the basis for further regulation.
There are other organisations too. Airships to the Arctic hold symposiums every couple of years (the sixth was held in December) with the aims of promoting LTA transport, dispelling the myths, and looking at viable applications and how to implement them. While much of their focus is on using dirigibles in the remotest regions of the world; Canada’s frozen north, isolated parts of Africa or Western China, where there are few or no roads and even less aviation infrastructure. There’s also Airship Initiatives, who act as a one-stop shop for everything LTA, from talks and arranging flights to specialist PR.
As impressive as it sounds, there is always the issue of whether LTA vehicles are needed when aeroplanes and helicopters are so readily available. “This is a speculative issue, as no hard figures yet exist for modern LTA Costs. They should not necessarily be considered an alternative, but complementary, to traditional forms of transport,” Peter says.
“The thoughts are that once development and certification costs are factored out, Transport Airships would occupy a niche between conventional air transport, and maritime transport. The cost per ton per mile is projected to be lower than conventional aircraft, but higher than maritime shipping.”
LTAs would travel at the speed of a ship, and require the same crew for several weeks, but would able to traverse rough terrain to remote areas. Realistically, tourism wont bring about a revival, but putting them to use as heavy lifting tool, able to carry payloads to places where roads and runways aren’t feasible, obviously has its merits. The German company Cargolifter AG were developing such a concept before going bust in 2002, but the torch has been picked up by the likes of AEROS and HAV.
Many of you reading this are probably still worried. “[The] public generally believe they are dangerous because they see the Hindenburg at every mention of the word airship in the media.”
It’s true, how many documentaries have you seen on the Hindenburg compared to all the other airships that didn’t crash? It was probably the first thing you thought of when reading this article. But airships are generally safe. Richard Van Treuren wrote in a presentation called ‘Airship safety in northern weather conditions‘ that all the fatalities from dirigibles since 1852, including ground crew, are less than the 520 one of today’s large jets carries. And many of those were people being too eager and jumping out too early. Of course nothing is ever completely safe, and in June a Goodyear blimp caught fire in Germany, where the pilot was killed. The cause of the fire isn’t yet known.
That was an isolated case, and the Goodyear blimps have a good safety record. It’s the perception of LTAs which have been the biggest dent to their development. Peter points to misunderstanding over their capabilities, especially by financiers, regulatory authorities and policy makers, as causing them to be held back.
“This has been dubbed ‘The giggle factor,’ and it is not currently being addressed.” He also cites hostility from parties with vested interests see LTAs as a threat, and the media, which “is able to print outlandish and unworkable ideas and pass them off as serious science because there are so few around and so little is known about them.”
He seems optimistic however, and once in the sky, people’s perceptions will change. “I suspect that the first of a Heavy Lift transport airships will be a sight that people will remember for the rest of their lives with a certain amount of awe. As with all things, familiarity brings acceptance, blimps have been familiar at sporting events for 3 decades or more. The use of airships for high-profile ‘good-work,’ such as Air-Sea-Rescue would also help.”
This reluctance is a problem faced the world over, and fear of he unknown isn’t the only problem. “Any country with vast land, under-developed infrastructure and inaccessible natural resources is a potential customer for the operating companies. However most BRIC countries have already rubber stamped the rules and regulations from Europe and the USA and incorporated them into their own law,” explains Peter.
“There is also a serious obstacle in the desire of developing countries not to be seen as “backward” and I have been quoted in one (which shall be nameless) ‘why should we have them if the US doesn’t have them?'”
Whatever our cousins across the pond do, will we here in the UK be seeing airships in its skies in the future? “The current infrastructure was built in the 1920s. Big investment is urgently needed starting with properly funded and targeted, serious research projects and feasibility studies,” he says. But with the UK being one of the world leaders in Aerospace, and Hybrid Air Vehicles and Lindstrand working on projects here, don’t rule it out.
Obviously it’s not just perception that needs to be looked at, engineers are always working towards making things as safe as possible. While the Hindenburg was a terrible disaster and lessons were learned.
“Fire has always been the enemy of airmen, including airshipmen. Early airships used hydrogen as a lifting gas, as helium was not available in any quantity until the US Government passed an act in the early thirties to collect and store helium for military airships. Since the loss of the Hindenburg in 1937, Helium has been the lifting gas of commercial and military airships.”
Helium is an inert gas, so while it doesn’t have as much buoyancy as hydrogen, it wont catch fire. And where the Hindenburg’s shell acted as fuel for the fire, today’s materials are far more fire-resistant.
“Fabrics are stronger, engine reliability, stress analysis and understanding of low-level weather are all greatly improved. Computers have been a double-edged sword as their ability to aid in complex calculation has been equalled by the ease of producing visually alluring virtual reality models that have no basis in fact and which deceive the new-comer to the subject. Lockheed Martin seem to have used computers to overcome perceived flight stability issues in their P791 prototype. Computerised Flight Systems are pretty standard on most modern aircraft, and are used in the Zeppelin NT series; they will almost certainly be used in future large airships.”
The technology is constantly moving forward to ever improve the case for reintroduction. Load Exchange, where either an equivalent ballast has to replace the cargo or gas has to be vented to keep the airship steady, is being addressed.
“Solutions are sought by using Hybrid Airship design, where the design of the vehicle uses aerodynamic lift to lift a much larger percentage of the cargo mass compared to traditional airship designs.”
There’s also research being done to try and compress the lifting gas, which would reduce the amount of lift. Improving efficiency of ground handling is always going on.
“Modern designs have turned to hovercraft technology, by using hover-shirts rather than traditional landing gear. By blowing air into the hover-skirts they ease movement on the ground, while sucking the air from the hoverskirts, they will “suck” the airship to the ground, enabling easier loading and unloading of cargo,” explains Peter.
In a world of climate change where reserves of fuels are slowly running out, how do airships rate? Pretty well. LTAs use much less fuel than their winged counterparts, the only real issue is the supply of helium.
“As a finite natural resource, there are potential issues, but there are new helium collection facilities coming on-line.” He also says that many of the fears about supply are unjustified in many cases. Currently the US supplies around 80% of the world’s helium, and holds around half of the planet’s reserves in a facility in Texas.
Used in MRI scanners and Fibre Optics, helium is produced as a by-product of natural gas and cannot be chemically produced in its own right, meaning new supplies of Helium are harder to come by than other resources. While many natural gas reserves do harvest the helium, there are just as many that haven’t, and the gas is ultimately vented into the atmosphere. Although it is possible to extract helium back from the atmosphere, it isn’t economically viable yet, costing around 10,000 times more to extract from the air than the ground.
It’s hard to tell if there’ll ever be another golden age for dirigibles, but they still enjoy a certain air of mystery that aeroplanes just don’t have. There have been some stumbling blocks along the way, even recently. But this is a technology that few in the world have ever come into contact with, let alone work on and develop. Maybe if people can come around to the idea without immediately referencing the Hindenburg, and the funding keeps dripping through, they might one day fill the skies again.