Why blimps and airships died out – and how they might make a comeback

Could this be the future of air travel? Image: Aeroscraft.

Many years ago, long before the era of massive international airports, online ticketing agencies, and pesky pre-boarding security inspections, the airship was going to be the future.

Needless to say, that didn’t quite work out. Today’s skies are ruled by jumbo jets, helicopters, and the occasional drone or two. But a recent invention may help these long forgotten flying machines to reclaim their rightful place in aviation history – or at least carve out a niche.

“Airship” is a term for all motorised lighter-than-air craft, including blimps (which have inflatable air compartments) and zeppelins (which have rigid ones). They first came into existence after the development of the internal combustion engine, though a few daring aviators tried to pilot airships powered by steam engines. The first modern airship, the Zeppelin LZ1, took flight in 1900 – three years before the Wright Brothers made their famous flight.

Due to their relative cost effectiveness and longer range, airships were seen as the more attractive form of air travel in the early 20th century. They also played a key role as military aircraft, and were used for bombings in World War I. By the 1930s, luxury airships were whisking well-to-do passengers across the Atlantic Ocean, and were considered a technological marvel. They even had an influence on the urban landscape; it’s rumoured that the spire of the Empire State Building was designed to be converted into an airship dock.

But all that came crashing down with the infamous explosion that destroyed the Hindenburg on May 6, 1937. During a landing in Lakehurst, New Jersey, the hydrogen-filed craft exploded in a massive fireball. The cause of the fire is still unknown today.

It wasn’t the deadliest airship disaster – that honour goes to the British-built R101, which crashed in France in 1930 – but it was perhaps the most dramatic, and even though the majority of the Hindenburg’s passengers survived, airship travel became an instant pariah. It seems likely that airships would have been phased out anyway due to improvements in airplane technology which allowed for much shorter travel times – but the Hindenburg disaster ended the era of passenger airships virtually overnight.

The R101, moored at Cardington, Bedfordshire, 1929. Image: Wikimedia Commons.

Since then, the use of airships has been extremely limited, as technological advances allowed airplanes and helicopters to dominate aviation. Though blimps played a useful surveillance role in World War II, airships today are mostly used for overhead photography at sports events, and as massive flying billboards. Today, the Van Wagner group, an airship organisation, estimates that there are only 25 blimps currently operating around the world; there are even fewer zeppelins.

But all this is about to change, if Igor Pasternak has his way. As a young man growing up in Ukraine, Pasternak’s love of airships led him to study engineering in search of the latest breakthrough in zeppelin technology. That breakthrough would ultimately come in the form of the COSH system, though only after he emigrated to California in the early 90s to escape a post-Cold War economic crash.

The COSH – Control of Static Heaviness – system works by rapidly compressing helium into storage tanks, making the airship heavier than air. While conventional airships take on air to descend, they must still dedicate most of the space in the helium envelope to actually storing the helium itself. That makes the landing process more difficult and dangerous, and means they can only land at larger landing areas much larger than the size of the airships themselves, and that come with specialized ground teams.

By contrast, the COSH system allows much more of the envelope to be emptied of helium during landing, making the airship much heavier. This could potentially allow airships to land on any flat area large enough for them to enter without the need for ground teams, increasing versatility and reducing costs.

This ability won’t do much to shake up passenger airlines, since airships will still be considerably slower. But Pasternak’s company, Worldwide Aeros Corp., is hoping its new airship will bring major changes to freight shipping.

It’s currently working on a prototype of the Aeroscraft, a new airship capable of hauling up to 66 tons, with a cruising speed of 120 knots and a range of over 5,000 miles; there are plans, too, for a larger version that can haul 250 tons. It will also be roughly three times as fuel efficient as shipping in airplanes. While it’ll still be less efficient than land or sea shipping, company representatives are hoping its landing capabilities will give it an advantage in hauling cargo to remote areas with little infrastructure.

“The Aeroscraft will be a breakthrough for cargo shipping, filling an important gap between current air shipping and land-based delivery,” says Aeros representative John Kiehle. “Since it will be so easy to land, it will also be able to provide needed assistance in disaster relief situations, where existing infrastructure is knocked out.”

And though it won’t bring major changes to passenger air travel, Kiehle says that the airship may have some limited passenger applications. “It can serve as a sort of airborne cruise ship for tourist trips, as well as potentially serving more practical passenger routes in rural areas,” he says.

An artists impression of the craft leaving its hanger. Image: Aeroscraft.

Aeroscraft has hit a few snags in the development process. Pasternak initially secured funding from the US military for an airship project using the COSH system in 2005. This was later cut, though the military continued funding the group in other projects, allowing them to move forward with a prototype.

Then, in October 2013, a section of the roof of the hangar where the partially completed Aeroscraft prototype was housed collapsed, damaging the airship beyond repair. After the crash, Pasternak told the Los Angeles Times that the destruction of the Aeroscraft, his lifelong dream, was “more than disappointing”. Aeros Corp. is currently in the process of dismantling the craft to build a new one, but no one can deny that the accident has been a major setback for the company.

And even if the testing phase goes smoothly, the Aeroscraft may still face several challenges when it enters the market. A New York Times article about Aeros cites concerns from transportation analyst Richard Aboulafa, who points out the difficulty new air vehicles have in entering the market. In addition, he notes that most of the Aeroscraft’s shipments of exotic cargo to remote locations will be one way, resulting in many empty trips, and higher operating costs.

Perhaps the biggest problem, though, is the cost of fuel. Airships (or at least, the non-exploding variety) require large amounts of helium, a rare substance, which can cost upwards of US $100,000 for one trip. In 2012, rising helium costs were enough to bankrupt a tourist airship company in Northern California.

Some scientists even believe that, unlike many resources, helium could one day actually run out: partly because it’s light enough to escape the earth’s gravity well, but mostly because it’s uneconomic to harvest the stuff once it’s escaped into the atmosphere. All this raises questions about whether a form of transport dependent on it could ever, well, get off the ground.

But Pasternak and his team remain optimistic. Without any further issues, the Aeroscraft will be up for certification by the FAA in 2017. After that, it’ll be up to the market to decide if there’s a place for this new airship.  It might not bring back the glory days of transatlantic zeppelins – but it might at least prove that airships can be more than floating billboards.

 
 
 
 

How bad is the air pollution on the average subway network?

The New York Subway. Image: Getty.

Four more major Indian cities will soon have their own metro lines, the country’s government has announced. On the other side of the Himalayas, Shanghai is building its 14th subway line, set to open in 2020, adding 38.5 km and 32 stations to the world’s largest subway network. And New Yorkers can finally enjoy their Second Avenue Subway line after waiting for almost 100 years for it to arrive.

In Europe alone, commuters in more than 60 cities use rail subways. Internationally, more than 120m people commute by them every day. We count around 4.8m riders per day in London, 5.3m in Paris, 6.8m in Tokyo, 9.7m in Moscow and 10m in Beijing.

Subways are vital for commuting in crowded cities, something that will become more and more important over time – according to a United Nations 2014 report, half of the world’s population is now urban. They can also play a part in reducing outdoor air pollution in large metropolises by helping to reduce motor-vehicle use.

Large amounts of breathable particles (particulate matter, or PM) and nitrogen dioxide (NO2), produced in part by industrial emissions and road traffic, are responsible for shortening the lifespans of city dwellers. Public transportation systems such as subways have thus seemed like a solution to reduce air pollution in the urban environment.

But what is the air like that we breathe underground, on the rail platforms and inside trains?

Mixed air quality

Over the last decade, several pioneering studies have monitored subway air quality across a range of cities in Europe, Asia and the Americas. The database is incomplete, but is growing and is already valuable.

Subway, Tokyo, 2016. Image: Mildiou/Flickr/creative commons.

For example, comparing air quality on subway, bus, tram and walking journeys from the same origin to the same destination in Barcelona, revealed that subway air had higher levels of air pollution than in trams or walking in the street, but slightly lower than those in buses. Similar lower values for subway environments compared to other public transport modes have been demonstrated by studies in Hong Kong, Mexico City, Istanbul and Santiago de Chile.

Of wheels and brakes

Such differences have been attributed to different wheel materials and braking mechanisms, as well as to variations in ventilation and air conditioning systems, but may also relate to differences in measurement campaign protocols and choice of sampling sites.

Second Avenue Subway in the making, New York, 2013. Image: MTA Capital Construction/Rehema Trimiew/Wikimedia Commons.

Key factors influencing subway air pollution will include station depth, date of construction, type of ventilation (natural/air conditioning), types of brakes (electromagnetic or conventional brake pads) and wheels (rubber or steel) used on the trains, train frequency and more recently the presence or absence of platform screen-door systems.

In particular, much subway particulate matter is sourced from moving train parts such as wheels and brake pads, as well as from the steel rails and power-supply materials, making the particles dominantly iron-containing.


To date, there is no clear epidemiological indication of abnormal health effects on underground workers and commuters. New York subway workers have been exposed to such air without significant observed impacts on their health, and no increased risk of lung cancer was found among subway train drivers in the Stockholm subway system.

But a note of caution is struck by the observations of scholars who found that employees working on the platforms of Stockholm underground, where PM concentrations were greatest, tended to have higher levels of risk markers for cardiovascular disease than ticket sellers and train drivers.

The dominantly ferrous particles are mixed with particles from a range of other sources, including rock ballast from the track, biological aerosols (such as bacteria and viruses), and air from the outdoors, and driven through the tunnel system on turbulent air currents generated by the trains themselves and ventilation systems.

Comparing platforms

The most extensive measurement programme on subway platforms to date has been carried out in the Barcelona subway system, where 30 stations with differing designs were studied under the frame of IMPROVE LIFE project with additional support from the AXA Research Fund.

It reveals substantial variations in particle-matter concentrations. The stations with just a single tunnel with one rail track separated from the platform by glass barrier systems showed on average half the concentration of such particles in comparison with conventional stations, which have no barrier between the platform and tracks. The use of air-conditioning has been shown to produce lower particle-matter concentrations inside carriages.

In trains where it is possible to open the windows, such as in Athens, concentrations can be shown generally to increase inside the train when passing through tunnels and more specifically when the train enters the tunnel at high speed.

According to their construction material, you may breath different kind of particles on various platforms worldwide. Image: London Tube/Wikimedia Commons.

Monitoring stations

Although there are no existing legal controls on air quality in the subway environment, research should be moving towards realistic methods of mitigating particle pollution. Our experience in the Barcelona subway system, with its considerable range of different station designs and operating ventilation systems, is that each platform has its own specific atmospheric micro environment.

To design solutions, one will need to take into account local conditions of each station. Only then can researchers assess the influences of pollution generated from moving train parts.

The ConversationSuch research is still growing and will increase as subway operating companies are now more aware about how cleaner air leads directly to better health for city commuters.

Fulvio Amato is a tenured scientist at the Spanish National Research CouncilTeresa Moreno is a tenured scientist at the Institute of Environmental Assessment and Water Research (IDAEA), Spanish Scientific Research Council CSIC.

This article was originally published on The Conversation. Read the original article.