The Airship Prize

Economic development in Northern Canada is constrained by the cost of transportation and logistics.  The limited transportation options available increase the direct costs of shipping and add to the indirect costs of inventories. Concerns about climate change impacts, delays in environmental approvals and uncertainty regarding First Nations land claims further increase investment risk. As a result, the transportation solution offered by airships is gathering increased interest in northern Canada.

A new generation of cargo airships would have a revolutionary impact on northern transportation and logistics.  Transportation and logistics costs would fall, and problems of environmental regulations and aboriginal land ownership would greatly diminish.  The airship may be the only means of transport that can mitigate the negative consequences of climate change on northern transportation.

Tipping points are periods of accelerated growth.  The concept of a tipping point is derived from the biological sciences, but it also applies to many economic phenomena.  The dissemination of new technology is an example of a tipping point that is closely related to the product life cycle.  In Figure 1 the classic product life cycle is illustrated together with the tipping point.

The number of units produced for the market is few during the introductory stage.  During this period technological barriers are overcome and markets are developed for the product.  At some point the needs of the market and the cost of producing the new technology meet, and sales begin to accelerate at an increasing rate.  Once the tipping point is passed the industry enters a period of rapid growth.  Sales finally level off when the technology matures and growth is similar to the general economy.  The maturity period can be quite extended, but eventually the technology enters a period of decline, or re-invents itself and returns to a growth path and extended maturity.

It is arguable whether airship technology has ever reached a tipping point.  An approximate histogram of the airship industry since 1900 is presented in Figure 2. The histogram divides the history of airships into four generations of technology.

1900 – 1939

In the early decades of the 20^th century giant airships were built in Britain, France, Italy, Germany, Russia and the United States.  The majority of these airships were built for military purposes, but in Britain and Germany airships were also built for civilian use.  In 1910 the giant airships entered regular civilian passenger service in Germany. The greater development of German airship technology during World War I enabled the Zeppelin Company to enter trans-Atlantic passenger services in the 1930s.  This era proved that dirigibles could operate scheduled services, provide 65 to 80 tons of useful lift and be safely moored and hangared.

The periods of commercial development produced relatively few civilian airships before the Second World War (WWII).  Although airship technology appeared ready to expand rapidly prior to the Hindenburg accident, the industry never reached a tipping point.  The outbreak of WWII ended the development of rigid airships, but introduced a new generation of non-rigid designs, or blimps as they are often called.

1940 – 1962

The war effort from 1939 to 1945 focused mostly on fixed-wing aircraft technology.  The combined combatants of WWII built a total of 500,000 airplanes and advanced the technology to high altitude bombers and jet engines. Civilian airplanes hit a tipping point after the war and an accelerated growth rate for the next 30 years.

The achievements of airship technology during WWII are less known.  The large US Navy blimps could lift about 10 tons of crew, supplies, accommodations, fuel and water.  They were used to spot submarines along the coast and escort convoys on the North Atlantic.  Endurance records set during this period still stand.  They proved the reliability of large non-rigid structures and engines.  The Navy blimps withstood hurricanes and weather on the north seas, but experienced a number of ground-handling incidents.

The envelopes were made of multi-ply cotton-neoprene fabric and painted to reduce permeability.  Damage to the envelopes occurred from stretching, flexing, scraping, scrubbing and unintended contact with hard surfaces. In service, all envelopes required overhaul and repair every two years.

1963 – 1990

When the US Navy terminated airship operations in 1962, the world supply sank to three small advertising blimps operated by Goodyear.  This changed in the mid-1970s when the dramatic rise in oil prices re-awakened interest in lighter-than-air technology.  Although the period of high oil prices ended before commercial airship developments could hit a tipping point, a number of technological changes were introduced.

The rigid airships where covered with painted canvas that served only to streamline the exterior and offer some protection from rain.  The canvas deteriorated within four years of exposure to ultraviolet light and proved to be very flammable.  The rubberized envelopes of the Navy blimps were more robust and provided structural support, but were also short-lived.  During the 1980s new composite envelope materials were developed that could last over 15 years in direct sunshine.

Gases pass through membranes in both directions; the rate increases with increasing pressure differential.  The Navy blimps lost 100 percent of their helium each year in part because the pressure had to be double the level of the advertising blimps. With less permeable materials and lower pressures, they lose only 10 percent of the helium annually.  The other significant advances in the third generation airships were FAA air worthiness certification, fly-by-light avionics and vectoring engines.

Despite the many technical advances, advertising blimps still need a crew of 12 or more holding ropes for ground-handling.  The large labour requirement makes these airships costly to operate and limits their size.

1991 – Present

The fourth airship generation includes a broad spectrum of innovations that permit unassisted landing and take-off.  The hybrid designs that are about 20 to 40 percent heavier than air are particularly interesting for cargo applications.  One approach is to use a catamaran hull shape to provide aerodynamic lift (Lockheed, HAV). When on the ground the catamaran hybrids use modified hovercraft pads that operate as suction cups to hold their position for loading and unloading.  Another hybrid configuration in development utilizes airship with helicopter technology to undertake precision pick up and placement (Boeing-SkyHook).  The airship lifts the craft and fuel, while the helicopter rotors lift the cargo.

Other technological developments include unmanned flight systems and very high altitude operations as telecommunication relay stations.  Robotic operation techniques have opened a wide spectrum of applications for unmanned automated applications, e.g. stratospheric lighter-than-air systems. Photovoltaic systems are being adapted to the specific requirements for stratospheric airships and hydrogen technology is proceeding towards a renaissance.

The Zeppelin NT07 is the only commercially available fourth generation airship. Technically, the NT07 is a semi-rigid airship.  An internal frame carries half the stresses, while the pressurized envelope carries the remaining loads. The NT07 can land and takeoff unassisted. Two side propellers swivel 120 degrees to push the airship up or down for landing.  A third aft engine drives a pusher propeller that can rotate down 90 degrees to assist with takeoffs and slow speed control. A second side propeller on the aft assembly revolves in a neutral pitch during flight, but can act as a helicopter tail rotor in takeoff and landing situations and in hover mode.  All this is controlled by computers that connected to the pilot’s side stick.

Way Ahead Towards Cargo Carrier Airships

One hundred years of technological change has created the opportunity to build large, robust airships that could deliver cargo to the most inhospitable corners of the earth.  At the current time, over 16 teams are working in 8 different countries with actual airships and aerostats.  At least as many airships are on the drawing boards waiting only for investment to explore alternative designs.  The development of a cargo airship now seems inevitable, and the race is on to find the dominant design.

Unlike passenger airships, cargo airships have to consider the replacement of the weight they are dropping off.  Hybrid airship concepts that are heavier than air when empty are being developed to eliminate ballasting.  Conceptually, they can drop off a load and return to base empty.  Other ideas for ballast control feature the compression and/or heating of helium to compensate for weight change.  Of course, the addition of ballast water or other material is possible.  Each method has its merits and more than one approach in combination may be used.

It is clear that future cargo airships will not depend on large ground crews.  The ability to vector engines and computerized control with GPS location has eliminated this barrier. And in any case, economics require unassisted landing and takeoff.

The materials exist to build cargo airships that are much larger than the giants of the past.  Envelope materials that can build a 250 ton lift hybrid have already been developed, and designers are projecting 500 to 1000 ton lift airships as likely.

Airships are compatible with Arctic conditions and terrain.  Colder air provides more lift and the lack of surface thermal activity is an advantage for smoother flight.  Airships need to be field tested in winter conditions to prove that they can deal with snow accumulation and extreme temperatures, but winds can only be managed.  Under some conditions many aircraft will not fly, but airships have long endurance which may allow them to wait out storms. Airship captains will have to work with the wind, rather than fight it.  A non-linear flight path that tacks against the wind may take a bit longer, but airships can cruise easily at 130 kmph so they will still arrive faster than a truck over any ice road.

The primary impediment to the development of cargo airships is the lack of business confidence.  This may be changing with the renewed military interest in the use of airships.  The US Government has organized a consortium to develop a Long Endurance Multi-Intelligence Vehicle (LEMV).  The LEMV is on a fast track for delivery of a prototype in 18 months.  The requirements are for an unmanned airship or hybrid airship that can remain aloft for 21 days at 20,000 feet providing continuous communications and surveillance to ground operations.  If brought down to lower elevations where cargo airships operate, the LEMV could carry about 13 to 15 tons.

The LEMV is being designed to deal with the threat of Improvised Explosive Devices (IEDs) that are used by insurgents to kill US, Canadian and other NATO forces in Afghanistan.  Only by continuous surveillance can the activities of the insurgents be discerned from the movement of the civilian population with which they blend.  Canadian Forces would welcome a solution to the IEDs, but there is also a need for similar airship surveillance in the Arctic.  Climate change is melting the ice cap and opening the Northwest Passage for increased marine traffic.  Canada needs a logistics and surveillance vehicle like the LEMV to protect our national sovereignty in the Arctic and react to emergency situations.

The airship industry has a history of false starts.  Several times military initiatives have gotten the development of civilian airships close to the tipping point, but it has never reached the critical mass of civilian demand to become a common place means of transport.  Perhaps it will be a case of “third time lucky”.  The size of airship manufacture and operations in Canada make it an appealing industry to encourage for its own sake, but the payoff to northern development could be nothing less than revolutionary.

For too long people in northern Canada have had to make the best of whatever transport they could with limited infrastructure and a sparse population.  Sufficient demand exists in northern Canada to produce cargo airships and no technological barriers remain.  The commercial tipping point is in sight, it just needs a final push to make it happen.