From “El Deber” newspaper supplement magazine Santa Cruz, Boliiva March, 2006
(Translation):
World: A “gas pipeline” that travels by air.
Text: Javier Mendez Vedia
Fotos: Jesse Blenn, History of Aviation, Airship
It is possible to use dirigibles to transport natural gas. Indonesia has a plan for providing this energy source to its numerous islands, a Bolivian company projects doing the same in the east of the country, the dirigible designer Jesse Blenn has worked on the model.
This story is so interesting, that it tells itself. Let’s see. Indonesia has many small islands. To carry gas to each one of them laying pipelines in the sea is not practical. The government was seriously considering using dirigibles to supply them; presently the function of these ‘ships is focused on security. Bolivia has no islands, but there are remote places where gas could be taken using these gigantic ‘ships. The project made the company Reparando, which functions in La Paz, start dreaming. Pablo Rovira, its commercial manager, had the idea and contacted a US expert. Both began to work on this dream.
In March of 2005, Jesse Blenn was in the government seat (city of La Paz) for nine days. He dedicated himself to designing the ship which would transport natural gas to Bolivian Cities. Who is Jesse Blenn? He is an expert in mechanics, “A gringo from Kansas”, as he puts it. He lives in Alabama (USA) and has more than 20 years experience in the design of airships. He lived 5 years in Costa Rica, native land of his wife. There he has a small farm of 3 hectares (7 ¼ acres) where he plants cacao (chocolate) and fruits.
He is a young man. At his 50 years he has gone from automobile and motorcycle mechanic to dedicate himself as a machinist, and hydroelectric and small airplane mechanic. People with his training and abilities earn easily $500 per day in special projects.. But his interest is in developing countries, so he has worked for a small fraction of what his colleagues charge. Six years ago he gave a presentation in the Senate in Colombia, leaving a basic (feasibility) study and photos of a scale model (of the 180 meter airship) which would carry 50 tons of cargo to remote zones. He also had contacts with the government of Malaysia, interested in scientific and tourism uses for dirigibles. He worked for four months on the design of a ‘ship of 45 meters.
In the web page of the Airship Association one reads that Blenn has a long experience en the design of these vehicles. This Association was registered in England in 1971. It has near 600 members – many of them consultants like Blenn – worldwide. When one thinks in these ships, the unavoidable reference is to the Hindenburg, a monster of 243 meters length which crossed the ocean various times carrying passengers. Because of its luxury and convenience, it was a true transatlantic flyer. The use of these ships came to be routine in the decade of the 30’s. That is, until in 1937 the Hindenburg caught fire in the US. 36 passengers died from the hundred which it carried. All told, the airship industry has had fewer than 200 deaths, but these were enough to paralyze it. They were very few victims, compared with the millions of kilometers traveled and the primitive aviation of the time.
There were other reasons for the disappearance of these immense balloons. They were not useful for war, since Germany used them in the First World War for bombing London. Fighter planes easily brought down these aerial elephants, which entered into a process of extinction. Basically, the design of these ships has not changed much. Of course, better materials are used, with better control and more exact calculations. Blenn explains that instead of using metal to maintain the gasbags in their place, now synthetic fabrics are used, which are tough and easy to work with.
“The idea is to carry the gas from the area of Santa Cruz to Trinidad and probably Riberalta. With this system gas can be delivered to remote sites with little infrastructure and, of course, without a pipeline. This promising project would put Bolivians to work and be a source for the export not only of the gas but of the dirigibles to transport it.” Simply put, that is the proposal.
The dirigible would have a length of 150 meters and would function with engines using the same gas. According to calculations, it would consume some 3% of the gas in a round trip of 1000 km at a speed of 100 kph. Twenty-five years ago, the Shell company did a study that contemplated the use of a gigantic airship. It was designed by English engineers. Blenn knows of the project and though he doesn’t supply numbers, he assures that the price is tremendous. If the plan of the Bolivian company Reparando becomes reality, they will have the rights to use the design for all of South America.
The natural fear in using this type of ‘ship is safety. What happens, for example, in bad weather? Rain causes an increase in weight, but with bigger dirigibles the effect is less significant. Hundreds of lightning bolts have struck airships, and they have not caused major damage. Of 130 cases of airships struck by lightning, fewer than five were burned. A detail: they used hydrogen. When traveling against a wind of 50 kph, it will only advance at 50 kph, but will reach 150 kph if it has the same wind in its favor. Since the time of Alberto Santos Dumont (yes, the same who gives his name to the avenue at El Trompillo airport), the Brazilian who flew for the first time with a vehicle heavier than air, it is known that the bow should be into the wind to land or anchor. One of his experimental vehicles crashed when it landed with the wind. Santos Dumont made the first flights in his ‘ships in 1898. In October of 1901 he flew almost ten kilometers over Paris.
Returning the the topic of safety, when it is anchored the apparatus withstands winds of up to 120 kph. “I have friends who flew in the Second (World) War and they have told me stories about storms”, Blenn remembers.
According to the information gathered by Reparando, there will be few problems with wind to arrive at cities like Trinidad. Initially, this city is the one chosen as anchor point during the nights or in case of bad weather. It is even thought to begin the construction in the Beni (provincial) capital. “It is possible to forecast the climate and strong winds in the area of Santa Cruz to delay flights”, Blenn explains. Mariano Dupleich, mechanical engineer with Reparando, assures us that they are awaiting an alliance with other companies outside the country for the project to go ahead. “It is only viable in the easter part of Bolivia,” he says. Before explaining why the apparatus functions better in the plains, it is necessary to know how a dirigible functions.
“Air is not so light as many people think, because it weighs close to 1.2 kg per cubic meter. Since the helium weighs close to 0.2 kgs per cubic meter, one meter of helium tries to “float” with a force of one kg”. Just that clear is Blenn’s explanation. Furthermore, the natural gas that it would transport also has a lifting force. One important detail: the gas is transported without pressure, to avoid heavy containers. Because of this, it is enough to enclose it in special bags, not metal tanks. The natural gas also can lift loads, but it has less force than the helium. The gas can lift approximately 0.5 kg per cubic meter. If 35,000 cubic meters are carried, they would have a lifting force of 17,500 kgs. That is equivalent to almost the full load of a double axle truck. Blenn suggests that 17,500 liters of Diesel be transported to counteract this lifting force. On returning, the dirigible can use a lesser quantity of water (near 3000 liters) as ballast. The process of loading the gas would take some 20 minutes, and the supply duct could be utilized as part of the mooring tower. The 35,000 cubic meters planned to be transported in each trip is equivalent, according to the calculations of regional superintendent Jose Ruiz, to 2,700 tanks of gas. Including its contents, each of these would weigh 23 kgs. Thus, each trip would do the work of three trucks loaded with gas tanks, and one with Diesel. Total: four truckloads in just one trip.
Now it will be easier to understand how altitude affects the operation of a dirigible. Simply, the lifting force is reduced by 1% each 100 meters (of altitude). To rise to 4000 meters, let’s say to Potosi, the lifting force will diminish some 40%. However, one should not throw out the possibility of using dirigibles to carry the gas, crossing the mountainous chain that separates us from Chile, to the maritime ports. For use in the Altiplano, a special design would be necessary, very light and larger, given that the gas would occupy more space. The advantage is that winds are less dense – Blenn explains- and aerodynamic forces are less.
Though no country is transporting gas by dirigible, it does not mean that Bolivia cannot do it. “It would be beneficial even for self-esteem,” comments Mariano Dupleich. In reality, not much time will pass before it occurs to someone else. Germany, the great pioneer in the building of these fantastic ‘ships, is developing the Cargolifter, called “the flying crane”. The apparatus will be capable of transporting more than 160 tons or a volume of 3,200 cubic meters to more than 10,000 km distance. In just one trip, the Cargolifter can carry food to feed 25,500 persons for two weeks. And what if we had one, even though smaller, to anchor in the zones flooded by the Rio Grande?
A very old history
The oldest designs of dirigibles consisted in taking a round balloon and stretching it in both extremes until achieving the form of an egg. These dirigibles kept their shape by means of the internal pressure produced by the gas they contained. This type is known as flexible or non-rigid. The problem was that this class of balloon bent under the tension produced by heavy loads or by bad weather.
This problem was solved by giving dirigibles a semi-rigid design. This is achieved on adding a light keel (a rigid frame) the length of the bottom of the airship. The keel lowers the tension of the envelope or canvas that covers the dirigible. Because of this larger airships were built. Count Ferdinand von Zeppelin (1900) designed a rigid envelope. This freed the envelope of the necessity of an internal pressure to keep its shape. Thanks to this, separate cells were used, filled with gas and held with wires, instead of one big envelope. This basic design is applied since then.