.

Airship Freight  Terry Drinkard

Those components and finished goods will travel by air, either in a conventional jet aircraft, or, intriguingly, in a freight airship, as will a range of other time-sensitive products like fresh meat, fruit, fashion-wear, mail, and even passengers.

Basic manufacturing requires bulk materials in and large quantities of fabricated goods out. Not all, or even most of those goods are finished and ready for retail sales. There are several intermediate steps, the precise number depending on the product being made. An electronic component manufacturer might make chips, or other components, air-shipping those parts to an assembler who makes circuit boards. The circuit board assemblers send their products by air freight to firms like Foxconn who assemble entire retail-ready goods which are flown to the US and Europe in the belly of large jet aircraft.

The joy of vertical integration

Once upon a time, here in the United States, vertical integration was the goal. I.e., do everything from smelting the raw ore to retailing the product and capture the entire value stream in one firm. The classic example is Ford's Rouge Complex, which was the largest integrated plant in the world when it was completed in 1928. Boats dumped ore at one end and cars rolled out the other. Literally.

We don't really do things that way anymore. Firms like to have have multiple suppliers for various stages of assembly; a single supplier is generally seen as a risk. Moreover, outsourcing parts to specialists in their particular industry makes a lot of sense, especially if there are a lot of those kinds of suppliers available to support our manufacturing process. Then we get to play Wal-Mart and demand prices so low that the supplier goes broke giving it to us, but they can't pass up the huge orders. "We lose a little on every part, but we make up for it in volume" is a joke, not an good operational methodology.

Planes, Trains, and Automobiles

Having a number of suppliers means parts have to be transported Somewhere Else. Depending on the circumstances, a supplier might ship their product by truck or rail. From farther away, by ship or by air, depending on the value and time criticality of the product. Henry Ford was the first, I think, to understand the time criticality of parts, shipping them by air starting in 1925.

Perceptions are changing. When I worked at the Boeing Renton facility, we used to get a 737 fuselage in by rail once or twice a day. We would patch up the bullet holes (I'm totally not making this up) and send it down the line. That was the logical transhipment solution twenty or thirty or forty years ago. Today, the 787 components all go by air. In fact, Boeing modified four 747-400 passenger aircraft into Large Cargo Freighters to do exactly that. Atlas Air has the contract to operate them, in case you were wondering.

Why airships make sense

Jets are expensive at several thousand dollars per hour to operate, or a something over a dollar per ton mile these days (fuel isn't cheap anymore and 500 knots doesn't come without burning a lot of fuel). A container ship, on the other hand, is only a few cents per ton mile, but a fast one cruises at about 25 knots. An airship fits in between with speeds of around 80 knots (depending on the design, of course) and ton mile costs ranging from a quarter to a dollar depending on the size of the craft (as in so many areas of life,

bigger is better here). This is a sweet spot for shipping things like fresh meat or fruit or even second day air packages. Once upon a time, there was even a class of mail called "airship mail." Airships can also handle what is called "indivisible" cargo, which jets can't. An indivisible cargo might be something like a set of turbines in the casing for a steam-powered electrical generation plant--something really large that can't be disassembled into smaller pieces, or the cost of disassembling and reassembling is prohibitive.

History of airships

The technology of lighter-than-air flight goes back to 3d Century BC China with the advent of the sky lantern (basically a candle under a paper bag,and still being made today). More than two thousand years went by before they got big enough to hold people; the Montgolfier brothers designed and built a series of hot air balloons that could hold people by the late 18th century. Shortly after that, Jacques Charles, another Frenchman, invented the hydrogen balloon. Right at the turn of 20th century Ferdinand, the Graf von (Count of) Zeppelin combined hydrogen lift with engines using a rigid frame to create the first airship. All of these craft are members of the aerostat family

A Montgolfier balloon

	First flight of von Zeppelin's airship was during the peak that glorious summer of 1900, some three and a half years prior to the Wright brother historic flight. That first flight lasted for twenty minutes, considerably better than the 12 seconds of the Wright's first flight. Of course, lighter-than-air technology was substantially more mature than that of the heavier-than-air having had a two thousand year head start. The airship was well received in Germany and enjoyed extraordinary public popularity.
First flight of an airship, 2 July 1900
	In 1909, the world's first airline was established: DELAG (Deutsche Luftschiffahrts-Aktiengesellschaft, or German Airship Transportation Corporation Ltd). After a decade of publicity and sightseeing flights, they began carrying passengers, mail, and freight on a scheduled basis until the start of Der Grosser Krieg, when the Imperial German government "repurposed" those airships to train crews for the military airships that would be used to bomb London, a traditional feature of modern European wars.
Norge, a semi-rigid airship, crossing the north pole

After WWI, airship development continued with the Germans concentrating on dirigibles and the Italians on semi-rigid designs. The Americans basically copied the Germans. This is the era of the Graf Zeppelin (the airship, not the guy), the Macon, the Norge, those great airships in Sky Captain And The World Of Tomorrow, and, of course, the Hindenburg. The rock stars and celebrities of the day traveled by airship. If the Beatles had come to the US in 1936, they'd have arrived on an airship.

Hindenburg

The biggest reason we don't see a vast fleet of highly capable, cost efficient airships crisscrossing our skies today is the Hindenburg. Not that it was a terrible airship, far from it. The Hindenburg was the lead ship of the finest class of dirigibles ever made. Big, fast, luxurious, and she defined the cutting edge of airship technology when she was launched. The Hindenburg was originally designed for helium to be the lifting gas, but the United States refused to sell any to the Germans. The US had a monopoly on helium--an element that was first discovered on the sun because it is so rare here on earth--as it was found only in natural gas wells in the Midwestern US.
	The Hindenburg's disasterous fire

There are a number of theories about how the fire started, but it is the fire and the resulting loss of life as conveyed in the vivid, even graphic, media coverage of the event that had such an outsized impact. While the Hindenburg disaster was as mediapathic a tragedy as can be imagined, it wasn't all that deadly. There were 35 deaths out of a total of 97 people onboard, a morality rate of about 36%. The Titanic, with which it is often compared, lost 1,517 out of 2,223 onboard, a mortality rate of about 68%. It wasn't the number of dead, nor even the percentage of deaths; it was that the Hindenburg fire was the very first major disaster to be captured on film and distributed to the world. While in today's media market, the story would last one news cycle, two at the most, this first ever disaster coverage seared the public consciousness with the idea that airship equals disaster. Like most media conflations, this wasn't actually true, but it was sufficient to annihilate the passenger airship industry.

Different kinds of airships

Customarily, we divide airships into three categories, with quite a bit of overlap in two of them. The easy one is dirigibles, or rigid-frame airships. Those are the ones with hard structure surrounding the lift cells (lift cells are just balloons on the inside of the airframe). The Zeppelins and their imitators used aluminum for frames, Schutte-Lanz used wood. The word 'dirigible' does not refer to the rigid frame, but is derived from the French verb 'diriger' which means "to steer." Those who believe it is related to the rigid framework have fallen into the evil clutches of a false cognate.

	The Goodyear blimp, a non-rigid airship
The Graf Zeppelin, a dirigible

The other two categories are the semi-rigid and the blimp, or non-rigid. There are differences, but where to draw the line is a bit fuzzy. A semi-rigid airship has a structural keel that runs pretty much the length of the airship. Usually. A non-rigid airship has a much shorter keel structure extending from the gondola. The cutoff point between blimp and semi-rigid is somewhat debatable, and generally has more to do with the designer's intent.

The keel is what connects the lift system to the gondola and the engines. The gondola, of course, hangs below the belly of the envelope and houses the flight deck, passenger quarters, and whatever else may be required. The envelope is the outside skin that we can see. Interestingly, the nacelles that hold the engines were originally called "engine cars."

The dirigible has the advantage of being strong enough to hold its shape without having to pressurize the envelope. This gives it an aerodynamic advantage at higher speeds. The semi-rigid and non-rigid airships are not as efficient at higher speeds as the rigid airships are, but they are lighter and less expensive. The rigids also tend to be larger, sometimes much larger, than the semi-rigids and non-rigids.

California corridor/LTAC

When I was an undergrad at Cal Poly, San Luis Obispo (also the alma mater of Burt Rutan, by the way), our senior design project was part of a multi-year study called The California Corridor where air and rail concepts were explored in some detail. At that point in my education, I knew I wanted to work at Boeing and figured I would be condemned to designing aluminum jet aircraft for the foreseeable future, so I decided that the aspect of the study that I wanted to work on was a big lighter-than-air craft (we called it the LTAC - pronounced "el tak") that circled the Los Angles basin at a couple thousand feet of altitude with VTOL air taxis climbing up and mating to the it to drop passengers off and pick up others for the return trip. Other teams designed the VTOL air taxis, and there were a couple of other LTAC teams.

The LTAC (note: we were into four letter acronyms before they were cool) was to cruise around the LA area at 200 knots and hold a thousand passengers and a thousand tons of freight. The VTOL air taxis were designed around a standard cargo container which held either passengers or freight, which simplified things considerably.

Here's where it gets interesting. My team (the both of us) felt that it would be impossible for a conventional airship, rigid or otherwise, maintain a stable altitude as people are added and subtracted, freight dropped off and picked up. Valving off the lift gas, or huge, high speed compressors to store it were terrible options, in our opinion. Instead, we opted to compensate for these rapid changes in weight by using dynamic lift generated by a configuration I had read about years before in a book by John McPhee called "The Deltoid Pumpkin Seed." Think of it as a very deep section flying delta wing. To haul a thousand passengers and a thousand tons of cargo, it had to be huge. We designed it at over 400 feet of wingspan (if I designed it today, it would be quite a bit smaller). Wingspan isn't a usual metric for airships.

To make it even more challenging, we decided that it needed neither helium nor hydrogen as a lift gas. Instead, we would utilize the waste heat of the dozen large turboshaft engines we had to have to push this thing along at 200 knots; so far as I'm aware, this was the only hot-air airship ever designed. Assuming we did our sums correctly, the waste heat produced by the engines was nine or ten times more than we needed to create enough static lift to make the empty airship fly. Turns out that the limiting factor for our design was the ability of the structure to tolerate the heat, not a lack of heat.

The 200 knot criteria was terrible. Initially created to provide a decent speed margin for the VTOL air taxis, it was simply too energy intensive for the LTAC part of the system (at 200 knots, we have to take drag due to compressibility into account as it becomes a significant fraction of the total vehicle drag). At some point, our adviser revised the requirement down to 100 knots, but my partner Jim and I were committed at that point to a 200 knot design, so we simply followed through to see what the answers would be. But, I digress.

The competitive landscape

Freight hauling airships can compete on the basis of speed and minimal infrastructure with trucks and trains over land and ships over water. With aircraft, the competition is on the basis of cost per ton mile, minimal infrastructure, and lower carbon footprint. There is no competition for handling indivisible cargoes.

The airship, at 80 knots or so, is considerably faster than surface ships. It is also quite a lot faster than trucks and trains when you consider actual routes and actual average speeds over those routes. Even over a straight route, the airship has a substantial speed advantage and costs per ton mile are comparable. If we add in the minimal infrastructure required (no roads, rails, or ports needed) the advantage increases. Moreover, the airship can easily handle hugely outsized indivisible cargo that no truck or train could.

Rendering of the CargoLifter CL160, a 160 ton capacity semi-rigid airship

In competition with jets, the cost per ton mile for the larger airships is much smaller and the fuel burn/carbon footprint is very much smaller. Again, the airship can get by with nothing in the way of facilities to pick up or drop off freight and the outsized indivisible cargo issue is just as significant for jets as it is for trucks and trains. Another big advantage is the cost of acquisition. To carry 150 tons of freight, a jet like the 747-8F costs about $300 million. The CargoLifter CL160 was to have sold for about $30 million, one tenth the cost of the jet.

Obviously, integrating a well-designed airship terminal into a larger multi-modal freight facility that can efficiently serve trucks, trains, jets, as well as airships--and even container ships--is going to be win in terms of low cost to transship cargoes. That efficient, low-cost transhipment of freight is a major reason for and advantage of the aerotropolis.

When?

The freight airship is coming. It's a matter of when, not if. The cost advantages over jets and the speed advantages over conventional surface transportation options is too good to miss. That isn't what concerns me. It is the question of whether we have the foresight to plan for it, to set aside land at our airports and shipping facilities to effectively integrate the freighter airships with the rest of our emerging global transportation system.

Terry Drinkard is currently consulting on an aviation start-up. His interests and desire are being involved in cool developments around airplanes and in the aviation industry. Usually working as a contract heavy structures engineer, he has held positions with Boeing and Gulfstream Aerospace and has years of experience in the MRO world. Terry’s areas of specialty are aircraft design, development, manufacturing, maintenance, and modification; lean manufacturing; Six-sigma; worker-directed teams; project management; organization development and start-ups.

Terry welcomes your comments, questions or feedback. You may contact him via terry.drinkard@blueskynews.aero

 Other recent articles by Terry Drinkard:

©BlueSky Business Aviation News | 30th June 2011 | Issue #132

.

BlueSky - your weekly business and executive aviation news - every Thursday

.