DARWIN: AIRSHIP EVOLUTION
PACIFIC BUSINESS WORLD
Interview with Mr. Joseph Singh,
Vice President, R & D, Turtle Airships
PBW: Mr. Singh, there have been rumors for several weeks now of a new type of airship being planned by Turtle Airships; specifically, an airship that does not have the same flat bottom used by all other models. Is the company now beginning to draw away from amphibious airships?
Singh: No, Turtle Airships will always design airships that are primarily for use as amphibious craft; this is in keeping with our basic philosophy, that being able to use seven tenths of the Earths’ surface by operating from the water is far more preferable than limiting our business; or limiting our customers, to specific single areas on land.
PBW: Would you tell us about the new airship design; how it can still be an amphibian even without the usual bottom hull configuration?
Singh: We are designing another first for Turtle Airships; a split keel, variable geometry airship.
The keel is actually divided into two longitudinal halves that can be moved outward for landings and ground handling; much like outriggers on a canoe; but will rejoin when the airship is in flight. This new design will allow the airship to keep its’ center of gravity directly under the center of lift during flight; while still giving it a large catamaran hull surface for water landings.
PBW: Why is the company making this change?
Singh: All of the company’s current airships rely heavily upon transfer of ballast and directed thrust during flight to maintain a level pitch. A complex system of GPS receivers coupled with laser gyros and pressure sensitive flooring in cabin areas has been tracked by computer to give instant reactions to the most minute variances in the airships’ stability; whether caused by passengers crowding to one side of the airships to view some attraction below, or by erratic wind currents. This is one reason for the ultrasmooth ride that Turtle Airships is famous for. The new design is meant to eliminate some of these systems with a much simpler and less costly method. By varying the shape of the bottom hull, we can maintain our large footprint for ground contact with a spread, or open keel; and minimized any of the past concerns with weight distribution by closing the keels together.
PBW: What about a timetable for fielding this new type of airship? Can you give us a rundown on what the company is planning?
Singh: Well, Darwin, as you know, is our Research and Development station; so things happen here at a somewhat slower pace than the rest of the company. Even with that proviso; however, I can tell you that we will be flying this particular airship design within the next three months (last quarter of 1996). We are investigating several more design changes that will enhance the new airship’s overall performance at the same time.
PBW: A variable geometry airship hull is an incredibly forward step in itself; please tell us about
any other attributes that the new airship will have.
Singh: Turtle Airships is committed to the development of solar powered airships. Our latest ship will also be a test bed for a full hull photovoltaic system.
PBW: Solar power has been touted for years by a number of airship visionaries; since airships have the needed surface areas for large solar cell arrays on their hulls. This is seen as an ideal way to gain air transport without any need for fuel; making them cheaper to operate and better for the environment. How does Turtle Airships plan to work towards airships with such capabilities?
Singh: As you have said, airships have the unique ability to generate huge amounts of electricity from photovoltaic cells because of their size alone; airplanes cannot utilize solar power efficiently simply because of this size difference. But there are other considerations too; airships do not need to generate the huge amounts of thrust that airplanes require; and so they can fly very well on less energy, and because of their great size, airships can use photovoltaic devices that are minimally efficient.
PBW: “minimally efficient”? Would you please be more precise about that term, please?
Singh: The very best solar cells today are the galium-arsinide types and are about fifteen percent efficient in conversion of sunlight directly into electricity; they are also quite costly.
Turtle Airships is using a much less efficient polysilicon device laid down on a plastic film which is
only about nine percent efficient; but because of the great amount of space available on our airships’ hulls, we can use more of them. The cost is substantially less. At the same time, the
plastic film upon which the photovoltaic material has been deposited is a piezoelectric battery which serves as storage for the electricity generated; and has a structural element, too.
PBW: You mean that the solar cells are not just simply attached; but are part of the hull of the airship?
Singh: Yes. The outside facing on the carbon fiber honeycomb panels that make up the hull of the airship have been replaced with a multiple layered film. There are four layers to this material; and it does double duty; the “skin” of the airship generates it’s own power as well as providing the usual strength and streamlining.
PBW: Would you please define each of those four layers your spoke of; and their purpose?
Singh: There is an initial backing of carbon fiber, a bit thinner than in previous designs. Attached to this is the plastic storage battery material layer; and the photovoltaic film that makes a third layer. The forth layer is the actual outside surface of the hull. It is a clear plastic with a low emissivity factor which is used to enhance the solar radiation captured.
PBW: “low emissivity”? What is that, exactly?
Singh: Low E film, as it is called, has been used to make windows that are more energy efficient.
It is a thin plastic that has properties within it’s molecular structure that makes it reflect infra-red light. Applied to windows, it essentially makes sunlight pass only one way through a double paned glass to retain as much heat inside a home as possible. Turtle Airships is using this material to multiply the natural “superheating’ of airship lifting gasses; and, to reflect solar radiation back onto the photovoltaic cells that would otherwise be lost, making them more efficient.
PBW: You spoke of “superheating”. Isn’t that the overheating of the helium inside and airship when it is flying in the sun, making it expand to much? Wasn’t that a huge problem for the giant Zeppelins in the past; and, if so, why would Turtle Airships want to multiply it?
Singh: It was a problem because the past airships would vent their lifting gases as they expanded in the sun. Often, this meant that the airship would be to heavy once the airship passed into cloud cover again and the gas cooled down and recompressed. If this happened under storm conditions, it could mean the airship would be in danger of crashing. It happened many times. Turtle Airships solved this problem long ago with its’ rigid hull design; the gas inside may indeed heat up, but cannot expand beyond the confines of the hull. There is no danger at all; either from losing gas, or from temperature extremes encountered while flying through different weather conditions. Instead of a danger, superheating can be used to advantage by Turtle Airships to simply expand helium when wanted. It is the same principle that was used by the airship Southern Cross when it flew to Antarctica.
PBW: Is the new variable geometry airship a “black ship” then; as Southern Cross was?
Singh: Yes, and no. Certainly the airship does not have the usual white reflective surface of our other airships because of the solar cells. So, I guess it could be considered to be a black ship; however, the solar cells are a deep blue color; so, black and blue!
PBW: Would you explain some of the other airship research and development activities taking place here?
Singh: In concert with our photovoltaic efforts; we are working on using a revolutionary electric motor as the sole means of propulsion. The new motor employs a superconducting flywheel and can generate over six times the force possible with past electric motors. When this is perfected, it will create airships that use no fuel at all except sunshine, and which can still reach the speeds that our other airships are capable of. I’m afraid that I am not at liberty to give out any further details about that particular work just now...
PBW: It seems there is a great deal of high-tech airship evolution going on here in Darwin.
Singh: Yes. However, Turtle Airships has been working with the Chinese for some time now on airship that are much less sophisticated.
PBW: Can you elaborate on developments in China concerning airship construction and operations?
Singh: Certainly. The Peoples’ Republic elected some years back to build their own internal airship industry; and Turtle Airships has been sharing technology and knowledge with them for some time. This is in keeping with the company mission established at the beginning by our president; of providing inexpensive and efficient air transport to as many people as possible; even if that meant some loss of business for the company. In China, we are helping to create an airship industry that is intended to reach the greatest portion of their population within ten years. This is being done by using simple and inexpensive means. Two of which I have personal knowledge about and can tell you are he experiments in using various natural fiber materials for hulls and structural members; and the use of hydrogen as a lifting gas.
PBW: How much different are the materials used in the construction of the Chinese airships?
Singh: We are speaking of a huge effort; a very rapid airship construction growth rate which is being undertaken using the most inexpensive and ready materials at hand; straw, bamboo, and other natural fibrous materials. These have been used as substitutes for the glass fibers and carbon composites normally used in airship hull panels. When bonded with epoxy, these kinds of materials have been demonstrated to have an acceptable measure of strength for airship construction; at mere fractions of the costs of more advanced materials.
PBW: Airships made of straw?
Singh: Yes. The straw is pressed together under extreme pressure and heat, causing the natural cell bonding to break up and to reform into a new solid material; much like the pressed strand board that is commonly used in home construction nowadays. With an epoxy bonding of several layers, the new material is surprisingly strong; although there is some weight gain.
PBW: So, the Chinese airships are heavier. Can they be built large enough to compensate?
Singh: The largest airship built thus far is over ten million feet in volume; larger than the Hindenburg, and about half of the volume of a Turtle Airships Millennium class ship. These are able to carry payloads of approximately eighty tons, or 200 passengers.
PBW: Tell us about the use of hydrogen in the Chinese airships; and why such a dangerous path is being taken there.
Singh: Well, it comes down to speed and money again. In creating an immense fleet of airships that can serve the entire country within ten years at the least expense; a decision was made to go ahead and use hydrogen; despite its’ danger. It is readily available; being man made instead of a natural product; and it can be used up or made up as needed at far less cost than helium. However, at this time, only airships that carry freight instead of passengers are being inflated with hydrogen. These are being used in flights in the most remote areas of the country, with the idea that even if there should be some loss of an airship due to the hydrogen exploding, it would be far enough away from populated centers not to cause any concerns; and that a loss of an airship cargo is better than a potential loss of life. The Chinese have a different view as to the amount of danger that hydrogen use entails; they are somewhat less inclined to worry
about possible loss of life in isolated accidents than we are. They also have an excellent ability to
suppress any media coverage of such an incident.
PBW: Have there been any “incidents”?
Singh: No. There are over two hundred airships flying in China already. Not one has been lost due to hydrogen fires.
PBW: What are your views; or, Turtle Airships’, about using hydrogen on airships?
Singh: As I said earlier, I have personal knowledge about the hydrogen airships; but I refuse to fly in one. Of course, Turtle Airships does not advocate the use of such a dangerous thing for passenger carrying airships. There is some discussion of using hydrogen on airships that fly strictly over the oceans; carrying only cargoes; and using a robot crew and satellite communications to control it; but I would hasten to add that this is just an idea being put forth as a trial balloon...no pun intended.
Even if such a strategy were implemented; and hydrogen airships were flying across empty oceans without any crew or passengers on board in perfect safety; there would still be problems with the eventual landings; refueling stops, and cargo handling needs. So, the company is reluctant to put forth such a proposal at this time. We are watching the Chinese history closely; perhaps it will be possible to field some sort of hydrogen airship fleet at a later time if they prove safe enough, and if some of these other concerns can be resolved.
PBW: Two weeks ago, Turtle Airships announced that it had broken an airship speed record of over 200 mph. What kind of airship is able to achieve such high speeds?
Singh: It was not Turtle Airships that made that particular announcement. That was in Aviation Week.
PBW: Is Turtle Airships unwilling to reveal details about this particular airship?
Singh: No indeed! I’m delighted to be able to confirm the Aviation Week story; and to give complete information about the new airship. It is fast! We have actually just completed a test flight yesterday, in which we have reached a speed of 261 mph!
PBW: That is incredible. Surely this must be some very radical design. Please explain how it is possible to build an airship that can be stressed to such an extent at such high speeds.
Singh: It is unlike any other airship ever built; in that it is not simply a container with a lifting gas inside; but is a solid structure through and through, in which helium can be contained. The entire craft is built of a material called an aerogel; which is a solid crystalline matrix which is phenomenally light.
PBW: The airship dies not have a typical envelope or gas cells inside?
Singh: No. The helium molecules are held within the lattices of the aerogel matrix itself.
PBW: The effect then; is something like mixing up white marbles; representing the helium, with black sticks; which would represent the aerogel matrix?
Singh: Yes. The aerogel is so light that it can be seen through; it is sometimes referred to as “solid smoke”; yet it is strong enough to resist a large compressive load. It has the qualities of something like balsa wood; strong and solid, yet lightweight.
PBW: Okay.., we have an ultralight material that makes up a solid body for an airship; and which can hold the helium as an integral part of the structure itself. How about the outer part of the airship; is it the same carbon fiber honeycomb used in other airships built by the company?
Singh: It is still a carbon composite material being used; but there is no longer any need for the strength of a honeycomb sandwich. It is simply a layer of carbon fiber laid on top of the contours of the airship body.
PBW: If the typical honeycomb panels, or sandwich materials are not used, does this mean a departure from the geodetic construction of Turtle Airships’ hulls also?
Singh: Exactly. There is no longer any need for that type of construction, because the aerogel supplies more than enough strength. The elimination of the flat panels used in other airships means that this new airship has a much more streamlined surface; there is no faceted shell for this new airship like the ones that gave Turtle Airships it’s name. The smooth surface reduces drag; and makes the airship able to reach even higher speeds.
PBW: To reach speeds in excess of 200 mph; you must be using very powerful engines; would you please give us details about the propulsion?
Singh: We are using small jet engines for this craft of the sort that are used in cruise missiles.
PBW: “small jets”, you say; just how big is this airship; and, what is it’s purpose?
Singh: This airship carries four persons, so it is quite small. While this particular craft is a pure research vehicle; the intent of the company is to develop a small airship that can be marketed as a personal airship; or as a business aircraft. That is one reason for the drive to reach a higher speed; we feel that this airship will be in direct competition with general aviation small planes.
PBW: Outside of the increased speed, what other features does the airship offer that can compete with airplanes then?
Singh: Vertical takeoff and landing; just as with all Turtle Airships designs; and the usual reduced fuel costs offered by airships over airplanes.
PBW: Is this airship also amphibious?
Singh: Yes; although it does not have the usual catamaran hull of our large airships. This airship is much more like a seaplane, with pontoons built into it’s wingtips.
Singh: This is a hybrid aircraft. While it is still a true airship; in that it is a lighter-than-air craft, it has wings that generate lift also. At full payload capacity, the ship is heavier than air, or neutral. It needs wings for aerodynamic lift.
PBW: You said that this was a pure research airship or vehicle. Will it ever go into production?
Singh: Not as it is currently. The aerogel is much to prohibitive as far as cost. We are working on a substitute material which is looking much more like a candidate for airship production in quantity.
PBW: Tell us about this other material.
Singh: I’m sorry; but the finer details about this is proprietary information that I cannot discuss at this time. I can say simply that we are developing an extremely lightweight material that will have some of the characteristics of an aerogel; but will be far less costly to produce. What we are looking at is a method of foaming a cold cure epoxy combined with carbon fiber, which can then be formed into shapes needed for airship parts.
PBW: What might be the next thing to come out of the Darwin hanger?
Singh: Well, there has been some speculation by our engineers that an aerogel airship could be built that would have no lifting gases inside it all; it would be a vacuum instead. That’s a real wild sort of supposition though. Much more likely would be the use of gases other than helium or hydrogen. We have already fielded a test ship which uses an ammonia based gas for lift.
PBW: So, to sum up; we have airships that use only sunlight for power; airships that change their shape; airships that are made of straw; airships that are faster than some airplanes; airships that have no crew on board to fly them; and airships that may or may not even have lifting gasses. It appears that Turtle Airships is about to change everything we know about airships; again.
Singh: We are certain to! Turtle Airships’ first stated purpose long ago was simply to create wonderful things. We will continue to do this.
PBW: A question arises however; won’t any new technological developments prove to costly to make any real impact on Turtle Airships’ business around the world?
Singh: That sounds as though we shouldn’t be trying new things. I disagree, of course; and would point out that each of the airship developments we have just talked about are really nothing new; even the use of aerogel as a structural member in airship construction was an idea that was first put forth almost twenty years ago. It was simply to costly then. The same can be said of using carbon composites; and yet Turtle Airships is using them.
PBW: How might each of these developments effect the market advantage that Turtle Airships has over other competitors?
Singh: My expertise does not extend to making business forecasts; nor even guesses. I am simply pleased to develop new ideas in airship design. When Turtle Airships was just an idea for a business; no one ever came forth and supported the concept of a new type of airship and its’ market potential. Each time that Turtle Airships proves a new concept or design, more companies enter the marketplace with knockoffs. That is perfectly alright with us: we are not out to maintain a monopoly; we continue to be altruistic in our purpose of bringing inexpensive and efficient air transport to as many people as possible.
My job in creating new airship materials, or engines, or designs; is geared to that single goal.
PBW: What is your favorite project?
Singh: Why, trying to reach 300 mph in an airship!
Want to go for a ride?