When the deadline for this column almost coincides with an event that is coming up, but doesn’t quite make it, I am faced with a dilemma. In a few days I will leave for Bitterfeld and the World Gas Balloon Championships which I have been invited to enter.
So that is on my mind and that is what I will use for my text this quarter. But by the time you read this it will be over and done with. You will know the results. You may know whose hydrogen balloon was shot down by terrorists, or whose balloon screwed up and never got off the ground, or who overslept from jet lag and never made it to the launch field in time.
The real American team consists of expert competition pilots in well proven balloons. We are supernumeraries that were added after the normal competitive selection process. My well qualified co-pilot has never flown in a gas balloon before and nobody has ever successfully flown a balloon quite like the Pleiades Seven, the one I have built especially for this event with help from “Balloon Sponsors” David Rapp, Bob Lindell, ArtServe, David Bradley & Eric Adams and support from Trimble Navigation Ltd. and United Airlines.
Nobody has ever successfully flown a two man Pleiades before. Malcolm Forbes’ Trans-Atlantic effort never got off the ground. Nobody has ever even successfully flown any polyester Pleiades before. Malcolm Forbes and Bob Gatch’s Trans-Atlantic attempts are the only examples I know of. Bob Gatch disappeared over the Atlantic on his attempt and has never been found. But Willie and I have each have flown solo in a single cell polyester (Mylar) balloon and I have flown solo polyethylene Pleiades balloons before in Pennsylvania and Iowa. Can polyester be that much different? It is much stronger, but has practically no tear strength—a single pin hole can propagate and destroy a balloon completely in a split second. The protection from that is the safety of numbers—we could lose several at once and still stay up by ballasting accordingly.
We have made 54 units of metalized polyester for this competition. We will use 28 on each flight. But as there are three events, we will have to have less than a 50% mortality rate on these cells to survive the whole event.
Ed Chapman holds the Montgolfier Diplome and several world records in hot air balloons. His record in international competition is exemplary. But as he does not have the gas rating he is not yet officially the Co-Pilot. So we’ll title him “Flight Tactician” and any success will be to his credit. We will blame any shortcoming on my balloon design.
Gas championship competition seems to be designed as a mimic of the traditional hot air events. This balloon is designed for traditional gas floating. I really think it would be far more suitable for a traditional gas expedition where one takes off, climbs to a desired altitude and then stabilizes for the majestic voyage. It really doesn’t seem like it will be very handy for the hedge hopping target seeking ups and downs of modern hot air balloon technique. So Ed will have his hands full planning a competitive program of operation tactics. I’ll have my hands full just getting it airborne.
There are advantages to the Pleiades concept as we have reduced it to practice, especially since we will be flying with hydrogen. Hydrogen balloon disasters seem to be mostly at landing or the result of hostile action while airborne. The landing fires may be caused by turbulence in valving or static sparks from the rip panel action. This balloon has neither gas valve nor rip panel. Both those functions are accomplished by inverting individual cells, either for only a moment for valving or completely for deflation. As they are all metalized, we have little fear of static discharges. (They are really like the plastic pouches computer boards come in.)
If there is a fire on landing, at least it will be 20 meters downwind from where we are. If there is a fire in midair there is the remote possibility that as it progresses from one balloon to the next the remaining array will become very heavy and may drop fast enough to outrun the fire, yet be controllable just before impact by ballasting to slow it down enough to be survivable. (Now isn’t that the tissue from which nightmares are fabricated?)
Each cell is simply an aluminum coated cylinder twenty feet or so long (654 cm long actually) and will have a volume of 35 cubic meters. When they are all full and standing in a 40 meter circle around the basket it will look like a giant Tiffany diamond necklace. When released on their suspension lines they will lurch upwards like deformed metallic jellyfish until they settle in with their mates in an umbrella array way up above the basket.
As the craft climbs, they spread out as the airstream pushes them apart. In level flight they gently nuzzle each other until we pull the top of one down to dump hydrogen out of its open appendix. Then we start down and once again the airflow separates them. If we go rapidly through strong wind shear they may do a form of square dance with each other and tangle the suspension lines like a May Pole. If they do, and form a Chinese finger puzzle, we will have a serious problem. (One solution would be to shinny up the beanstalk to reach above the woven web to control a cell or two, but we probably would just try to ballast and get above pressure height and let the balloon start back down by itself, hoping for a good landing trajectory.)
If these balloons survive several cycles of flight we will have a very economic system. Each cell only costs about $300 to make. The costs are about equally divided between the plastic film, the sealing tape, labor and the suspension and control cords. If it was to be used strictly for helium or ammonia there would be a saving in not having to metalize the film, with ammonia or methane the individual cells could be bigger which would be more efficient. One nice feature of the design is that one would only use just as many cells as is needed for any given flight: the number of people to be flown, how long and how high a flight.
In a single cell balloon, when one valves gas the system acquires a new higher pressure height (float altitude). With this system, when one vents gas from one cell the pressure height for the remaining units is unchanged. That may be a great convenience for a cruise evolution as floating at pressure height can be almost like putting it on autopilot.
Time will tell. I hope I’ll have an interesting column to write next quarter. I know I’ll have an interesting time finding out about it.