Soaring’s Dream -Forever Young

by Bob Dodgson

What is it that binds together the weird hodgepodge of humanity (for the PC crowd I mean hu-person-ity) who make up the diverse R/C soaring community? The only thing I have found that we share in common is the dream of and wonder at powerless flight! We are the ones, who as kids, stood in awe watching the birds fly overhead while our peers were more interested in shooting at them with BB guns. We never cease to be amazed when we see a thistledown parachute or a maple seed helicopter rising magically skyward and soon floating out of sight. As a result of our infatuation with defying gravity, we have been trying to make things fly all of our lives, from dime-store gliders to sleek, multi-channel high performance soarers to our priority-plagued marriages. We are people who have refined our building skills, through continuing practice, research and determination, to the point where we can now construct our own gliders that seem to want leave the building board to leap skyward.

Model soaring is a wonderful and fulfilling learning process that revitalizes our enthusiasm with each success along the way. Every model that we construct is a mystical sculpture of boundless possibilities. Even if it is one’s third model of the same kit, there are so many “construction improvements”, weight-saving techniques and wing leading edge shaping variables that we always have the hope this new model will be the best performing model yet. Nor is this a totally vain hope. All of us have seen exceptional gliders, built from a kit, exuding performance that seems to transcend the kit’s design limitations by flying much better than other models from the same kit. Often it is not the immaculately constructed glider or the model with the show finish that is the standout performer. Sometimes the best flying model looks downright offensive to the accomplished craftsman. Yet it is the possibility of that next (even if imperfect) glider being the occasional breakthrough glider and outperforming the pack, that is the dream from which we draw our sustenance.

For example, one local flyer built a Camano that flew and performed like an absolute dream. After its untimely demise, he built a succession of Camanos and even a Lovesong. None of these planes could match his Camano Dream. This flyer now has a Pixy which comes about as close to his Camano Dream as a 2-meter ship can, and he has a good flying Lovesong but, oh, that one Camano. This dream flyer may never have another glider that he likes as well. For some reason, that one model did everything right and no one knows exactly what it was that made that one plane so special.

I know another flyer, who has one of the local Anthems. There are better looking Anthems around and there are definitely better flyers around, but this particular Anthem in his hands is a wonder to behold. It outperforms nearly everything else at the field. When asked why his particular Anthem flew so well, the creative and opportunistic flyer replied, “I modified the airfoil a little.” Upon hearing this explanation, the questioner, adroitly responded, “Oh, you mean that you were too lazy to use the leading edge templates when you were shaping the wing leading edge.” With this brilliant insight, the inquisitor had his answer. There would never be another Anthem that had quite the exact same airfoil as this one particular Anthem.

With recent test results from the Selig/Donovan Princeton wind tunnel tests, as published in Soar Tech #8, we designers have considerably more information at our disposal than ever before. New airfoils were even designed from the new data while the tests were in progress. Using the Sailplane Design computer program by David Fraser (now available through Herk Stokely), one can easily try many different airfoils and model configurations in the lab without having to even construct the prototype gliders. This new capability is a wonderful tool and it can be used to achieve excellent results in a short period of time.

While we now have this great body of data on model glider airfoils and performance, due to the practical limitations of time and resources it is important to realize that of the infinite number of aerodynamic possibilities only a small and finite number of possibilities have been tested. It is obvious that every possible airfoil shape could not be tested. Even every possible airfoil-trip location could not be tried for one airfoil, let alone for every airfoil. As amazing as is the amount of data to which we now have access, it is still a drop in the bucket compared to the potential knowledge that is still beyond our reach. The vast knowledge that we do not yet have is like a black hole that can suck in even the most careful of designers. Happily for me, it is this presence of the vast unknown that still makes glider design a creative and artistic experience. Coming from an architectural background, I drive the button-down engineers crazy. They like to work with absolutes, even if the available information is not conclusive. This blinders on reliance on partial data and imperfect technology can lead to false assumptions and erroneous design concepts when the artistic side, common sense and design intuition are factored out of the equation.

I am reminded of the World Soaring Championships that were held in Sacramento California in about 1980. This was truly a battleground of art verses technology. The epitome of technology was the Swiss team’s stable of magnificent all molded glass, hollow winged Spartacus gliders. The technology and workmanship rivals the best that can be seen today. Since these ships were all from the same molds, they were basically identical to each other. Any team member could fly any of the 12 Spartacus gliders at any time and achieve equal results. Everything was great except for the fact that a major design parameter, based purely on scientific rationale, proved to be a false premise, rendering the pilots and gliders embarrassingly ineffectual. The major premise error was that instead of using ballast, the Spartacus would use a remote controlled CG-shifting mechanism. There was one person with the team whose sole job was to go out with each team flyer to calculate exactly where the CG. should be for that particular flight, event type, humidity, wind speed and direction. Even if the scientific basis of the idea were sound, the artist-designer should have known that constantly shifting a glider’s CG is a bad idea even if it offers theoretical scientific advantages. You see, changing the CG changes a plane’s handling and flight characteristics to such an extent that flying the Spartacus must have been like flying a different glider every time a pilot went to the flight line. In spite of a spectacularly poor showing in competition, these gliders received endless praise from a mindless US press. The praise that was thrust upon this ill-conceived technology reminded me of a saying that I heard from an old professor: It is not what you do, it is how you do it that matters. In glider design, it also matters that your design premise is sound.

The plane that actually won the World Championships was designed and flown by Dwight Holley. This former Maestro flyer admitted to me after his win that his F3B World Championship glider was much like a smaller, beefed-up Maestro, utilizing the same control configuration. This glider did not sport the hollow-core fiberglass construction techniques used on the Spartacus, but it was a much more consistent and reliable performer.

Another possible technological leap of faith is the unquestioning acceptance of the Schuemann planform as being the ultimate wing planform. This in spite of the fact that many Schuemann winged model gliders have tip-stall and other problems and as far as I have seen, there appears to be no field experience that would show it offers a performance advantage on thermal competition gliders. In fact, the basic 1982 designed straight winged Lovesong is still beating the new designs on a regular basis.

Now our hobby is inundated with numerous similar Spartacus technology gliders among which a modeler can choose. These coexist along with the more traditional foam wood and fiberglass kits as well as the all wood kits. Unlike with traditional kits, theoretically all of the plastic gliders made from the same set of molds should fly exactly the same. This is good, right? The down side of all this sameness is that it robs the pilot/builder of one of soaring’s most exciting and creative aspects. No more can his mind wonder unrestrained, as he is inhaling an airborne elixir of balsa dust and CA fumes, while he is imagining a finished bird that will fly like his dream the dream that this one glider will be that special glider with performance on loan from God.

With the advent of the off-the-shelf glider, the mystery, the wonder and the dream of this artistic sport will have been reduced to a common formula that may even stifle future breakthrough development. In the past, designers and would-be designers were free to try anything. Sometimes a glider would defy the odds and perform above normal expectations. This success would aid advances in design by providing tangible performance improvement for evaluation and further testing. With the investment of time and money required to make molds for plastic gliders, no one is going to go out on a limb to try something that is not already tried and true. As a result, we are getting a herd of fair to good performing look-alike gliders but we miss that occasional standout glider that seems to defy the accepted wisdom of the day and thus provide a building block for the future. In a molded world, there are no freaks no anomalies and no happy accidents. Think about that while you are joyously spending weeks (in some cases months or if you are like Sal, even years), building your Saber or Anthem while your good buddy is out at the flying field terrifying bystanders with the plastic wonder that he received only last week!

Oh sure, for F3B where high-speed and great strength at-any-cost are important, some of the exotic plastic gliders appear to offer the advantage. However, in the multitask requirements of serious thermal competition, the plastic ships are still playing catch-up. Many times they are either heavy or they are fragile and vulnerable and cannot withstand the rigors of the sustained competition environment.

Lest you think that I have lost it altogether and am simply bashing the hi-tech approach to soaring, fear not. Great strides are being made in this facet of the hobby to make good performance more accessible to more people. I just do not want to see the world of instant gratification totally overshadow the spirit and the dreams of the individual builder/flyer who has always been the backbone of this remarkable sport. Fortunately, in a plastic world there is still room for individual craftsmanship and innovation.

From a performance standpoint, many factors come into play that are not anticipated by the computer polars particularly at thermaling and searching speeds. As a result, happy accidents do happen. Excitingly, no one knows exactly what unpredictable air-flow patterns are being generated by the hand-sanded flying surfaces on your individualized glider. The blending of art and technology along with a generous infusion of the hand-crafted dream is still the heart and soul of R/C soaring and this dream, along with the wonder and anticipation are still alive and well. Just consider that each new hand-crafted and hand-sanded glider you complete and proudly carry onto the flying field may be the one offering the unexplainable breakthrough performance that will make you a champion and local hero. No one else can ever have a plane that flies exactly like yours! At best, a molded wing can only faithfully reproduce a known airfoil along with its known limitations. In a cookie cutter, disposable sacrificial parts plastic world, may we never lose sight of the hand craftsmanship and the individual innovation that keeps the best of th

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