Radio Control Soaring
Darwin Barrie [[email protected]]
Dick Barker — "Father of Discus Launch" — speaks out on the birth of the technique
Also included in this column:
- Additional thoughts on discus launching
- Notes on the 18th International Hand Launch Glider Festival
- Update on the author's RV-7
HAND-LAUNCH sailplanes have been around for more than 20 years. Until roughly six years ago the launch method was a typical throw, or javelin launch. Then in the late 1990s the "discus launch" (DL) became the technique of choice.
The DL opened the door for virtually everyone to enjoy hand-launch sailplanes without ruining arms and shoulders. By 2001 DL was the only method used for competition. The Father of Discus Launch is Dick Barker. He said the following about the birth of this launching style.
"I was active in Northwest thermal competition in the 1970s but then found work taking up all available time. I retired in 1995 and quit teaching scuba in 1997.
"I checked the Seattle Area Soaring Society (SASS) field and found I was 10 years behind. I remembered HLG [Hand Launched Glider] only as the test toss you gave a new airplane to check the trim! Now there were people bringing three identical airplanes out just to trim them for the next contest—the Monarch D, Orbiter II, Glass Err, SunSpot, Climax, Chrysalis, and others, all with a finger hole or cross peg in the fuselage to allow a controlled overhand throw.
"Harold Locke had designed a foam wing that he launched almost straight up by using an underarm swing while holding the wingtip. He also had a very small T-tail pod-and-boom thing that he launched the same way.
"Adam Weston put the wing (called the Red Herring) into production, and they multiplied like rabbits. I decided I wanted a full-sized HLG that I could tip launch. One problem was that you would need to be 9 feet tall to do the underhand launch.
"I had tossed a discus around in high school and thought that I might be able to do something similar if I could make the HLG strong enough. Phil Pearson had presented his method of vacuum-bagging wings at a SASS meeting, so I went that way for the wing and 'borrowed' his T-tail design for my new airplane.
"The boom was easy; everyone in the area was using the SkyShark P3 carbon booms from the kite shop. I taught myself to vacuum-form the fiberglass pod as halves over male forms.
"The next months of the process were mostly finding weak spots and correcting them while learning how to control the launch. I finally hit using a switch to allow a preset of the rudder and elevator during the first part of the launch.
"I entered the last SASS contest of 1998 and finished next to last. I thought the concept had merit and spent the next year tossing Uplinks around at IHLGF, Visalia, some LA-area contest in an old oil field area, the Southwest Classic in Arizona, etc.
"I also sold about 50 short kits that shipped in a 12 x 12 x 3 box. A bunch of them went to John Erickson of SCSA as a club project.
"HLG advanced very quickly from 1998 to 2001, driven mainly by the Internet and a bunch of fliers willing to share both process and aerodynamic information. RCSE [RC Soaring Exchange] at Yahoo and later SALglider brought all kinds of information and tools.
"We had Xfoil from Mark Drela, LiftDist from John Hazel, sage advice from Don Stackhouse, online wing design from Martin Simons, a video on finding thermals from Joe Wurtz and the Professor, BarnYard Science on testing sink rate from Dave Register, and in October of 1998 Joe Wurtz admitted to throwing over a 50 foot power line if he had a 6063 winged toy."
Additional thoughts on discus launching
That's interesting dialogue about how DL began. I remember being limited to roughly 25–30 throws before my arm was sore enough to stop—despite playing adult-league baseball until my late 30s and A-level softball until just a few years ago, where my arm was in good shape. DL now allows nearly unlimited throws without problems.
DL also helped neutralize the launch in competition, letting the older and less athletic get their models close to those of top dogs on launch. There are always a couple pilots who can outdistance others, and DL is no exception. Hand launch teaches many things, but the most important is how to work low-level lift. A good hand launch (especially before DL) was almost as low as you would dare to try to work lift with an Open-class sailplane. If you don't work that with a hand launch, you aren't going to have a very long flight.
Do you remember the first time you skied out an HLG? What a great feeling. With hand launch you can work lift from approximately 5 feet off the ground with minimal risk. This produces a confidence level to work low lift with the big iron.
The HLGs also teach how a model reacts when a thermal is encountered. Even with light lift, the indications provided by a hand launch are quite pronounced. Something that is subtle and barely noticeable with an Open-class aircraft is significant with a hand launch.
With the knowledge gained from hand-launch experience, you should be able to recognize and work lift with your larger airplanes that you might not have before. I don't know of any Open-class flier who has not benefited from hand-launch experience.
The advent of the DL spawned an entire new breed of sailplane. The extreme forces of the DL required a much stouter airframe. Specifically, the fuselage boom had to be built to minimize flexing. I have seen video of a DL in slow motion, and it is amazing how much the tailbooms flexed. Now more carbon and Kevlar are used in construction.
You don't have to mortgage your home to get a DL airplane that will teach you the basics and help your thermaling ability. Several are available for a reasonable price. The Great Planes Fling and the Hobby Club Long Shot are good starters.
The Fling is inexpensive and basic. The Long Shot is more advanced but still less expensive than the all-out competition models. You probably aren't going to win the big trophy with one of these, but they will teach you what we discussed.
18th International Hand Launch Glider Festival (IHLGF)
The 18th edition of the International Hand Launch Glider Festival (IHLGF) hosted by the Torrey Pines Gulls (TPG) was held June 3–4, 2006, in Poway, California. This year heat was an issue, with temperatures hitting the high 90s both days.
This event has evolved into the premier hand-launch competition in the world. This year three countries and 18 states were represented.
Although the competition is fierce, the IHLGF is a great social event with a fairly relaxed atmosphere. This is one of the most enjoyable contests I have ever attended. I heard around the Kiwis for most of the event and had many laughs and made lifelong friends. I forgot to mention: these boys can fly!
This year attendance was down from the usual 90-plus contestants. I suspect the high gas prices and increased airfares have cut many peoples' discretionary income for such events. Sixty-five pilots posted scores.
The IHLGF involves 10 rounds of competition and then a top-10 playoff to determine the winner. You can find the specific tasks for each round and a final finish order on the TPG Web site at www.torreypinesgulls.org.
The newest airplane on the block was the Vandal flown by Paul Anderson. It featured Kevlar construction with complete RADS system for the ailerons and flaps. This was the cleanest aerodynamic model at the contest, with no linkages exposed.
Paul was able to range out and get back, although he had a couple close calls. His gutsy take-no-prisoners flying style earned him the top honors. I'll bet there will be more Vandals next year; many will go after what the top guy flew. It's a great airplane, but it still depends on the pilot.
Nonobvious improvements included hybrid airfoils by Mark Drela. Improved technology in the form of smaller, more powerful servos has contributed to the airplanes being lighter. Most pilots used two models: an extremely light sailplane for the morning light lift and heavier or ballasted sailplanes for the afternoon. The trend is definitely toward building an aerodynamically clean airframe.
Other hand-launch events are beginning to gain prominence. The Polecat Challenge and the East Coast Hand Launch contest are worth attending. The Polecat Challenge is on my list for next year.
Update on the author's RV-7
I have received several e-mails asking me about the status of my full-scale Van's RV-7 airplane. It is all painted now and has 135 hours of flight time. I flew it to the IHLGF in Poway with two airplanes and gear. I also took trips to South Dakota; Denver, Colorado; and Oshkosh, Wisconsin.
What a great way to travel without the hassles of the airlines. Long-distance travel is fun and easy with autopilot and GPS steering and, most important, the XM Satellite Radio.
MA
Transcribed from original scans by AI. Minor OCR errors may remain.
