HLG Definitions

In April 2003 the SALglider e-mail group had exchanges on definitions:-

Allan Wright said:-
Discus launch involves spinning the body through careful use of footwork and puts the maximum amount of energy into your model. Discus launch planes are usually realeased parallel to the ground in both axis. Side-arm launch is done from a standing position with a partial twisting of the torso but no foot movement. Planes are usually released with the span parallel to the ground but with the nose angled upwards anywhere from 10 to 45 degrees depending on the pilot's style and the model flown. In a nutshell. Others can go on in much more detail I'm sure.

Jaffee said:-Discus Launch/DLG usually specificaly refers to gliders launched side armed, with a full 360 degree spin. Side arm itself often refers to a technique that was the precursor to DLG, in which the glider was launched with sort of an underhand side arm motion, where the thrower did not do a full spin with his body. Usually this involved gliders with spans smaller then 60", since it was impossible to do the underhand toss with anything larger. DLG evolved as a method to do a side-arm launch with a full sized HLG.

Scobie in Seattle said:-
Allan provided a pretty good nutshell, but there are some things worth clarifying here.

1. The most impressive Side Arm Launching that I've seen, and I've seen the true masters at work, has almost never been done without foot movement. Just as with Discus Launching, the proper foot movement makes all the difference to maximum energy. It's just a different (shorter) dance with fewer steps.
2. There is often less overall rotation of the glider in a Side Arm Launch. (Discus Launch often involves a full 360, more or less). But there is no rule about how much rotation you can use with a smaller model. From time to time, I throw my 42"-span Seeker through a full 360. The launch takes longer, but I find it's a little easier on the body, especially when I'm tired, and I can get just as high as I do with less rotation, maybe higher if I hit things just right.
3. There is some real design elegance in throwing the best of the Side Arm glider designs. If the glider is balanced neutral or very near neutral, then there are no presets or gyro needed, and the model simply takes the release trajectory for it's entire climb-out. In a fraction of a second, you can decide exactly how steep you want your climb, choosing a steeper release for pure altitude, or using a shallower release for some distance upwind to explore the oncoming air, all without any adjustment of the glider or radio.
4. The advent of modern Discus Launching grew out of Side Arm Launching, when Dick Barker saw the Seattle based SAL designs and decided he wanted to be launching a competition-size HLG glider from the wing tip. He realized that this would require a flatter overall circle during launch, developed his own Uplink designs, and worked with rosin on the wingtip for grip (no peg) for quite a while. He figured out a lot about presets, and got damn impressive results. It was Dick showing up at contests that finally 'woke up' the rest of the competition world to discus launch as a viable option for 1.5 meter HLG's. Now it's thought of as almost the only way to fly HLG. He really did 'Turn HLG Around'.
5. The very existence of this discussion group under the name SAL has gone a long ways towards pushing the definition of SAL to mean: Any kind of launching from the wingtip, discus or otherwise. Perhaps there's nothing wrong with this. If I were the king of language, I'd make Wingtip Launching, or Tip Launching the 'overall' category, since it's the fact that we launch from the wing tip that represents the fundamental change in the way we get our models UP. Then I'd preserve Side Arm and Discus as useful divisions within that 'overall' category. But language change doesn't happen through monarchy, and even if it did, I wouldn't actually want to be king, so I'm just going to sit back and see what happens to all these terms... and enjoy the evolution.(or revolution?)