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International Hand Launch Glider Festival |
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Commentary To explain the feeling and the thrill of a contest is a very hard task. Each flyer interprets the experience differently. Part of the interpretation corresponds to how you placed as well as previous experience. The author placed 3rd in Dave Thornburg's First HLG contest back in the 70's, and knew quite well that advances in airplane design, building materials, as well as technique had outdistanced any similarities to early HLG contests. Knowing that there would be significant changes, this author tried to record the technology do that next year, he could come with competitive airplane. The plane I used was competitive, and only suffered form the lack of pilot experience with the HLG tasks and flying time. The Weather Pilots flying at Poway, know of the general conditions that they experienced in past years. Previously, the early morning rounds are flown under calm conditions with small thermals. This is generally due to the presence of the marine layer and as the clouds burn off thermals are more frequent with the wind slowly coming up in the afternoon. In the afternoon, the winds can be as high as 15 mph. This diversity of conditions makes the pilot consider using 2 or more different planes to match the varying conditions present throughout the contest. This year the weather played a large influence in the strategy used in each round. Practice day on Friday provided typical Poway conditions. The early morning was slightly overcast, cleared by midday as the sun burned off the marine layer and the thermals started popping. By the afternoon, the winds came up. Everyone had a fun experimenting with launching, Trying out the new hot techno device advantage, the gyro, and trimming our their planes. Many planes were damaged due to simple mistakes. Those pilots who were not local flyers, spend the day trimming out their planes. The conditions East coast, or Midwest, flyers know are quite different than those conditions experienced by west coast flyers. Saturday Saturday dawned with the typical marine conditions, however the forecast was for much cooler weather. Cooler it was, and the marine layer did not burn off to expose the sun. These conditions made the early morning rounds very important, and throughout the day the conditions made the experience of the pilot with the plane a very important factor. Early morning rounds had the pilots congregating on the downwind end of the flight area. As pilots found weak, or nearly zero lift, their planes circled very close together. This flying was not for the light hearted. Some pilots tried to work upfield, however these pilots were mainly acting as thermal spotters for those flyers downwind of them. In some instances, pilots went up field to the furthest part of the field and found light lift on their own. In these cases, the thermal often had separated from the ground, and had slowly ascended. When this occurred, some downfield pilots tried to launch into the general lift area, only to be met with the sink that went along with the original thermal. As the day progressed, a breeze did come up, however the clouds did not burn off. Under these conditions, the latter rounds were more difficult to attain. Lift was spotty, and the conditions separated many of the pilots in the standings. The first day separated many of the pilots. Sunday Sunday dawned with the same marine layer conditions. Many of the pilots had followed the weather forecasts expecting the day to develop unlike Saturday. This was indeed the case. The early morning light lift provided challenging conditions and soon the marine layer started to burn off. The light lift gave way to moderate, yet spaced out thermals. Some of the rounds required the pilot to come upwind to find new lift just prior to their next launch. The conditions often required the pilots to drift downwind, out of the launch area and stretch the plane's flying and penetrating abilities. As the planes drifted downwind, they met a tree line about 250 or more feet from the downwind boundary of the field. Pilots has to make the decision of whether to leave the thermal as it broke from ground level at the trees and continue further downwind, or leave the thermal and proceed upwind. Some planes ended up in the trees. Later in the afternoon, the hill just downwind of the field came into play. Some pilots upon launch immediately went downwind to the slope to attempt to use slope lift to make their times. This task was made more difficult because this year the downwind boundary of the field was moved further upwind. This permitted cars to enter the field by a road downwind of the field without influencing any flight. Pilots could, and often did, run downwind to keep a better view of their plane, yet they had to return back to the field to catch the plane, and make the flight official. During the afternoon, the wind started to play a role. Pilots were able to find lift, but needed to decide if their plane had enough altitude to return. In the late rounds, many gaggles of planes were in general lift. Launches Launches were the main topic of each day. The highest launchers were Phil Barnes and Joe Wurts, followed closely many of the top 10 pilots. As judged by this author, the top pilots were consistently getting above 110 feet. Nobody was getting 150 feet despite the claims. This author goes out on the limb once again in the launch height controversy! Nobody had a measuring device. However, the discus throwing technique was clearly a equalizer. Never again will contest be totally dominated by those who could launch high. Many pilots who could not reach the heights of the best, had planes which had lower sink rates. The overhand, javelin type launch was not eliminated. The overhand launch was often used for lower duration flights which require rapid turn around times between the hand catch and the relaunch. I would like to say that when the pilots believe they are launching to 120 or more feet, they may not be doing that well. What we are seeing is and increase in flight times for the average launch. With new designs come some increase in launch height, but better yet there is a decrease in sink rate. The only true measurements that could be equated to performance, in this author's opinion, is the dead air time. Many pilots believe that the duration tasks will become more easily achievable, expecting 2 minute dead air times soon. Whether this is due to the launch height, the sink rate, or a combination of both, is to be seen soon. Discus Launches To try to explain the discus launch is some ways a difficult task. To say that it requires fancy footwork is in some respects true. Some term it a ballet, others just a dizzying experience. As shown in the wing peg section of this technical report, flyer gripped the wingtips using either a peg or by squeezing between the thumb and fingers. If you are trying to do the discus launch for the first time, try gripping the wing tip and, while holding firmly and not letting go, spin around in a circle. Just prior to starting to spin, be careful not to rest the outboard wingtip in the ground as it places stress along the wingspan in various locations. Non-flying induced wing failures are common. As you spin, do it slowly trying to keep the plane in a level flight position. As you reach the 360 degree point and the plane is pointing directly into the wind, release the plane. If the plane had sufficient speed, it will climb upon release and may bank left, that is if you are holding the left wingtip and rotating counterclockwise when viewed form above. Let the plane loose speed then level it out into a normal glide path. This is going to be one of the most important things to learn. The pilot must know when to release the plane, and once the plane had climbed out, know when to give it down to prevent the stall. A stall can cause the plane to loose as much as 10 valuable feet. Originally, this user only spun 180 degrees during the launch, and added and extra bit of force much like the force used in an over hand launch. This is poor technique. The pilot must spin and rapidly as possible, with outstretched arm, to keep the plane as far from the body as possible. The further away from the body, the faster the plane can be accelerated. Some flyers have their shoulder and arm leading the plane, and this is good. However the final 90 degrees of launch rotation, imparts a lot of speed to the plane. More speed, greater height. After the main rotation and release is mastered, then the fancy footwork comes into play. If one watches an Olympic discus thrower, you will see that the rotation combined with the footwork is not a normal turning, rather a series of steps that extend the discus and body such that there is a greater distance between the plane and the body. In the examples below, you can see how Bill Watson catches and releases his plane during the launch. Bill waits until he can get a good grip of the wingtip, then spins to keep the plane in motion. Release is upwind. These photos were taken during several rounds while trying to capture the launch, hence the differing pilot positions. |
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| Here Bill slows down his plane as it comes in to land | Walking slowly by beside the plane, Bill waits until the target time is met, then grabs the wingtip, spins, and relaunches. |
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| Fancy foot work adds a lot to the launch. Note Bill's arm is held back, with his body leading the swing. The last few degrees are important. | The release is as important as the windup. Hold it too long and the plane will oscillate more after launch. |
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| A smooth release is as important as the extra effort for speed. A smooth transition going up, and from the top converts speed into altitude. | |
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