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Serious Handlaunch

So, You Want To Get Serious About Hand Launch...

Fred Sage
Reprint from TPG Newsletter

This column will discuss the relative merits of aileron-equipped handlaunch gliders. Although pilots have been experimenting with aileron-equipped HLG for years, it was Joe Wurts at the Riverside hand launch contest last year (1994) that effectively campaigned this type of glider. Again, in the prestigious two-day International Handlaunch Contest staged by TPG at Poway in October (1995), Joe used his aileron-equipped HLG to great advantage against many of the best handlaunch pilots in the country. Of course, Joe won both contests. Many of you will say that Joe would have won even if he were flying a baseball bat, and you're probably right. But this attitude doesn't address of whether a straight wing, low camber (RG15) aileron equipped, light wing loading handlaunch glider (SWLCAELWLHLG) offers any performance advantage over the traditional polyhedral floater type design (TPFHLG). Recently, we've seen that several prominent hand launch pilots have adopted the SWLCAELWLHLG, including Arthur Markiewicz, Don Van Gundy, and Rick Shelby. More importantly, they've done extremely well in recent contests with consistent high placings. Were they just jumping on the bandwagon or do they know something that we haven't considered?

Traditionally, HLG's have been polyhedral designs that relied on just the rudder and elevator for control. This was necessary because, given the state of construction techniques and radio gear, the only way to achieve light weight (approximately 15 oz.) was to employ only two servos and control just the rudder and elevator. However, in the last year or two as construction techniques and micro radio equipment improved, we've found the weight of competitive TPFHLG's decrease to the range of 10-12 ounces. Although they offer very low minimum sink speed, they begin to suffer from lack of throw height and ability to penetrate or cover ground. A few people started experimenting with thinned or blended airfoils in an attempt to recapture these abilities, and this eventually led to the SWLCAELWLHLG. At this stage of development, the SWLCAELWLHLG has only slight dihedral and relies on ailerons to achieve rapid turn response. Low camber means less than the traditional 3 to 4 degrees and the light wing loading is less than 6 oz/ft2 to retain good minimum sink performance. The design philosophy at this time is that with the SWLCAELWLHLG, you can have your cake and eat it too. With light wing loading, hang time doesn't suffer; but with thinner or less cambered airfoils, the glider can be thrown higher and cover more ground.

Next, let's discuss the pros and cons of the SWLCAELWLHLG. Starting with the cons because they are relatively minor, the SWLCAELWLHLG has the following disadvantages:

• Requires two additional micro servos - 4 total - and a computer radio. I consider this a minor disadvantage because a contest pilot is willing to do almost anything to gain a competitive edge and would almost certainly already have a computer radio. That being the case, a free program in either a 4 or 8 program computer radio is all that's required. Are two additional micro servos a significant disadvantage? Come on... if $60-80 is going to make the difference, you're playing the wrong game!

• Weight will go up by approximately one ounce. Even after taking out two of four screws and shaving the micro servo case, two servos in the wing still cost you one ounce. However, this isn't a significant disadvantage as a SWLCAELWLHLG can still be completed in the 11 to 13 ounce range.

• Flight pack battery time will be reduced with two additional servos. This is definitely true again, not a significant disadvantage. If you're using a 110-mah battery and are used to 20-25 minutes operating time, then you will be restricted to 15-20 minutes with two extra servos. However, remember that the longest contest window is only 10 minutes. Most contest HLG pilots put their flight pack on quick charge after a round is over anyway. In the worst case, where you're required to fly two rounds back to back, you only have to swap flight packs. An extra flight pack is not a serious detriment.

On to a discussion of the positive attributes of the SWLCAELWLHLG. These characteristics aren't necessarily listed in the order of importance, as they will shift under different flight conditions.

• Greater throw height: The differences in throw height between a 10-12 ounce TPFHLG and a 12-13 ounce SWLCAELWLHLG that is reflexed can be dramatic. The extra 10 feet might not seem significant, but this represents approximately a 25% increase in throw height and will most certainly overcome any slight advantage in hang time a TPFHLG might enjoy.

• The ability to range further: With a lower drag airfoil (less camber), a cleaner planform (no polyhedral joint interference wave drag) and a greater launch height, you had better believe that you can search more air. This becomes a significant advantage during a contest as you can maintain a relatively static position on the flying field and fly to the thermal as opposed to having to run and position yourself before throwing. In addition, you can also work a thermal much farther downwind with the absolute confidence that you can make it back to the field before landing. In fact, the ultimate design criteria for an effective HLG is quickly changing from that of maximizing hang time to being able to cover ground. In addition, transit speed with reflex greatly increases so that you can thermal downwind until the last possible second and still make your task or window time restriction.

• Flexibility: How many times have you done well in the first few rounds, but by the third round you're having to add weight because the wind has come up. With a low drag airfoil and planform, this isn't a problem. Under all but the most extreme conditions, you can continue to fly dry knowing that you can penetrate when necessary. Reflex and go!

• Ability to camber the airfoil: With full span ailerons and a computer radio, you can not only reflex to throw and penetrate, but camber to help core small, low level HL thermals. In fact, with 1/16 inch of camber and when flown at a light wing loading, the RG15 Will thermal as well as the SD7037.

• Instant maneuverability: With rudder/elevator only, if you're flying at minimum sink speed just short of a stall, and you want to initiate or change turn direction, it can take a long time from control input to glider reaction. With full span ailerons, control response is almost instantaneous. This will allow you to core a thermal more quickly. In addition, the glider becomes much more fun to fly and almost seems to anticipate your control input. Although not important in a contest environment, the full spectrum of aerobatic maneuvers becomes available.

• The final advantage and becoming more critical all the time is the ability to control approach energy through use of spoilerons. Many of the new HLG contest tasks require that you catch and relaunch quickly many times during a round. Not only do you have to relaunch immediately, you also have to catch exactly on the required second. With a TPFHLG, this can take several seconds as there's no way to control approach energy. If you catch and relaunch this type of glider, you can easily waste 5 seconds of window or task time as you have to run to catch your glider. In fact, I've seen several TPFHLG damaged because a catch or a dork landing was required after approach energy was misjudged. With spoileron control that SWLCAELWLHLG offers, catches on the second, at the spot, are as routine as precision landings during thermal duration contests.

In conclusion, do the advantages of the SWLCAELWLHLG out-weigh the disadvantages? Only you can answer that question, but for the serious contest pilot the answer seems obvious.