Somewhere around the beginning of the year, I set out to do some systems design, analysis, and optimization work on the F3J/B toys. The first order of business was to do some airfoil analysis and design. For familiarization and training, I decided to attack HLG. I broke down the HLG design into two parts. One was to do a poly 2 ch ship, and the other was to do a 4 ch toy. The 4 ch toy has some more degrees of design freedom in that one can let the TE deflection wander about a bit in order to get some optimization at various edges of the flight envelope. The primary design goal was to come up with toys that could fly well in the "Poway" conditions (windy, turbulent, frequently strong lift and sink), but still had the light air performance that the early morning rounds required. It turned out to be a more encompassing task than I originally envisioned, particularly in that airfoil design is a highly iterative process that requires more than a little intuition. This is particularly true when considering TE devices. To make a really long story only long, I finished up with two airfoils, one for a poly, and one for the 4 ch. Both had a planform optimized for the airfoil, considering the differing flight weights of each. I did not plan this, but the 4 ch planform ended up being almost exactly the same as the Encore, something that was pointed out to me after I finished my design optimisation. The geometry was shipped off to Don Peters and Phil Pearson, and the real work began. Phil started the construction process, making the poly ship first. He started calling up with glowing reports on the legs of the plane, along with comments on the low minimum sink, but he seemed to want to get beyond the poly, I think the quote went something like, "the world doesn't need another poly HLG". Phil and Don had been working on a pod/boom fuselage for some time, and the new toys were recipients of this treatment. I was cautious, but they used these way cool free flight tail booms that are really light and stiff. As an added plus, they have a very thin aluminum skin that gives a sharp flash in the sun twice in every circle. They are not cheap, but well worth it. A couple of weeks before the IHLGF, he finished up a new 4 ch bird, and proclaimed it successful once he flew it. The goal was for me to get a version of each the week before the contest, but UPS did not cooperate. He shipped about 10 days before the event, but I did not get them until just about the same time as when he drove by on his way to Poway. Lesson learned, don't count on second day delivery... Got my first flights on the toys in gathering darkness on Thursday evening, and now I was satisfied. Friday was spent in figuring out the setups, and remedial HLG stick time. The poly flew great, but is kinda one dimensional (cruise around, find lift, repeat...). It does have an amazing speed range belieing its under 7 oz weight. Hook a thermal, go up, scoot off to the next ride. Very relaxing compared to driving a 4 ch bird around. The poly has a couple of quirks that we still have to iron out, but it is pretty close. Just have to solve a small pitch instability that appears with high yaw rates. The 4 ch plane was a step up from the 6063. Not as much as I'd been expecting, but it seemed to have a better low end and mid range without sacrificing the upwind dash unduly. Where it really was nice, was with ballast. Weight did not really hamper the thermalling characteristics, whereas the 6063 kinda hates weight. Also, adding + camber for thermalling really worked out as advertised. The 6063 has a fairly narrow operating band when using camber, but the new airfoil has a much wider useful range with camber. Could go on more, but enough for now. Joe RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED]
