"Shortly after the SAL came here we began experimenting to optimize our existing poly ships we just made molds for, so they would a) be "salable" at all and b) withstand the stress of the new launch technique. At the same time some were adapting F5B wings or the outer panels of F3B wings to create aileron SAL-HLGs.
The latter launched drastically higher right from the beginning. The drawback was their poor hang time, besides they required different flying tactics.
Being able to perform a repeatable, safe launch with a plane that had a low sink rate seemed to be the most important issue to sort out and there were two sides from which the optimizing process started.
That was when I built my first DLG and I decided to go with the flat wings but add a bit of HLG flavour so my design featured a zero dihedral wing, an airfoil that had been developed for our team s last molded javelin style HLG design and a fairly swept back planform with a classic HLG 6-panel chord distribution. This made for a very precise, reasonable high launch, good penetration and an acceptable hang time despite it s pretty high weight, but had awful handling when searching for thermals and I m sure I missed most of them without even noticing.
At competitions I saw that some made the oppsite approach and reduced the dihedral of those planes that were developed from the poly design concept and prolonged the tail boom until they launched more precise. Even if they did still have problems with launch precision, handling and height, their overall performance was better compared to the still higher launching F5B derivates.
It came clear some some minimum dihedral was needed while ailerons/flaps were a nessecity.
While I tried to increase the dihedral of my flat wings until they became flyable others further flattened their poly wings until they allowed for a precise launch. It is interesting to see, that while I ended up with a low dihedral poly flaperon wing (45mm=1,75"), most have converted to a single `deep dihedral in an otherwise straight wing now.
I do not believe this is due to performance only, but also for reasons of simplified construction in production DLGs wich became more and more common in competition flying.
I still see a lot of DLGs with poly tip panels or similar, which perfom well especially in thermaling, but these are usually flown by those who build their own designs.
The difference in performance of all current DLG designs is getting smaller each year, and given a limited time we can spend for our passion, it already is a performance factor to go buy our competition gear and rather spend the time on the field practicing than in the shop scratch building or experimenting with a (maybe) optimized own design, besides the precision in production has reached a level hardly achievable in a private workshop.
Nevertheless, I m going to go on scratchbuilding because I do not only want to be successful in a competition, but I also want to learn why one design is good, while the other is even better and because it is fun to tweak things. Maybe I ll come up with a little surprise now and then to keep development going? Just my personal view... " --Martin
"Thank You!" for the read--give some thought to passing on a piece of your mind :-) ! --Sky Pilot
http://www.kcat.zaq.ne.jp/skypilot/ (dated)
SKY PILOT'S HANGAR--RCHLG-DHL AFICIONADO
