Spoilers work, but weigh a lot, and would move the mass outboard on a very light structure. If you flew FF much at all, you'd know that a wing with dihederal would increase the AOA on the forward side of the wing and decrease the AOA on the rearward side. Since such a light weight structure would surely flex spanwise, there is a 99.99% chance that there would be effective dihederal, whether built in or not.
A lot of FF gas guys do skew the wing for that reason, rather than building in wash-in or wash-out. Turning into the wash-in under power is a stable mode, while turning into wash-out is a crash waiting to happen. Steve
I got my "ins " and "outs" mixed up, and fixed my post. They washed in the inboard wing to keep the inboard wing lifting in turns, with a very subtle wing warping, just like on an indoor free flight model. Speed is the critical thing here. Keeping wings level is a critical thing here also. Hell, even Jimmy Doolittle figured out the the best immediate solution to turning the Gee Bee R-1 was to keep the turns flat! You can't see it in the video but the Condor was a heavily braced structure. I don't know what they used but the big main king post and two smaller posts out on the wings had bracing of some kind going out to stabilize the structure. Probably Kevlar since DuPont was a major sponsor of the effort. Just so small that the film couldn't pick it up. Flying that slow, in that kind of speed envelope, does it create any kind of drag that is significant? If so, that drag is a good trade off to keep the wing in a good profile to do it's job. I have flown quite a bit of free flight, and in trimming a model for a turn even on an outdoor model is pretty similar. Lots of simple tricks to help keep wings as flat as possible, ranging from warping in some wash in at the wing tip trailing edge or like today, using a wedge to get the same effect to keep the inboard wing up and keep the wings level. In the old days, it was common to have the nose of the fuselage shaped into a curved, drooping profile so that if the model got upset and banked too much, the nose weight had a pendulum effect and rolled the fuselage back towards the outside of the turn, leveling the wings and keep the AOA across the whole wing as close to the same as possible so it doesn't spiral out of the thermal. I don't ever recall reading about or hearing about skewing a wing for trim purposes. On hand launched gliders, the tips are sometimes skewed a bit at a dihedral break to build in some wash out, then a wedge on the bottom of the trailing edge to keep the wing tip up at slower speeds. Most free flight models are trimmed for a higher speed portion of the flight at launch, either a power plant of some kind, catapult, arm power, then have to transition to a slow speed for thermal flight, and the difference between the launch speed and the glide speed is significant. Thermal flight has to be very stable so the model doesn't get tossed out of the thermal, and then if it does, it needs to recover as quickly as possible. That's the realm , I think, that the human powered flight enthusiasts are operating in, but most don't have a back ground that includes that kind of thinking. McCready did, and that is why he succeeded.
Type at you later,
Dan McEntee