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are you using the same rubber?

jcollier wrote:For winds, check out the rubber thread. For torque, it depends on how stiff the motor stick is and how tall the site is. For wing setting, all you can do is experiment. Since they have a fixed stabilizer, you could start with the wing at 0 incidence, then work it up 1mm at a time to check the flight and cruise. Bottom line is no one can really tell you how your plane will fly best. I saw 6 Freedom Flights models at the regional I supervised, and no 2 flew exactly alike.

What were the times of the best ones? What school were they from?

JCollier, we used a method where we have half the rubber motor and the rest a piece of wire weighted half of the band to simulate a full flight in a small gym, It does not glide down at all but when it lands it a minimal wind somewhere around 40-50 and it probabaly stays at its peak for 20-40 seconds, not sure.

someone in my school clocked 3 minutes

does anyone have an idea as to where i can get curved wing ribs to create the aerofoil?

illusionist wrote:does anyone have an idea as to where i can get curved wing ribs to create the aerofoil?

IMS sells them.

[hardurl]https://www.a2zcorp.us/store/Category.a ... e+Olympiad[/hardurl]

Will having an aerofoil give me a large advantage? Is it going to significantly improve the flying ability of the airplane?

I believe you can fly on a flat wing, but it has to be at a high AoA, which means a lot of drag. I believe it flies similar to those light rc planes that fly basically solely on thrust from the propeller and the ailerons. Many people on here know more about the physics involved with airfoils, but I'd say you definitely want to use an airfoil to be competitive. I'm not sure what's making people think of using a flat wing, since real planes and every plan I've seen use airfoils.

There was a document link posted somewhere that describes the lift given by an aerofoil, but the gist of it is that the differences in air pressure cause it to rise. Therefore, the lift is much better and the rag is lower (for the amount of lift).

illusionist wrote:does anyone have an idea as to where i can get curved wing ribs to create the aerofoil?

Cut them yourself. Its easy once you see how.

Make a pattern (a simple arc works fine for these planes, simplex curve is nice too) from heavy poster board, mat board, illustration board, the back cardboard off a notepad. Start with a simple rectangle, say 3-4 inches wide by the longest rib you want (say 15 cm) Now, along the 15 cm edge draw a nice smooth curve (you can print out a curve from you 'puter and paste it on the cardboard). Cut along that curve as smooth as you can. Harden by soaking it with thin CA. Sand smooth.

Now, take a rectangle of balsa as long as your rib. Grain should run along the length of the rib. Cut along your pattern so that rib length edge is now curved. Slide the pattern down 1/16 to 3/64 of an inch (or per plan). Repeat cut. You now have a nice curved rib piece. Slide down again, repeat cut. Another rib. And so on.

Jeff Anderson
Livonia, MI