Flight Club Flies The Estratos

My name is David Medlock and I am the faculty adviser to Cascade High School's Flight Club. Cascade High is located in lovely Turner, Oregon, where the people are friendly and the weather is not. Add to that the fact that we meet during lunch and only have 15-25 minutes per day to build and fly our models and a theme emerges; anything we fly must be easy to build and water resistant. It was with that in mind that today's featured pilot, a very intelligent and enthusiastic junior named Shaylee, went looking for a new project to build. She landed on the Estratos, a very user friendly design by Dave Reap.

Shaylee is new to the hobby this year but her talents are developing quickly. She got some of her first flight time on a "V" shaped flying wing but, though she had a blast flying it, she found it to be a little squirelly. With the Estratos's low wing loading and large stabalizers she hoped to produce a mildly aerobatic sport plane that could slow way, way down, something that could do everything that a traditional wing could do but that would do it at half speed. In this she was not dissapointed.

There aren't any plans to cut. Instead the designer provides a diagram on his thread at RC Groups. It's in milimeters, which surprised Shaylee, though she thought it would be cool to use something she had learned in Math class. We broke out the old meter stick and went to work drawing it out on a single sheet of foam board, then cut it out and covered it with packing tape.

Shaylee spent about four lunch periods painstakingly creating a red, white and blue design, mixing solid colors on top with stripes on the bottom for in-air contrast. She probably enjoyed this part of the build more than anything else (she enjoys art class and is always doodling on something). Several of our other members contributed suggestions and a few begain their own Estratos builds when they saw how good her model looked.

Next it was time to rig her plane. She drew a centerline down the underside and then fitted an FT Power Pod to it by tracing out the tabs on the wing and cutting them loose. Finally she fixed a popsicle stick and zip tie on top (standard Flite Test stuff... see the Swappable Pizza Box Flyer video for a more detailed discussion), glued on the servoes and control horns and we were ready to fly.

The Estratos lifted off easily with an old hundred watt motor (something about the same weight as a blue wonder but with a lot less power) and a 9x4 slowfly prop. It had no bad habits in the air and the 1000 mah battery gave us about 10 minutes of flight time, with most of that spent at about 2/3 throttle. Stalls were straight forward and mushy, rather than dramatic. I have a feeling that with more elevon deflection this thing could be pretty exciting but we kept it mild at about 3/4 inches either way.

After trimming it out (which didn't take much; she built it straight) we landed, set up the buddy box and matched the trim to the student transmitter. Once it was aloft Shaylee found the plane to be forgiving and just maneuverable enough. After a few passes she was able to fly it on her own with very little correction from me. It flies slow and smooth, with that "swoopy" feeling you get from a good flying wing. Rolls were fast enough without being confusing and loops were big and round. Inverted flight required about half the forward stick, but Shaylee's plane probably won't spend too much time upside down.

The video doesn't show the best of her flying as we had a camera battery issue, but what it does show is the big smile on her face when we were done.

"It's a real sense of accomplishment" she told me. "I'm going to hang it up in my room when we're not flying."

In the future we will take the designer's suggestion and add a KF step on top, both for strength and lift. We didn't do it this time because we were eager to build and we were down to one sheet of dollar tree foam, but even with a flat airfoil the Estratos did everything we had hoped it would do.

If you're interested in building one for yourself do check out Dave's thread. He is very generous with his time and is happy to make suggestions and work through issues. His Estratos, by the way, is a modified version of the Great Hanno Prettner's Stratos, which was much larger and made of 1 inch polystyrene. It ran on glow power and tore up the skies during the 1970's (judging by Mr. Prettner's hair style).

Legendary RC designer and aerobatic champion Hanno Prettner showing off his Stratos

If this style of plane interests you do yourself a favor and check out the "All Things Round" thread at RC groups. Pardshaw, the thread's moderator, keeps an index of easy-build flying wings that come in many different flavors: square, round, delta, "squareoid," "deltoid," plank... virtually all of them can quickly be made into swappables using Josh Bixler's excellent power pod design. That's how Shaylee found the Estratos, and she's very glad she did.