Skydancer (oz13898)

About this Plan

Skydancer. Radio control rocket glider model.

Direct submission to Outerzone.

Update 22/6/2022: Added article, thanks to RFJ.

Quote: "Fascinating combination of space, aero, and RC flying. Nine-pound-thrust rocket motor sends this boost glider 200 feet straight up for a long fast glide. Skydancer, by Larry Renger.

Have you ever seen a big dual-digital-proportional model blast two hundred feet straight up under nine pounds of rocket thrust? Skydancer is just such a breakthrough in the wide-open field of RC boost-gliders. This model also has good duration coupled with aerobatic capability following that spectacular launch! Its graceful performance has earned it the name Skydancer.

This boost-glider is an experimental project by the Research and Development staff at Estes Industries and was originally conceived by John Simmance, Director of Model Products Development and five times champion in scale at the British Nationals. The design, construction and development of the model were assigned to me because my indoor model and free-flight experience would aid in design of a light airframe. I also had designed and flown RC slope soarers and had originated both the front-engined boost glider and the 'pop-pod.'

Although NARAM 12, the Rocket Nats, was but four weeks away when this assignment was given, it did seem possible to have the glider ready for a demonstration at that annual meet. Construction took two and a half weeks from initial sketch to first flight, and Bert Striegler, Technical Editor for Continental Oil Company, was asked to fly Skydancer for a NARAM demonstration.

The model was test flown successfully several times at Estes' Penrose, Colorado test grounds. Then, just before Skydancer was to be shipped to the Houston contest site, its wing was destroyed when the ship collided with a power line. Enough had been learned by then to develop a new, larger wing. The old wing had a 36 in span, which was now increased to 44 in. At the same time, 3/4 oz was cut out of the structure. After some late hours building, the improved model was sent off to NARAM 12 only one day behind schedule.

With the help of Bill Simon, Executive Director of Research and Development at Estes, Bert Striegler made several test flights and found no serious problems. Despite high winds on the day of the demonstration, Skydancer made a perfect flight before the assembly at NARAM - a satisfying milestone in an interesting project.

Normally, Skydancer is powered by a single D-13-3 Estes engine for a vertical flight of about 100 ft. The model is completely controllable, even during the boost phase. Transition to glide is easy and smooth. The best flight with the old 200 sq in wing at 12-1/4 oz was 1:06. Using two-stage motors and the new wing, flight duration usually has been over two min, even with an occasional loop thrown in.

Two Kraft KPS-12 servos, one 225 mah battery pack and a Kraft three-channel receiver for an airborne weight of 6-1/2 oz provide aileron and elevator control. Although the equipment could have been modified to further reduce weight, flying with off-the-shelf gear was one of the project goals. This model works quite well, but it is just a starting point. The structure can be lightened and the tradeoff of boost altitude versus glide must be investigated.

All recent flights have been with a D-13-0 booster taped behind the D-13-3. This is not legal for the NAR, nor is it good practice. A true, legal, two-stage pod is next on the list for development. One flight was attempted with twin clustered D-13-3 engines for liftoff thrust of 18 lb. The model nosed over off the launch rail and accelerated across the field at an altitude of about one foot before the speed built up enough for the elevator to overpower the nose down thrust moment. That experiment has not been repeated!

Construction: The wing, with the aileron servo, is built first. Cut out forms for ribs R-1 and R-13; the forms should be 1/32 undersize from the outline of the airfoil. Use 1/16 plywood and cut in the spar notches..."

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