Zephyr (oz7106)

About this Plan

Zephyr. An interesting all sheet single channel glider by Dave (Bird of Time) Thornburg. From April 1967 AAM.

Quote: "If a lean pocket book and nervous stomach have kept you on the sidelines of RC, here is a ship to get you on the field quickly and painlessly. All-balsa, it uses almost any single channel radio. Zephyr, by Dave Thornburg.

Zephyr can be built for three to five dollars (depending on the affluence of your scrap box) and will handle almost any single-channel radio. Its slow, graceful flight characteristics make it an ideal stepping-stone to powered models - if you still yearn for noise and grease and vibration after flying a sailplane!

The Zephyr came into being as a slope soarer, when I migrated to sunny (windy) California a year and a half ago. It is one of those rare designs that didn't require a long, painful evolution. Like Pallas Athene, it sprang full-grown from its pappy's head. The only real improvements we've made on the original have been structural rather than aerodynamic.

Old No.1 soon died of an overdose of Mother Earth (the extra-strength plane reliever), but not before it had proven itself an excellent towliner. And which taught me the value of Celastic, and how to avoid the turbulent leeward side of hills! A second Zephyr was built and presented to a fellow modeler who was just getting started in radio. It not only gave him his first controlled flights, but very nearly reconciled his wife to RC! Needless to say, it was adjudged a complete success.

Ten more Zephyrs have been built since then, two of them by 14-year-old modelers. They go together quickly and are consistent performers. And if you have any qualms about towline flying in general, forget them. The Zephyr is very easy to tow; in any breeze at all she will drag 500 ft of 18-lb monofilament straight up over your head.

Now a word to you experts lurking at the edge of the crowd. Here's a plane that will let you find out what all the soaring's about with a minimum of time and effort. Fly it on your old super-regen equipment - an occasional stray signal may be annoying, but is seldom fatal to a glider. And don't look askance at her escapement simply because the whole world is going proportional. She flies with an absolute minimum of radio gear, and Murphy's Second Law still ap-plies: the less equipment, the more flights per headache.

Too lazy to run, you say? Then slope soar, or build a drop-off power pod with parachute. You'll find a good .049 takes her up like an FAI gas job.

True, the Zephyr's no acrobat. A diligent spin will net you a loop or two, but violent maneuvers are out. She's a stable, graceful sailplane, and it takes a lot to upset her dignity. On the other hand, she retains her poise in a 15-knot wind, when all but the most daring of the multi boys are grounded.

And if rudder-only is too tame for you, multiply all dimensions by 1.5 and pack in the multi gear. I am presently flying a nine-footer with a Midas and two Transmites.

Fuselage: The fuselage is literally built around your radio gear. It can be widened or deepened as necessary, so long as the same moment arms are retained. The version shown will handle almost any commercial single-channel receiver and enough sponge rubber for crash protection. A regular escapement is shown, but here again you can modify to suit equipment on hand. If you use a servo, simply omit the bulkhead.

Cut the 3/32 sides from straight-grained hard balsa. RC stock is best. Using a coping saw, rough out the nose block from a 3 x 8 inch block of the necessary thickness. I usually laminate it from scrap, adding layers until it's about 1/16 in thicker than my batteries. The battery compartment, as shown, holds two alkaline C cells - enough juice for hours of trouble-free soaring with a relayless receiver and escapement.

Join fuselage sides around the nose-block, pinning tail together for temporary alignment. Glue tail block in place, checking final alignment over top view on plans. Install escapement and torque rod as a unit, protruding part of the escapement through a small hole in the fuselage side..."

Supplementary file notes

Article.

Corrections?

Did we get something wrong with these details about this plan (especially the datafile)? That happens sometimes. You can help us fix it.
Add a correction