Estrellita and Stinger (oz11074)

 

Estrellita and Stinger - plan thumbnail image

About this Plan

Estrellita and Stinger. Radio control scale pylon racer.

Plan shows both low-wing and mid-wing variants.

Quote: "Combination of two winning Formula Ones make for an outstanding project for the all-out racing man - it won in full-scale, and can win for you on our Pylon Race Circuit. Estrellita and Stinger, by Bob Owens.

Several years ago I had the privilege of working at a drafting board next to the designer of Goodyear (Formula I) racing planes, Art Williams. Our mutual efforts were on the preliminary design phase of an SST. However, Art's noontime efforts on the design of a new full-size Formula I midget pylon racer were more interesting. Thinking that someday I might get around to building a model of his new racer, I persuaded him to allow me to trace the three-views, (at noontime, of course).

His plane eventually came to be known as 'Stinger', and at the hands of John Paul Jones finished a close second behind the perennial winner, Shoestring, at Reno in 1974.

Formula I models of Stinger hit the Southern California NMPRA circuit in 1974 and 1975, built and flown by Jack Lee and Laird Owens. Each of these models was an excellent racer with honest and smooth flight characteristics. The 'frequency gods' and 'control gods' made short work of five beautiful models, but not before Jack Lee was officially clocked at 1:20.2.

Giving up is not one of my habits. Model plane racing has been in my blood since 1946, when my original-design U/C speed job, powered by a Torpedo 29 running on gasoline, oil and spark ignition, clocked a record-breaking 92 mph. Thirty years later my reflexes have slowed, but those of my 15-year-old son, Laird, have just become sensitive. His is an extension of my limited ability; he has already racked up an impressive display of racing trophies.

While Stinger is beautiful in appearance and an excellent flying model, it was hard to build and handle as a single-piece model. When the wing was made removable, the fuselage lacked rigidity due to the deep notch for the wing seat. That causes the fuselage to deflect (bend) during high-G-turns. My calculations indicate that about 40 G's are pulled around No.1 pylon. Any flexing of the fuselage changes the wing incidence relative to the engine thrust line and the horizontal stabilizer. This causes deviations from the desired flight path. Let's see, what other racers have low wings and elliptical wings? That way, there will never be a problem with fuselage rigidity with a take-apart model.

Scanning the race plane books turned up an older design by Art Williams. Sure enough, Estrellita was there in 1947, and it was very much a low-wing forerunner of Stinger. I got on the phone with Art to query him about this plane, and to talk him out of a set of three-views and some photos of Estrellita. Art was busy on his new racer, Falcon, and didn't get around to sending those three-views until the model was ready to test-fly.

Working from a single photo in a racing plane book, it appeared feasible to use the existing proven outlines, moments, wing and tail of Stinger, only mount the wing on the bottom of the fuselage. The only other modifications were the landing gear and the cheek cowl. Some quick overlay sketches proved the validity of the concept. There was plenty of room for large radio gear, the fuel tank would be removable, and the fuselage would be plenty strong.

Why am I so hung up on elliptical wings? There are several reasons: appearance, superior lift distribution which reduces wing-bending loads and reduces the drag - producing tip vortex, appearance minimizes profile drag (what other wing can get away with so thin a tip section?), appearance, lower aspect ratio without high drag tips, and finally, appearance. Besides, the lap-counters and flagmen love it, for it is so easy to identify!

Estrellita made her debut in the initial race of the 1976 season at the Suplulveda Basin..."

Estrellita, MAN, December 1977.

Direct submission to Outerzone.

Supplementary file notes

Article pages, thanks to RFJ.

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Estrellita and Stinger - completed model photo

Datafile:

003.jpg
003.jpg

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