Pioneer 15 (oz7977)

About this Plan

Pioneer 15. Electric powered RC sailplane.

Quote: "A 74in span Astro-15 powered sailplane that utilizes the full potential of electric power, combining the best of soaring with silent powered flight.

The Pioneer 15 is an electric powered sailplane designed for the sport flyer. The model is built around the fabulous Astro 15 elec-tric motor system. Using a Cox gray 8/4 prop, the Pioneer will quickly climb to thermalling altitude from even the most confined flying sites. Because it is electric the noise problem associated with gas models is nonexistent. This brings the possibility of flying in areas now not open to conventional glow powered RC models which might also be too small for high start or winch.

Once Pioneer 15 is flown up to 800 feet (in about 80 seconds), you simply shut off the motor and begin to soar. From the time the prop is stopped by the unique prop stop system, incorporated in the design, until the moment you land, the Pioneer 15 reacts like a high performance RC sailplane. Like any sailplane, flight duration is a function of the lift conditions and the pilot's soaring ability. The Pioneer 15 will not let the thermal chaser down. It will circle upward on the slightest puff of lift. If, however, you fail to find the big thermal the first time up, the nature of the electric powered sailplane allows you to turn the motor back on and climb back up to altitude. You get a second chance.

The average duration of the Pioneer 15 with the Astro 15 system is between 10 and 15 minutes in still air conditions depending on the ready-to-fly weight of the model. Twice my Pioneer has surpassed 45 minutes in the warm thermals of an Ohio summer morning. Thirty minute flights are not uncommon.

Landing is no problem. The Pioneer 15 can be slowed to a walking pace and gently brought to a stop on the grass of your flying site without even wrinkling MonoKote. If, however, you fly from a rocky or otherwise treacherous flying field, a single rubber or metal skid should be added.

Once on the ground a full recharging of the motor battery can be obtained in 15 short minutes. By all means use the Astro Flight charger because the 15 minute shut off timer will save your precious batteries from being ruined by overcharging.

Another advantage of electric power is that the model can be disassembled quickly and you can be on your way home (or to the model shop) without reeling in a high start and without degreasing your model as would be required with a sailplane or glow powered sport planes.

Design evolution. During 1975 and 1976 it became apparent after the success of the Electroglide 62 (oz5272) in August 1975 RCM, the Astro Flight Fournier RF4, and several of my own designs, that a truly high performance RC sailplane could be developed for electric assisted launches. After talking to Bob Boucher at Astro Flight, it became evident that the Astro 15 motor system has the best power-to-weight ratio of any of the electric systems currently available. Thus, the Astro 15 was chosen as the foundation around which the Pioneer 15 was designed.

Using the 57 ounce weight of my Fournier RF4 as an example of the weight of an Astro 15 powered model, it was determined that the Pioneer 15 could be built to a design weight of 50 ounces including a 3 channel radio installation. To assure soaring capability, a wing area of 730 square inches was chosen to yield a design wing loading of 9.9 ounces/foot. The key to the light weight of this model is a strong light airframe and the use of a 5 volt voltage regulator to convert power from the motor battery for the use of the RC units.

The NACA 4412 section was chosen for the wing ribs. Since the wing is built without leading edge sheeting, the MonoKote shrinks between the ribs giving approximately a 9% - 10% wing thickness. This is the key to the use of this thick airfoil for wing ribs of electric models..."

Hi Mary/Steve - Here is James V. Zarembski's Pioneer 15 from RCM magazine issue 09-77.

Direct submission to Outerzone.

Supplementary file notes

Article pages.

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