Author: Paul Bradley
Edition: Model Aviation - 2010/08
Page Numbers: 88,89,90
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Rubber-powered RC models

Paul Bradley | [email protected]

I have been fortunate enough to be part of the model aviation hobby for a number of years. One aspect of aeromodeling that I have always gotten special enjoyment from is rubber-powered free flight (FF).

Within that category are high-performance models that use many strands of rubber strip for power. Watching one of those airplanes climb out under full power is amazing.

A major challenge for people who build and fly high-performance, rubber-powered models is having access to a flying site that is large enough for full-power flights with enough glide time to evaluate the overall setup. Even with the timer set for a short glide, the normal small field is inadequate for such flights.

Steve Morris, a modeler from Palo Alto, California, developed a high-performance rubber-powered FF model that uses RC assist. The RC feature provides a level of control that allows his airplane to be flown on sites that would otherwise never be considered.

That means Steve can use his local park or schoolyard to enjoy his rubber-powered aircraft without the risk of having it fly off the field or landing in a tree.

Steve's design uses a microreceiver and two microservos for rudder and elevator control. The electronics are powered by a single 90 mAh Li-Poly battery. The propeller is powered by 32 strands of 1/4-inch rubber that are 24 inches long.

If you have Internet access, you can watch a great video of one of Steve's model's many flights. See the "Sources" list for the Web site address.

I like Steve's approach. He can practice winding technique, evaluate power patterns, try different trim ideas, and simply have fun flying his high-performance rubber-powered aircraft at the nearby small field.

When it comes to building a scale airplane, some subjects seem almost perfect; the Piper Cub comes to mind. I guess most of the full-scale, high-wing Piper airplanes fall into this category. A design that I find especially appealing is the Piper Pacer.

Robert Dance and Pat Tritle must share that feeling. Robert has built a beautiful small Piper Pacer. As you can see in the photo he provided, the 18-inch-span model is a work of art. Robert is a well-known nautical artist from Kinston, North Carolina, who has been building model airplanes since the 1940s. He constructed his Pacer using three-views by James Triggs. Robert said that he has not drawn plans for the design but might do so one day. The Pacer weighs 36 grams ready to fly. It is covered with Japanese tissue, onto which color was applied with an airbrush. The electronics are from a ParkZone Ember. Great work, Robert.

Pat Tritle’s Piper Pacer is a bit larger than Robert’s. You might recall that I shared Pat’s Piper Tri-Pacer with you in the April column. When you have designed a Tri-Pacer, I guess it is natural to develop the companion Pacer.

Pat’s Pacer has a 50-inch wingspan and sports functional flaps, ailerons, rudder, elevator, and throttle. With a wing area of 423 square inches and a flying weight of 26 ounces, it translates well to small-field flying.

Pat is selling short kits for this terrific design. Please see the "Sources" listing at the end of the column for Pat’s Custom Models.

Where there is a Piper Pacer, there must be a Tri-Pacer lurking nearby. Pat Tritle’s rendition of that classic airplane has a wingspan of 50 inches. If that’s a bit larger than you would like, check out the version that Bill Bradley (no relation) developed.

Bill’s nice 36-inch-span Tri-Pacer has a flying weight of 20 ounces when using the recommended two-cell, 1500 mAh Li-Poly battery pack. The prototype used a Turnigy 2209-28 brushless motor that turns an 8 x 4 propeller. All controls are functional and include flaps.

Bill is selling short kits for the intermediate-size Tri-Pacer. Contact information is in the "Sources" list under Parkflyer Works.

Small-Field Flying

ParkZone Sukhoi Gets a Makeover

Referring to the April 2010 column again, I shared with you a biplane conversion of the popular ParkZone Sukhoi. It turns out that using that airframe as a platform for a personalized model is something more than one modeler likes to do.

Look at the photos and see if you can spot the Sukhoi. It’s how that nice-looking Hughes H-1B started life.

This design is the handiwork of Ron Sims from Saint Joseph, Missouri. He went a bit beyond a few tweaks to create his beautiful rendition of the famous racer.

He reworked the fuselage in the canopy area, moved the wing down and forward, reshaped the wingtips, added dihedral, sanded the fuselage to create a ring cowl, added a simulated engine crankcase, put on new tail feathers, and added wing fillets. And with a new paint job, he had a Hughes racer where there was once a Sukhoi.

Really nice work, Ron.

Small-Field Slope Glider With No Slope

From time to time I have shared with you projects my brother Ralph has developed. He likes to experiment.

Near where we live in Northern Kentucky, there is a nice community park that includes an amphitheater. Ralph felt that although small by model airplane standards, the amphitheater would be ideal for a micro slope soarer.

He developed the I-Soar, which has a 10-inch wingspan and is great for a small hill. The only problem was an uncooperative Mother Nature, who would not provide wind coming from the correct direction. Site observations made before building the model did not pan out.

What to do? Make your own hill. Not really, but how about letting one of your small-field models carry the new glider to thermal height via piggyback.

Using his tried-and-true Guided Mite, Ralph developed a slick glider mount that can easily be placed on the model and then removed later. It includes a microservo to release the glider, controlled by the fifth channel of a Spektrum AR500 receiver.

The resulting arrangement worked perfectly, and the small I-Soar demonstrated nice flying qualities after being carried aloft. It is hoped that one day the wind will blow from the correct direction, to allow some small-field slope soaring.

A Pat Tritle Beauty

In addition to the Piper Pacer I mentioned earlier, Pat has released a short kit for a wonderful rendition of the striking Stinson Reliant SR-10. It falls into the category of larger small-field flyers, but, as is typical of a Tritle design, it is lightly loaded. That means flying in smaller fields is practical.

The model sports a wingspan of just less than 57 inches. With a wing area of 465 square inches and a flying weight of approximately 28 ounces, the SR-10 is easy to see in the air and flies at a comfortable speed.

In addition to all functional flight controls, the Stinson has functional flaps. That makes for fun touch-and-gos.

Pat is offering short kits for the Stinson Reliant. See the "Sources" listing for Pat’s Custom Models.

I am looking forward to hearing from you and sharing your latest projects. My contact information is in the "Sources" listing.

PB

Sources:

Transcribed from original scans by AI. Minor OCR errors may remain.