Author: Paul Bradley
Edition: Model Aviation - 2009/04
Page Numbers: 101,102,104
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Small-Field Flying

Paul Bradley | [email protected]

RTF models: a boon to the builder

It sure is interesting to see how far the world of RTF models has come in recent years. The range of size and capabilities continues to expand, and the prices of many are also appealing. I have dabbled with some of the smaller RTFs.

My reason for mentioning this growing segment of model aviation is to comment on what some innovative modelers are doing with these products. Many of the RTFs were introduced as toys rather than as equipment hobbyists would use, but because of their popularity the mainstream model aviation companies now make respectable RTF products. Many current RTFs offer nice components to modelers who like to have more of a hand in creating their flying objects. One I see mentioned often lately is the ParkZone Vapor — a nice micro RC RTF that can be flown in tiny indoor spaces.

An excellent feature of the Vapor is the use of a 2.4 GHz DSM2 digital spread-spectrum radio system. The receiver is a small "brick" that contains the receiver, two servos, and a motor speed control. The complete airborne package weighs only 3.3 grams and is approximately 1 inch square.

It did not take long for builders to start experimenting with the ParkZone brick radio. The small size and integrated component layout are ideal for indoor flyers and some of the smaller outdoor airplanes.

Although small models are nothing new, dealing with the smaller components has often kept people from trying this enjoyable aspect of the hobby. The brick layout of the ParkZone radio is a big help. You don't have to install and wire servos or actuators inside a small airframe.

With the ParkZone brick, the electrical hookup is already completed. You just need to plug in the motor, run the pushrods, and mount the single-cell Li-Poly battery. That makes life in the small RC world much easier.

I have some examples of models set up with the ParkZone brick radio. One intended for indoor flying comes from regular contributor John Krouse. If you recall any of John's models from past columns, you might know that he likes to innovate. His current project explores the use of a ParkZone brick radio along with issues associated with transporting an aircraft from home to the flying site.

The photos John provided show his foam-wing airplane. Spanning 20 inches, it becomes more of a handful to transport. Most indoor models are carried inside a box to protect them from wind and other elements between storage and flying spaces. Rather than find or build a box large enough for a long wing, John adopted a common outdoor-sailplane practice of setting up the wing with plug-in panels.

He uses small carbon-fiber tubes in each wing half that slide onto piano-wire stubs on the fuselage pylon — a nice arrangement. The close-up photo shows the wing mounts along with the ParkZone brick radio.

The model is powered with a 6 mm pager motor that drives a 4-inch propeller through a 5.4:1 Gaspard gearbox. A 70 mAh Li-Poly single-cell battery is used for energy, and the total flying weight is 18 grams (0.6 ounce). The stock Vapor weighs 15 grams.

The open layout of John's model makes it easy to see the nicely integrated ParkZone package. You can see how easy it is to hook up the pushrods, motor, and battery.

Pat Tritle let me know about a friend, George Laskar, who used a ParkZone brick radio to convert a rubber-powered FF Aeronca Chief kit from Dare Design and Engineering into an electric RC model. It is a nice example of what can be done with the ParkZone brick for models flown in outdoor small-field venues.

The Chief has a wingspan of 28 inches. You might think, as I did, that an airplane that size is too large for the ParkZone brick. George has shown us not to limit our thinking. His RC Aeronca Chief, which sports Coverite Microlite covering, weighs only 1.5 ounces and performs well using a 110 mAh single Li-Poly cell.

Based on John Krouse's and George Laskar's models, I can see an almost unlimited set of possibilities for the ParkZone brick radio system. Apparently Bob Selman does too; he is now selling the radio separately. You no longer have to buy a complete RTF package to gain access to the system. See the "Sources" listing at the end for Bob's contact information.

Half-Size Vintage Pattern Models—A Continuing Story

In past columns I have shared information about half-size versions of the Fred Dunn Astro-Hog and Ed Kasmirski Taurus that I built. They give me a feel for the vintage RC Acrobatics (Pattern) aircraft at my favorite small-field venues.

Brian Malin of BMJR Model Products is also interested in half-size vintage Pattern airplanes and is adding some to his lineup of laser-cut kits. To get things started, Brian built a half-size Ed Kasmirski Orion. It has a wingspan of 36 inches that yields 194 square inches of wing area. The flying weight is 16.5 ounces using a three-cell, 850 mAh Li-Poly battery pack and a Himax 2808 brushless motor turning an 8 x 4DD propeller. Brian reports that the model performs nicely.

The half-size Orion comes as a full kit containing laser-cut parts, canopy, color photo-illustrated building manual, and hardware. See the source listing for BMJR Model Products' contact information.

Pat Tritle produces many nice kit designs for manufacturers. The only "problem" with this is the lead time required for a kit maker to get a new model into the eagerly waiting builder's hands.

Fortunately, Pat sells some of his designs as short kits through Pat's Custom Models. The time required to place a short kit on the market is considerably less than that required to produce the full kits vendors offer.

Pat's short-kit business is especially good news, considering what he has recently added to the lineup. For starters, he has a wonderful version of a popular general-aviation-manufacturer twin used in the later episodes of the old Sky King television series — an airplane that has been a longtime favorite of mine.

The photos Pat provided have lit my fire. The model spans almost 54 inches but has a flying weight of only 33 ounces. Power comes from two Suppo 2208/17 brushless motors turning 9 x 4.7 propellers, driven by a two-cell, 1320 mAh Li-Poly battery pack in each nacelle. The Suppo motors came from LightFlite RC. All control functions are included. Pat also shows the different tail configurations used on the full-scale airplane so the builder can choose the version they prefer.

In addition to his extensive line of models representing full-scale aircraft, Pat likes to dabble in fantasy scale — models of airplanes that could have been full-scale aircraft. His other new short kit offering is in this category: the appealing Inspirer biplane.

The Inspirer has a top wingspan of 42.5 inches and a bottom wingspan of 34.8 inches, for a combined area of 395 square inches. The flying weight is only 14.1 ounces, which is excellent for small-field flying. Pat used the cowl and dummy engine cylinders from his 1:8-scale Piper L-4, so the Inspirer is roughly a 1:8-scale model of what might be. The Inspirer has full flight controls and is powered by a Suppo 2212/13 brushless motor turning a GWS 9 x 5 propeller, driven by a 1320 mAh two-cell battery pack.

This brings me to the end of this installment.

With flying season upon us, I hope to see some of you at upcoming events. I look forward to hearing from you regarding your modeling projects or others' models you find interesting. I can be contacted by e-mail or postal mail; my contact information is in the Sources listing.

Sources

  • Paul Bradley — 10201 Scarletoak Dr., Independence KY 41051

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