namic devices, such as side force generator (SFG) fences on the wings or wingtips, thick or reflexed trailing edges (especially on the rudder), and T-canalizers of a variety of shapes. The traditional monoplane is the most popular configuration, with a small number of biplanes. Also found is the “1.5”, such as the Axiome+; the “1.5” reference due to the very large size of the T-canalizer (ap- proximately 15% of the wing area). As I have been flying electrics for Pattern competition since 2006, and anticipate a con- tinued shift to electrics in the future, I will be using electric power for the not yet named subject of this second iteration of Project Pat- tern. Nonetheless, a sidebar including de- tails about the state of the art YS setup will be included for those that prefer IC. Additionally, looking into my crystal ball,
The text describes how changes in the aircraft restrictions and maneuver schedules spurred changes in the aircraft design since the days of “Baby Huey” to the current day.
wood, increased carbon fiber reinforcements, and lighter finishing techniques. Traditional fiberglass fuselage layup techniques proved to be quite heavy as the fuselage volumes in- creased, and the use of composite materials (carbon fiber and Kevlar®) increased, as did the use of laminates—thin layers of various foams or balsa between layers of fiberglass, carbon, or Kevlar cloth. The once familiar one-piece wing is now a rarity, giving way to plug-in wings (and stabs), a concession to the difficulty/cost of shipping, transporting, and storing a one-piece 75-inch span wing. By 2005, a number of manufacturers (CompARF, Jaroslav Mach, and WistModel, to name a few) were producing full compos- ite “kits”. My quotation of “kits” is merely to distinguish the modern composite kit from a traditional molded or composite molded fuselage. The modern day composite kits minimally have the base color painted as part of the molding process, and often are available with 100% completed color schemes (and even custom schemes for ad- ditional expense). Wings and stabs include “live” top hinges in the skins, and the better examples include curved leading edges on the ailerons and elevators to seal the hinge- line on the bottom side. Construction requirements are minimal
in comparison to the effort required to con- struct “Baby Huey”. Many kits have prein- stalled wing and stab tubes, servo trays, landing gear mounts, hatch mounts, and even firewalls in some kits. The other big in- fluence on construction is 100% attributable to electric powerplants. With greatly re-
duced vibration levels, and no concerns of fuel soak, electric airframes can be con- structed (and finished) much lighter than airframes built for IC use. Approximately 4–8 ounces can be saved when an airframe is built specifically for electric power. This is a considerable amount of weight on a 10.5- pound plane, especially when this weight savings is coming from approximately 60 ounces of basic structure. Current day, the majority of Pattern kits
are either composite molded, or of the ARF variety. Traditional kits are still available, but in decreasing numbers due to the ever increasing quality of the ARFs for minimal additional cost. Also decreasing in avail- ability are kits/ARFs for IC power, due to the substantial rise in the popularity of the electrics, used by approximately 60% of competitors at the 2011 WC, and by at least 80% of the competitors in the F3A and Mas- ters classes at the 2011 US Nationals. As seen during the 2011 contest season, the more popular designs currently include Amethyst, Asyuler, Axiome+, Visa, Wind S Pro, and Xigris. As this review of Pattern history arrives
at the present day, I dare say the airplane designs have stabilized to an extent. Virtu- ally all designs are 2 meters in length with slightly shorter wingspans and all are “large volume” fuselages. The size of the planes is primarily controlled by the 11-pound weight limit, and to a lesser extent by the power that can be produced while remaining under the 94 dB FAI noise limit (96 dB for AMA). Many designs utilize one or more aerody-
the biggest influence I see on the horizon (barring substantial rule changes) for Pat- tern designs and development is the in- creased use of counter rotating propellers with aircraft specifically designed to compli- ment the performance parameters of the counter rotating propellers. For several years, the EFactor (designed by Michael Ramel, Germany) counter rotating propeller system has been available and used in limited numbers in Europe, most notably by Sebastiano Silvestri. In 2010, engineer Brenner Sharp teamed up with Gaishin Man- ufacturing to produce a US made counter ro- tating prop system (“Contra Drive”) that Brenner used in the 2010 US NATs. Both of these systems utilize a single electric motor and would have been much more difficult to produce (if at all) prior to the use of electrics. Stayed tuned to FMfor detailed information on the Contra Drive in future issues. At this juncture, a couple of introductions
are overdue. Firstly, the project model for Project Pattern Redux, the Europa Pro LT, from RC-Composit
www.rc-composit.com in Lithuania. In consideration of the eastern European lineage of the Europa, and the al- literative appeal, the Europa Pro LT will henceforth be referred to as Yuri. Given the rather extensive degree of con- struction completed by RC-Composit as part of the manufacturing process, portions of Project Pattern Redux will be written by the man behind RC-Composit, Lithuanian na- tive Algirdas Ungulaitis (“Algis”). The next installment of Project Pattern Redux will come direct (as it were) from RC-Composit in Lithuania, where Algis will detail the manufacturing steps involved in the pro- duction of Yuri.
The Dick Hanson Models EMC2 was a massive airframe (at left) and years ahead of its time when it arrived on the Pattern scene in 1997. The EMC2 was arguably the first large volume fuselage design that set the stage for the large volume fuselages used through the present day. Ready boxes (above) at the 2011 WC show a good cross-section of current day designs. Left to right; Amethyst electric powered biplane (Richard Christopher, Great Britain), YS powered Axiome+ “1.5” (Loic Burbaud, France), and EFactor electric counter- rotating prop Wind S Pro(Robin Trumpp, Germany).
FLYING MODELS 37
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