Monarch (oz5848)

About this Plan

Monarch. Radio control thermal soarer.

Quote: "A 10 ft 6 inch span, lightly loaded sailplane that captures the best in thermal soaring. Monarch, by Chris Barns.

Those who are familiar with the Pages of R/C Modeler are aware that, although much of the public may consider making model aircraft 'kid stuff', the majority of those involved are adults. An exception to this pattern is Christopher Barns, now seventeen, who designed his R/C glider Monarch in the Fall of 1971 at the age of fourteen and turned fifteen while building it. His first two RiC gliders were a Phoebus built from a kit and a Cliffmaster (oz1032) built from RCM plans; Monarch is his third. In addition to his his model building activities and his normal school responsibilities (he is a high school senior) he found the time and energy to serve as president of the local group of model enthusiasts, the Davis Aero Modelers, several seasons ago.

The Monarch has a wingspan of 10 ft 6 in, weighs 41 ounces ready to fly and has a wing area of 1016 square inches, giving a wing loading of 5.9 ounces per square foot. This is about 75% of the wing loadings of most other aircraft of its class. The aspect ratio is 14:1. The airfoil design is a modified Clark Y 11% section, with the high point at 36%. The radio gear is a Kraft Series 70 four channel with two KPS-12 servos. Readers can see from the photographs that there is a considerable similarity between the Monarch and Airtronic's Grand Esprit (oz9015). The Monarch, however, had been flying eight months before Chris' first knowledge of the Grand Esprit, which came in the RCM issue for August 1972.

It can be seen that the design differs in some important respects from that of most thermal gliders. The lack of a visible antenna is one of the more hidden innovations; it is inside the fiberglass tail boom. The full flying Vee tail is the most prominent of the design features. The flying surfaces are held to their pivots at the end of the boom by the pressure of the control rods. This technique was chosen for its strength, ease of construction and economy.

As a result of having seen a number of mid-air collisions at slope soaring races Chris instituted one easily constructed and completely hidden feature: the insertion in a slit on the leading edge of the wing of a length of .035 in music wire glued in place. This has proven highly satisfactory crash insurance when the aircraft has struck unyielding objects, resulting in only slight or no damage where major damage might otherwise have occurred. He has not been able to determine the weight of the glue holding the wire in place, but is quite certain that it and the wire, which weighs only 3/8 of an ounce, do not add as much as an ounce to the weight of the ship. This is very cheap, light and effective crash protection indeed!

The Monarch has proven itself to be very effective design; a highly responsive, high performance aircraft with a low rate of sink, penetration equivalent to gliders of higher wing loading, and a normal flight speed about 75% that of most thermal gliders. As with most other sailplanes with a 65% Center of Gravity it has a quick but predictable stall. Its polyhedral tips allow it to turn quickly, maintain its hank angle and recover equally quick. The Monarch has given flights of twenty to forty minutes at the local airport, the city park, and the playing fields of the University of California at Davis, On Picnic Day 1972 on the UCD campus it was flown as part of the Davis Aero Modelers flight demonstration where it showed to hundreds of spectators, many for the first time, that a motorless aircraft can sustain flight for many minutes.

The Monarch's towing characteristics are excellent, whether on the winch or by hand. It climbs straight, with no tendency to snap roll, and can sustain a very high towing angle..."

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