Author: Dave Garwood
Edition: Model Aviation - 2010/08
Page Numbers: 105,106,107
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Radio Control Slope Soaring

Dave Garwood <[email protected]>

Dynamic Soaring breaks all speed records

A dynamic soaring pilot has broken the latest speed barrier. Man oh man, what a time to live, when a glider flies at more than half the speed of sound and far faster than any other type of model airplane.

On April 5, 2010, Spencer Lisenby flew his production sailplane 416 mph at Weldon Hill in Lake Isabella, California. The model is a Czech-made, 100-inch-span Kinetic DP. Congratulations to Spencer.

ARF, RTF, and RR slope sailplanes

Are you curious about what is available in ARF, RTF, and RR (Receiver Ready) slope sailplanes? To gain some knowledge in this area, I inquired at the local hobby shop and then online on the RCGroups Slope Soaring message board.

I purchased an ARF and an RR glider, and I found the former to be unsuitable for our purposes. The latter exceeded my expectations in two important ways.

Many so-called ARF (Almost Ready to Fly) models require considerable work to make them truly ready to fly, including cutting and hinging control surfaces, installing control horns and control cables, gluing the fuselage halves together, engineering a way to strengthen the nose (spray-on foam, perhaps?), and applying stickers to the airframe. It is my conclusion, from examining the GWS Zero, that any glider that ships with fuselage halves you must join to assemble the airframe and includes landing gear is not a top candidate to be an ARF slope sailplane. By today’s standards, GWS models are more similar to kits, but their parts count is lower since they are made from foam.

The ARF/RTF/RR slope market is not densely packed, but interesting offerings are available—especially at the light-lift end of the scale. What do not seem to be available are RTF warbirds or other PSS (Power Slope Scale) gliders, nor many tough-guy, hard-body, lead-sled composite sailplanes that fly fast in heavy lift and can withstand a cartwheel landing.

The top four recommendations from RCGroups contributors were:

  • The Elapor-foam Multiplex Easy Glider
  • The composite-construction R2hobbies Speedo
  • The new injection-molded EPP-foam Dream-Flight Weasel Pro
  • The Elapor-foam Multiplex Blizzard

Chip Greely at CR Aircraft mentioned that his company has begun producing bagged-wing, heavily prefabricated slope sailplanes from the legendary lineup. Another contributor recommended Ward Hagaman’s Volare wingeron as a sloper fitting my specifications for high performance and heavy prefabrication. The Multiplex Xeno (a flying wing that folds for storage and transport) was also mentioned.

At the height of this information gathering, I ordered an RR (servos installed) Multiplex Cularis. I was smitten with its lines and its 100-inch span, and I had already formed a high opinion of Multiplex engineering. I was down one thermal sailplane because of a crash, and I thought that this full-house model could work on the flatland field as well.

Multiplex Cularis — my RR experience

The Tower Hobbies web site describes the RR version as the radio-controlled 2.6-meter glider, which includes four Nano-S servos installed in the wings and two Tiny-S servos installed in the fuselage. This Cularis requires a transmitter, receiver, battery, and charger.

The RR version cost less than purchasing the six Multiplex servos separately (including the required servo extension cables). When I ordered it, I did not know how much, if any, construction work the manufacturer had done.

When the box arrived, I was stunned and amazed by how much building work had been done at the factory. Essentially the 29 construction steps in the big manual had been reduced to nine. I received my Cularis Wednesday afternoon and flew it on Saturday.

Following is my construction log.

  1. First night (35 minutes): Read instruction sheet and glue on wingtips, fin/rudder assembly, and nose cone. Let cure overnight.
  2. Second night (45 minutes): Paint wingtips, rudder, and canopy. Let dry overnight.
  3. Third night (25 minutes): Install receiver and battery pack, and balance. Ready to fly!

Basically, the Cularis became receiver-ready after 25 minutes on the workbench and ready to fly with less than an hour of workbench time (paint time not included)—and this is a full-house, six-servo machine.

It flew fine with hand tosses at the local schoolyard and did okay, not great, on the flatland field. In my hands it needs some attention to keeping the speed up to avoid stalls. This is a graceful soarer, and I can’t wait to get it on the slope.

This model exceeded my expectations with its lower cost and more prefabrication than I had anticipated. We can get a 98%-built sailplane with servos installed and control linkages set up that we can easily and quickly decorate with stickers, for a reasonable price.

Notes on new RR gliders

While preparing this column, Tower Hobbies sent an e-mail notice of two new RR gliders: the ST Model DG-1000 EPO Brushless and the ST Model Fox EPO Brushless.

  • The DG-1000 has a tough EPO-foam fuselage that allows for precisely aligned construction and simplified assembly. It should be flown only when the wind speed is 16 mph or less.
  • The Fox is made from durable, reparable molded EPO foam. The manual states it should be flown only when the wind speed is 6 mph or less; I believe this is a typo and that it should be 16 mph, as in the DG-1000 instructions.

I take this information to indicate that these are lightly loaded models, unsuitable for high winds and strong lift conditions. Both come with motor and propeller. That is an advantage for some fliers and a disadvantage for others.

Many of the models I’ve mentioned here have construction manuals available for download. With some research, you can quickly and accurately find out how many steps and roughly how much time is needed to get these gliders ready to fly and what components are not included.

Remember that many high-end sailplanes are heavily prefabricated and that many scale sailplanes are delivered ready for servo installation and setup and then become RR. You can find both high-quality and scale sailplanes at suppliers such as Art Hobby, Hobby Club, ICARE RC Models, JARTWorld, Nitro Planes, Skip Miller Models, and Soaring USA.

Sources

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