New Products at the AMA Nats

Free Flight Sport By Don DeLoach | [email protected] As seen in the December 2023 issue of Model Aviation. AS I WROTE THIS, I had recently returned from an outstanding week of Free Flight (FF) fellowship at the AMA Outdoor FF Nats in Muncie, Indiana. Two new products stood out that deserve mention here.

Nats Catapult Glider Winner

Len Surtees came all the way from Australia and won the popular AMA Catapult Glider event using his 18-inch Sting MK2 design. This is a refinement of his early 2000s Sting glider, featuring significant upgrades such as a molded carbon-fiber wing saddle, optimized wingtips, and a built-in dethermalizer (DT). Josh Finn, himself a kit manufacturer and champion flier, said of the Sting MK2, "This is the most technologically advanced kit on the market."

A top view of the Nats-winning Sting MK2. The kit includes a lightweight balsa wing, the stabilizer and fin cut to size, a carbon-fiber wing saddle, the DT built into the fuselage, a nearly ready-to-fly fuselage featuring a DT timer, a hinge, a molded wing saddle, and a steel incidence adjustment screw. The Sting MK2 includes what Len terms as a "full lifting wing," rather than the common rounded wingtips, coupled with Michael Towell’s wingtips. Michael claims that these wingtips provide 17.5% more efficiency.

The Sting MK2 Catapult Glider is a complete, handmade kit from Australia. The fuselage is non-pivoting and ridged, which means that it can be javelin-launched as a Hand-Launch Glider (HLG). A finger rest for HLG is included in the kit. The wing is glued to a lightweight carbon-fiber saddle that pivots to 45° to bring the glider down from thermals. It is activated by a viscous timer built into the fuselage, which allows an internal steel spring to pop the wing up.

The beautiful, lightweight balsa wing blank of the Sting MK2 kit.

The prefinished ARF fuselage of the Sting MK2 comes as shown with an embedded DT timer and a carbon-fiber wing saddle with the hinge pin predrilled and fitted. In addition to the AMA Nats, this design has won two Australian Nationals, as well as Australian state titles. The kit can be ordered from Len for $45, plus $20 shipping. His website information is in "Sources."

Thermal Detector

Mark Freeland, the ever-enthusiastic cottage supplier at Retro RC, has just released the advanced RRC Thermal Detector for FF flying. The unit is a quite sensitive electronic thermistor that graphically displays the subtle changes in air temperature that indicate rising (or sinking) air currents.

The RRC Thermal Detector is an advanced, handmade system that made a big splash at the 2023 Outdoor FF Nats. The unit is straightforward to set up and easy to operate. It is assumed that you already have a pole of some sort on which to mount the system. Most people use a long fishing pole that collapses in segments. It is best to mount the display box at eye level, 5 to 6 feet off of the ground. The sensor head has a "V" groove in its lower body. You can epoxy a suitable stick into this groove that will fit into the top of your pole. You could use rubber bands to strap it to a dowel or even to strap it to your pole. (Replace the rubber band frequently if you use this method.) There is approximately 10 feet of cable attached to the head, with a small, two-pin male connector at the other end. Plug this connector into the black female socket on the bottom of the unit—polarity does not matter. Some people would prefer the sensor element to be fully exposed and only shielded by a foam disc above the element. If you wish, Mark can provide a thermistor on the wire without any housing so that you can create your own preferred head arrangement. The unit comes with a 1S LiPo battery, a strip of self-adhesive Velcro, and a length of 1/2-inch wide double-sided hook-and-loop. Use the wide Velcro to attach the battery to the bottom of the unit. The double-sided piece can be cut into sections and used to tie the wire to the pole. Use at least one near the display unit so that wind whipping the wire around does not cause the connector to come loose. Only use a 1S LiPo battery; a 2S will permanently damage the unit. The battery that is supplied will offer several days of use between charges.

How It Works

Over time, the display builds a graph that shows the small fluctuations in the pole’s top temperature. The graph is self-centering, so as the ambient temperature changes throughout the day, it will self-correct. A new point is plotted every 2 seconds for slightly less than 4 minutes until the graph reaches the end of the display. It will then wrap around and start over at the left side of the screen, clearing a small portion of the previous graph. The unit will repeat this four times then stop. Thirty seconds later, it will erase the graph, and in another 30 seconds, it will clear the screen and go to sleep until you restart the unit by pressing the black button slightly behind the red LED. This shutdown is to save battery life when you are not using the unit. (It might also minimize the queue of other fliers who want to stare at the neat device at the bottom of your pole!) The unit is quite sensitive. Turn it on and then hold your hand a couple of inches below the sensor head. It will register the "thermal" that your hand is creating! If you blow into the holes in the bottom of the sensor body, the graph will quickly go off scale and take a good number of seconds to return into the window. Note: The unit can be supplied with temperature readings in either Fahrenheit or Celsius. Mark credits Bob Sifleet and Phil Calvert, whose insights and help in testing it were invaluable during its development. The unit costs $225, plus shipping.