Sport Rocketry

28 JANUARY/FEBRUARY 2020 SPORT ROCKETRY A few years ago, I began to try my hand at building an RC rocket glider as part of the NARTREK Advanced program. "It can't be that hard," I reasoned to myself. I have scratch built many rockets from 1/2A to L total impulse. I built and flew many radio- controlled planes from the 1970s to the 1990s, nearly all of them from scratch. Al- though I haven't flown RC in more than two decades, combining my wealth of ex- perience of over 40 years should make this task a piece of cake, I reasoned. Wrong. It absolutely can be "that hard." To begin with, there are not many RC rocket glider kits available (none, actual- ly), and not that many plans to be found on the Internet, either. Long story short, I succeeded in converting three different designs to splinters of balsa in short or- der. I was somewhat successful at the "up" phase, using E and F motors. But after the motor burned out, all hell broke loose. The tale is best told in the before and after pho- tos attached (see Figures 1, 2, and 3). I decided to swallow my pride and study the blueprints of the only really suc- cessful RC R/G kit that was marketed for a few years, the AeroTech Phoenix, designed about 30 years ago by Bob Parks. I ob- tained a copy via the Internet. Inspection of the photos, plans, and a very complete builders guide confirmed my suspicions that the Phoenix was anything but a begin- ners plane. With a foam core, balsa sheet- ed wing having both sweep and dihedral, and a curvy contoured balsa body, this de- sign was already well beyond anything I had ever constructed. Plus, it had ailerons for turns and roll control. In my 15 years of building and flying radio-controlled planes, I had never graduated to aircraft with ailerons ("ailerons and elevator with right hand, throttle and rudder with left"). Nearly all my RC inventory in those days were rudder-elevator controlled train- ers, with plenty of dihedral to let the rud- der bank the plane. I did build and fly a few big quarter-scale planes over the years that had ailerons, all right, but I always re- lied on a cheater device called a "Y-connec- tor" in the planes. This electronically cou- pled the ailerons and rudder movements together so I could fly the things pretty well (nowadays, this control coupling can be build right into the transmitter). With coupled controls, I could only, for exam- ple, do barrel rolls but no axial aileron rolls. And landings had to be made pretty much straight into the wind (or I'd dig in a wing tip and cartwheel). So...if I was go- ing to scratch-build a Phoenix-like plane, it would have to be redesigned to utilize Figure 1. Three of my initial rocket glider prototypes awaiting their first test flights. (Spoiler...they all failed.) by Larry Brand NAR 79591, L2 LARGE RC ROCKET GLIDERS for beginners LARGE RC LARGE RC ROCKET GLIDERS ROCKET GLIDERS

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