Radio Control: Sport/Aerobatics
By Ron Van Putte
It's newsletter month, an opportunity to share a gem gleaned from club newsletters around the country. Below is a slightly edited maneuver description by an unknown author that appeared in the Thundervolts (Schenectady, NY) newsletter. I think it's worth preserving for its humor and insight into a precision maneuver—the Figure 9.
Figure 9 (anonymous, edited)
In striving for perfection, a delicate combination of proper airspeed and control inputs is essential. Abrupt corrections are to be avoided, since they greatly diminish the gracefulness of the maneuver. As with all precision flying, be certain your equipment is up to the task: range-check the radio, ensure servos and linkages work flawlessly, and tune the engine so it runs strongly with the aircraft held nose-down (we don't want it to sag during the most important part of the maneuver).
- Phase 1 — The Entry
- Best started downwind, preferably directly out of a Split-S. Speed is a determining factor in the success of the maneuver.
- Entry altitude is not critical; two to four feet often works well. Experience will determine what's best for you.
- Phase 2 — The Pull Up
- Execute a nice, gradual upward sweep with the wings level—smooth lift-off.
- This preserves airspeed and gives onlookers time to turn and watch your stick-manship.
- Phase 3 — Over The Top
- Your engine should now be on its back. Tighten up a bit with more back pressure on the stick.
- Relax the stick slightly as the aircraft comes around to vertical—about now it will really be moving.
- Phase 4 — The Plunge
- Continue around until about 30° from vertical. At this point, it can be helpful to have a buddy taxi his plane to the impact point to get a good look.
- Important: stay off the rudder and avoid gross aileron inputs. Yaw-producing inputs will detract from the overall result.
- Phase 5 — Impact
- Impact is very short and barely a "phase," but many pilots report a kind of time-shift—slow-motion scenes of pride and joy disintegrating piece by piece. Even without that sensation, you can often conjure an instant replay by closing your eyes for a few seconds.
- If everything is done as described, the plane should meet the ground at about a 30° angle. This tends to produce maximum horizontal component without sacrificing undue speed, creating a large area of destruction. Angles up to 45° can be spectacular, but 30° is found to be about optimum.
- Remember: practice, practice, practice.
I wish I knew the anonymous author; we owe him a debt of gratitude for this entertaining addition to pattern maneuver descriptions and for encouraging us to perfect our flying techniques.
Lightning and RC Receivers
After reporting an incident of lightning interference in my October 1983 column, I received several responses that shed light on the hazards of flying near thunderstorms.
George M. Myers (M.A., "Radio Technique" columnist)
"Lightning is an electric discharge of very high voltage and amperage; hence high power. Because it has the nature of an electrical arc discharge, the discharge has an oscillatory characteristic..." Lightning gives off electromagnetic vibrations that can occupy a very broad frequency spectrum—from DC up through light frequencies. Those radiations are presented to your RC receiver's antenna. Receiver RF circuits have some ability to reject unwanted signals, but that ability is limited to power levels near the design power of the control transmitter. When presented with stronger signals, the circuits may overload, forcing interference through the set. In extreme cases, currents induced by lightning can physically damage active circuit parts, melting transistors and ICs or punching holes in capacitors. Whether physical damage occurs depends largely on the distance between the receiver and the lightning bolt.
A practical warning: if you see lightning, don't fly. You can often tell a storm is approaching because any broadcast AM receiver will start to crackle and sputter in response to lightning bolts tens of miles away—hearing such noises should be warning enough.
Gary Malchus (Milford, UT)
Gary, who has worked for the National Weather Service for 28 years, related his firsthand experience: Four years earlier, while flying, a thunderstorm developed about three miles away. He was flying a Q-B 40S with an Aero Sport radio on 72.320 MHz and, during a high-speed flyby about 20 ft off the ground, a bolt hit about two miles away. His plane rolled over and hit the ground at about a 45° angle. A friend flying a Q-B 20S with a Cirrus radio on 72.160 MHz, at about 200 ft, experienced a spin of about four rotations when the lightning hit, but was able to recover and land.
During the local "monsoon" season (a flow of moist air off the Gulf of Mexico), Gary had numerous glitches and decided he would no longer fly when lightning was within about eight miles. He also spent three days at Reno during Aero Scale '82 and saw thunderstorms develop each afternoon—he is convinced at least three crashes in the area were due to lightning.
These accounts support the technical explanation: avoid flying when thunderstorms are in the area.
Winter Notes
As this was written, cold weather has arrived in my part of Florida. I don't like shivering at the flying field, so I'm starting winter hibernation. I've cleaned all my engines and given each a shot of rust preventative to keep them in good shape until spring. If you forgot to winterize last fall and it's February as you read this, it wouldn't hurt to do it now—better late than buying new bearings in spring.
Ron Van Putte 111 Sleepy Oaks Rd. Ft. Walton Beach, FL 32548
Transcribed from original scans by AI. Minor OCR errors may remain.
