Author: G. Myers
Edition: Model Aviation - 1979/06
Page Numbers: 22, 23, 106, 108
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Radio Technique — George Myers

What's New?

The big event in the dreary passage from Christmas to spring in the Northeast is the Eastern States R/C Jamboree, better known as the WRAM show. Highlights and interesting products seen at the show:

Small receivers / Frequency section

  • Novak Electronics receiver (shown at the show): weighs about 1 ounce; features an IC front end, IC intermediate-frequency section, and an IC decoder.
  • Crystal: fifth-overtone type (very thin) and shock-mounted between pieces of foam rubber — shock mounting recommended by Formula I fliers from flying experience.
  • Mixer: double-balanced mixer that cancels mixing products except the desired intermediate frequency.
  • Novak flight packs use this receiver and Bantam Midget servos.

Novak / Bantam Midget servos

  • Features: 6 µs deadband, temperature-controlled over 0°–150°F.
  • Performance: 21 in./oz. torque, 90° movement in 0.27 seconds.

Kraft Systems / Antennas and FM module

  • FM transmitter module and receiver intended for the 6-meter ham crowd; anticipated for the 72 MHz PRS band when FCC-approved.
  • New antennas:
  • 18‑in. antenna with built-in loading coil (P.N. 200-184) — plugs into current Kraft antennas and reduces excess antenna length on small airframes; loading coil also doubles ground-test range.
  • 12‑in. whip antenna (P.N. 200-185) for boats and cars; reportedly flown on airplanes with good results.

Cannon Electronics — Super-Micro servo

  • New repairable servo-amp and micro motor originally made for Super‑8 camera zoom lenses.
  • Very small (coin in picture was a dime for scale). Plastic mechanical parts expected for the Toledo show in April.
  • Potential for very small models or even an indoor scale B-17 with multiple CO2 motors.

M.E.N. Automatic R/C System Charger

  • Allows leaving the R/C system connected indefinitely: recharges batteries then drops to a trickle charge as needed.
  • Better than not charging at all; recommended during the flying season for improved system service.
  • Caveat: most battery manuals discourage continuous trickle charging of nickel-cadmium cells. Verified development of battery “memory” is associated with trickle charging combined with a consistent discharge cycle. Unclear whether continuous winter trickle charging is better than a full recharge once a month.

Servos — the big news

Many manufacturers showed larger servos for scale and 1/4-scale enthusiasts. Highlights:

  • Royal Electronics:
  • "Chevron" servo and a smaller, cheaper kit servo (around $26.50) using Jomac racing-car mechanicals and Chevron servo amplifier.
  • Kraft Systems:
  • KPS-16 servo (current) and upcoming KPS-19.
  • KPS-19: somewhat larger, metal gears, choice of two operating speeds, up to 160 in./oz. torque.
  • Ace R/C, Inc.:
  • Developing a large servo using new D&R mechanicals.
  • Dunham / D&R:
  • Supplying mechanical parts to manufacturers for large servo production.
  • Logictrol International Corp. (Bill Haga, Bob Elliot):
  • New servo due in April: same size as MM servo, T1544 IC, 24-ohm motor, glass-filled nylon gears manufactured with molybdenum-disulfide to toughen gear teeth and control molding dimensional variations. Designed to resist gear rounding better than current offerings.
  • World Engines S-12 (custom for pattern fliers):
  • Design intent: extreme durability.
  • Uses a drum-shaped potentiometer:
  1. Longer resistance track for given diameter — better wear resistance and improved resolution for accurate centering.
  2. Wipers arranged parallel to the potentiometer shaft — better isolation from vibration transmitted by the pushrod, reducing wear.
  • Geartrain: three-gear set with an internal first gear for a tighter system than typical four-gear setups.
  • Price: $75.

Don Clark — Thermic Sniffer (Soaring Products)

  • System for R/C sailplanes to detect thermals:
  • Tiny variometer + 49 MHz transmitter mounted in the sailplane.
  • Walkie-talkie receiver carried in the pilot’s pocket.
  • Emits rising tone for rising air; falling tone for sinking air.
  • Important: intended for license-free operation when type-approved by the FCC.
  • Note: transmitter frequencies are shared with other users (model racing cars, single-channel Cox airplanes), so interference possibilities exist; sailplanes likely unaffected if conflicts arise.

Final note

Apologies to exhibitors whose products were not mentioned — omission indicates lack of space, not criticism. Keep the letters coming!

WRAMS SHOW NOTES

Engines

  • Fox Twin:
  • Essentially two .60‑cc engines connected back-to-back.
  • Produces over 3 hp at 14,500 rpm.
  • Heavy structural parts allow use of large props.
  • Adjustment tip from Duke: tune twin carburetors back-to-front and low-to-high.
  • Simultaneous opposed firing yields very low vibration.

Transmitters & Controls

  • Royal Electronics — Royal Classic transmitter:
  • Twin throttle trims.
  • Channels 4 & 8 can be tied together electrically for twin-engine operation.
  • Throttle levers only operate in the low-throttle position for optimum idle adjustment.
  • Switch selects full- and half-linear control or exponential control.
  • Four flight controls can be reversed by reversing plugs inside the transmitter.
  • Pro-Line:
  • New servo underway (PLS-15-3) compatible with positive or negative pulse systems.
  • Waterproof, ball-bearing output, uses Geisendanner potentiometer.

Servos & Electronics

  • Logictrol International Corp.:
  • FM set under development using new Signetics encoder/decoder ICs.
  • XM servo for large models: 2.4-ohm motor, glass-filled nylon gears, output ~6 pounds of thrust.
  • Cannon Electronics:
  • Model 825 system enters the "Under $200 club."
  • All‑NiCd system with Bantam servos and Tint transmitter.
  • Charlie R/C:
  • Featuring the Bantam Midget servo with a new IC servo amplifier.

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