Control Line Navy Carrier - 2007/10
Dick Perry [[email protected]]
A look at electric power for Carrier models
In the last column I promised to report on the first contests in which electric-powered models competed in the Navy Carrier events. However, the first event didn't take place as early as I had hoped.
Two contests in Iowa were scheduled in May and June, but the May event suffered from weather that kept the Carrier models grounded. Things worked out better for the Sig contest in June. Sig originated the Skyray Profile Carrier event and allowed electric power in it as an experiment this year. Several electric Skyray models competed against entries with conventional power. I included photos of some of the aircraft and their power systems.
Not all models were flown successfully, with problems in the conventional control systems (not the electric-power portion) and the expected issues that come with new airplanes and new ideas. In the end, Pete Mazur finished on top with his electric-powered Skyray.
Skyray and .15 Profile events were chosen as the first test cases for electric-powered Carrier because the speed limits imposed in those events make power much less critical for overall performance. With the speed limit, it was believed that electric- and glow-powered models could compete more or less equally.
The real advantage to electric power is simplicity. Electric power is easier for someone who is new to the technology to set up successfully, whereas glow engines can be challenging to get the fuel tank and throttle optimized—especially for someone who is new to throttled engines.
Typical electric-power configuration and components:
- Motors: mostly outrunner brushless motors (high torque, relatively low RPM).
- Batteries: lithium rechargeable packs; Li-Poly is most common for weight advantage, though Li-Ion is also used.
- Propellers: most installations use pusher props to improve low-speed handling; outrunners favor larger-diameter, lower-pitch props.
- Speed control: a single-channel electronic servo controller (Clancy Arnold design) driving the ESC is the accepted method; the controller is simple, light, and can be powered by the ESC’s battery-eliminator circuit (BEC).
- Control input: the controller uses a 10,000-ohm potentiometer for throttle input. Clancy originally intended the potentiometer to be on the handle with power running through the lines, but most Carrier modelers find a conventional three-line control system simpler—mechanical throttle output goes directly to a control horn on the potentiometer shaft. With that configuration, existing glow-powered models can be converted to electric without building a new airframe.
Propeller size and pitch don't seem to be overly critical for most electric models being flown so far. Because outrunner motors turn relatively slowly compared to brushed motors and inrunner designs, the common choice is a larger-diameter, lower-pitch propeller. Starting is greatly simplified; typically the only required action is to insert the arming plug.
The finish on electric-powered Carrier models can be whatever you want to use—including spray paint from a hardware store or even leftover latex from a house paint job. The only thing you'll likely have to clean off the model is oil left on the deck by other competitors' glow engines.
Transcribed from original scans by AI. Minor OCR errors may remain.
