CL Scale
Bill Boss <REDACTED>
Bill introduces Victor Gearhart and showcases his electric Scale work
I WELCOME VICTOR Gearhart of Torrance, California, as a new contributor to the column. He is a longtime CLer who started building and flying CL models during his high school days in the early 1950s.
Victor traced RC models and gliders, and sometime in the 1960s he dropped out of the hobby and took on other endeavors. Finally, in the early 1990s, he retired and considered getting back into the sport of model airplanes.
Approximately five years ago Victor learned from an old high school friend about Fred Cronenwett and how electronic controls are being used for CL Scale. He obtained a copy of Fred’s electronic-control information, and that got him excited about getting back into CL modeling.
One thing led to another, and Victor bought a Bill Young electronic handle. After not building for roughly 30 years, he jumped in with both feet.
An interesting thing about Victor’s return to CL modeling is his latest endeavor: an all-electric B-25. It is his first attempt at an electric-powered model, and he must be complimented on the approach and thoroughness with which he undertook the project.
The aircraft was adapted from an old Berkeley B-25 kit that was first produced in the late 1950s. The original kit was of a B-25B, which he converted to the “Gun Nose” J model. Victor’s version is painted in the colors of the 345th Bomb Group “Air Apaches,” 489th Bomb Squadron “Falcons.”
The basic olive drab color was applied using latex house paint, the wing stars and tail insignia are homemade decals, and the lettering and nose art were done with acrylic paints. An advantage of being able to use house and other types of paints on electric-powered models is that there is no worry about engine-fuel residue to clean up after a day’s flying session.
The B-25 spans 42 inches and weighs 3 pounds, 7 ounces. Operational features are flaps and throttle. Power is supplied by two PJS 800E rotating-case (outrunner) motors with Jeti controllers. Batteries are two 1320 mAh, three-cell Thunder Power Li-Polys, with one located in each of the model’s engine nacelles. Propellers are two Master Airscrew 8 x 5 electrics.
Victor noted that the computer program ElectricCalc figured the propeller rpm as 8.9K and the motor thrust as 34 ounces per motor, providing a thrust-to-weight ratio of approximately 1.1. That should be more than sufficient to make the model fly well.
ElectricCalc also predicted that the model’s top speed should be around 50 mph. In actuality the flying speed is in the 35–40 mph range because of line drag of the insulated fishing line used. As Victor put it, test flights showed that the model needed some "tweaking." A slight bit of nose and outer wingtip weight was added for improved flight performance.
As of this writing the model has been through a couple flight-testing sessions. The first set of tests was limited to three or four minutes, with only a couple laps each time at full throttle. Victor was trying to determine whether or not the airflow through the nacelles was sufficient to cool the controller devices and batteries. He notes that Li-Poly batteries can have problems if heated too much, so he is gradually working up to sustained high-speed flight.
A second set of three flights was made, for a total of eight minutes and 59 laps. During this session of tests the throttle was held at full for approximately 98% of the flight time. The batteries were still in decent shape and not overly hot.
As Victor pointed out, the ElectricCalc program indicated that flights of 12 minutes at cruising speed should be possible. From the reported results of his test flights it seems that something near the 12-minute flights should be possible. He also noted that the B-25's flight has an actual maximum of approximately 35 mph.
Victor learned that flying with electric controllers is quite different from flying with gas power. The motor seems so much more responsive to throttle inputs, and it is easy to drop rpm too fast, resulting in a faster descent than desired.
Victor's next project, already in the works, is an electric-powered 1.5-inch-to-1-foot-scale (68-inch-wingspan) World War II Westland Whirlwind that will have retractable gear, bomb drop, flaps, and throttle. He is shooting for a weight of 8 pounds and will be selecting the power plants as the project progresses.
I wish Victor much success with his electric projects, and I thank him for sharing his electric experience with us. I hope his electric involvement and project report will somehow encourage other CL Scale modelers to try electric power and share their experiences with this column's readers. Judging from the B-25, it looks as though with careful planning and testing, the use of electric power for CL Scale models is a viable alternative to glow-engine power.
Transcribed from original scans by AI. Minor OCR errors may remain.
