Control Line Scale - Allen Goff’s C-182 - 2015/06

Author: Fred Cronenwett

Edition: Model Aviation - 2015/06
Page Numbers: 121,122,123

Allen Goff’s C-182

Control Line (CL) Scale pilots have long been converting RC kits to CL Scale. This is where Allen Goff of Muncie, Indiana, found his next project. The Top Flite Gold Edition kit for the Cessna C-182 Skylane has an 81-inch wingspan and the box says it will weigh between 10 and 12 pounds when completed. Although this model is larger than an average CL Scale model, it is not the biggest or heaviest one that has ever been flown.

Allen built the aircraft from the kit with modifications that included landing, marking, and strobe lights. The rudder and Robart nose gear are controlled with a servo, which is helpful for taxi operations. The model also has flaps and is powered with an O.S. .65AX two-stroke engine.

Taking advantage of the new rules, a Spektrum DX5e 2.4 GHz radio system was used to control the throttle, flaps, lights, rudder, and steerable nose gear. The Skylane has plenty of surface detail and is painted with Brodak dope. The clear coat is DuPont Nason 497-00 SelectClear 2K urethane.

Allen’s model weighs 9.5 pounds, which is lighter than the advertised weight. This is a great example of a large RC design that was converted to CL Scale.

Electric Power

Choosing an electric motor requires more research than selecting a glow engine. I will not cover everything here, but I will share one practical method for selecting an electric motor for CL Scale. Because we fly with throttle control, we can always throttle back if we have installed a too-powerful electric motor.

Motor names do not always indicate power or the size of model they can fly. For example, E-flite gives names like Power 60 (comparable to a .60-size glow engine). Other motors are listed with designations such as C4130/16 390 Kv, which makes it harder to figure out suitability. You may need to consult propeller data charts or call technical support to match motor, prop, and battery to your model.

An engine or motor will produce a certain amount of power: glow engines list horsepower, electric motors list watts. Watts vary with propeller and battery. A useful rule of thumb is to allow about 100 watts per pound of model weight; 125 watts per pound gives increased performance. For example, a 9-pound model would need at least 900 watts (100 W/lb) and would get better performance at 1,125 watts (125 W/lb).

A good way to get started is to take an ARF or existing model where you know the weight and use published motor data (for example, from E-flite) to choose a motor. Using the Top Flite 60-size P-51D Mustang as an example: Top Flite lists the 60-size P-51D with a 64-inch wingspan and a glow-engine weight of about 8.75 pounds. A .65 glow engine will easily power this model with a 13-inch propeller, and some pilots use a .95 four-stroke with a 15-inch prop. The narrow cowl makes this model a good candidate for electric conversion.

For a 9-pound model you would look for an electric motor with at least 900 watts. The E-flite Power 60 400 Kv motor is rated at about 1,200 watts and is recommended for 6- to 10-pound models. It can use a 5S, 6S, or 7S LiPo battery and spin a 14 x 8 to 16 x 10 propeller. Approximately six years ago I installed a Power 60 400 Kv on an 80-inch sport model that weighed 12 pounds with a 6S pack and a 16 x 8 propeller, and it worked well.

If you want to experiment with electric power, take a single-engine model, get a motor, battery, charger, and speed control, and try it. Use manufacturer data to choose components compatible with your model. With 2.4 GHz controls, the speed control plugs into the receiver to control the motor RPM. You can install a different motor later if you find a better match.

Follow safety instructions when storing, charging, and handling LiPo batteries. Ask other pilots for help; I received great advice from others when I moved to electric power.

The P‑51 makes a great Scale project because of the many options you can use on the model, including throttle control, flaps, retracts, air scoops, lights, and a sliding canopy.

2015 Nats

It's time to tune your engines and get ready for the CL Scale Nats in Muncie, Indiana, if you plan to attend. Read the updated rules, because there are changes that affect documentation, line diameters, and flight options. See my April 2015 Model Aviation column for details about what has changed.

Go to the National Association of Scale Aeromodellers (NASA) website to download the updated score sheets and fill them out before you arrive. The score sheets allow you to type in your information and print the form. Bring at least eight flight score sheets and three static score sheets per model.

The 1/2A Scale event is now an AMA-sanctioned event, so registration is on the AMA form you mail in with your Sport, Profile, Team, or Authentic Scale entries. This is the first year for Authentic Scale at the Nats. Send in your entry by June 19 so AMA has enough time to order the awards.

Scale Contest Updates

The Northwest CL Regionals will be held May 22–24 at the Roseburg Municipal Airport in Roseburg, Oregon, and will again feature CL Scale after taking a year off. CL Scale is again being flown in the northwest part of the country, which is great news.

I have flown at this contest before and it is an awesome event worth attending. It will also feature Sport, Profile, and the new Authentic Scale event (528) that has been added to the rules, as well as other CL flying including Precision Aerobatics, Combat, Navy Carrier, Racing, and Speed.

The Dayton Buzzin' Buzzards CL club will host its West Ohio C/L Stunt and Scale Contest on August 8–9 in Dayton, Ohio. This is the second year for this event.

It's nice to see clubs adding CL Scale to contests. The Brodak Fly-In will host CL Scale on June 15–20. Check the Brodak website for a schedule of events.