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 it’s completed. Although this model is larger than an average CL Scale model, it is not the biggest or the 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 91/2 pounds, which is lighter than the advertised weight. This is a great example of a large RC design that was converted to CL Scale.
Trying to decide what electric motor to install in your new model requires more research than choosing a glow engine does. I will not pretend to cover everything here, but I will share one 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.
Depending upon the manufacturer, sometimes the name of the electric motor does not give you any clue about how much power it has or what size model it can fly. However, E-flite has given names to its motors such as the Power 60, which is comparable to the .60-size glow engine.
Other motors are listed as C4130/16 390 Kv, which makes it difficult to figure out what size aircraft it can fly. You might have to dig through the propeller data chart on a company’s website or call for technical help to find the best motor based upon your model.
An engine or motor will produce a certain amount of power. A glow engine will tell you how much horsepower it has and an electric motor will tell you how many watts of power it has. How many watts the electric motor has will vary depending upon the propeller and battery used.
One rule of thumb that can help you size an electric motor is to allow for 100 watts per pound. If the model weighs 9 pounds then you would need at least 900 watts. If you allow for 125 watts per pound then there will be increased performance.
The best way to get started with electric power is to take an ARF or an existing model, where you know how much the model weighs, and use the data published by E-flite to figure out what motor would be a good choice. Using the Top Flite 60-size P-51D Mustang as an example, let’s look at what is available from E-flite.
The data published by Top Flite shows the 60-size P-51D has a 64-inch wingspan and will weigh 83/4 pounds with a glow engine. Experience tells us that a .65 glow engine will easily power this model with a 13-inch propeller. Some pilots will install the .95 four-stroke that can spin a 15-inch propeller. This model has a narrow cowl so it is a great candidate for conversion to electric power.
We are looking for an electric motor with at least 900 watts to power the 9-pound model. The E-flite Power 60 400 Kv motor says that it has 1,200 watts of power and will fly a 6- to 10-pound model. The motor can use a 5S, 6S, or 7S LiPo battery and spin a 14 x 8 to 16 x 10 propeller.
At this point you have read the motor’s data and figured out how many watts the motor has and how much the model will weigh. You are probably asking yourself, “Can I use this data and be successful?”
Approximately 6 years ago I took my 80-inch wingspan sport model that weighs 12 pounds and installed the Power 60 400 Kv motor with a 6S battery and 16 x 8 propeller, and it worked great. Flying at half power, the model matched the performance data on the website.
If you have considered experimenting with electric power, take a single-engine model, get a motor, battery, charger, and speed control, and give it a try. You can use the E-flite data to choose something that is compatible with the model you want to fly. If you use 2.4 GHz controls, the speed control will plug into the receiver to control the motor’s rpm. Remember that you can install a different electric motor later if you find one that is a better match for your model.
Follow the safety instructions when storing, charging, and handling LiPo batteries. Never charge the LiPo batteries using your car’s battery.
Ask for help if you need additional data or ideas on any of the components of the electric-powered model. I got some great advice from other pilots when I got into electric power.
The P-51 makes a great Scale project because of the options that you can use on the model, including throttle control, flaps, retracts, air scoops, lights, and a sliding canopy.
It’s time to tune the 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. Look at my April 2015 Model Aviation column for details about what has changed.
Go to the National Association of Scale Aeromodelers (NASA) website to download the updated score sheets and fill them out before you arrive. The score sheets allow you type in the 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 that the AMA has enough time to order the awards.
Scale Contest Updates
The Northwest CL Regionals will be held on 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 now 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 that is 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 the schedule of events.
2015 CL Scale Contests
• Northwest Regionals: Roseburg, Oregon, May 22-24
• Wisconsin Stunt and Scale Championship: Walworth, Wisconsin, June 7
• Brodak Fly-In: Carmichaels, Pennsylvania, June 15-20
• AMA CL Scale Nats: Muncie, Indiana, July 17-19
• West Ohio C/L Scale Contest: Dayton, Ohio, August 8-9
• Midwest Regional CL Championships: Sugar Grove, Illinois, September 6
• Broken Arrow 28 Stunt Scale Contest: St. Louis, Missouri, September 19-20
• NASA Scale Classic: Lexington, Kentucky, September 25-27
• 9th Tucson 1cc Multi Engine Scale: Tucson, Arizona, October 10-11
I welcome contest reports, upcoming contest flyers, pictures, and any projects you are building and flying.