Author: Ted Kraver
Edition: Model Aviation - 2013/02
Page Numbers: 133,134
,

Changes to CL rules

by Ted Kraver [email protected]

Significant changes made to AMA CL general rules during the 2011–2012 rules cycle have moved pilot control of flight options into the 21st century. Using 2.4 GHz (utilizing spread spectrum, per Code of Federal Regulations, Title 47, Part 15), radio control is now allowed to accomplish functions other than providing aerodynamic control of the model’s elevation on CL models.

All control functions must be under the direct control of the pilot and only the pilot. The chairman of our Scale Contest Board, Mike Gretz, reports that at the time of the writing of this column, the expected new rule for CL and RC fixed‑wing Scale will be:

1.1 Use of Radio Signals: The use of 2.4 GHz radio control signals shall be allowed for controlling auxiliary operations, including but not limited to throttle, flaps, retracts, landing gear doors, droppable stores (bombs, torpedoes, fuel tanks, parachutes, etc.). Radio control cannot be used to provide aerodynamic control of the model’s elevation. Elevation must always be controlled by way of one or more control lines which manipulate the model’s control surfaces during flight by traditional means, as mandated in the CL General Rules.

Many CL fliers have been experimenting with 2.4 GHz systems. Eric Conley of Reno, Nevada, has built a Bill Bischoff‑designed custom handle that incorporates a Spektrum transmitter on top and a battery on the bottom. Eric formed a 1/8‑inch aluminum structural square to carry the pull test and added a carved wooden hand grip. The two‑line connectors are fixed and elevation neutral is adjusted via line clip size.

Will a 2.4 GHz CL handle emerge from a commercial enterprise? The world wonders ...

Multiengine Profile Contest

The concept for a boutique 1/2A, 1cc multiengine Profile Scale contest was invented in 1976 by Ron Duly and Dave Braun of the Valley Circle Burners in Southern California. This dying event was picked up by Mike Keville and has been a rousing success. The mid‑October contest wraps up the Cholla Chopper’s flying season in Tucson, Arizona. Mike keeps us on our toes by changing the rules each year, with changes such as adding points for more than two engines and for multiwinged aircraft. His Limited event is similar to the 2012 Nats event, but the Unlimited event has three elective maneuvers and throttled engines are desirable.

This year saw a number of new aircraft such as Keith Trostle’s German Mistel version of a Junkers Ju 88A‑4 with a Messerschmitt Bf 109 on top—three engines turning, plus two wings lifting. Lou Wolgast went a more traditional route with a de Havilland DH.66 Hercules 1920s trimotor with two wings, two elevators, and three rudders. Leroy Black built a Heinkel He 177 that towed a wing‑shaped drop tank. Leroy tried, but failed, to convince the judges that his arrangement constituted a biplane. Jim Fruit donated his Laird Super Solution model to the EAA AirVenture Museum.

I compiled the data on the models and the average wing loading was 19 ounces per square foot. Jim Hoffman’s wing loading of 11 for his Lockheed Electra 10A delivered aerobatic flying capabilities. Al Culver’s Fokker D.XXIII push‑pull arrangement was a challenge to fly at a wing loading of 30. Aircraft weight per engine averaged 13 ounces and ranged from 6 to 26 ounces. Wing area per engine averaged 100 square inches with a range of 50 to 200. Norvel .061s were the most popular engines.

The rule of thumb for using modern 1cc engines is 100 square inches of wing area and 13 ounces of aircraft weight per engine. Successful aircraft deviating widely from these numbers indicates flexibility for CL Scale designers.

Airplane Museums

Airplane museums are a two‑way street for CL Scale modelers. We both acquire inspiration and documentation for the next aircraft and also receive intrinsic rewards by donating museum‑quality models.

One Saturday afternoon, I took my annual trip to the Pima Air & Space Museum in Tucson, Arizona, of which I am a life member. The museum’s more than 350 aircraft are mostly military. Many were culled as escapees from the aluminum smelters that devoured the thousands of post‑war surplus aircraft parked in the Arizona desert.

I took landing gear photos for the third sprucing up of my 1/2A Profile Grumman F7F‑3N Tigercat.

Jim Fruit of Zion, Illinois, went the other way when he donated his Laird Super Solution to the EAA AirVenture Museum in Oshkosh, Wisconsin. This significant model donation complemented the full‑scale airplane on display in the EAA museum. Jim had used the real airplane for photographic model documentation. He belongs both to EAA and AMA, which influenced EAA’s decision to accept the model.

The scratch‑built model is at a scale of 2 inches to the foot. It was originally designed to be powered by an O.S. .90FS, but was converted to electric power before completion. Its flight performance was relatively poor, contributing to the decision to make it a queen in the EAA hangar.

I am just getting started writing this column and I could use an uptick in the flow of information about CL Scale, including pictures, from readers. Many thanks in advance.

Sources

Ted Kraver — (602) 944‑8557 — [email protected]

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