Author: Bill Boss
Edition: Model Aviation - 2011/04
Page Numbers: 130,131
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Control Line Scale — 2011/04

New rule for Profile Scale competition

Bill Boss [[email protected]]

A NEW RULE for AMA CL Profile Scale (event 521) adds paragraph 2, describing design and static-judging guidelines. It is as follows.

"To maintain the scale wing and tail span, the leading and trailing edges of the wing should be extended to the center line of the body without changing the overall wing span of the model. Since the flaps and ailerons are part of the wing they should remain scale size and shape. If the airplane had a wing fillet, the fillet should remain scale size and shape and located at the profile body. In a like manner, if the plane modeled (like a P-51 for example) has a leading edge extension or other similar feature, the feature will be of scale size and be located at the profile body. The Horizontal Stabilizer and Elevator should be done in a similar manner as the wing. Reducing the model’s overall wing and tail span the same amount the fuselage was reduced to create the profile, is cause for loss of static points."

This subjects the contestant’s model to close examination and possible penalties during the static-judging process. If you are building a profile aircraft for competition purposes, follow the preceding guidelines as closely as possible. Keep the dimensions to the scale to which you are constructing the airplane and in adherence to the three-views you will present for judging.

However, even during Profile Scale events at particular contests, judges may still have the choice of following this new rule or scoring as they see fit. Profile Scale events were established to get non-scale modelers interested in scale events and competition. If you build profile models and are uninterested in competition, construct your aircraft as you please and then go out and have a good day of flying. Perhaps in time you will get into the more technical aspects of building and follow the new guidelines.

Although there is this new guideline, you still cannot make a "true" scale model from a profile; you can only try your best to make it "look right" and hope the judges agree. If you’re looking for a truer scale airplane, you’ll have to step up to full-bodied models.

I thank Mike Gretz and Kent Walters, who are members of the AMA Scale Contest Board, and Ted Kraver, editor of Replica—the National Association of Scale Aeromodelers (NASA) newsletter—for their words of wisdom and input on this subject. I greatly appreciate it.

Since I posed the question in the October 2010 column about using 2.4 GHz RC systems in CL, I have received several responses, most of which have been positive. A few modelers replied that they have used 2.4 GHz systems in their CL aircraft with great success, without creating interference issues with nearby RC flying.

Keith Bauer of Williamsport, Pennsylvania, president of the Wings of Williamsport RC Club, submitted one of the accompanying photos. It shows how he converted a 2.4 GHz car control system to use with his Bearcat for CL Navy Carrier.

The top and bottom rods go through the 2.4 GHz handle and are potted with epoxy at the handle area. There is also a means for adjusting the leadout connections.

Keith used the throttle trigger control for engine throttle, and he modified the steering channel with a switch to release the landing hook and line-release mechanism for slow-flight requirements. The system provides smooth throttle control. If Keith pushes the throttle trigger to the brake position (forward), the engine carburetor will close, thereby shutting down the engine.

He noted that the system comes in a four-channel version that he plans to use for throttle, flaps, and retracts in a scale P-38. He had intended to fly his Bearcat at last year's Brodak Fly-In in the non-AMA Sportsman Carrier Class but was denied entry because he was using the 2.4 GHz system.

After having passed all of the preliminaries, such as pull-tests, it seems odd that Keith was not allowed to compete in a non-AMA event. I suppose that any other electronic system would have been acceptable.

Grant Heistand of Chicago, Illinois, modified an electric-powered ParkZone Bind-N-Fly Wildcat with a bellcrank, and he has been having a great time flying it with the 2.4 GHz system. He is converting all of his CL airplanes to electric power and hopes that the 2.4 GHz system is approved for CL use.

According to Grant, the biggest improvement in flying with the 2.4 GHz system is that he no longer has to use the insulated lines that were required with modified radio or digital systems. This gives him better control of the aircraft because of less drag on the flying lines, and better flight performance.

An item in Replica mentioned that Don Burke of California has submitted a proposal to the Control Line Contest Board that would allow the use of 2.4 GHz systems. It would change "Control Line, General" section 2 in the AMA rule book. The last line of that section reads, "The use of radio control to accomplish any control functions on Control Line models is specifically prohibited." Don suggests adding a sentence that reads: "The use of 2.4 GHz radio systems to accomplish functions other than providing aerodynamic control of the model's elevator on control line models is allowed."

If passed, this would allow a 2.4 GHz system to be used in any CL model. It is time for all CL modelers to get behind this proposal; contact the Contest Board member in your district and let him know how you feel about it.

We have come a long way in CL, with simple two- and three-line setups and various versions of electronic systems. It is time for all dedicated CL fliers to be able to use this new technology to their advantage, as long as it doesn't interfere with other radio operations or compromise safety in any way.

The Cholla Choppers Model Airplane Club's fourth annual 1/2A Multi-Engine Profile Control Line Contest was held October 16–17, 2010. According to a report by Ted Kraver, editor of the Round-the-Circle newsletter of the Central Arizona Control Line Club, the weather was great and the contestant turnout was equally great.

The event featured two days of excellent flying and competition. Ten fliers entered the Limited Class, in which controls such as throttle are not used, and there were three entries in the Unlimited Class, in which flight controls are allowed.

Limited Class results:

  • 1st: Lou Wolgast, de Havilland D.H.88 Comet — 104.5 points
  • 2nd: Keith Trostle, Westland Whirlwind — 103.0 points
  • 3rd: Leroy Black, de Havilland D.H.103 Sea Hornet — 100.5 points

Keith's exceptional model was finished in the Royal Air Force (RAF) color scheme. The Westland Aircraft Company developed the single-seat, twin-engine, cannon-armed Whirlwind design in the 1930s. During World War II, only two RAF squadrons were equipped with the Whirlwind. Although successful as a fighter-bomber, it was withdrawn from service in 1943 and gave way to more successful single-engine fighters.

Unlimited Class results:

  • 1st: Charlie Reeves, Chance Vought F7U-5U — 130.0 points
  • 2nd: Keith Trostle, Boeing XB-47 (bomber) — 112.0 points
  • 3rd: Leroy Black, Focke-Wulf Fw 190 — 106.5 points

All scoring was based on accuracy of model outline, color scheme, and flight. According to reports, Keith Trostle will be retiring his successful XB-47. All contestants had some outstanding flights and, above all, great camaraderie. They are looking forward to this year's event.

Sources:

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