The 1/2A Multi-Engine Profile Scale Contest was the brain child of Mike Keville (former PAMPA President and founder of VSC). Mike established the rules for two events - Limited for not throttles and Unlimited for throttled engines. I do not have the rules in front of me right now, but extra points for more than two engines, extra points for more than one wing in both events. Options could be used similar to the AMA Scale rules for the Unlimited class. The event was initially held in Tucson for the first 4 or 5 years but had to be moved to Phoenix because the one Tucson circle for the shorter lines deteriorated so badly that the small airplanes could not be flown in Tucson. The two other paved circles were donuts that were too small for most of the 1/2A scale models. The flying site in Phoenix for several years was a parking lot for a large shopping center, but the shopping center management wanted to start charging an exorbitant amount to use the facility. The event then just died. The last event was probably seven years ago.
Members from the Tucson and Phoenix clubs helped organize these contests. The contests were well managed and run. The rules were adjusted as experience was gained. At first, the rules gave extra points for each engine more than two. This was changed early on to give bonus points if just more than two engines were used. The profile definition was similar (I think) to the AMA rules definition for CL Profile Scale, basically maximum width for the fuselage of 1" and maximum for engine nacelles of 1.5". Another sub category was added for the last two years to the Limited Class for the "Slab Award". A perpetual trophy was set up for this. The rules were that the entire construction could be no more than 1/4" sheet except for the engine nacelles. A couple of "interesting" airplanes appeared for this category. Airplanes could be proxy flown. There are/were several "seasoned" pilots in the Tucson area that helped with the several airplanes that were shipped for the competition or when the builder was physically unable to fly his own airplane.
There were often several contestants from out of state that would attend. Attendance was not huge and I think Mike was disappointed (as were several of us) that the event did not get more support. The magazines at the time gave some coverage, particularly Flying Models, some passing photos in Model Aviation, I think Stunt News had a few articles, and the Brodak Control Line Flying magazine gave some coverage. A surprising number and variety of airplanes appeared that had not been previously seen as models.
The St Louis Club has held 1/2 A multi-engine scale contest several times. I am not familiar how often they have done so or what kind of participation they have had.
The Norvel engines with their functional throttle controls made the unlimited category a reality. Several 4-engine airplanes appeared, several more 3-engine airplanes also appeared. I know a B-36 was contemplated by one serious Tucson builder. A Heinkel 111Z was also in the planning phase in Florida. This has 5-engines which Ron Duly in California has had for a number of years.
I know that Mike Keville was disappointed (as were several of us) that more interest was not generated. I think that with more time and if a good venue could have been consistently obtained and with support/coverage by the magazines, I think participation could have grown. The proxy flying and the relative ease in shipping these smaller airplanes I think would make it attractive for more to try these models. Unfortunately, when the event moved to Phoenix, it became more difficult to organize the event and participation did not warrant the work necessary to continue.
Electric power was not initially contemplated, but in the later years, there was some consideration to adopt rules to allow electrics, but this never went beyond the discussion stage.
Others might have more insight to this Tucson/Phoenix 1/2A multi-engine profile scale matter.
Keith