Special Exhibit:
First Controlaire Proportional
An American Tragedy with a Happy Ending
(Click on any of the images on this page to see a larger version)
This was the first Controlaire proportional. It was jointly designed by Controlaire’s legendary chief Jack Port and electronics wizard Don Baisden in mid-1964. Baisden, who lived in Columbus, Ohio then, sent Port a PC board layout for the encoder.
Here are 2 publicity photos (1 photographically reversed, the other mislabeled) of Jack Port working on the first proportional:
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Initially it looked nothing like this on the outside. We believe it was housed in a modified silver Controlaire reed case and had simple Pro-Trol sticks (which may still be in the above publicity photos). After initial testing it was clear Port and Baisden had achieved a major milestone, but their promising new proportional would need some work.
Port and Baisden extensively modified and refined this system and purchased five cases to produce finished-looking pre-production prototypes and take the system to the next level. Three of these cases were the customary silver but the other two were blue and brown to test possible color variations under consideration. The cases arrived before the pre-production prototypes were done.
Evidently, when Port saw the brown case he couldn’t resist or had to meet the deadline for the above publicity photos, and promptly put his initial prototype in it despite the fact that the sleek new case was too thin for his thick original prototype. To this day the back won’t fit on all the way.
This first ever prototype was obviously very different on the inside including the unique size and layout of its P.C. Board, identifiable in the publicity pictures. But it was also different externally and mechanically. It is hard to tell from the publicity shots whether the sticks were the same as now. The gimbal“L” brackets the sticks attached to were different than later prototype and production models. The left one was smaller with a different shape, different holes and adjustment screws and a different spring centering mechanism. The trim and auxiliary levers were solid aluminum with “teeth” on the tips. These were unlike later prototypes and production models, appear identical to those on early Orbit transmitter and can be positively identified in the publicity photos with a magnifying glass.
Baisden’s blue set was the second Controlaire Proportional completed, or if you prefer, the first Controlaire Proportional ever made in the refined, “final” form. It may also be the only blue Controlaire ever built. Here they are together, number one and number two/one.
The First Controlaire Proportionals.
From Toledo to Toledo
The story of this system began at the March 1964 Toledo tradeshow. It was at this show that Jack Port met Don Baisden. They were mutually impressed and quickly hatched a plan to chase the Third Dream of Radio Control and jointly develop a full-house proportional system for Controlaire. One year later at the March 1965 Toledo show, the system was unveiled.
Design Duo
Right after the 64’ Toledo show the two men went to work on the new proportional system. There was no time to waste. Proportional was recognized as the way of the future and other manufacturers seemed to be introducing new systems every month or two.
Baisden (pronounced Bays´-din) was a top engineer for North American Aviation (and other companies) who helped develop such famous full-scale aircraft as the C-5 Galaxy, the Lockheed Jetstar and the Gates Learjet. He was also an avid modeler and inventor of the “Baisden Pulser” – an early pulse proportional system kitted by Ace Radio Control. See “Baisden One”. His advanced-degree credentials neatly complimented Port’s self-taught genius. He served as consultant only, keeping his “day job” at North American. He was principally responsible for the encoder/decoder and Port for the RF section. Jim Lanterman designed the servo amplifier.
Port knew he liked Baisden and the way his engineering brilliance was wrapped in an easy-going, modest personality; what Port didn’t know was that he was training his successor who would soon struggle to fill his shoes when Port tragically passed from this world just months later.
Jack Port was “Mr. Controlaire”. He founded the company and continued to run it after its merger with World Engines. In the early 50’s Jack developed a reliable single channel system which he dubbed “Controlaire”. Some RC elites looked down on him as merely a lone midwestern tinkerer, not with a big company, who only flew home-made, single-channel equipment. Then something happened. The 1953 Nationals. Nobody ever looked down on Jack Port again.
Jack Port won the radio control competition at the 1953 Nationals and did it with his single channel Controlaire. This stunned the RC world at the time and it should have since the underdog Port beat all the other contestants even though most of them had multi-control systems. How could this happen? How could it be even scientifically possible for a rudder – only ship to beat more capable aircraft with multiple controls flown by ace pilots? Two words. Jack Port.
After this win, Jack went on to develop a full line of Controlaire radios—single and multi/reeds. They were known for power (e.g. the power of a mule) and reliability. The one thing Controlaire lacked was a multi-proportional system. They were a little late getting into the proportional RC race and determined to make their entry the best.
Best Sticks Ever Made
The quality of these sticks was so high, in fact, that they had to be discontinued almost immediately due to their exorbitant cost. Soon after production began, Controlaire switched to the much less expensive Bonner sticks widely used by other manufacturers. We are uncertain how many open-gimbal models were made but our best guess now is only 15 – the 5 prototypes (one of which was featured in early ads) plus the first 10 production units. Research continues. Let us know if you are ware of any open-gimbal Controlaires in existence and we will add this to our database to clarify this part of Controlaire history.
The desire to have the best quality regardless of cost continued beyond the stick components. For example, Baisden was enamored of silicone controlled switches (SCS), enabling reliable receiver function in a compact single-deck configuration. They were employed in initial production units despite their staggering cost – over 6,200 percent higher than the standard transistors used later.
Finally, the color had to be selected. One day Don Lowe, the famous flyer, was visiting with another competition pilot, and John Maloney decided to put it to a vote. Baisden voted for blue, and Port preferred the brown/gold color which was evidently intended to hark back to the color of Controlaire’s first radios (See Controlaire Section), but also liked the blue better than the silver. However, John Maloney, Don Lowe and his flying friend all voted for the silver color and the matter was settled by this 3-2 verdict.
With the pre-production prototypes ready, everyone waited for the winter weather to clear enough for the first test flights. Finally, on December 23, 1964 Jack Port, John Maloney and Don Baisden watched as Jack flew Maloney’s silver prototype in Jack’s best plane – a Taurus.
Dramatic Debut
Years later World Engines would produce a top of the line open-gimbal contest system called the World’s Expert Series. This was heavily influenced by three consulting pilots who truly were “world’s experts” – Jim Kirkland, Dave Brown and Don Lowe. Don Lowe’s custom made “world’s expert” transmitter is now in the Radio Control Hall of Fame® museum. See World Engines.
Interestingly, the pictured 3 channel was probably just a mock-up of a then-planned system which was never actually produced or even prototyped. Years later Controlaire again considered making a 3-channel version and went so far as to produce 2 prototypes, but these never went into production. (See “Controlaire Three Channel”)
As the initial production units went out the door everyone turned their thoughts to the expected acclaim, massive sales and commercial success that seemed sure to come.
Fate had other ideas.
Trouble Then Tragedy
Shortly after the first sales the complaints began. Airplanes were crashing due to episodic loss of control. Pilots were angry and Controlaire’s sterling reputation for quality and reliability was tarnished. All advertising and sales were halted for over a year until the problem could be solved and the solution verified.
Then things got worse, much worse.
Baisden Takes Over
The Controlaire team turned its full attention to solving their Proportional Problem. They faced a mystery. Why did most units work fine all the time while others suffered an occasional, but fatal flaw? They all appeared identical. Eventually, by excluding pilot error and other factors they narrowed the problem to about 15 of the first production systems. Even these 15 worked well most of the time but occasionally, at certain flight distances and angles, all control was lost. When this happened with insufficient altitude to recover, the result was catastrophic. Crashed systems worked fine when returned to the factory and there appeared to be no explanation for these frightening failures.
Solving The Puzzle
Finally one of the technicians accidentally discovered the problem while viewing a monitor. By holding the transmitter at certain angles and distances the technician saw on the oscilloscope that the receiver (on its own) would direct full hard-over controls without touching the transmitter’s sticks. This happened because, on some transmitters, the oscillator signal leaked through the buffer and filled in the “off” portions of the signal.
Controlaire always prided itself on the exceptional power of its transmitters. To achieve extraordinary power output for its proportional system, a three stage RF section was devised. The first was a crystal-controlled oscillator running constantly; the second, an amplifying/impedance matching “buffer’; and the third was a power output stage.
The signal inversion discovered by the technician sometimes occurred because the digital keying (modulation) was accomplished at the transmitter’s buffer stage. By switching this function to the oscillator stage the problem vanished.
They never had a chance to celebrate this solution to their Proportional Problem because their system continued to crash planes. In fact their problem grew worse as system failure became the rule rather than the exception. Flyers would suddenly lose all control mid-flight and helplessly watch their expensive planes fly away or crash, depending on the last position of the control surfaces at the time control ceased. As the chorus of angry modelers grew louder and returned systems piled up, the very future of Controlaire was threatened. John Maloney said: "It's a good thing Jack isn't here, 'cause this would've killed him."
Eventually, the culprit was found. It wasn’t the transmitter or receiver this time, the problem was in the servos. This problem never occurred in the test flight with prototypes since they used modified Bonner servos as an interim measure. The production systems were to use a newly developed servo with linear, double-ended output and an advanced motor and amplifier.
To prepare for the expected production volume of Controlaire’s promising new proportional system, John Maloney bought 2,000 Mitsumi Motors as a great price. These little motors were excellent performers in applications up until then such as advancing film in cameras. But the duty cycle and environment of model aircraft servos were very different.
The turning point came when Don Baisden was awakened at midnight by a call from his boss. Maloney was in a lunch meeting in Japan with a lot of worried Mitsumi executives and engineers. He asked Baisden to explain how the servo motors were failing. Slowly, Baisden laid out the whole, terrible truth.
During periods of sustained activity the servo motors would heat up. This caused insulation between segments of the spinning commutator to soften and ooze out onto the conductive surface. Each portion of the commutator covered by this ooze was a “dead spot”, effectively insulated from the motor’s brushes. So long as the motor was running, the contact points would skip over these dead spots and everything was fine. There was also no problem after a servo motor stopped, provided it stopped anywhere but on a dead spot (it would start up again and perform normally).
But whenever a servo motor happened to stop on a dead spot it would not restart. This locked the aircraft into whatever control surface position it happened to be in at the time the servo stopped. All subsequent commands were as ineffective as if the transmitter had been turned off, and the plane was doomed.
By the time Baisden completed his groggy, midnight explanation, the Japanese were convinced. Mitsumi agreed to replace all the motors without charge, despite the financial blow to their company.
System Returns To Market
The next month Model Airplane News published this review of the system (July, 66 MAN):
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Note that Bonner sticks have replaced their magnificent predecessors (although the sleek Craig Asher 5th channel control is still there) and that numerous changes are evident on the circuit board.
One change stands out. The names “Jack Port” and “Don Baisden” are gone. And there is a hole in the heart of the circuit board where they once proudly stood.
Epilog
Success soon returned to Controlaire. Although sales of the reformed system were slow at first, they picked up after a third redesign replaced the Bonner sticks with O.S. models. Controlaire briefly considered introducing a budget 3 channel rig (see Controlaire Three Channel) but decided instead to do the M.A.N. 2-3-4. This was a substantially redesigned and updated Controlaire proportional offering 4 channels of control in an affordable kit format. Its introduction was teamed with a series of monthly construction articles by Don Baisden in Model Airplane News. These enabled even electronics “dummies” to build their own modern proportional system by simply following Baisden’s step-by-step recipe “like baking a cake”.
Here is a sample page from one of Don Baisden’s articles on how to build the M.A.N. 2-3-4:
Here is the cover of the September 1968 Model Airplane News showing John Maloney and Don Baisden, with Don holding the M.A.N. 2-3-4.
The Controlaire Proportional had finally secured the prominent place it deserved in the radio control landscape.
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