A Brief History of Control Line Flying

Mono Line

Flying a model with a single fixed line was not a new idea as we have already seen and flying something around on the end of string is probably as old as humanity itself. Even a modest kite can be made to fly horizontally in an arc. So the claims of "Full Control" with G Line are bit suspect.

The only exploited addition here was the pole ( think fishing rod ) which would exaggerate any whipping effect.  Whipping is a term used to describe the pilot leading, in effect pulling, the model by whatever means. 

If the line is shortened by pulling the pilot end of the line in front of the model is acting as a lever and also shortening the radius,  any revolution of the circle will be achieved with a shorter radius,  so it will fly faster.  

After one infamous  example with two lines, whipping the international rules ( FAI ) for control line speed models were changed to outlaw the such dubious tactics. Doing the same with a monoline is almost impossible,

Monoline went on to be a more sophisticated  system mainly used on CL speed models due to it's significantly lower drag properties and some clever handle like control systems. It works by twisting a single solid steel line, stranded steel will not work properly.

Monoline does have one downside, it has no neutral setting on the elevator, making it basically an on-the-fly trimming device. In modern day terms it would be like trying to fly an RC model on trims and with no indication of where neutral is.

There where other designs that allowed models to be aerobatic, but I would image it would be a totally different experience to flying with the common two line bellcrank. I would love to experience a Monoline flight at least once in my life.

Two Lines

Controlline flying in general as we know it today, is general attributed to Jim Walker in the USA around 1938. 

However there was a interesting court case on September 24, 1953, when  Jim Walker filed a case against L.M. Cox Manufacturing Co., Inc., charging them with patent infringements on two counts; the Bellcrank system and the control handle/reel. Jim also charged that the trademark U-Control had been indirectly used by Roy Cox and that constituted unfair competition.

The court ruled that the control handle patent was valid only on the points that related to reeling the control lines out and in during flight. Evidence was presented that Oba St. Clair flew his airplane more than a year prior to the issue of Jim's U-control patent, and a January 1938 issue of Model Airplane News listed for sale, construction plans and specifications for building a, "Miss Shirley” Control Line airplane.

The judge sent a letter to Oba naming him as, “father of Control Line flying.”

None of this detracts from all the model innovation  Jim produced, but credit where credit is due.

Three Lines

Again it looks like Jim Walker played a key role, although whether he was the first no one will know.

Later a innovative control handle arrived with the J. Roberts, Flight Control system, replacing the previous free floating third line. This new handle cleverly incorporated the throttle into the handle and balanced the movement with a matching double bellcrank that cut down on the interaction between the throttle and elevator movement.

Note: Having personally tried both the above, and also used predominantly a simple two bellcrank and third line with a key-ring setup, I can honestly say from an experience and feel point of view, there is no real advantage to the Roberts system as far as controlling a model is concerned.

This type of handle  has fallen out of favor over recent years, being replaced with simpler less sophisticated but no less effective mechanical setups,  and latterly surpassed first by electronic signalling down the wires,  for controlling the throttle. Then with the advent of cheap readily available 2.4GHz radio sets for throttle control, and every other device, except elevator control which has to be mechanical or the the whole point and experience of flying a controlline model would be lost.