Oba St. Clair


Miss Shirley




Oba St. Clair's daughter was born August 12 after much difficulty to all involved. When things settled down, design work on the new plane began. It was named after his new daughter, Miss Shirley. Although not yet proven, Oba believed if one line worked, two lines must work and four lines would give him full house control. He had no metal control lines, only fishing line that he found stretched in unequal amounts with equal pressure.

To solve this problem, he used a large handle. He attached this handle to four poles to replace the fishing pole he used on the biplane. He had already reasoned that his large control mechanism was not necessary and could never be used commercially, but the name of the game to Oba was safety. No way would he take a chance with his dream. The long poles could take up any slack in a second without running to gain line tension.

The system could be improved later as it had been on the single line biplane. Oba was asked how he knew where to place all the four lines. He replied that it just seemed obvious to him that all four lines should be slightly behind the center of gravity.

When Oba was asked if he had a lot of questions about the design, he answered, “Oh, I had lots of questions; when you start designing something like this four-line control system, you want to use every safety precaution you can think of and still have that plane fly. You're going to have a lot of questions that you've got to search out in your mind, don't you see, because you're putting all your eggs in one basket and you're going to send them up into the air.

“[If] you have never flown a plane yourself, you have got to learn to fly that plane and [that] you're not going to crack it up. That is what I told myself. It's got to be able to fly on its own ... hands off controls like we'd be flying a large airplane ... take your hand off the control, the inherent stability is there ... it's trimmed out and, if you've got the motor power, the motor rpm just right for you, trim and all, it will go ahead and fly level.”

Oba called the four-line control “full house.” His design thought was, “I won't need the rudder, except offset for right hand turn, and, of course, test flights will use plenty of rudder to hold the nose out, but for take off, I will attach another line to that rudder so when I push the stick full forward, it will almost straighten out the rudder. That will keep it from having tendencies of going sideways around the field when I take off.”

The control system has two lines for elevator control, the other two lines are connected to the engine throttle and aileron. To lower engine rpm, a quick left aileron control, then return to neutral. For more power, you flip right aileron control then return to neutral. Rpm will increase each time operation is performed until full throttle is reached.

The airplane has an eight-foot wingspan with a 16-inch chord. Weight is 10 pounds. It's covered with silk and painted blue and yellow. All strength members are spruce and filled pieces are balsa. Oba went out by himself on July 4, 1937, to test his dream, Miss Shirley. He didn't want anyone around in case he wasn't successful, or in case it was, he wanted to protect his idea. He cleared off a circle by cutting and clearing the hay and then driving a company truck around and around in circles until it was smooth.

The plan was to taxi around for a few tank-fulls until he got the feel of the controls. There was about a six-foot rise and fall around the circle. Oba released the airplane, turned on the throttle to get up the rise and when the plane came around to the lower side of the circle, it took off. Oba was totally unprepared for flying.

He took his hand off the control stick to let the airplane fly itself. It was about six feet from the ground and coming around to the high side when he decided he should give it a little up control, but it was too little too late – the airplane hit the ground and blew out a tire.

The airplane was OK, but Oba was a wreck! He smoked four cigarettes in 30 minutes while he thought about the situation and patched his tire. He fired up the Forster again and this time taxied around properly, decreasing the throttle on the downhill side. Oba then made history that day by putting in several flights. He continued to fly the airplane until 1941, when the war started, and he never had that first crash.

He did install his twin engine as planned (two Forsters geared together, using auto oil pump gears). The airplane had excessive pull downwind, but Oba soon learned to correct for this by feeding a little left aileron into the control. If it felt light on the lines, he would use a little right aileron.

When you think about all the problems he overcame – from the control handle to the flying line stretch problems, the airplane design and control mechanism, the twin engine pulling a single prop with throttle control – it is staggering. When you think of how this man, or genius, was able to anticipate all these problems and logically solve them, put the solutions into practice and fly the airplane for four years without so much as a CG adjustment, you begin to get a small glimpse at the creativity and practicable ability of Oba St. Clair.

Oba made his first successful Control Line flight on July 4, 1937. Shortly thereafter, the news was out. On July 15, 1937, the Telephone Register [newspaper] of McMinnville, Oregon, ran a large spread with photographs of Oba's Control Line design, Miss Shirley. Several articles were printed in model airplane magazines and the science magazines.

Union Oil Company came out and took pictures for a monthly employee magazine in 1939. Oba made a newsreel at Swan Island Airport in Portland, but never saw the film. The photographer wanted him to dive his plane at him and come as closely as possible. Oba obliged and did just that. The only problem they had was controlling the crowd. Would you believe it? The world's first Control Line airplane and people were walking on the lines!

In the summer of 1936, after he had flown his biplane on a single line, but before his four-line control airplane, Oba saw an ad in Model Airplane News advertising the Elf Engine. It was manufactured in Portland, Oregon, by Dan Calkin. Calkin made them in his basement. Oba had to make a trip into Portland for supplies anyway, so he thought this would be a good time to see the engines. At that time, Dan was making single, twin and four-cylinder engines. Dan was kind enough to show Oba his aircraft, which included a twin-engine design similar to the Ford Trimotor without the center engine. This was quite a thrill for Oba, since Dan was the first model builder he had ever met. Oba can still recall that Dan had cut holes in the basement walls about three feet from the ground to exhaust his engine gases.

Dan told Oba to go to the golf course and he would find Jim Walker flying his gas-powered airplanes. Oba rushed to the golf course and was delighted to find him flying a little airplane. It used about an eyedropper of fuel and would fly 15 to 20 seconds in a small circle about 30 feet high. Jim would estimate where the model would come down and snatch it out of the air before it could hit the ground. Oba didn't introduce himself to Jim Walker, he only watched; he had the two-line idea in his head, but hadn't tested it and he feared that if he started talking about it, he might slip and say something that would give away his idea.

Oba built and tested his four-line control plane. He decided to show it to Jim Walker to see if he thought it had any commercial value. It was October 1937. Oba put his Miss Shirley in the back of the pickup, and, along with his wife, headed for the Junior American Factory in Portland, Oregon. The people at the factory told Oba he could find Jim at Dan Calkin's. Oba found Jim, introduced himself and told him he had something he wanted to show him.

He showed Jim and Dan the airplane and told them it could be flown on one line, two lines or four lines with full house. Jim didn't say much, but did ask a lot of questions. One was, “Do you find your engine speeds up when you're airplane gets in the air? I find these little ones always do.” Jim also asked about crashes and slack lines. Oba told Jim that if he had any interest in using the idea, to get in touch with him in McMinnville. That was their second meeting. Oba had planned to fly for Jim, but didn't because it was raining that day.

The following year, 1938, a sawdust hauling contractor wanted Oba to fly his airplane in Portland in a rented stadium, towing a banner with his company name on it. They made plans, but the flight never happened. Approximately two months later, the contractor came back to Oba and said, “Say, I saw a fellow in the schoolyard flying an airplane a lot smaller than yours and he had just two lines running out.” Oba's reply is difficult to put into words.

Oba went to Portland to pay Mr. Walker a visit. Oba can't remember if it was the fall of 1938 or the spring of 1939. He didn't find Jim at the plant, but was told he could find him at the schoolyard. Oba got to the schoolyard just as Jim was finishing a flight with his two-line control airplane. This was their third meeting. Jim asked Oba to carry his airplane back to his starting spot where he had his fuel. When Jim got to the airplane he said, “Hey, I remember you.” Oba responded with “Yeah, we talked about my aircraft in 1937.”

Jim fired up his airplane and left the motor running a little rich. He told Oba, “When I get to the handle, you tune it in until I signal.” Jim then took off and had a ball flying his little airplane, doing loops and figure eights. Oba recalls the engine was an Ohlsson 23 or something similar. The airplane was similar to a Fireball, but wasn't. Oba can't remember where it differed from the yet-to-come Fireball. After the flight, Jim said, “I've got to get back to the plant,” and did.

Oba found himself alone and unsatisfied since they didn't talk about the thing Oba had most on his mind. Oba followed Jim back to the plant. When Oba got there he said to Jim, “Well, it kind of looks like you are trying to commercialize on my idea.” Jim then put his hands in the air as if swearing to God, and said, “We've got proof that we have been working on this system for years before you showed me that ‘thing’ of yours.” Oba was insulted because Jim called his airplane a ‘thing.’ He thought that perhaps Jim had really been working on line control for years, but didn't understand why Jim had been flying Free Flight airplanes on all their previous meetings.

Jim invited Oba into the backroom to see his experimental aircraft. Oba recalls that there were about two dozen airplanes, all the approximate size of the Fireball and all had obviously been crashed and repaired – some many times.

Jim was quite knowledgeable about the airplanes and explained to Oba how and why each change was made and how it worked. Jim obviously enjoyed explaining to Oba the design principles. But, in the back of his mind, Oba was wondering if Jim and his workers had time in the year and half since they saw his four-line control to build and test that many airplanes. He concluded they did indeed have enough time.

Oba also reasoned that he still had time to patent his system since Jim had not patented UControl yet, but a long lawsuit would surely follow. Oba had no money for that. Oba and Jim parted company in a friendly manner.

Oba saw Jim Walker for the fourth time at Mayland Sweed in Oregon in 1948. Jim was scheduled to fly an Radio Controlled (RC) airplane at a Free Flight contest but didn't, due to a radio problem his crew couldn't solve. Oba didn't approach Jim that day. He had concluded that, “He's not my friend now.”

The fifth and final time Oba St. Clair saw Jim Walker was in Portland. Oba went to make a deposition for the court case. Jim Walker's Junior American Aircraft Company was suing Roy Cox's company, L.M. Cox Manufacturing Co., Inc., for patent infringements on two counts; one covered the bellcrank system used to control the elevator, the other was the control handle, with attached reel. Jim felt that the Skylon Reel produced by Roy was a copy of his patented Ureely.

The first Oba heard of the court battle was in 1952, when Roy called Oba and told him Jim Walker was mad at him and would sue if he continued to produce his ready-to-fly airplanes without a license. He asked Oba to furnish him with a list of all the evidence he could find that proved he was using a line control system to fly his airplanes prior to Jim's patent.

The list Roy received must have been a pleasant surprise, because Oba had many dated photographs, newspaper articles, company publications, sets of plans and still had the original plane!

Roy Cox made his decision to produce his airplane and fight the impending lawsuit. Roy felt that the items were not legally patentable and that he could prove that Oba flew his airplane prior to Walker's patent. He was also aware that Oba had shown Jim Walker his Control Line plane prior to the patent date of U-Control.

It took three years from the time Oba received that call from Roy Cox to the start of the trial in 1955. Oba, his wife, father and brother went to Portland to make their depositions for the court. Jim Walker, his attorney and a clerk were also present. No conversation transpired between Oba and Jim, but Jim's attorney asked Oba if he saw Jim Walker in the room. Oba pointed out Jim. Jim's attorney turned to Jim and said, “Don't you suppose he could have seen you at one of your demonstrations?” This statement led Oba to speculate on the idea that Jim hadn't told his attorney about their prior meetings.

They broke for lunch, the plaintiff and the defendants each going to separate restaurants. Roy's attorney told Oba that it was obvious that, “We have the case sewn up,” and they fully expected Jim to drop the case. To continue in the face of overwhelming evidence would surely put his patent in jeopardy.

Much speculation has been suggested on why Jim continued with the case, but one point should be considered if you want to speculate yourself. Jim had won a similar judgment by consent against an R.W. Pickney, Case No. 47C458, in the United States District Court of the District of Illinois, Eastern Division.

The court had ruled Jim's U-Control Patent No. 2292416 was good and valid and was infringed upon by the defendant. It would seem logical to assume this must have given Jim confidence in the present case against Roy Cox. The case lasted four days.




Information about Oba St. Clair is taken from two articles that appeared in Model Builder magazine’s
November and December 1981 issues. The articles were written by Charles Mackey and Dale Kirn. Charles Mackey submitted the information to the AMA History Program.