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Written by Michael Smith
As featured on page 31 in the February 2013 issue of
Model Aviation.
As featured in the
Model Aviation tablet app.

Museums are treasure troves of amazing, and often unique, pieces of our cultural heritage. They preserve these pieces so that we might learn how the world has developed and changed.

On rare occasions museums get the opportunity to share these fantastic items with visitors, as well as provide a venue so that those originally involved can share their experiences.

On July 20, 2012, the National Model Aviation Museum in Muncie, Indiana, held the first of what we hope will be many such events. A reproduction of the first documented CL model airplane to be built and flown, Miss Shirley, was unveiled.



























On hand for the event were Shirley St. Clair, daughter of Oba St. Clair, the original designer and builder; CL world champion, former MA editor, and editor of Stunt News, Robin “Bob” Hunt; and well-known CL builder and manufacturer, Tom Morris. Noted CL historian, Charles Mackey, joined the program via Skype and offered his unique perspective about Oba St. Clair as highlighted in his book, Pioneers of Control Line Flying.



The presentation is available for viewing on the museum’s website, listed in “Sources.”



Born in 1912, Oba, like so many others of his age, was inspired by Charles Lindbergh’s flight. Aviation excited him and at the age of 15 he built his first model, a rubber-powered airplane covered with butcher paper.



Other models followed, but it was an advertisement for a Brown Jr. engine and a construction article for a model of the Berliner/Joyce fighter in Modern Mechanics and Invention magazine (August 1935) that really excited him. Plans for the Berliner/Joyce were reprinted in the February 1977 issue of Model Builder magazine.



Oba started construction on the model immediately, while saving money a Forster Model A engine. As he neared completion, the realization of his project hit him: he was building a FF model in the woods of Oregon. His creation would most certainly not survive.



Feeling that the solution was to fly the model around in a circle, Oba attached a fishing line to the left wing and set the airplane’s controls to turn right. He also designed an engine shut-off system that would cut the engine upon landing.



Oba cleared and leveled an area next to his home, creating his own flying field. Using a fishing pole to keep the line straight, he made his first flight in June 1936. Although the flight was successful, experimentation led to improvements. Oba noticed how the airplane climbed when it flew into the wind and descended as it flew downwind. He determined that the solution was adding more lines, allowing him to actually operate the model’s control surfaces, just as on a full-scale airplane.





The Miss Shirley with a very young Shirley St. Clair.





At first Oba was going to modify the Berliner/Joyce, but as it neared winter he decided to continue to enjoy flying his model and construct a completely new airplane. The new model had an 8-foot wingspan, weighed 10 pounds, and was constructed from spruce and balsa and covered in silk. Named Miss Shirley after his newborn daughter, it first flew on July 4, 1937.



Miss Shirley featured ailerons, rudder, elevator, and throttle control and was flown using a four-line system Oba called “full-house.” He had no metal lines, only fishing line, which he found stretched in an uneven manner.



Oba’s next step was to devise a control handle that would eliminate the uneven line slack. The result was a rather large and cumbersome handle with four poles and a joystick. The poles took up the uneven line slack, yet still allowed Oba to control the aircraft. He knew that this system would have no commercial applications; safety was his main concern.



Word of Oba’s airplane quickly spread and on July 15, 1937, the Telephone Register newspaper of McMinnville, Oregon, ran a large spread with photographs of Oba’s CL design. Several articles also appeared in model airplane and science magazines. In 1939, the Union Oil Company came and took pictures for a monthly employee magazine.






Oba St. Clair in his shop in 1960.





Although Oba’s achievements with the model are significant in their own right, Miss Shirley also played another significant role in the history of CL models.



In 1952, Jim Walker (whose company, the Junior American Aircraft Company, played an important part in the development of CL models), filed a patent-infringement lawsuit against the L.M. Cox Manufacturing Co., Inc. over the use of a bellcrank. Roy Cox heard about Oba’s flight and refused to pay royalties to Walker when he began to produce his COX TD-1 model airplane, believing that Walker’s patent on the bellcrank was not legal.



In 1955, the case was finally heard and Oba supplied Cox with dated pictures, newspaper articles, and even Miss Shirley, as evidence. The judge’s decision ruled in favor of Cox, and with Walker’s patent ruled null, the marketplace was quickly flooded with a wide variety of new CL aircraft.






(L-R) Bob Hunt, Tom Morris, Michael Smith, Shirley St. Clair, Scott Cheslik, Don Sanqunetti, and Alan Hokenson at the Miss Shirley presentation. Photo by Gene Martine.





For the National Model Aviation Museum, this important milestone in the history of CL aeromodeling had to be documented for visitors to see. With the help of Shirley St. Clair, museum volunteer Scott Cheslik accepted the challenge of building a reproduction.



Shirley supplied some construction drawings along with photographs of the original model, which proved extremely valuable as Scott strove to duplicate the original as accurately as possible. As construction neared completion, additional assistance was provided by museum volunteer Don Sanqunetti, who constructed the main landing gear and tail wheel; Alan Hokinson, who assisted with the dummy engine; and Gary Bussell, who lent his painting expertise.





If you are interested in learning more about Oba St. Clair and Miss Shirley, Oba’s biography is available online as part of the Museum’s History Program. The link is listed in “Sources” or click here. Additional information about Oba is also available on Shirley St. Clair’s website. The drawings that Scott used to build the Miss Shirley are available through the AMA Plans Service.


—Michael Smith

msmith@modelaircraft.org



Order The Miss Shirley

Sorry, plans for the Miss Shirley are no longer available.




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SOURCES:

Miss Shirley

www.modelaircraft.org/museum/missshirley.aspx



Oba St. Clair History Program Biography

www.modelaircraft.org/files/StClairOba.pdf



Oba St. Clair: Father of Control Line Flying for Model Aviation

www.obastclair.com/index.html



AMA Plans Service

(800) 435-9262, ext. 507

www.modelaircraft.org/plans/plans.aspx





2 comments

How come there is no pictures of the control system, either at the pilots end or in the plane?

Hi Mark-

The National Model Aviation Museum recreated the Miss Shirley as best as they could using the documentation available. Unfortunately there was little conclusive information about the control system. For that reason, the museum's Miss Shirley reconstruction does not have a functioning control system.

You can view photos online from Ms. Shirley St. Clair, Oba St. Clair's daughter, at http://www.obastclair.com/gallery/gallery.html.

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