Cox model engine

Cox model engines are used to power small model airplanes, model cars and model boats. They were in production for more than 60 years between 1945 and 2006. The business is named for founder Leroy M. Cox. He started L.M. Cox Manufacturing Co. Inc, which later became Cox Hobbies Inc., then Cox Products, before being sold to Estes Industries, when it became Cox Models. On February 7, 2009, Estes Industries stopped producing Cox engines and sold all of their remaining inventory – mainly spare parts – to several private buyers from Canada and the US. One of the new owners of the remaining Cox engine and parts inventory has launched a website with an online store. After the bankruptcy of Hobbico in 2019, MECOA (Model Engine Corp of America) purchased Cox Hobbies in its entirety from Estes Corporation.

Millions of engines were produced. They became the most common 1/2A Class 0.049 cubic inch engine in the world, and probably still are today. Although the production of the engines ceased some years ago, engines made as far back as the 1950s are still sold "as new" and are in abundance on eBay worldwide.

Cox history The Cox range of model engines were the brainchild of entrepreneur Leroy (Roy) M. Cox.The Engine Collectors Journal, Issue 105, May 1993, History of the Cox Engines Part 1 by Dan Sitter

Cox Manufacturing started out in Cox's garage in 1945 where he made wooden popguns for kids and employed local housewives to assemble them. Metal was scarce due to the war which is why the toys were made of wood. In 1946 metal became readily available again and competitors quickly moved into the market, making their metal popguns cheaper, so Cox moved to something else, making metal tether cars for kids. In August 1946 a fire in Cox's garage forced him to move to newer and larger premises at 730 Poinsettia Avenue, Santa Ana, California. In 1947 Cox developed a racing car which used an engine manufactured by Cameron Brothers. The cars sold for $19.95 and generated $200,000 in sales in their first year of production. In 1949 Cox developed their own engine for their racing tether car which included some parts from Mel Anderson's Spitzy engine. This engine was called the "O Forty Five" as it was .045 cubic inch displacement. In 1950 with sales of the car proving to be a success Cox moved on to development of a model plane engine.West Coast Model News. L.M. Cox Company. Howard G. Puckett. Editor and Publisher. December, 1958. Page 22. Cox felt the need for dependable, easy-to-start engines and spent eight months of 1950 in research.Playthings. "The L. M. Cox Story". April, 1957. Page 153. His three-man engineering crew (himself, Mark Mier and Bill Fogler)Mier, Mark F. Interview with author. Brian L. Winney. Bonner, Montana. 28 November 1995 spent seven days a week, day and night, developing the .049 Space Bug contest engine.American Modeler Annual. How Roy Cox Turns Out World’s Smallest Engine…plus other fascinating facts on America’s biggest non-modeling model maker. Downie D. 1962 Edition. Pages 29-32. The result was the Space Bug .049 Contest engine, Cox's first model plane engine which was completed in October 1951.L.M.Cox Manufacturing Co., Inc. Unpublished company biography. December, 1960 In 1952 the first name change was made to L.M. Cox Manufacturing Company Inc. The Space Bug engine set the scene for all the Cox engines that followed, and went into full production in 1952. This engine was so popular that it caused problems for other model engine manufacturers. In 1953 Cox produced their first ready to fly (RTF) airplane, the TD1, which was powered by the Space Bug engine. In 1953 L.M. Cox Manufacturing was sued by Jim Walker (American Junior Aircraft Co.) for copyright infringement because Cox was using Walker's patented bellcrank system in the TD1 and because Walker believed the Cox Skylon Reel was a copy of his U-Reely control handle. The court case lasted for three years. In 1955 Cox won the court case against Walker. Walker's patent on the bellcrank control system was ruled void and invalid because it was determined that the system had been designed before Walker's patent and by someone else - a man named Oba St. Clair, who was the first man to fly a control line airplane (in the US) back in 1937 and the design was published in 1938. St. Clair had shown his design to Walker, who took it upon himself to patent the design. The court also ruled that the Cox reel was not a copyright infringement.Biography of Oba St.Clair - AMA National Aviation Museum In 1956 Cox developed the Babe Bee 049, designed by William (Bill) Selzer, which had an extruded aluminum crankcase, not cast like the others. This engine sold for just $3.95 and was the final nail in the coffin of many competitors whose engines were selling for substantially more. The Babe Bee was a high quality high precision engine that started easily and was very reliable, unlike some of the competition. In 1957 Cox took over the Flying Circle at Disneyland, which was a major coup for the company. The model planes were flown each day in front of tens of thousands of people and they had a hobby shop right there full of Cox RTF planes. The Cox Flying Circle remained in operation until 1965 when it was closed to make way for expansion of Tomorrowland. In 1960 Cox hired an engineer named Bill Atwood (who had already built his own line of engines), to develop a new .010 cubic inch engine. Atwood was also responsible for the Tee Dee and Medallion line of engines. These engines put Cox on the map as a leading engine in the world for many years to come.Biography of William E. Atwood - AMA National Aviation Museum In 1963, due to continuing growth, the company moved to larger (225,000 square feet) facilities which were three times larger than the old site. Shortly thereafter Cox got into slot cars and focused attention on gearing up for this fad. In 1965 Cox International was established in Hong Kong to meet the demands of the slot car craze. In 1967 the slot car fad ended, leaving Cox with excess stock that couldn't be sold, resulting in cash flow problems. In 1969 Cox's wife Myrtle died and he had health problems of his own, so he retired and sold the company to Leisure Dynamics Inc. Leisure Dynamics continued to expand the range of Cox model aircraft as well as adding trains, boats, rockets, kites and radio control, boosting sales to 25 million dollars per year. Cox retired with the distinction of being the world's most successful model engine manufacturer. In 1970 William H. Selzer was appointed as President of L.M. Cox Manufacturing Inc. (a subsidiary of Leisure Dynamics). In 1971 Leisure Dynamics broke the company in two, moved the model production to Minnesota, and left the engine production in Santa Ana, California. In 1976 Leisure Dynamics changed the company name to "Cox Hobbies Inc." In 1980 Leisure Dynamics filed for bankruptcy, taking Cox Hobbies Inc. with them. In 1981 Leroy Cox died on September 22, at age 75. In 1983 former Cox engineer and president Bill Selzer (whom Cox had hired in 1952) purchased the company out of bankruptcy. All manufacturing was returned to Santa Ana. The company once again flourished into the 1990s, with new products being added and another move to even bigger facilities. In 1990 Cox Hobbies moved to new facilities at Corona, California. In 1993 the company name was changed again to "Cox Products". The Pee Wee, Babe Bee, and PT 19 Trainer were still in production. In 1995 Cox celebrated 50 years and introduced some new engines and RTF models. In 1996 Cox was sold to Estes Industries / Centuri Corp. and moved to Penrose, Colorado. Things changed considerably from then. Cox, as the hobbyists of the world knew it, was gone. The high reputation Cox engines had declined. One by one each product item was withdrawn from sale as stock ran out. Parts from different engines were mixed and matched, making hybrid engines that performed very poorly compared to the Cox engines from previous years. Estes added new products to the Cox line using the Cox name, but these were electric radio control models. Some of these were known to explode, resulting in a massive product recall by the company.U.S. Consumer Product Safety Commission Recall notice. In 2005 an online company calling themselves Cox Hobby Distributors (owned by Estes Industries) appeared selling RC and electric products and some of the "classic" engines and RTF models. However, as each item from the classic era sold out it wasn't replaced. In February 2009, Estes Industries sold all of their remaining classic Cox stock to several private buyers, one of them being a small company from Canada. In June 2009 they launched a website to sell their remaining stock online and also via eBay. In January 2010 Estes-Cox Corporation was purchased by Hobbico, based in Champaign, Illinois. In 2011 Cox International continued to revive the classic Cox brand as well as introducing new engine versions, spare parts and accessories. After the bankruptcy of Hobbico in 2019, MECOA (Model Engine Corp of America) purchased Cox Hobbies in its entirety from Estes Corporation. All molds, machinery, inventory, tooling, and drawings were moved from Penrose, Colorado to MECOA's Irwindale, California facility over the next two years during the COVID outbreak. MECOA had been producing OEM parts for Estes-Cox since the mid 1990's and was negotiating to buy COX from them in 2009, but Hobbico bought both Estes and Cox around the same time. MECOA now owns the COX Registered Trademark

The engines

The Cox .049 Engine is a 2-stroke internal combustion glow plug engine. These engines use an electrically heated glow plug to ignite the fuel/air within the cylinder on start-up. Once running the battery is disconnected and ignition is similar to a diesel engine. The self ignition is due to the heat produced from the compression of the air/fuel mix, and the catalytic reaction between the platinum element in the glow plug and the methanol in the fuel. Fuel intake to the engine is controlled by a simple needle valve and venturi system. Fuel/air mixture intake to the crankcase is controlled via a reed valve or rotary valve depending on the engine design.

In a reed valve engine, the valve is drawn open by suction as the piston moves upward on the compression stroke. As the piston moves down on the power stroke, the pressure in the crankcase causes the reed valve to close. The fuel-air mixture in the crankcase is then forced past the piston via the transfer/bypass ports in the cylinder. One characteristic of a reed valve is that the engine will run in either direction; an advantage for a "pusher" model but a disadvantage if the engine is finger started, as it may start in the wrong direction. (The Cox engines employed a starting spring which kept fingers free of the propeller and generally ensured correct rotational direction.)

On rotary valve engines, the process is similar except instead of a reed, a rotary valve is used (incorporated in the crankshaft), which opens and closes as the piston moves up and down. The rotary valve is more efficient and adjustable (at design time) as there is a larger and clearer path to the crankcase than in the reed valve setup, but such engines can run in only one direction; pusher configurations require a special propeller, sometimes difficult to find.

The fuel used to power the engine is called Model Engine Fuel, a mixture of methanol (70–40%), castor oil (20%) and nitromethane (10–40%).

The Cox line of reed valve engines designed prior to 1960 used a rear reed valve induction system. In the late 1950s Cox experimented with rear rotary valve induction (as used in the RR1) before moving forward with front rotary valve induction for their Tee Dee and Medallion lines .

Early engines

1949 O Forty Five Power Pak (Special Racer Car Engine #PP-45 - manufactured 1949)