Private company

Cox model engine

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.2 Wikipedia text CC BY-SA 4.0

Last updated Oct 21, 2026.

Overview

  • Industrygame industry1
CoxModelEngines
Photo: Warrenlead69, CC BY-SA 4.0, via Wikimedia Commons4

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.2

The story

Cox history

The Cox range of model engines were the brainchild of entrepreneur Leroy (Roy) M. Cox.

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. Cox felt the need for dependable, easy-to-start engines and spent eight months of 1950 in research. His three-man engineering crew (himself, Mark Mier and Bill Fogler) spent seven days a week, day and night, developing the.049 Space Bug contest engine. The result was the Space Bug.049 Contest engine, Cox's first model plane engine which was completed in October 1951.

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.

Read the full text

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.

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.

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.

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

Original equipment manufacturer (OEM) engines

Over the years some Cox model engines were sold to other companies for use in their products and sold under the other companies names. Examples of these companies were, Testor Corporation, Sanwa & Kyosho of Japan, Johannes Graupner of Germany, Jerobee Industries trading as JoMac Products, Lite Machine Corporation, Kenbrite Corp. Australia and Tissan Haifa in Israel. Of all of the above-mentioned companies, only Tissan Haifa assembled their own engines called the Banana.049. All the rest used motors manufactured by Cox themselves.

The 1989 Cox Banana.049 (Cat#250) engine looked like a standard product engine with plastic backplate. It also had a spring starter and red aluminum spinner, and the fuel intake tube was extended below the plastic backplate. Cox also supplied a specially printed "Banana.049" box insert to fit their standard box.

From Wikipedia’s article on Cox model engine, shared under CC BY-SA 4.0.3

Products and brands

  • scale model

Listed on Wikidata.1

Product engines

These are all variations of the Baby Bee with different back-plates and other parts designed for different RTF aircraft, cars and boats. There were literally hundreds of different models with subtle differences. Listed below are just a few of the more common ones.

1959 Super Bee (Cat# 350-1)

Babe Bee with twin bypass cylinder to give more power for the P40 Warhawk RTF model. Early version had 'P40' stamped on the cylinder. It had a standard Babe Bee tank.

1964 Silver Bee (Cat# 350-6)

Read the full text

Similar to the Super Bee but it had a larger 8cc non-vented fuel tank. It did not have P40 stamped on the cylinder but it did have the twin bypass ports. This engine came with the Spitfire RTF airplane.

1961 Series 190-x Product Engine (Cat#190-x - manufactured 1961 to 1971)

Babe Bee type engine with "postage stamp" type Delrin backplate and brass needle valve instead of the integral Babe Bee fuel tank. Various shapes were used depending on the model they were fitted to. Each time they made a modification for a new model that was built a new Cat number was produced. (e.g. 190–8) Some had dual bypass port cylinders while others had single, it depended on the airplane. e.g. JU-87D Stuka, P-51 Bendix Racer, P-51 Mustang & Miss America models.

1972 Series 191-x Product Engine (Cat#191-x - manufactured 1972 to 1975)

Babe Bee type engine with "horseshoe" type Delrin backplate and brass needle valve. The horseshoe backplate had additional mounting holes drilled in the plate allowed fitting to after market and kit aircraft. Various shapes and colours were produced depending on the model they were fitted to. Some had dual bypass port cylinders while others had single, it depended on the airplane. e.g. Sopwith Camel, Fokker DVII, ME-109, Super Stunter, PT-19 Trainer and others produced in the mid 1970s.

1976 Series 192-x Product Engine (Cat#192-x - manufactured 1976 to 1978)

Similar in appearance to the 191 series engine, produced for the 1977 Wings series of air craft. i.e. Hustler, Mantis, F-15 Eagle and F-15 Falcon air planes.

1963 Series 290 / Spook Product Engine (Cat#290)

Came on a blister pack as a "Two Ninety" replacement engine. Basically a replacement 190 engine. An aluminum back plate was used for the "Spook" flying wing combat model kit engine (290-1).

2000 Surestart (Cat#191)

Another variation of the modern Babe Bee. These were pretty good because they have a choke tube attached to the grey plastic backplate. The choke tube makes the engine even easier to start. They were fitted to the very last RTFs (e.g. PT19 and Hyper Viper) before they went out of production.

Aftermarket glow heads

Standard glow plug head—uses standard conventional glow plug—low compression—standard performance. Still produced by MECOA K&B Manufacturing.

Hi Compression Head - Trumpet shaped - High Compression - knurled top. Still produced by MECOA K&B Manufacturing.

Turbo glow plug head—medium compression—high performance and several heat ranges available (makes them very good for RC applications)

Norvel Freedom Glow Plug—high compression—high performance— (available from NV engines)

Galbreath Head with Nelson Plug Combo—high compression—high performance—most popular for small prop/high rpm applications, gives the engine an immediate performance boost by up to 2,500 rpm depending on the engine.

Cox International Insert Style glow head—available in both Standard and Texaco style

Merlin insert style with clamp ring; very high compression ratio (needs extra head shims); high performance

Use in radio controlled models

At the time Cox developed the first Cox engines, they were used in control line and free flight model planes as there was no market for throttled radio control engines back then. Radio control, although first developed in the 1890s it was not available for model airplanes until the 1950s and did not become economically viable for small model planes until the mid-1970s and even then was for the modelers who could afford it. It was certainly out of reach of the hands of most children.

From the mid-1960s Cox produced throttle control devices for some of their engines; however, these were not as effective as throttles on other brand engines as the Cox throttle worked by restricting exhaust flow. Exhaust throttles were produced for most Bee and all Medallion engines but not Tee Dee.

In 1988, Cox produced an engine with a true throttle-able R/C carburetor and that engine was the Queen Bee.074. In 1994, Cox produced the Tee Dee.05 and.09 both of which had a conventional R/C carburetor with adjustable airbleed and a full muffler.

In 2010, an after market R/C throttle/choke was developed for the.049 reed valve engines. The throttle attached to the choke tube on Sure Start.049 engines and acted like a cold-start choke on regular engines. The throttle was developed by Saras Associates and was marketed through Cox International.

From Wikipedia’s article on Cox model engine, shared under CC BY-SA 4.0.3

Sources

The numbers on this page point here. Each one links to the record it came from.

  1. 1
  2. 2
  3. 3
  4. 4