Cox Models
Cox Models is an American hobby brand best known for miniature internal-combustion engines, control-line aircraft, and ready-to-run model vehicles.
Last updated October 14, 2026
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Overview
Cox Models is an American hobby brand with roots in the postwar model-engine and control-line aircraft market. The business was founded in 1945 in Placentia, California, by machinist Roy Cox, initially making wooden pop guns in a home garage at a time when metal was difficult to obtain. After metals became more readily available, the company moved into die-cast vehicles and tethered, or “whip,” cars. It subsequently developed miniature engines and powered models that helped make model aviation accessible to a mass audience. The brand became particularly associated with small glow-fuel engines, especially the .049 cubic-inch class. These engines powered ready-to-fly control-line aircraft, cars, boats, and other compact vehicles. Cox products combined relatively simple operation with durable construction, making them suitable for beginners while also giving experienced hobbyists an inexpensive source of power. The company’s product ecosystem helped introduce generations of hobbyists to model flying, miniature propulsion, and mechanical tinkering. Cox expanded substantially during the postwar growth of American consumer hobbies. Its operations moved to a larger Santa Ana, California, factory in 1963. The company broadened its portfolio beyond engines and aircraft to include slot cars, model rockets, HO-scale model trains, and other toys and hobby products. It also produced unusual powered craft, licensed or themed vehicles, and ready-to-run models based on recognizable aircraft, cars, and television properties. Its aircraft range included trainers and military subjects such as the PT-19, T-28 Trojan, and Douglas A-1 Skyraider. Roy Cox sold the company to the hobby conglomerate Leisure Dynamics in 1969. Under that ownership, the range expanded into products such as kites, toy walkie-talkies, and yo-yos. Leisure Dynamics also acquired Airtronics in 1976, giving the business a stronger connection to radio-control equipment. The company later faced the financial difficulties of Leisure Dynamics and was acquired in the early 1980s by engineer William Selzer and a local business partner. The resulting Aeromil Engineering Company renamed the business Cox Hobbies, Incorporated, in 1984. Operations were consolidated in Corona, California, in 1990 after years of occupying multiple leased sites. Estes Industries acquired Cox Hobbies in January 1996 and moved operations to Penrose, Colorado. The brand was then marketed as Cox Models, with more products directed toward mass retail, chain stores, and discount outlets. The transition connected Cox with Estes’s established model-rocket business but also changed the emphasis of the brand’s distribution and product strategy. Ownership changed again during the restructuring of the hobby industry. In 2009, Estes sold surplus Cox inventory to private buyers in the United States and Canada, while Wm. K. Walthers acquired the former Cox model-train line. Later that year, Estes-Cox became part of Hobbico, which formally assumed ownership of the Cox name, logo, and product line in 2010. Following Hobbico’s bankruptcy, MECOA acquired Cox Hobbies and its associated assets from Estes in 2019. The transaction included trademarks, logos, molds, machinery, inventory, tooling, and engineering drawings. MECOA subsequently relocated these assets from Colorado to its Irwindale headquarters, with the move occurring amid the logistical disruptions of the COVID-19 period. Today, Cox is principally recognized as a heritage hobby brand and as a source of collectible and replacement miniature engines, historical models, and related technical knowledge. Its cultural importance rests less on contemporary mass-market scale than on the durability of its products and its role in popularizing small-engine model aviation. The brand’s .049 reed-valve engines, Pee Wee engines, Tee Dee rotary-valve engines, Medallion engines, and associated aircraft and vehicle models remain significant among collectors, restorers, and model-engine enthusiasts.
History
Cox Models began as The L. M. Cox Manufacturing Co., Inc., founded by machinist Roy Cox in Placentia, California, in 1945. The company’s first product was a wooden pop gun made in Cox’s garage. Wood was chosen partly because metal was scarce during the Second World War. Once metal became more available in 1947, Cox began producing die-cast vehicles and developed tethered “whip cars,” a popular form of miniature racing vehicle that was swung around a central point by hand or powered by a small internal-combustion engine. The company’s early vehicle work led to miniature powered models and engines. Cox initially used engines supplied by Cameron Brothers of Chino, California, before establishing its own highly recognizable engine lines. The business grew rapidly during the postwar expansion of American hobbies, particularly through miniature glow-fuel engines and control-line model aircraft. Its products provided a comparatively inexpensive and durable entry into model aviation, allowing beginners to learn with ready-to-fly models rather than constructing and powering an aircraft entirely from scratch. In 1963, Cox moved to a new factory in Santa Ana. The initial facility covered approximately 80,000 square feet and was expanded several times to about 225,000 square feet. During this period the company diversified into slot cars, model rockets, HO-scale model trains, and other toys and hobby products. It also briefly produced a full-sized gasoline-powered chain saw and developed numerous powered vehicles and aircraft. The brand’s best-known models included the PT-19 trainer, T-28 Trojan, Douglas A-1 Skyraider, Ryan trainer variants, and themed cars such as an AMC Matador police car associated with the television series Adam-12. Cox’s miniature engines became its defining technical product. The .049 cubic-inch reed-valve engines were valued for sturdy construction and ease of use. Their fuel tanks, crankcases, cylinders, and crankshafts were designed to tolerate crashes and repeated handling, while the protected rear-mounted needle valve and carburetor reduced vulnerability during impact. The company also made the smaller .020 Pee Wee engine, rotary-valve Tee Dee engines ranging from very small displacements up to approximately .09 cubic inches, and Medallion engines positioned between the relatively mild reed-valve products and more demanding Tee Dee units. Roy Cox retired in 1969 and sold the company to Leisure Dynamics. Under Leisure Dynamics, Cox added kites, toy walkie-talkies, yo-yos, and other products. In 1976, Leisure Dynamics acquired Airtronics, supporting expansion into the growing radio-control hobby. Leisure Dynamics later experienced financial problems. In 1983, engineer William Selzer, associated with the design of the Babe Bee .049 engine, joined with a local businessman to acquire the Cox business. The new Aeromil Engineering Company renamed it Cox Hobbies, Incorporated, in 1984. Continued growth left the company’s activities distributed among several leased buildings, encouraging a move to a consolidated facility in Corona, California, in 1990. Estes Industries purchased Cox Hobbies in January 1996. Operations moved from Southern California to Penrose, Colorado, and the business adopted the Cox Models identity. Under Estes, the brand’s marketing shifted toward mass-market products sold through large chains and discount retailers. This broadened distribution but also represented a change from Cox’s earlier identity as a specialist engine and model-aircraft manufacturer. The brand went through another sequence of ownership changes in the late 2000s. In February 2009, Estes sold surplus Cox inventory to private buyers in the United States and Canada. Wm. K. Walthers acquired the former Cox model-train line. Although MECOA explored buying Cox Hobbies directly, Estes-Cox was instead sold to Hobbico later in 2009. Hobbico became the official owner of the Cox name, logo, and product range in January 2010. Hobbico entered bankruptcy in 2018. In 2019, MECOA purchased Cox Hobbies in its entirety from Estes, acquiring the product-line trademarks and logos as well as original molds, machinery, inventory, tooling, and engineering drawings. The assets were subsequently moved from the former Penrose facility to MECOA’s headquarters in Irwindale, California. The relocation took place during a period affected by the COVID-19 pandemic. Cox therefore survives primarily as a heritage and specialist hobby brand, with continuing importance for collectors, restorers, model-engine enthusiasts, and participants in control-line and miniature-engine activities.
- 2019
MECOA acquires Cox assets
[1]MECOA acquires Cox Hobbies and its associated intellectual property, equipment, inventory, tooling, molds, and engineering documentation.
- 2010
Hobbico assumes brand ownership
[1]Hobbico becomes the official owner of the Cox name, logo, and product line after acquiring Estes-Cox.
- 2009
Inventory and model-train assets are divested
[1]Surplus Cox inventory is sold to private buyers, while Wm. K. Walthers acquires the former Cox HO-scale model-train line.
- 1996
Estes Industries acquisition
[1]Estes Industries buys Cox Hobbies and relocates operations to Penrose, Colorado. The brand adopts the Cox Models identity and moves toward mass retail.
- 1990
Operations consolidate in Corona
[1]Cox moves its scattered leased operations into a consolidated facility in Corona, California.
- 1984
Renamed Cox Hobbies
[1]Aeromil Engineering Company changes the company name to Cox Hobbies, Incorporated.
- 1983
Acquisition by Aeromil Engineering
[1]Engineer William Selzer and a local business partner acquire the Cox business as Leisure Dynamics approaches bankruptcy.
- 1976
Airtronics acquisition
[1]Leisure Dynamics acquires radio manufacturer Airtronics, strengthening the business’s participation in radio-control hobbies.
- 1969
Roy Cox sells the company
[1]Founder Roy Cox retires and sells the company to Leisure Dynamics.
- 1963
Move to the Santa Ana factory
[1]Cox moves into an 80,000-square-foot Santa Ana facility that is later expanded to approximately 225,000 square feet.
Products and positioning
A heritage-oriented American hobby brand centered on compact, durable model engines and accessible powered models, with particular appeal to control-line flyers, collectors, restorers, and miniature-engine enthusiasts.
Model engines
.049 Reed-Valve Engines
Cox’s .049 cubic-inch reed-valve engines are the brand’s signature products. They were used in control-line aircraft, ready-to-fly models, cars, boats, and other small vehicles. Their compact packaging, protected carburetor arrangement, and robust metal construction made them particularly suitable for beginners and for models likely to experience crashes. The Babe Bee, Golden Bee, and later Sure Start are among the best-known examples.
Model engine
Pee Wee .020
The Pee Wee is a small .020 cubic-inch engine produced for compact models and sold both separately and in ready-to-run or ready-to-fly products. Its low displacement made it suitable for lightweight aircraft and unusual small-scale craft, including the Little Stinker model. The engine was produced in significant quantities over multiple decades and remains familiar to collectors of Cox miniature engines.
Performance model engines
Tee Dee Engines
The Tee Dee, or Thimble Drome, range used rotary-valve architecture and was designed for higher performance than Cox’s mass-market reed-valve engines. The range covered displacements from approximately .01 to .09 cubic inches. These engines were favored by serious hobbyists but were more temperamental and less suited to casual mass-market use. Their performance reputation has made them important collector and competition engines.
Model engines
Medallion Engines
Medallion engines occupied a middle position in the Cox range. They offered stronger performance than the basic reed-valve engines while being less demanding than the Tee Dee series. This made them appropriate for hobbyists seeking additional power without moving fully into the more specialized high-performance segment. They are now chiefly encountered in collections, restorations, and specialist model-engine markets.
Model aircraft
Control-Line Aircraft
Cox produced ready-to-fly and engine-powered control-line aircraft that introduced many users to model aviation. Trainers such as the PT-19 emphasized accessible learning, while military and scale subjects included the T-28 Trojan, Douglas A-1 Skyraider, and Ryan trainer variants. Some models incorporated multiple control lines or throttle arrangements, extending the range beyond simple elevator control.
Powered model vehicles
Powered Cars and Vehicles
Cox’s powered vehicle range developed from early die-cast and tethered cars. The company produced miniature vehicles driven by its engines, including themed and licensed subjects such as an AMC Matador police car associated with Adam-12. These products combined toy-like accessibility with real miniature propulsion and helped extend Cox’s appeal beyond model-aircraft enthusiasts.
Model railways
HO-Scale Model Trains
Cox operated an HO-scale model-train line during its diversification into broader hobby categories. The line was later separated from the remaining Cox assets, with Wm. K. Walthers acquiring the former Cox model-train business in 2009. The range is therefore primarily of historical and collector interest rather than a current core Cox offering.
Model rocketry
Model Rockets
Model rockets were among the products added during Cox’s expansion beyond miniature engines and aircraft. The category became especially relevant after the brand joined Estes, a major model-rocket manufacturer. Cox’s rocket products formed part of the wider hobby portfolio rather than replacing the brand’s central association with small internal-combustion engines.
Brand decisions
2019
MECOA acquires Cox Hobbies assetsM&ABackground
Hobbico’s bankruptcy led to a restructuring of the ownership of its hobby assets.
Action taken
Model Engine Corporation of America acquired Cox Hobbies from Estes, including trademarks, logos, molds, machinery, inventory, tooling, and engineering drawings.
Aftermath
Cox became part of MECOA’s specialist model-engine business, and its physical and technical assets were later moved to Irwindale, California.
2010
Hobbico assumes control of the Cox name and product lineM&ABackground
Estes-Cox was sold to Hobbico in late 2009 after a separate sale of the Cox brand was not completed.
Action taken
Hobbico became the official owner of the Cox name, logo, and Cox Models product line in January 2010.
Aftermath
Cox remained within a larger hobby-industry group until Hobbico’s later bankruptcy and the subsequent MECOA acquisition.
2009
Selected Cox assets are divestedM&ABackground
As ownership and industry conditions changed, Estes disposed of surplus Cox inventory and separated the former model-train business from the rest of the brand.
Action taken
Private buyers in the United States and Canada acquired surplus inventory, while Wm. K. Walthers acquired the former Cox HO-scale train line.
Aftermath
The divestitures reduced the scope of the integrated Cox product portfolio before the broader Estes-Cox business became part of Hobbico.
1996
Estes acquires Cox Hobbies and changes distribution strategyM&ABackground
Estes Industries acquired Cox Hobbies and relocated its operations to Penrose, Colorado. The new ownership connected Cox with Estes’s distribution capabilities and changed the brand’s emphasis toward products for chain stores and discount retailers.
Action taken
Estes integrated the Cox business, used the Cox Models identity, and directed more products toward mass-market retail.
Aftermath
The move broadened the intended customer base but marked a shift away from the company’s earlier specialist-manufacturer profile.
Recent events
- 2019
MECOA acquires Cox Hobbies assets[1]
M&A · Bankruptcy
Following Hobbico’s bankruptcy, Model Engine Corporation of America acquired Cox Hobbies and related brand assets from Estes. The transaction included trademarks, logos, molds, machinery, inventory, tooling, and engineering drawings.
- 2010
Hobbico becomes owner of the Cox brand[1]
M&A
After Estes-Cox was acquired by Hobbico in late 2009, Hobbico became the official owner of the Cox name, logo, and product line in January 2010.
- 2009
Cox model-train line and surplus inventory change ownership[1]
M&A
Estes sold surplus Cox inventory to private buyers in the United States and Canada, while Wm. K. Walthers acquired the former Cox HO-scale model-train line.
- 1996
Estes Industries acquires Cox Hobbies[1]
M&A
Estes Industries purchased Cox Hobbies and moved its operations from Southern California to the Estes facility in Penrose, Colorado. The business subsequently operated under the Cox Models name and pursued broader mass-retail distribution.
Sources2 sources
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