The Jetex motor is a miniature solid-fuel

rocket motor A rocket engine uses stored rocket propellants as the reaction mass for forming a high-speed propulsive jet of fluid, usually high-temperature gas. Rocket engines are reaction engines, producing thrust by ejecting mass rearward, in accordance ...

produced for use as a powerplant for flying model aircraft. Its production led to a number of imitators and, after its demise, successors of similar type. __FORCETOC__

Original Jetex motors

Jetex was developed in 1947, by Wilmot, Mansour & Company Ltd of

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, which had started operations in a decommissioned hangar at

RAF Beaulieu Royal Air Force Beaulieu or more simply RAF Beaulieu is a former Royal Air Force station in the New Forest, Hampshire, England. It was also known as Beaulieu airfield, Beaulieu aerodrome and USAAF Station AAF 408. It is located next to the villa ...

. The first motor was demonstrated in early 1948 and was available to the public in June 1948, when ''Aeromodeller'' magazine featured Jetex power on its front cover. The first motors were the Jetex 100 and 200, with the more powerful Jetex 350 following in November 1948. The most popular motor, the Jetex 50, was introduced in May 1949, along with kits for a model plane and model car using Jetex power. The subsequent popularity of Jetex led to the manufacture of numerous kits by third-party companies such as KeilKraft and Skyleada. Jetex motors are powered by a solid pellet consisting mainly of guanidine nitrate, which burns to release an exhaust gas in large volume, leaving little solid residue. Thrust developed is modest and sustained, making it suitable for aerodynamically lifted flying models. The exhaust gas is not excessively hot, which confers a safety advantage. Motors are loaded with one or more solid fuel pellets and a combustible 'wick' is led through the exhaust nozzle to ignite the fuel. Fuel and wick were manufactured by

Imperial Chemical Industries Imperial Chemical Industries (ICI) was a British chemical company. It was, for much of its history, the largest manufacturer in Britain. It was formed by the merger of four leading British chemical companies in 1926. Its headquarters were at M ...

(ICI). The engine casing of the early motors is made of an aluminium alloy. On introduction, fuel pellets and wick could be purchased separately, meaning that the system is reusable. Jetex power made a big impact in the late 1940s and early 1950s, allowing new sorts of models, scale and duration, to be designed. During the 1960s, Jetex propellant pellets found another use by AP Films/Century 21, in their '

Supermarionation Supermarionation (a portmanteau of the words "super", "marionette" and "animation")La Rivière 2009, p. 67. is a style of television and film production employed by British company AP Films (later Century 21 Productions) in its puppet TV ...

' TV series, when they were fitted to the undersides of miniature ground vehicles to emit jets of gas resembling dust trails. Jetex went through a change of ownership in the mid 1950s. Gradually its popularity waned. Ron Baddorf speculated that the development of

radio control Radio control (often abbreviated to RC) is the use of control signals transmitted by radio to remotely control a device. Examples of simple radio control systems are garage door openers and keyless entry systems for vehicles, in which a small ...

and the increasing reliability and power of diesel motors caused a lack of interest in "the little Jetex".

Jetex imitators and successors

Velojet

The Velojet 50 and its larger sibling, the Velojet 100, were

New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island country ...

designed and manufactured. They used standard Jetex fuel and had a safety pressure release at the front in the form of a disc against a pre-tensioned coil spring.

Jet-X

In 1986, Powermax in the UK launched a range of newly formulated size 50 fuel and wick under the Jet-X brand. In the latter half of the 1990s, the company introduced their own 'Z' series motors, corresponding to the original Jetex 35, 50 and 100. From August 1995 Jet-X motors, fuel and fuse were commercially imported into the US. ''Flying Models'' told its readers that "safe and viable rocket power for model airplanes is back".

Rapier

With the new millennium came another revival. A non-reusable motor, called Rapier, was launched. This has similar weight, thrust and duration to Jetex and many old plans for Jetex powered models were dusted off and built and flown with the new motors. The Rapier is a single use motor with a cardboard case and a ceramic nozzle. In appearance it is more like a model rocket motor than the original reloadable Jetex.

Tendera

In early 2020, another range of non-reusable motors was introduced, called Tendera. These are similar to the Rapiers, being one-time use motors having cardboard cases and ceramic nozzles.

References

External links

Jetex.org
This non-profit site is "the premier Web resource for information and advice about models powered by micro rocket motors, especially those exemplified by the Jetex series of engines".

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