Micro Rocket Motor and Model Jet Resources
HISTORY – From Heyday to Hard Times


From Heyday to Hard Times
by John Miller Crawford

  Sebel takes over the controls – 1956 - 1959

  << The Jetex Heyday
The Micro Rocket Revival >>  
Wilmot Mansour's final ad During the eight years since 1948 which had seen Jetex established as a major model technology, Wilmot Mansour had also developed expertise in packaging. In 1956, the company took the strategic decision to concentrate on that side of the business. Bill Wilmot parted company (at least in a commercial sense) with Joe Mansour, though Wilmot, Mansour & Co. Ltd remained the firm’s name. Among major contracts gained by the repurposed company was one for the packaging of all atomic bomb-making equipment shipped to Christmas Island. Wilmot Mansour lost even nominal contact with Joe Mansour when it became Wilmot Packaging in 1961. Bill Wilmot retired as Chairman of Wilmot Packaging in 1972, and subsequently the company underwent many further metamorphoses, though remaining on the original Totton site until the 1990s.

Today, the direct descendant of Wilmot, Mansour & Co. Ltd is Dytecna Engineering Ltd (formerly GEL Engineering Ltd and now part of the Dytecna Group) and, with products that include avionic control systems and customers that include BAE Systems and Boeing Aerospace (right), it maintains aviation links that would surely gladden the hearts of the original partners. For many years, Wilmot Mansour’s descendant company was based in Totton, Hampshire, just a few yards from the site of the original factory which was housed in the transformed Beaulieu hangar where Bill Wilmot and Joe Mansour had developed their Jetex engines and had used them as an entirely new means of powering model aircraft.

All Wilmot Mansour's model production was sold to in 1956 to D. Sebel and Company of Erith, Kent (right), manufacturers of the Mobo line of toys, which had begun in 1947 with the construction of rocking horses. (For the early history of the Sebel company and Mobo Toys, visit the D & S Pedal Car Restorations website.)

The design and technical expertise that Wilmot Mansour had built up in Jetex motor and model production passed to Sebel in the shape of Joe Mansour himself, together with Bert Judge, Mike Ingram and two of the technical staff. Despite the upheaval, Model Aircraft was able to reassure its readers in April 1956 that “the Jetex range will continue as before, with a number of new kits scheduled to go into production”.

In fact, Jetex not only continued strongly under Sebel ownership, but indeed expanded, with the new owners introducing new motors, new fuel and new kits.

Wilmot Mansour's final ad

From Wilmot Mansour’s final Jetex advertisement
- Aeromodeller, Jan. 1956 (p. 6)

GEL simulator

A Fast Jet Maintenance Trainer produced by the direct descendant of Wilmot Mansour

Sebel's first advertisement after the sale gave greater prominence to the 'Hollows' plastic non-flying models than to the new Jetex Gnat
- Model Aircraft, Apr. 1956 (p. xi)

New fuel Wilmot Mansour had contracted the manufacture of Jetex fuel to ICI, who by 1956 were finding this line of minor significance and minimal profit. (Wilmot Mansour themselves sold the fuel at cost.) ICI took the opportunity offered by the change of Jetex ownership to withdraw from fuel manufacture (they had withdrawn from sponsoring the ICI Challenge Trophy after the last contest in 1954).

Sebel took on the task of propellant manufacture, resulting in new Sebel fuel coming on the market in 1959 (right). It was produced to a different guandine nitrate/potassium dichromate formulation (patented in the name of C A Rassier), which burnt at a higher temperature than the ICI formulation.

New motors The higher temperature of the new Sebel fuel proved unsuitable for the duralumin cases of the Wilmot Mansour motors and Sebel introduced new steel cases.

The 50B motor, for example, became the steel-cased 50C, preserving the same configuration but able to withstand the new fuel's combustion temperature. In the case of the Jetmaster, Sebel replaced it with the PAA-Loader motor (right), named for the US PAA-Load contest. However, while stocks of the ICI fuel remained, Sebel equipped it with the duralumin Jetmaster case, eventually replacing it with a steel case.

New kits Whereas many of the Wilmot Mansour kits had been of duration models, the new Sebel kits decidedly favoured the scale modeller. The most notable introduction in this area was the series of ‘Tailored’ kits.

  The sun sets on the heyday – 1960 - 1972
  Sebel 50C fuel

Sebel’s new fuel for the new 50C in its distinctive tin
- Andy Blackwell

American Telasco promoted the new PAA-Loader motor on its introduction by Sebel
- American Modeler, Apr. 1957 (p. 46)

At the start of the 1960s, despite the transfer to Sebel (and in some respects, because of it), Jetex was in a sound position, both in the marketplace and in the modelling community. Sebel was a major exhibitor at the British Toy Fair of 1961, with a full show of Jetex kits and ready-builts. It was, however, a sign of the way the wind was blowing that the prime Jetex exhibit and the latest Bert Judge design was a rubber-powered indoor model (right).

Jetex-powered contest flying was certainly in decline in the UK by 1960. From a peak in 1951, when Bill Henderson had won the SMAE Jetex Challenge Cup against 52 fellow competitors, entries in the event had declined to a tiny band of three in 1960. After a swan-song increase in the following year to 14 entries, the event was discontinued (and the whereabouts of the cup forgotten).

In the US, contest flying achieved a peak with strong entries in the Jetex classes of the 1958 and 1959 PAA-Load Contests (below right), which had added the Jetex events in 1956, but discontinued them in 1960. North American interest in contest flying persisted well beyond the decade, however, with a Rocket class for Jetex flyers in the US Nationals (bottom right). In 1971, for instance, there were five placings in each of three classes, and the Rocket event continued to be flown until at least 1983.

A factor in the decline of interest in Jetex contest flying was increased competition from the new breed of small diesel and glowplug motors. Additionally, a certain novelty factor which Jetex had benefited from over the previous twelve years had undoubtedly also faded, particularly among some contest flyers who had initially felt the attraction of a new form of motive power.

Nevertheless, Jetex interest remained high with the ‘hobby’ group of modellers, particularly in the US. While in the UK Jetex advertising and publication of plans became increasingly sporadic thorugh the 60s, in the US Flying Models, in particular, continued to publish plans and Jetex advertisements through to the end of the decade. Even so, obtaining satisfactory fuel and wick became an increasing problem. In response to an enquiry from Bill Henderson (now in Canada) in 1971, Bert Judge guardedly admitted that Sebel had “had a certain amount of difficulty with Jetex wick”.

By the late 1960s, Sebel had begun to feel the effects of a general decline afflicting the British toy industry, which had come under siege from cheap Asian imports. Faced with dwindling profits, in 1970 Sebel accepted a buyout offer from John Bentley of Barclay Securities. The Barclay Toy Group was formed and by 1971 had also taken over Chad Valley, Charles Methuen and Tri-ang.

Losses continued, however, and a major restructuring in 1972 saw the Erith factory closed down, with the cessation of Jetex and Mobo Toys production. Bill Henderson, again seeking wick, was informed by Barclay Toys that “the position on ‘Jetex’ is in abeyance”. In the end, the Jetex manufacturing equipment was sold for scrap. Coincidentally, this same year saw the death of Joe Mansour. The sun had truly set on the heyday of Jetex.

    << The Jetex Heyday The Micro Rocket Revival >>    

Bert Judge launches his new rubber indoor model at the British Toy Fair – in front of the Jetex stand!
- Aeromodeller, Apr. 1961 (p. 191)

PAA announces a new Junior Jet class for the 1957 contest – though the actual entries were very far from resembling the Boeing 707 Clipper
- Air Trails Model Annual, 1957

Into the sunset – Charlie Sotich launches his Jetex 100 powered Fizz-Dip at the 1971 US Nationals
- Aeromodeller, Oct. 1971 (p. 574)



Text by John Miller Crawford, based on the following sources provided by MC Black, David Carpenter, Stuart Guy, Bill Henderson, Rolie Lelliott, Bruce Ogden and Ben Nead:
- Editorial obituary: Joe Mansour, Aeromodeller, January 1973
- ‘Jetex’, Kenneth Brothwell. SAM 35 Yearbook #3, Dec. 1984, pp.138-149
- ‘Whatever happened to Jetex’, Kenneth Brothwell. Aeromodeller, Oct. 1985, pp.596-599
- Bill Henderson's personal correspondence with AA Judge (Wilmot Mansour/Sebel)
- Letter over name of Barclay Toys Chief Inspector (H Black) to Bill Henderson
- Personal correspondence of AW Thatcher (Wilmot Mansour staff, 1961- ) to Stuart Guy (Head of Engineering, GEL Engineering Ltd)
- Personal correspondence with Steve Long (GEL Engineering Ltd)
- Personal correspondence with MC Black, great-nephew of David Sebel

- Andy Blackwell, Stuart Guy, Bill Henderson, Roger Simmonds, MAAC archives via Bill Henderson


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