Jetex
Atom 35
click image for enlarged drawings
- drawings
by Carlo Godel
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Although
the
Atom 35 was the baby of the family of Jetex motors, it was one of the last to be introduced
by Wilmot Mansour, in 1953.
More than its siblings, it tended to suffer from blow-back.
Most pellets were a tight fit in the main case. Being of thin
gauge, it was easily dented, making loading more difficult.
These annoyances, and its relatively short duration, led to
fewer modellers interested in using this motor.
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Jetex
50 (original)
click image for enlarged drawings
- drawings
by Carlo Godel
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As
the most popular unit of the range, the Jetex 50 underwent a
succession of developments and modifications (see next
item). The original (a.k.a. standard) 50, had a turned ribbed
main case and end caps.
Sensing a demand for a smaller addition to the range, Wilmot
Mansour brought it to the market in their second year of production,
in 1949. Production was phased out in favour of the later versions,
in 1954.
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Jetex
50B (also 50 Export and 50C)
(50B shown at half actual size – click image
for full-scale drawing)
- drawings
by Carlo Godel
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For
the
the U.S. market, Wilmot Mansour introduced the Export 50. From
this evolved the 50B, a longer motor with more free space for
combustion and to aid wick ejection. Both differed from the
standard 50 in that they had a pressed alloy case and a dome
shaped end cap, which favoured the use of an augmenter tube.
When Jetex manufacture was taken over by D. Sebel Co. Ltd.,
the 50C was added to the range. It retained the shape of the
50B, but was made of steel throughout. However, while it proved
more durable, it still required as much attention, if not more,
than the 50B in order to avoid corrosion.
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Jetex
50R (aka 50HT in the US)
(50R shown at half actual size – click image
for full-scale drawing)
- drawings
by Carlo Godel
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This boosted-thrust dual-spring motor was introduced by Wilmot Mansour in 1955 and marketed in the UK as the 50R (‘R’
for ‘rocket’). It was brought to the US market by Telasco in 1963 as the 50HT (‘HT’ for ‘high thrust’).
It used fuel prepared in such a way that it burned at a much faster rate than in the 50C, thus achieving significantly higher thrust – 5-6 oz for up to 4 seconds was claimed.
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Jetex
100
click image for enlarged drawings
- drawings
by Carlo Godel
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One
of the pioneers of the range (along with the Jetex 200) in
1948, the Jetex 100 had a turned, rather than drawn, case. To
provide for safety release, it employed three helical springs,
which could make loading troublesome.
Despite its popularity, the 100 was eventually phased out in
1954, in favour of the Jetmaster.
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Jetex
Jetmaster
click image for enlarged drawings
- drawings
by Carlo Godel
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The
Jetmaster was introduced in 1952, using the same fuel as the
Jetex 100 and able to take an additional half fuel pellet, thus
increasing the duration to 22 seconds.
Loading was easier than the 100, with only a single spring to
retain the end cap, which was designed as a matching fit for
an augmenter tube. However, cleaning was less straightforward,
owing to the many parts that required disassembling.
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Jetex
150 PAA-Loader
click image for enlarged drawings
- drawings
by Carlo Godel
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The
Jetex 150 was produced by D. Sebel Co. Ltd, after Jetex manufacture
passed to them in 1956. It acquired its PAA-Loader designation
from its association with the Pan American Airways-sponsored
international duration contest, where it had a class to itself.
Having a longer body, with a single retaining spring clip, it could
take up to three Jetex 150 fuel pellets. It achieved a high
degree of popularity, and was the inspiration for many fine
duration designs.
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Jetex
200
click image for enlarged drawings
- drawings
by Carlo Godel
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One
of the two initial motors to be marketed (along with the Jetex
100) in 1948, the Jetex 200 also had a turned case.
With five coil springs for end cap retention (as compared
to the three of the Jetex 100), it proved similarly troublesome
to load and did not achieve a high level of popularity. As
evidence of its relative obscurity, there are very few surviving
model plans.
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Jetex
350 / Spacemaster 600A
click image for enlarged drawings
- drawings
by Carlo Godel
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The
Jetex 350 joined the range in 1948, shortly after the 100 and
200 models. It acquired its rather ambitious 'Spacemaster 600A'
designation when it was marketed in the US by American Telasco
Ltd.
Known as "a strong man's motor", it required a lot
of effort to remove the five springs, but with a duration of
36 seconds (on three charges) it was popular for duration flying.
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Jetex
Scorpion 600
click image for enlarged drawings
- drawings
by Carlo Godel
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The
Scorpion was the most distinctive and powerful motor in the
Jetex range. The 600 (= 6 oz. of thrust) designation was rather
ambitious, with tests showing an average of 5 oz., for 8-9 seconds
duration.
With just two spring rollers which snapped easily into place,
it had the attractions of easy loading and a tubular end mount for simple model attachment.
First marketed in 1953, it was the final motor to emerge from
the Wilmot Mansour stable.
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