the Classic Jetex archive
the Classic Jetex archive
PLANS
Fixed Wing – Jetex 350
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Model Aircraft Plans for the Jetex 350

Although the Jetex 350 motor was known as "a strong man's motor" (since it required a lot of effort to remove the five springs), it was popular for duration flying. On three charges, it offered a duration under power of around 36 seconds.

Regrettably, few plans for this motor appear to have survived. At this stage, we can offer only two – but they're two of the best! – from "strong man" Bill Henderson.

  What you'll find here:
Vindskreenviper
Firebird
 

Vindskreenviper by Bill Henderson

Click image to view or download dimensioned plan
Bill Henderson's Vindskreenviper Bill Henderson's Vindskreenviper
Bill Henderson's Vindskreenviper
- heading: Aeromodeller, Mar. 1952 (p.143); photo: Bill Henderson

In 1951, Bill Henderson won the S.M.A.E. Jetex contest with his Vindskreenviper, an aircraft that was to earn legendary status both for itself and its designer.

Developed as the eighth of the 'Puff-Adder' series, Vindskreenviper was designed for the 1951 season. The third Puff-Adder had placed third in the 1949 ICI Challenge trophy. Vindskreenviper was created with the aim of placing even higher in the same event for 1951. It gained top place in the newly introduced S.M.A.E. Jetex contest, with an outstanding 24:1 ratio flight. Unfortunately, lowered performance from damage sustained in that contest prevented it gaining a placing in the subsequent ICI contest.

Aeromodeller featured Bill and his craft in March 1952. We have a reprint of the article and the construction plan available to view or download.

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Firebird by Bill Henderson

Click image to view or download enlarged dimensioned plan
Click to view or download enlarged dimensioned plan for Firebird
- SAM 35 Yearbook #5, Dec. 1988 (p.79)


This is a another contest duration design from Bill Henderson. It gained a third placing in the 1952 I.C.I. Challenge Trophy contest at Fairlop.

From Bill's notes:


"The event was won by John O'Donnell with an 18.92 ratio. Second was B. Wheeler with 15.44 and third once again was the writer with 12.37. This was with a totally new low thrust-line design called Firebird, the plan of which appeared in the 1953 Zaic Yearbook."

The 12.37 ratio was calculated from a flight time of 4 min. 32 sec. on two charges. Its average duration in evening air, on one charge, was 1½ min.

Bill insists that we should "not make too much of my efforts at Jetex duration designs; many of them were not too successful." As evidence, he cites his experience with Firebird's successor:

"There was a Firebird 2 designed and built for the 1953 International Jetex contest. This model was the same basic design as Firebird 1, but used geodetic construction on the wings and tail. The finished weight, less motor, was 1.1 ozs. compared to 1.5 ozs. for Firebird 1. It qualified for the International and was proxy flown for me (I had left the UK for Canada) by my Grange club mate Tony Brooks."

"Unfortunately, I had carried the weight saving too far and the model broke up in the windy weather conditions.

"Another difficulty with this design was that the motor position was too close to the launch holding point, creating considerable problems to achieve a good launch. This became critical with Firebird 2, with the resulting break up when trying to hold it into the wind."

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Acknowledgements

Plan and information source:
- Vindskreenviper: Contributed by Bill Henderson
- Firebird: Contributed by Bill Henderson

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Construction and operation  |  Kits  |  Plans: Fixed Wing Aircraft  |  Plans: VTOL Craft - Cars - Boats
50 | 100 | PAA-Loader 150 - Jetmaster | 200 | 350 | Scorpion 600 | composite


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