Long John (oz3914)

About this Plan

Long John. A 42 inch span C/L FAI class team racer. From Model Aircraft, August 1960.

Quote: "FAI class team racer designed by M Basset, M. Greenough and E Cheesman.

THE result of the pooling of several modellers' ideas, Long John was designed when the 1959 competition season had already commenced. It was necessary, therefore, to formulate a design which would fly 'straight off the drawing board' with some reasonable expectancy of success. To date six of these models have been built, all have performed well and have been easy to handle, both in the air and on the ground.

The best performance over to km. has been 5 min. I sec., including three pit stops, but we confidently expect that one stop can be eliminated, for with the model now doing 30 to 31 laps per tank, it should be possible to improve this to 35. Obviously the time to aim for, if one is interested in international competition, is around the 4 min 30 sec mark (without whipping). To achieve this time the airspeed of the model must be 98 mph, but with one stop it need only be 90 mph. Ten km in 5 min 55 sec incidentally requires an airspeed of 94 mph, so existing performance is approaching the theoretical goal.

In our opinion the Tornado 7 x 8 is the most suitable prop to use, but as these are now no longer in production, the Top Flite 7 x 8 power prop is a good alternative. On the question of fuel we usually start with the 'standard' 50 percent paraffin, 30 percent ether, 20 percent oil plus 3 percent amyl-nitrite mixture and go on from there, but we find that a fuel which suits one motor will not suit another. One point of interest is that a molybdenum disulphide additive seems to do more harm than good, tending to give inconsistent runs.

Constructional Notes. First seal off the exhaust port and intake on the engine (use Sellotape or similar method), cut the bearers to length, drill to suit the motor and bolt these to it. Cut the wing from medium-soft 1/2 in sheet or build up as shown, and glue the engine bearers (with motor attached) to it. Face each side of the wing round the bellerank position with 1/16 in plywood, mark the pivot position, and drill. Cut the bellcrank from mild steel..."

Update 12/11/2015: Replaced this plan with a clearer copy (patterned background removed) thanks to TonyP.

Supplementary file notes

Article page, text and pic. Also, previous scan version.

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