Sixpence Mk1 (oz5650)

About this Plan

Sixpence Mk 1 Mini Glider. Single channel soarer for piggyback launch. Note both this plan and the 2 channel Sixpence Mk.2 (oz1582) appeared in the same article "Micro Gliders", along with details of the piggyback launch mechanism.

Quote: "Horst Fenchel goes Micro for some cheap fun.

Micro Gliders. You dedicated large model fans won't have any time for these little aeroplanes, the best I can hope for is a sympathetic smile. But why should I care? This much you can't dispute - Micro models provide a better fun/expense ratio than anything else.

With a wingspan of just on 600 mm (23.6 inches) the 'Sixpence' presented here definitely counts as one of the gnats of the model flying world. And yet wherever you turn up carrying such a dwarf of a model you are guaranteed to arouse astonishment and enthusiasm. Not least because the Sixpence features its own 'special function', a complete mini piggy back launch mechanism.

Sixpence Mk.1

Wingspan - 600 mm
Weight - 80 to 100gms
Control - Rudder (single channel)

The photos and sketch give a good impression of this flyweight. The factor which governs fuselage volume is the size of your receiving system; the servo, receiver and battery (50 mAh) simply cannot be too small and too light.

Fuselage - Arrange the electronic components in line astern on a piece of 1.5 mm balsa sheet and draw the fuselage outline round the outside. The fuselage is a simple box construction reinforced on the outside of the nose with 0.5 mm ply.

Wing - This is a built up rib/spar construction, use Clark Y or similar. The same rule applies; build as light as you possibly can. The wing is banded on.

T-Tail - The rudder is actuated by a closed loop system using two lengths of thread, one to each side. The Tailplane is also banded on, so that you can pack up the leading or trailing edge to adjust pitch trim.

Piggy Back.The mechanism is simple but effective. The release pin (Bowden cable inner tube) is coupled to the rudder servo, and runs out through the canopy at the front. At full rudder deflection the pin disappears into the fuselage and releases the retaining band. Simple as that. The Piggy back mount shown below is used if the suction from the wing of the carrier model pulls the wing of the Sixpence to one side. The simple version has no side supports.

Make the cradle from 2mm/3mm balsa, its quite strong enough for such small models. In any case low weight is vital for small tugs (one of the authors is a powered mini model fitted with a Cox Tee Dee 020). The Sixpence fuselage should be a snug fit in the cradle. The cradle is slightly cambered to follow the wing section of the tug plane. The piggy back unit is held on the tug using rubber bands, the photographs should make this clear.

The release band for the Sixpence runs from the release pin, back over the wing, under the cradle, then forward again, over the nose and back once more to the release pin. As already mentioned the Sixpence is released by applying full control throw, the pin retracts and the loops at the end of the rubber band fly off to the rear and release the glider.

Flying. Controlling a single channel glider is not especially difficult provided that the model is properly trimmed. You can kill an incipient stall by applying rudder to initiate a turn. Too much height, and a spiral dive saves the day. Wait for a day with minimal wind (at the slope) or no wind at all (flat field), otherwise it is very likely that your Sixpence will disappear downwind..."

Sixpence Micro Gliders, Quiet Flight International, August 1994.

Update 01/05/2018: Replaced this plan with a clearer copy, thanks to Circlip. Also added article, thanks to RFJ.

Direct submission to Outerzone.

Supplementary file notes

Article.

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