Jack in a Box (oz7706)
About this Plan
Jack in a Box. Two function sports glider designed for easy transporting in a small box.
A suitcase model. When demounted, the Jack-in-a-Box fits into a travelling case 29-1/2 x 11-3/4 x 3-3/4 inches.
Quote: "A 44 inch span sports soarer for transporting in the smallest practical space. Jack in a Box, by Geoff Sprawson.
We all know the frustration of finding a perfect flying site in perfect weather conditions and not having a model to fly. Perhaps you have no model to fly because the wife, kids and all their clobber fill the car right up, or your favourite model won't fit the suitcase, or your boss objects to the company car being full of toy aeroplanes.
Here is the answer! A fun-to-fly sports slope soarer that will slip in under the luggage, fit into a large suitcase, or even look like a case full of memos from head office. Jack-in-a-Box is designed to be a good sports model, not too difficult to fly, which fits with transmitter, charger and a repair kit, in a box small enough to slip into an odd corner of the car. It is simple and quick to rig on the field, cheap to build and big enough to carry full size radio gear, (the prototype flies happily with 500mAH nicads, a seven function Futaba receiver, and two standard servos).
Construction: To keep the airframe as light as possible, select the lightest wood available, avoiding any of the really cheesy brittle pieces, for all of the structure except the wing leading edge and main spars, which need to be hard.
Start with the wings (they are needed to line up F3). Cut out the ribs and drill, the inner three for the main joiner tube, lining them up at their top and back edges. Plane the lower bevel on the leading edge, glue the ribs and spars together over the plan. Lay the halves of the wing sheeting to-gether, tape them on one side, hinge the joint open on the tape, glue the edges and weigh them down flat on the board. Mark the rib positions on the lower skin, squar-ing from the trailing edge. Glue the frame onto the lower skin, pin down flat with the leading edge over the edge of the board and hold the sheeting on the leading edge with clothes pegs.
When both wings are dry lay them both out on the board with joining tubes and wires in position, support them at the dihedral angle and epoxy the tubes in place. Add the filling and webs around the tubes and epoxy the hooks for the retaining bands in place. Razor plane the leading and trailing edges to section, fix the top skin, the tips, torque tubes, trailing edge pieces and the ply root rib.
Before starting work on the fuselage check that your radio gear will fit, if it won't adjust the size of the nose to suit. Epoxy the main wing joiner tube accu-rately across F3, assemble the aileron bellcranks on their mounting plates, and fit over the rear wing joiner tube. Slip the whole assembly onto the wing joiner wires with the wings in position and..."
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