Prop Secret (oz12954)

About this Plan

Prop Secret. Free flight sport model for 1.5 cc motor.

Quote: "PROP-SECRET is the solution to the problem of airscrew position on a crescent wing, rather than any desire to be different. The first power flight of the original proved its efficiency, and with prop so concealed gives the appearance more akin to a crescent jet liner of the future.

Construction: Main differences in building are card tube fuselage, and cap-strip wing ribs. Use 1/32 Bristol board for fuselage tube, lap joined at bottom, make 1/8 cross grained, jointing wings at ends, and plank nose and tail cones with 3/32 x 1/4 strips. Make a solid job of wing C/S as this construction forms torsion boxes which hold nose and tail together via the two 3/4 inch dowels.

Build up prop drum around a 9 x 6 ED prop and balance carefully. Trim prop to 8-3/4 in dia this seems to leave very little area, however it is the part that usually gives most thrust.

Starboard wing and tailplane halves are built in the following manner. Pin down LE and TE spars, add 1/16 x 1/4 strips at rib positions, cement on tapered spars, and complete with further 1/16 x 1/4 in top ribs, 1/4 in sq tips and 1/8 sheet root ribs. When dry remove from plan, turn over, and pin further LE and TE strips to existing and so build port wing halves on bottom of starboard ones.

Cement tailplane halves together and add wing boxes between wing ribs. Plug on wing and prop up to dihedral angle before packing boxes round with scrap, and cementing. All other details are quite straightforward."

Direct submission to Outerzone.

Supplementary file notes

Article pages, thanks to RFJ.

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