Snipe (oz3854)

About this Plan

Snipe. Sports model for single channel RC. A 36in rough field flyer for single channel radio and Cox .049 power, designed by Harry Purser.

Direct submission to Outerzone.

Quote: "Your FULL-SIZE plans. A 36 inch rough field flyer for single channel radio. The Snipe, by Harry Purser.

NOT BEARING any resemblance to the KeilKraft Snipe, this model is nevertheless a direct descendant thereof! The original free flight version had been flying around for about four years with an ED 46 when I acquired my MacGregor single channel gear. Against advice from learned R/C types, the equip-ment was fitted to the dear old Snipe, which flew reasonably successfully despite the low power. The changes began when it flew through a fence and shattered the wings. A stronger, smaller set were constructed (Mk2) and again flying was good but the fuselage gradually came apart. Hence the present one was constructed (Mk3).

Purely functional (both sides can be cut from one sheet of balsa) and very simple, this fuselage is as near unbreakable as any I know. All sheet tail surfaces completed the model which was now powered by a Cox .049. Strong by comparison to the original Snipe f/f wings, the new ones were well and truly bent during removal from a tree, dictating even stronger construction for small field work. The present set were designed making Snipe Mk4. Mine are tissue covered, but despite dozens of prangs have not even holed (I am now fully convinced that full depth spars will require some beating for strength). Almost like new, the twelve month old original has had more flights than I could possibly recall.

For those who are endowed with more patience than I am, elevators are shown on the plan for use with a Compact or similar escapement. I tried this with some used and abused RS Navigator gear which skipped sufficiently to almost always give a control which was definitely not required, ie spiral dive to right, either left or up elevator would be handy - I usually got right, bang!

An ordinary (left, right, left) Conquest escapement was then fitted with the original MacGregor gear, and I find the model very easy to fly. It can even be 'control lined' (flown round the operator in tight circles at about eight feet altitude).

Now for the construction: It is recommended that the whole model is built using a PVA or similar glue (except where detailed) and that all parts are cut out and marked before commencing construction.

The mainspar is built first, carefully glueing the halves onto the plywood dihedral brace. Next attach the 1/4 in square leading edges to the lower wing sheets. When these items are set, the leading edge, trailing edge and centre section sheeting (note grain) are pinned over the drawing. The completed main-spar is now securely glued onto the rear of the lower sheeting (adequate support must be given until set), the ribs added and also the leading edge dihedral brace. When set, this structure may be removed from the board, the leading edge carved to shape (follow-ing the rib contour) and the upper leading edge, trailing edge and centre section sheeting may be added. Note that the sheeting on the left wing should end on the centre line of rib W1 to allow mating with the right wing, which is now built ex-actly as the first around its mainspar over the plan. Add the 3/4 in soft sheet tips, tape reinforcing and sand the whole structure smooth.

The tailplane is made from good quality 1/8 balsa sheet as shown. Add the braces to the tailplane to give that extra strength and help to resist warps. Moving surfaces are hinged, using thread stitching or tape, whichever is preferred. Add the wire yoke(s) either by bolting as shown or even cementing in position. The original model was fitted with the yoke cemented to the rudder with no sign of this coming adrift, but careful adequate cementing using a good balsa cement is a must.

When building the fuselage, note that the right hand doublers and 3/16 square front members are set a shade back for right sidethrust. Add doublers to nose and tail (grain vertical), escapement rails and all braces and gussets to sides as indicated. Note that F 4 is built up over plan. Join sides on formers F2, F3 and F4 and leave until set.

Drill F1 to take 8 BA engine bolts, insert these and solder wire across the slots to prevent their turning. Firmly glue the completed former F1 in position and join sides at tail, using rubber bands to hold sides in position until set. Add 3/32 in sheet floor, cross members and fin platform. Also the two ply cheeks to the inside of the extreme nose..."

Supplementary file notes

Planfile includes article.

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