Plover (oz12202)

About this Plan

Plover. Control line stunt model.

Quote: "Aan out-of-the-rut sports control-line stunter for 2.5 - 3.5cc motors. Plover, by John Stroud.

MANY CONTROL LINE stunt men spend hours and hours looking for full size aircraft designs to crib, and to make a good stunter that looks different. Development along logical paths seems to lead to models that look alike and I have never found designs that look like a jet fighter and fly like a Tiger Moth very attractive. After building a couple of crop-duster like models I still yearned for something more unusual.

During the First World War and just after, a few full size aircraft were built which looked like Plover - the Junkers DIIV is a good example and with just a little licence, I think I have produced a model with the atmosphere of that era, and an excellent performance.

The basic proportions and construction follow accepted practice - only the fixed 'ailerons' and undercarriage construction are unusual. I have tested the undercarriage fully and consider it well worth the time and effort involved. The fixed ailerons worried me before I flew the model as I was sure that they would incur an aerobatic penalty.

My friends who profess to be aerodynamics experts agreed, but would not put a figure to the loss of performance. To my delight there is no loss in performance, and there may even be an increase. My friends then set about explaining why it flies well - the desirable increase in thickness/chord ratio is achieved by the fixed ailerons. Certainly the model is light (28ozs) and the OS 15 produces ample power. Whatever the reasons, it flew straight off the drawing board and needed no trimming.

My one regret is that I did not wait for the local shop to get some transparent plastic covering - the solid colour has hidden the structure and lost some of the atmosphere.

My original drawings were for a 35 cu in stunter and anyone preferring this size model only has to add 25% to all the dimensions.

The construction is straightforward and will present no problems to anyone who has made a few models beforehand. Select medium to light balsa unless otherwise stated on the plan - a good stunter must be light, be accurately built and have a free moving control system. Time spent on achieving these objectives on a successful design is never wasted. Strength comes from a simple but sensible structure with good joints and glue - I prefer PVA glues and find the longer setting times acceptable if one works on several components at a time.

Construction: For some reason I prefer building wings, and thus always start with this component. Cut two rib templates from scrap 1/16 or 1/8 plywood, as shown on the plan. Cut 18 x 1/16 and 2 x 1/8 rectangles of quarter grain balsa and sandwich them between the templates, then carve and sand the resulting block until a complete set of ribs is formed. Cut spar notches, and file to an exact fit on the spar, then carefully drill the block of ribs to make the leadout holes. Now select two 1/16 ribs and the two 1/8 ribs to make two ribs R2 & R3 respectively. Mark a line on these ribs 1/16 in from the edge contour by the 'thumb gauge' method. Trim away the surplus wood to produce ribs 1/16 in undersize (to be covered with 1/16 sheet centre section covering later).

Carefully cut out the bellcrank box components from 1/16 ply and assemble as shown in the sketch. Make bellcrank from paxolin or dural and mount on a suitable piece of brass tube which provides a good bearing on the pivot bolt. Fit bellcrank between top and bottom of the box and ensure that it is free but not sloppy.

Add R3 to each side of the bellcrank box using PVA glue, and check for squareness all round - I leave mine to set lightly held in a vice. Cut out leading edge and trailing edges and select mainspars. Note that wing is built to 36 in wing span but that the left hand wing is 1 in longer than the right hand (tips added later, bring the span up to 43in).

Pin down bottom trailing edge and glue all ribs, including bellcrank box, in place using bottom spar as shown to support ribs until dry. Add top spar and LE and top trailing edge..."

Plover, Aeromodeller, October 1976.

Direct submission to Outerzone.

Supplementary file notes

Article pages, thanks to RFJ.

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