About this Plan
Snark. Free flight towline gider model.
Quote: "The Snark is a 63in span glider to the A2 specification by Dick Twomey who was a well known designer and flier of gliders at that time. The design had impeccable credentials then and is still thought well of in today's SAM crowd. The swept back, plug in wingtips and the curvaceous fuselage certainly make it easy to spot out on the field. As always if you do decide to build from my plans take care and ensure you measure well before cutting."
This is a modern redrawn plan in PDFvector format.
Quote: "With plug-in wingtips, aerofoil fuselage and simple structure. Dick Twomey's latest sailplane, the Snark.
THIS curvacious sailplane to Nordic A/2 specification, has a pedigree that many another towline soarer would envy. Developed from Dick Twomey's Snoek design, the Snark is a real thoroughbred with a history.
Its predecessor first flew in a steady downpour of rain; Dick just could not wait for tests, and even though soaked, the Snack maintained an average of just under three minutes. First fair weather tests boosted the average to over four minutes, and the first contest found it third with. a maximum of over five minutes on the first and only flight. This A/2 development makes use of the required increase in weight by sheeting the fuselage, thus utilising weight for extra strength.
With less span and greater loading, the Snark has many advantages over the original Snook, not the least being its remarkable consistency, which is shown in last season's results. For distinctive appearance, both static and airborne, we know of no other comparable design.
CONSTRUCTION: Fuselage: First cut out two fuselage sides from R in. sheet, and join with formers A and B. Add in. spacers, nose formers and nose decking in in. wide planks of 1 /16 in. sheet. Add fins.
Now bend tow hook, D /T hinge wire, other wire attachments and skids. Add noseblock and shape. Brace the rear end of the fuselage with ply as shown. When cockpit is added, and auto-rudder is hooked up, the fuselage is ready to cover.
Cockpit moulding is very easy. All you have to do is to carve and sand a balsa block to fit as a cockpit itself. Then take a large sheet of thickish celluloid, and stretch over the balsa 'mould' in front of an electric fire. In two minutes the job is done, and all that remains is to tidy up the edges of the celluloid with a pair of scissors.
Wings are built in a slightly different way from the normal. The complete wing is composed. of three pieces, a 36-in. centre-section, and the two tips, which are dowelled into position and sealed with Sellotape. This makes for great wing strength against towline stresses. The centre-piece is straightforward. A small block is shaped to fit flush with the back of the cockpit. Dowel tubes are fitted. in the end ribs.
The tips are best built in two pieces each tip - consisting of the 3 in wide flat-panel, and the actual tapered tip. Dihedral (4-1/2 in each side) is built into each tip assembly. Leading edge sheeting on the tips is on top only.
Tailplane is straightforward and is kept as light as possible. Do not forget the wiring for D/T, and make sure the fitting is firm.
Trim. Flying should present no difficulty. Ensure that auto-rudder pulls central, and returns to flight position (left or right turn) when hook is released. When glide is satisfactory, towing adjustments can be made with slight alterations to the 'straight' or 'towing' position of the auto-rudder. Any prevalent instability on the line will be found to be caused by a too rear-placed CG. The recommended CG position is 3-3/8 in back from the LE.
When built, the model may easily be under-weight. Note that A/2 minimum is 14-1/2 oz. The recommended method of ballasting is by finishing, polishing and doping the fuselage. "
Supplementary file notes
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by Dick Twomey
all formers complete :)
got article :)
Found online 07/10/2012 at:
Format: • PDFvector • CADfile
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User commentsWing ribs R3 R4 R5 are not drawn to scale on the plan sheet correct length is shown on the top view of the wing tip panels . Former F5 is shown as 2.375 wide correct to 2.125 wide. I have a Snark ready for covering
wmdbowman - 31/03/2015
l am currently building a 2 meter version of the Snark, and to fix the wing tip faulty rib sizes l have used r2 as a guide, r3 is copied @84%, r4 68%, r5 @47%, hope this helps.
Mark - 28/01/2021
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