Ultra Stunter (oz4094)

About this Plan

Graupner Ultra Stunter. Control line stunt and combat model. 900mm span, for .06 to .09 engines.

Direct submission to Outerzone.

Printed over 2 sheets, the plan includes detailed build instructions text in both German and English.

Quote: "Hi-performance Control-Liner for stunt and combat to suit model engines from .061 to .09 cu. in. (1-1.5 cc) displacement. Installation drawings featured for: Taifun 'Hobby' (1 cc) model diesel, and Taifun 'Hurrikan' (1.5 cc) model diesel.

Preface. Ultra Stunter has been developed from the now famous and popular Super Stunter (oz4278) design of 1952 vintage. In fact, this initial design appeared as the first German commercial design and kit in the control-line stunt field, pioneered by Graupner.

In the course of development, a detachable wing, such as used for Super-Stunter, was discarded. This resulted in a far greater overall stability. Dimensions of both stunters mentioned are moderate; so there is no pressing need to disassemble the plane. Therefore, a fixed wing layout is no transport handicap. Size of model suits now very popular 1-1.5 cc (.06 to .09 cu in) displacement model diesel engines. Glow motors may be used equally well. However, larger displacement engines are definitely 'out', as model stress analysis is not sufficient to cover such additional loads and stresses.

Ultra Stunter may be built and flown with or without a fixed, cantilever landing-gear as detailed in the plans. If the potential builder is not a contest fiend, however, we recommend to construct the model without a landing-gear. In view of moderate diameter wheels used a smooth concrete runway for take-offs and landings is a MUST. On unsuitable flying grounds, such as cropped lawns, perfect take-offs are impossible, and your plane will ground-loop on many a landing.

HOW TO BUILD ULTRA STUNTER. To begin with, study plans and instructions carefully, in particular construction chart phases featured. Note that plans are in full scale. Balsa is the principal building material. Use a hard grade of 'wood where specified. Cutting of balsa should be done with a hobby-knife; for thicker sheet than 1/8, a fret-saw or vibrator-saw is advantageous.

If the model is to be built from stock material, trace contours of wood parts onto covering tissue. Dope tissue to sheet of appropriate thickness. With less than 1/4 in thick sheet, we recommend doping reverse side of sheet too, to forestall any warping of cut parts. Carefully sand every item prior to assembly and cementing. Use a reliable, quick-drying type of hobby-cement. Covering tissue may be applied with either, tissue-paste or thinned cement.

HOW TO ASSEMBLE FUSELAGE. Begin by cutting to shape bulkheads (1-9) and fuselage sheet sides (17). Prepare engine bearers (10 & 11), mark bulk-head spacings on same. Don't forget to sandwich fuel-tank (25) between bulkheads (2 & 3) now, as its impossible to add tank at a later stage. Also, note balsa locking strips (25a & 25b) used to hold tank securely in place. Unless a home-made metal tank is used, engine bearers (10 & 11) must be cut or filed away a little. Tank (25) should slide into place smoothly. For better fuel-feed to engine, bend tank feed tube downwards a little; but do this only when tank is in place. Seal off firewall carefully when tank is installed.

After basic fuselage assembly is cemented and dry, continue by adding sheet sides (17), cemented against bulkheads (1-4). Make sure that top edge of sheeting is parallel to that of part (11). Hold in place with pins till dry. Then, add remainder of bulkheads (ie: 5-9). Bottom edges of some must be flush with underside of (17). Be sure that fuselage remains symmetrical and straight. For details, compare with construction-chart, phase (2).

To tackle control mechanism, begin by cementing bellcrank support (12) into slots of bulkheads (4) and (5). Fill up gap between support and fuselage port side with (12a). Insert bellcrank axle, which consists of a 1/8 dia machine screw, secured to support with a nut. Add a brass washer, then bellcrank (27) and put another brass washer on top. Secure with two locked nuts (may be soldered). Pushrod (30) and also flap actuating wire (31) must be bent to shape with great care. Solder flop control link (28) to pushrod (30) where indicated. Insert pushrod into bellcrank (27). Secure with a soldered cup-washer. Carefully engage to (28) and (31). Check for free and easy movement.

When control mechanism is in place, don't forget to add extentions to tank vent and filler tubes. Also fuel-proof inside of tank compartment by rubbing balsa twice with cement. Insert wing central spar (13) of hard balsa through slots in (17). Add a thick cement skin over joints, before bottom sheet (18) of 1/8 sheet is cemented in place. Secure with pins till dry, and start on turtle deck planking. Cut to shape tapered strips of 3/64 sheet, match by cut and try and leave no ugly gaps or seams. Cement on strip by strip, hold with pins till dry. Sand turtle deck lightly and cut cockpit opening to match canopy (26). Also make rear slot for fin (21) as shown in construction-chart, phase (3). Add fin fairing cnd rudder (22). Make sure that rudder is offset 15 degrees outboard, as shown in three-view G. A. Secure rudder in position with a cement sleeve.

Engine cowl comes next, which consists of ports (14) to (16). Parts (14-15) are cemented into place permanently. However, bolt engine into place first. Secure mounting nuts by spot-soldering each to a wire-pin, pushed into bearers (10 & 11). Now you may take out or exchange engine any time as required. Remove, to sand cowl and block (161 into shape, which is hinged to fuselage later, by a length of linen tape. Cut passages for cylinder and needle valve as required. Main plan sheet shows installation of HOBBY model diesel. Installation of new reed induction HURRIKAN is on on auxilialy sheet. Note different bulkhead shapes, etc, given there. Note also changed lengths for cowl blocks and fuselage sides. Cut a passage into cowl rear so that you can finger-choke rear carburettor of HURRIKAN-engine. All the interior of engine compartment then is fuel-proofed by rubbing several coats of cement into wood..."

Supplementary file notes

Planfile includes full build instructions.

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