“TOMAHAWK” ON THE LUNGE | MODEL CONSTRUCTION

Published in “M-K” № 9, 1993 fundamentally new scheme of auromodele immediately liked by our members. Attracted her not only a win-win for aerodynamic resistance and stability in the race, but… the strangeness of the forms, which allowed to finally make something new after wandering from year to year, the classical variant “Bertoli”.

Theoretical calculations that accompanied the publication does not stray from the accumulated in our mug practical knowledge and experience. Therefore, the basis for creating models for the next sports season, we chose “Tomahawk” (as the boys instantly “christened” the new scheme due to the characteristic hull form of the model).

Despite the fact that proposed in the journal layout of the power unit seems perfect, when drawing drawings of model with the engine working volume of 2.5 cm’ (in the publication of the proposed version of 1.5 cm ) is back to the side position of the engine cylinder. The reasons for this decision are several. First — simplifies the production, which is important for beginners. The second facilitates access to the engine, its maintenance, especially in terms of the competition, which is also important. Of course, the translation engine side location proigrysha on the total resistance and requires a higher placement of cord strap. However, for “mass” model of training-sport use this is not so important. A variant of a plant with a vertical position of the cylinder of the motor, we left for championship purposes.

What we got as a result of design searches, is clearly visible in these images. The new model turned out to be no more complicated than the classic, even, perhaps, simpler and smarter. When designing the maximum attention is paid to the availability of raw materials. The only place where it was not possible to do without the “exotic,” the empennage. Since the removal of each and every gram of this zone model improves the stability of the stroke, had the design of the stabilizer to use balsa (albeit in a very small size and volume). If you have this wood is absolutely not available — replace it with brushed fins up polyfoam or PVC type PS-4-100. The result of the departure from the balsa will be slightly proigrysha by weight, but will slightly decrease the strength and stiffness of the tail.

Notice the unconventional arrangement of the tail a pair of ice skates. Unlike the standard version, the skates are put on the ends of the stabilizer, the new one is better for several positions. First, it now eliminates the Bouncing of the tail section caused by a spring properties of any thin stabilizer. Secondly, the stabilizer can now be much easier, as it does not carry any load except a small aerodynamic. And third, due to the lower loads and the shoulders of their actions and greatly facilitated the site of installation of the stabilizer on the tail boom case, turning of the screw connection in a simple adhesive joint. And after a couple of MZ screws with washers and nuts in the kit is heavier than the whole aircraft stabilizer.

The model design is self-explanatory. After completion of the work side of the tail boom pasted thin strong paper on the epoxy, then proceed with sanding and painting of the hull. Stabilizer this technology, in addition to Stripping edge finishing is not required.

R and S. 1. Control line speed model snowmobiles with motor working volume of 2.5 cm3.

Fig. 2. The basic structure of the balancing model that provides the stabilizer with a positive lifting force expressed in screen mode.

R and p. 3. The scheme of suspension of the main skate

R and S. 3. The scheme of suspension of the main ridge.

A – the calculated position in the race, the B — position when hitting the uneven ice skating rink. COG the center of gravity of the model L₂— leverage between the fulcrum of the main ridge and vertical level of the center of gravity.

Fig. 4. The design of the model:

1 — taper-nut (D16T), 2 — coke (D16T), 3 — the support washer (D16T), 4 — pole motor (team detail made of plywood thickness of 6 mm with double-sided taping the plywood with a thickness of 1.5 mm), 5 — modified boosted motor KMD-2,5, 6 — fuel feed pipe from tank nozzle to the spray nozzle, 7 — needle adjustment the jet tank, 8 — fuel tank 9 — the screw of fastening of the tank (3 pieces M2,5), 10 — the attachment of cord strap, 11 — contour of the cutout Windows of relief in plywood with a thickness of 6 mm pole motor. 12 trim (birch), 13 — horse (steel), 14 upper longitudinal beams (pine section W X 16 mm, the end reduced to 3X8 mm) 15 beam filler (packing foam), 16 — lower spar (similar parts 14), 17 — rear bracket auxiliary rear pairs of skates (glass 0.6 mm thick), 18 — boss (Linden), 19 — Logement plane 20 to a fixed part of the motor fairing (lime), 21 — window, the air intake of the carburetor of the engine, 22 — fixed sock (lime), 23 — removable part of the cowling of the motor (dugout detail of lime or Vileika GRP), 24 — window for the exit of cooling air.

R and S. 5. Fuel tank.

1 – intake tube integrated injection tube (annealed copper diameter 3X0. 7 mm), 2 a fuel feed pipe to the spray nozzle (nagarebana copper diameter Z X0,7 mm on the end to cut an external thread MZ X 0.3 for mounting the nozzle), 3 — tube for filling and pressurization of NZ crankcase (copper diameter SX X0,7 mm: at the end of napati ring wire diameter 0.5 mm), 4 the tank body (tinned tinplate of a thickness of 0.3 to 0,4 mm; pattern to make taking into account allowances for flanging).

Fig. 6. Manufacturing technology of stabilizer:

1 — base (glossy sheet of plexiglass with a thickness of not less than 4 mm), 2 — fiberglass with a thickness of 0.005 mm, impregnated with a limited amount svezhenakleennyh epoxy, 3 — assembled stabilizer (trim — lime 3 X 3 mm, zakonczenie elements — lime 3 X 5 mm, the Central insert — lime W X 5 mm 2 PCs, filler — balsa is lightweight with a thickness of 3 mm), 4 — cover overlaid with a sheet of fiberglass. After folding the items and the integrity to pull the package through a rubber bandage to complete the curing of the epoxy resin.

The engine presented is modified in accordance with the latest achievements boost engine KMD-2,5. On a set of measures to be carried out with the motor, repeatedly written “M-K”, so to repeat there is no need.

The fuel tank is also a progressive scheme with an external nozzle the win-win kind of acceptance was also covered in the journal). For those who haven’t upgraded to this power supply circuit will be useful for at least the following information: none of the models from KMD we do not have standard scheme, all converted to the “tank” and the nozzle is rotated 90″ in the course of the crankshaft rear wall of the housing.

Knowing that some athletes are outspoken supporters of springing major skate on aeromodeler driven suspension system, which give the obstacle a “flat” movement of the model, without changing the angle of the tail boom. Models of new type, which require some unusual balancing along the length of the hull, this is important. Although in fairness it should be noted that we consider the need for suspension of the main ridge at least controversial.

In conclusion, I would like to say that “Tomahawk” is proposed today the construction can successfully be designed as left-hand direction along the path of the track and right — depending on the used mug in primary school run and adjust aeromodel.

V. vitin,

the head of the circle of aviamodelirovaniya

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