BOAT RUNNER | MODEL CONSTRUCTION

In this article we want to introduce you to one of the last successful boat designs intended for participation in endurance racing. It was created by the master of sports of international class V. Osadchiy, who took the class up to 6.5 cm3 first place at the USSR championship in 1983 with a score of 64 laps and first place at the international competition in the GDR with a score of 71 circle. Similar microtiter helped the master of sports N. Alexandrov to become the second in the match of the strongest athletes took place in Chisinau. New hull lines provide excellent course under difficult weather conditions, significant wave and wind.

Simplicity of design-rotor, the rejection of the use of difficult to manufacture high-precision reducer allows you to use published drawings and novice athletes. Still a valuable replacement engine “Vebra-40” can be a local MDS-6,5 with the cylinder pair in the “color” version. Trial runs of the model with this motor showed that it is not inferior in its characteristics to foreign sample. MDS-6,5 operated in the serial version, the revision only applies to the adapter that connects the exhaust pipe of the crankcase with a resonant exhaust pipe, and installation of ring nozzles water cooling on the shirt of the cylinder. At the request of the editorial Board V. Osadchiy, N. Alexandrov told about the features of the design boats-marathon runner.

The case of The model, the bulkheads, the transom and cover the same technology in the form of a sandwich of perekleiv: fiberglass — foam — fiberglass. As a filler used foam stamps PVC-1 thickness 4— 5 mm. Minimum weight with sufficient durability and high quality external surface provides vacuum forming, which are all elements of the case. A similar process is described in detail in the article by A. and S. Microskin, Chukalenko “RC F1 class-V5” (“M-K” No. 6, 1983).

Cover wikiepedia integral with the deck portion of the housing and after the curing of the resin is cut along the breaklines in the surface of the workpiece to the aft bulkhead. The front edge of the cover has a beveled end, securely holding it in the closed position in the housing. The foam is opened in the recess of the deck is sealed with a broad strip of fiberglass epoxy resin ED-2 at the perimeter of the hole in the hull and following the contour of the cover.

The rigidity of the body attach to the transom and bulkheads. Before installing them you need to mark and cut holes in the fiberglass or thin-walled dural tube forming a channel for the resonance of the exhaust pipe with extra silencer. The parts fit exactly to each other, they are glued in the housing. Also on the epoxy glue mounted water inlet with a pipe for supplying cooling water to the engine and an exhaust pipe. Only after this you can install the deck.

Theoretical hull lines of the model.

The sub frame consists of two parts bent at a right angle from a stainless steel sheet having a thickness of 1.2 mm. At the ends of them hard solder “welded” flanges with holes O 4.5 mm. the legs of the engine parts are laid out and drilled holes for connecting the motor to the frame.

The absorbers significantly reduces the level transmitted to the hull vibration, and hence noise of the entire model, made of oil-resistant rubber. They brewed brass bushing, bearing and the threaded shafts (screws M4 flat head screws). The collected dural sleeve are inserted into a mold, where fit and raw rubber. The mold is compressed by the clamp, is placed in an oven and aged at a temperature of 135-145° for 30-40 minutes.

Ready to the absorbers are inserted in the flanges of motors and fixed with nuts M4 split washers. The free ends of the shock absorbers are vertical grooves of the corners on the bottom of the model and fixed the same nuts.

Due to the fact that the model used Microdrive “Vebra – 40”, the operating speed does not exceed 20 000 rpm, the propeller shaft is connected with motor directly, without a gearbox. The propeller site has a collet that allows you to quickly replace propeller shafts even during the race. Shaft material — heat treated spring wire O 4 mm.

Stern tube made of stainless steel O 8X1 mm, the front end carries soldered the bushing with the ball bearings 4X13 mm PTFE inserted into the rear sleeve with a length of 20 mm.

Container of radio equipment represents a sealed box with receiver, three steering servos and battery pack. Insights of machines equipped with rubber rings to prevent ingress of moisture into the container. It is fastened by four M4 screws to lugs preferovany on the bottom of the case. To compensate for the heeling moment caused by the unbalanced installation of the resonance tube with a silencer, a container offset to starboard.

Gelmanova pipe made of aluminum alloy D16T, blank — pipe 6X1 mm O. the rudder Stock — spring wire O 4 mm, it is solid solder is attached to the rudder of stainless steel with a thickness of 1 mm.

The fuel tank capacity of 1500 cm3, soldered it from thin sheet metal. Of the cavity are two copper tube O 4 X 0.5 mm — feeding and pressurization. Pressure is taken from the resonance tube near its maximum section. On the top wall of the tank is mounted in the bore of O 20 mm filling port with removable plug.

RC sudomodel class FSR of 6.5:

1 — antenna, 2 — container radio system, 3 — mounting brackets starting numbers, 4 — fuel tube tank, 5 — nasal septum, 6 — propeller shaft 7 — snap sleeve, 8 — deadwood, 9 — sleeve, 10 — resistant nut, P — propeller, 12 — wheel 13 — housing 14 — rubber ring, 15 — pipe 16 — aft bulkhead, 17 — fuel tank 18 — pressure tube, 19 resonance tube with additional chamber muffler, 20 — tube tank, 21 —cover 22 — cardan, 23 — gon, 24 — seal 25 — sub frame 26 and the exhaust pipe, a 27 — engine, 28 shock, 29 longitudinal bulkhead, 30 — latch.

The node that is acting as the needle of the nozzle is located outside the engine in close proximity to the tank, connects with it and with the carburetor of the engine with rubber hoses. Cover deck has two brackets for installation starting numbers and the latch holding it to the frame. The connection of the exhaust pipe of the engine With a tuned exhaust pipe is made by means of a tube of heat-resistant silicone rubber. From the same material made of the ring, worn on the aft part of the muffler and tightly included in the channel of the housing. The exhaust pipe is mounted on the engine with the band.

Propeller with a diameter of 42 mm has a constant pitch equal to 55 mm. the Blades are made of steel 40X13 a thickness of 1.2 mm, on the hub are attached by hard solder.

Weight of complete model without fuel is approximately 3.2 kg. the Center of gravity is helpful a few to shift to the left side with the prevalence of rotations in one direction on the race route. The length of the center of gravity is situated in the center of the output shaft tube from the housing, the Exact position of the alignment model determined during the training runs, changes in alignment — by moving the fuel tank or the placement of additional ballast.

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