However, after the release of “M-K” No. 5 in 1983, where he talked about design is very interesting racing córdoba models, there was a kind of self-similar “technical microevolution”. The decision, prompted by the journal, was able to minimize the seemingly insurmountable chasm, the gap between the protozoa and sports APPA-
drugs. Now, not only KMD-2,5 and any other engine without alterations have become “subservient” hands boys. In the proposed variant was absent node turns racing a pipe dream for the beginner, — the rear axle with a classic shaft drive and gear reducer. Ninaka “space” materials, all the details without any problems made in the school office work.
Since the publication of this “Modeler” quiet life of our circle changed. It seemed that the boys Wake up from their slumber, they began to go to every single class (most often now complain that too few hours per week we do!). And how many were born bold and original ideas!.. The new scheme opened the way for a wide and affordable design search brought boys from the narrow framework of traditional designs. The main thing — the young avtomodelistov appeared promising, became a reality the creation of a “real” sports equipment.
For two years the club has built under the “Vyatka” many models, they vary the decision of those or other nodes and used engines. But the greatest success can be considered racing under the series a micromotor on the MK-17 “Junior”. It is, in principle, iterating on the engine “Vyatka-2,5”, we want to tell you today.
Cord racing car:
1 — base plate, 2 — front suspension spring finger under the machine stops, 3 — pin speed us machine gun forward, a 4 — whisker automatic stop 5 — brake Shoe, 6 — screws of fastening of the engine, 7 — arm rear axle, 8 — M3 screw mounting axis, 9 — wing, tin solder, 10 — rear (driven) axle, 11 — driven wheels Assembly, 12 — fairing the hull, 13 — tube-guide for the screw tightening, the fairings 14 — cord strap, 15 — block drive wheel Assembly, 16 — hour sample of us machine 17 — the drain pipe of the tank, 18 — a corner of fastening of a tank 19 fuel tank 20 Igla nozzles 21 — supply pipe of the engine, the 22 — bracket support tube feeding, 23 — frame, 24 — Microdrive MK-17 “Junior”, modified, 25 — fairing power plant.
First of all, about the schema of the chassis model. It is front wheel drive. We chose it because of the stability of motion, front-wheel drive racing with noradrenaline bridges is higher than that of the apparatus of another construction. Below and the probability of detachment of the rear driven wheels of the track Assembly of tail part of the model is constantly, though slightly, pressed against the canvas of torque from the propulsion system. Additionally, the resistance increased due to significant increase in the base.
When designing “Vyatka-1,5” we are particularly concerned about the simplification of the manufacture of all its parts and details. Even a minor complication were admitted only if it could have a significant positive effect on driving performance. Has worked much, and as a result was born a quite non-standard microcomputers.
The basis for it is a flat aluminum plate with a thickness of 6-7 mm. its Processing along the contour of the simplest plumbing equipment is easy even for a beginner. Thick base provides exceptional rigidity and strength of the entire model, its weight (160-180 g) only benefit handling characteristics, improving the clamp to the track. Just need to mention a new race had to reload to bring it up to the weight allowed by the rules (for lighter models increases wheelspin, which reduces the develop in the arrival rate). This has never happened before: in the limit of 1 kg
managed to meet only with great difficulty!
Before cutting the base in the billet necessary to make a hole under the toe of the crankcase. The dimensions of the uncut sheet will be used to set it on the table of the drilling machine. The deployment hole is running on the same machine after rough drilling. Requirements for the accuracy of the layout of the axes and the tolerances of the diameters of all other holes is minimal. The last operation is the cutting with a jigsaw, slit-like grooves that produce at the base of the sponge clamp of the engine, and getting tapped holes M4 locking ainty these sponges.
The base may be made even of steel, it uses billet with a thickness of 3-4 mm. the engine Mount on the other. In the regular legs on the crankcase hole is drilled along the axis of the crankshaft and cut thread M2,5. Long screws heat-treated steel firmly pressed Carter to the side surface of the base. After final Assembly and control of mass detail release excess weight and drilling holes in the “plate” between the rear axle and the engine bonnet.
Tested in our circle, except for dural, and the plywood base. However, ordinary plywood was weak, had to “spacetravel” epoxy resin solid billet of five sheets, with thickness 1.5 mm each. A model with the same “chassis” necessarily loads in addition in the bow. It should be noted that despite tough training conditions, breakdowns that critical parts are not marked. The engine on a plywood base installed on the dural area with a wall thickness less than 4 mm, privernuty to an external “Board”. Moreover, the area was not conducted under the legs of Carter, and clamped with three screws fixing the cooling jacket of the cylinder! More rational was the mounting of the motor on a wooden base in the same way as steel. The legs are attracted to a metal plate with a length of about 80 mm, and it privertyvaetsja screws three MZ on the left side of the base.
However, with all the variety of choice of materials for the part that unites the nodes into a single racing design, the best have yet to acknowledge D!6T. And it’s not the strength, stiffness and ease of processing. The main thing — is the basis of the mass of well dampens vibrations from the engine. Less affected by their influence on the adhesion to the surface of the track, unsprung wheels and a maximum speed of “Junior” compared to the other options increase by 300-500 rpm.
By the way, a few words about clutch unsprung wheels. As we could see, slipping our lorry less than the “Vyatka-2,5”. We believe that the positive effect given the absence of a balancing cut on the cheek of the crankshaft “Junior”. Usually, when designing engines strive to reduce the overall level of vibrations as would distributing them circumferentially around the axis of rotation of the crankshaft. The oscillation frequency of the push-pull micromotor, balanced by all the canons of the engine, 2 times higher than the unbalanced. Thus, establishing a perfect engine for the car, we turn it into… good high-frequency “shaker”! What about the rubber grip with the track can then be discussed? And isn’t that what determines the jump racing models after the fact at the time of transition of the driveline, in fact, only reduce the transmission of vibrations to the drive wheels?
The engine model:
1 — tank (tinned sheet), 2 — nozzle, 3 — a feeding tube(copper d 3X0 7), 4 — screw M3, 5 — spacer, 6 — frame, 7 — motor, 8 — fairing power plant (Linden), 9 — fairing of the hull (Linden), 10 — rubber wheels (rubber sheet), 11 — spacer wheel (steel, the ends of the handle cutter for high feed), 12 — long nut, 13 — hub (steel), 14 — nut M5, 15 — split cone (steel), 16 — notched nut М16Х0.7 (mounting the engine on a continuous base plate), 17 — base plate, 18 — parts (solder on tank), 19 — drainage tube (copper d 2X0,5). The clamp and screws wall of the crankcase conventionally not shown.
What is more profitable MK-17 with its imbalance? First, the frequency of vibration when in two times less. However, their amplitude is significant, but they are directed along the motion of the model, and, therefore, not affect the clutch! For vibrosensitivity to the drive wheels in a vertical direction, this race is almost equal to the versions with cardan shaft!
But back to the design of our model. To reduce the removal of the wheel block relative to the base plate, the front of the engine has undergone some improvements. First of all deepened by 5 mm Jack socket underneath the bow bearing, the same was shortened and the toe of Carter. The result was the release of a polished section of crankshaft suitable for a precise fit of the wheel unit (on a production engine support cone is placed on the area of the shaft, not subjected to grinding and therefore do not ensure the quality of the landing wheels). In its own way solved a method of tightening the supporting parts. Unlike conventional nut tightening cone is now threaded on the shank of the cone. This effort significantly reduced the overall width of the entire plant.
Different from the regular system and carburization of fuel. Installation of regular Zolotnik rear wall with the usual carburetor made us hard to move the fuel tank to the side of the nozzle. The abolishment of the customary carburetor possible to reduce millevoi section racing, the mode of the operation of the motor improved. The introduction of the spray tube exactly on the axis of the intake air flow reduced aerodynamic losses at suction in the same passage section of the carburetor, spray the “bottom” of the tube increased the vacuum, absorbing the fuel and thus increased the stability of the operation. All this was achieved by moving the nozzle into the cavity of the fuel tank. Before his seal at the outlet opening of the regular corps planted the pipe d 3X0. 7 mm, which after final Assembly, introduced 3 mm in the hole clipped the back wall of the engine and fixed in this position by the clamp. (If necessary to “squeeze” the throat of the carb at the end of the feeding tube cut into small thread and it is the base of the cone in the direction of the crankshaft’re in for a conical nozzle.)
The tires of the wheels of both “bridges” are cut from sheet rubber. On the drive wheels it is sandwiched between a set of hubs, spacers and longer nuts (the latest it can be controlled in an arbitrary way) on the slave using four MZ bolts between the disks. They are both the place of installation of ball bearings for easy rotation of the wheels of the rear axle.
The last stage is fit to complete model elements of the fairing, the recess in the motor part of the openings of intake and exhaust engine cooling and exhaust exit. After the final adjustment and securing of all joints of the wooden parts are triple coated with parquet lacquer and painted with synthetic enamels.
In addition to clarifying the situation of cord strap, racing other debug work is not needed. Adjusting the compression ratio of the engine through an elongated tubular key.
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