TIMER “JUNIOR”

TIMER Floating timer… One of the most complex and controversial requirements to the technology requirements of the class of models of free flight. A complicated structure, powerful power plant, rise to dizzying heights after the launch. What kid does not want to build such a microplane!
But, as a rule, to young timerite no balsa, no aluminum foil, not even a reliable and powerful engine working volume of 1.5 cm3. Still the same MK-17. However, using an elaborate, well-established pattern, the bearing concave-convex wing profile, to find the optimal elongation of the bearing surfaces, after working on “Junior” MK-17 and equipping it with a brake of the air screw, you can achieve very good results.
 
How to create for participation in competitions of such a technique, says one of the oldest model aircraft instructors of Ukraine, the head of the circle with more than thirty years of experience V. N. Doroshenko.
 
More than a dozen years boys build time similar designs, and successfully participate with them in various competitions. Therefore, the proposed model worked as they say, to screw. Similar devices are used by us in the “adult” class. Such time, calculated under the engine working volume of 2.5 cm3, different size, while maintaining all the design features “lorry”.
The peculiarity of the design — abandonment of the use of balsa and relatively simple power circuit. Despite this, we managed to achieve from models of good aerodynamic qualities, in particular through the use of concave-convex 9 percent profile with a small prognosti average. The latter promotes good motor and improved takeoff performance planning.
 
Svobodnaya timer model airplane engine cylinder capacity of 1.5 cm3.
Svobodnaya timer model airplane engine working volume of 1.5 cm3:
1 — engine, 2 — body, 3 — keel, 4 — rudder, 5 — stabilizer, 6 — wing, 7 — clockwork (timer).
 
Considerable attention is given to the engine. Serial MK-17 have changed, and some parts are made anew. Improvements allowed to increase the capacity by 1.5 times compared to a normal sample, and with timername screw it overlooks the regime of 18-19 thousand rpm On the toe of the crankcase is mounted a braking device that allows you to clearly stop the propeller literally a tenth of a second a deadline engine operation time. And this is the result — plus the tens of meters altitude of takeoff.
 
The fuselage. The front part is lime. First two bars 20Х40Х350 mm with the use of paper strips glued blank, and then machined to Ø 37 mm. After turning the belt with a length of 25 mm under the tail boom fit the workpiece is cut along the length to 295 mm (including the length of the belt). In the paper “streak” it hurts and hollows out a from the inside so that there were wall thickness of about 3 mm, and rear — 2.5 mm. Assembly of the halves is white glue, uninstall remnants of the previous strip and the adhesive joint.
 
The front part of the fuselage.
The front part of the fuselage:
1 — engine mount (D16T), 2 — power frame (plywood of 4 and 1.5 mm), 3 — planting the crutch (the wire OVS Ø 2.5 mm), 4 — fuel tank (tin 0.3 mm), 5 — a niche for timer, 6 — false ribs (Linden 3 mm plywood 1 mm), 7 — pylon wing (plywood 3mm), 8 — power tube Ø 37 mm (Linden), 9 — pull output, 10 — pin hinge wing (OVS wire Ø 3 mm), 11 — filling and drainage tube 12 — screw М3х25 (3 piece), 13 — supply pipe of the engine.
 
Tail boom wikiepedia of fiberglass epoxy resin. Will need a bar of lime, which grinds the front, Ø 36 mm, and the rear — Ø 10 mm. the surface of the wood is impregnated with epoxy resin and sanded before any work sealed with mastic for flooring. Fiberglass, annealed in a muffle furnace, cut, impregnated with epoxy and circumferential to the mandrel. If you use tissue thickness of 0.12 mm beam should be formed by two layers, with a thickness of 0.1 mm or three. The finished tapered tube is removed from the mandrel, for checking the quality of veclachi and adjust to the front of the fuselage. Gluing the two parts — epoxy resin, the butt surfaces are degreased prior to Assembly with acetone.
 
The tail part of the fuselage.
The tail part of the fuselage:
1 — the elements of border (Linden), 2 — Kiel (foam 5 mm), 3 — pull timer (line Ø 0.4 mm), 4 — “antennae” for clamping the wick (OVS wire Ø 0.4 mm), 5 — rudder (Linden), 6 — rocking of the rudder (celluloid 1 mm), 7 — tail boss (Linden), 8 — bezel (lime), 9 — emphasis of the stabilizer (foam), 10 — hook (OVS wire Ø 0,8 mm), 11 — bracket (celluloid 1 mm), 12 — unit control deflection, 13 — area of stabilizer (plywood 1.5 mm), 14 — tail boom (GRP).
 
SPAW fuel tank of tinned steel (Ø 25 mm, length 30 mm), it is placed in front of the lime tube. Then prepare the front frame of chetyrehkilometrovoy plywood (it must be a tube of the fuselage). Reinforce it by gluing a disc from polutorametrovoy plywood Ø 37 mm, then drilled three holes and mounted with glue screws with washers and nuts for mounting the motor and landing skids. The entire Assembly and the tank stuck on the front end of the fuselage.
The pylon is performed from selected quality plywood with thickness of 3 mm. After you cut it vyskazyvat and drilled two holes for the pins. The latter must be hard, must use wire brand OVS or piano. The installation of the pins is as follows. First, the middle of each is cleaned and degreased, wrapped in one layer of fiberglass, the seat is impregnated with epoxy resin, and the pins are inserted into the holes of the pylon. Immediately put the fuselage ribs and the whole package is clamped to the resin curing in the clamps. It should be noted that the ribs are prepared in advance, collecting each of the lime plates, mm plywood and accurately processed on the contour and the plane of contact with the pylon. After trimming the finished pylon to the fuselage it was glued tightly. The “feet” of the pole must pass through lime tube through.
 
A keel from the plate of foam with a thickness of 5 mm, on the perimeter of a banded fake reek. If you plan to cover the keel macalintal paper on Amalia, after profiling the entire part “varnish” slightly diluted PVA that will protect the foam from dissolving. The finished keel hung rudder and nodes mounted on the tail boom with epoxy resin.
 
Engine mount due to the fixation at three points ensures that unlike other options, a simple adjustment of the position of the axis of the propeller. The detail is milled from aluminum billet to fit the motor. In its rear wall are laid out and drilled three holes Ø 3.2 mm, and the center — Ø 11 mm for the branch pipe of the carburettor.
 
The finished fuselage after careful checking and correction of defects treated with sandpaper, fitted by a long-staple (michaletos) paper on Amalia and re-polished. Finishing — parquet varnish that protects wood from absorbing fuel and the associated increase of mass.
 
The wing consists of two consoles. Before starting preparation, it is necessary to mount the frame of two straight boards and to prepare sheet dural profile templates. Stapel, in addition to the Assembly frame is useful in painting trim and storage planes.
 
The console of the wing.
Console wing:
1 — power rib (1 mm plywood), 2 — the skin of the forehead (Polovtsian), 3 — rear spar, 4 — front edge pine (3X4 mm), 5 — spouts (Linden 1 mm), 6 — wing (micuenta paper), 7 — rib “eye” (Linden 0.8 mm), 8 — tip “lug” (Linden 0.8 mm), 9 — scarves (Linden 2 mm), 10 — ending (foam PVC), 11 — back edge (pine upon a time 3×13 mm, planing to wedge up to 1 mm) ,12 — mortise connection edges (celluloid 1 mm), 13 — rib (Linden 1 mm), 14 — rear spar.
 
The profiles of the wing (scale 1:1).
The wing profiles (scale 1:1):
1 scarf (lime 2 mm), 2 — spar wall (plywood 1 mm between the first four ribs, then Whatman), 3 — shelf side member (pine 3X4 mm), 4 — shelf rear spar (white 2,5X2,5 mm), 5 — root rib (lip 3 mm plywood 1 mm), 6 — piping holes for the pins (celluloid 1 mm) 7 — wall (Whatman, between the first four ribs), 8 insert (Linden 2 mm).
 
Frame Assembly features does not, and ends with the installation of the root rib of parklea basswood and plywood. Toe covered with paper or polovitkina “wet” method, and all plane — dyed macalintal paper on Amalia. The paint is applied in three layers. During the drying in the stocks under the edges of the wedge enclose the slats to the desired twist in consoles. And they are: right console +1° left centroplane part -0,5°, the left “ear” of -1°.
 
Stabilizer the same as a wing, is going on the slipway-Board. The Central rib of slightly thicker fake veneer (1 mm) between them are pasted plates of PVC foam. Cording to her forehead — glassine imposed “wet” method. The cording of long-fibre paper varnished with Amalita only twice. Drying and storage are also on the stocks, which guarantee the preservation of a given shape during the period of operation of the model.
 
Stabilizer:.
Stabilizer:
1 skin of the stabilizer (micuenta paper), 2 — the skin of the forehead (parchment), 3 — hook rubber ring (wire Ø 1.2 mm), 4 — skin-strengthening (foam PVC 2 mm), 5 — nozzle (Linden 0.8 mm), 6 — rib (Lipa 0.8 mm), 7 — shelf side member (pine 2X3 mm, without wall), 8 — the front edge (white 2,5X2,5 mm), 9 — ending (foam PVC), 10 — trailing edge (pine 2X8 mm, planing wedge), the 11 “mustache” determinator (OVS wire Ø 0,8 mm), 12 — hour (pine 3X3 mm).
These models
 
Wingspan, mm: 1300
 
Wing area, DM2: 18,23
 
The wing elongation: 9,2
 
The surface of the stabilizer, DM2: 4,84
 
The total bearing area, DM2: 23,07
 
Total weight without fuel, g: 465
 
Load, g/DM2: 20,2
 
Diameter/pitch propeller, mm: 170/80—90
 
Alignment, % SI: 60
 
Engine capacity, cm3: 1,5
 
The mass of the model elements, g:
 
Fuselage Assembly: 310
 
Wing (both consoles): 110
 
Stabilizer: 20
 
Timer: 25
 
Floating timer

 
DOROSHENKO, Uman

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