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opposite directions to the crankshaft by means of seven capscrews each. The flange for this attachment is extended radially outward to form a sidewise locating flange for the bearing. A 0.156-in. thick tongue extends into the space provided by the difference in crankshaft bearing journal OD and bearing race ID; thus the radial load is carried on this lip. This method of mounting differs only in detail from that used on certain American engines for a similar application.

The front extension of the crankshaft front section incorporates, in addition to the front main bearing journal, 3.54-in. OD square splines for mounting the reduction driving gear. There are 14 splines spaced on the basis of fifteen with one omitted. The designers apparently found it desirable to index the driving gear. The gear is retained by a large nut per conventional practice. The inside of the extension is bored out to receive a 2.12-in. ID copper-lead- lined heavy steel backed bushing for supporting the rear propeller shaft journal. The rear extension of the crankshaft rear section mounts the rear main bearing with conventional retaining nut and is splined internally to receive a coupling for connection with the starter and accessory drive

plugged by means of a 17S aluminum-alloy spool pressed in and not otherwise retained. Lubrication to the master connecting-rod bearings is by means of five holes in each crankpin. Four of these holes are located (two on each side) in a plane normal to the plane of the crank throws. The fifth hole is close to the center of the pin, a few degrees in advance of the plane of the crank throws on the side unloaded by rod inertia. Oil jets for piston lubrication are provided by drilled holes through the counterweights to the main journal

bores (see Fig. 11).

CONNECTING RODS — connecting-rod system in each

The bank

is

of

the

conventional

master

articulated

type.

The

master-rod

length is 11.25 in. from crankpin to the piston-pin center. It is of I- section construction with the typical carving required for transfer from hub to shank sections. See Fig. 12. The hub section has the appearance of being rather small compared with the rest of the rod, with flanges scalloped quite closely around the knuckle-pin bores. Material is the all-purpose steel mentioned in the “Ge neral Discussion,” hardened to Rockwell C 40. Master rod bearing is a heavy-steel-backed, copper-lead- lined, shrunk-in bearing with a flange at one end. Steel is soft, 0.094 in. thick. Lining analysis corresponds to American practice with a small amount of tin and 1 percent silver. The lining structure is

good for fracture ductility

medium loading. Bond and examination were good,

  • good, X-ray — good.

Micro examination distribution but coarse

shows good structure with

irregular dendrites in section and shrinkage in

the the

cross- surface

structure. 0.020 in.

See Fig. 13. Lining is thick. The flange is cut

away

at two points to mate with keys

shaft. The

crankshaft

is

drilled

for

milled into the rod hub rotation. As mentioned

to prevent previously,

lubrication of connecting-rod bearings and all parts forward. The oil passage through the center cheek is of some interest in that a large axial hole serves as a point to start diagonal drilled oil holes to each crankpin. These oil holes are offset to allow th drilling spindle to miss the crankpin. The large hole is then

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    $

the

crankpins

are

3

by

3-3/8

in.

The

bearing shell is chamfered off to provide 2.87 in. length. Bearing clearance approximately 0.005 in.

and cut bearing used is

Articulated rods are 8.7 in. long between knuckle-pin and piston-pin centers. They are the conventional I- section rods and appear very similar

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