Vedeneyev M-14P, Maintenance Manual, Page: 192 / 381

2.3. IMPELLER
Impeller (5) (Ref. Pig. 1) is the most stressed part of the blower. At take-off rating of the engine its
rotational speed reaches as high as 23,700 r/min. To decrease inertia forces and dynamic loads on the impeller
drive shaft bearings, the impeller is stati-cally balanced before installing in the engine by removing metal from the
surface between the blades.
The blower impeller is stamped from aluminium alloy and comprises a hub and a disk with fourteen radial
blades.
To ensure smooth entrance of mixture in the impeller passages, the blade leading edges are curved in the
direction of the impeller rotation.
The impeller disk has fourteen inclined through holes (6) connecting the Impeller passages with the
annular space defined by the conical surface of the impeller disk recess and the diffuser surface. These holes are
intended for equalizing pressures on both sides of the impeller, thus decreasing axial pressure on the Impeller.
The impeller hub has six internal rectangular splines to mount it on the blower shaft. The Impeller is
anodized for protection against corrosion.
Impeller shaft (33) is a hollow cemented steel part having an integral gear rim at the rear.
The shaft outer surface features a cylindrical band, annular groove, six splines, a cylindrical surface with
an annular groove and thread for nut (17) intended to secure the parts on the shaft.
Two longitudinal grooves extending through two opposite splines are made between the annular grooves.
The grooves interconnect front (8) and rear (35) blower seal bushings.
Bronze bushings (16) and (31) pressed in both ends of the shaft'are used to support the impeller shaft on
the necks of accessory drive shaft (9).
The blower impeller shaft mounts: oil baffle (34), rear bushing (35) with four bronze oil sealing rings (27)
and (30), adjustment ring (7), impeller (5), spacer (22), front bushing (8) with four bronze oil sealing rings (19) and
(21) and lock (18) which locks nut (17) securing the stack on the shaft.
Adjustment ring (7) is intended to set the impeller for the required gap between it and the walls of the
mixture collector and diffuser.
2.4. BLOWER IMPELLER DRIVE
The blower impeller drive comprises drive shaft (9) (Ref. Fig. 1) of the accessory drive with blower coupling
(29), twin gear (25) and impeller shaft (33).