Section Ill. REPAIR
This section provides instructions for accom-
plishing complete and detailed maintenance on
the engine within the scope of the Maintenance
Allocation Chart. Each subassembly or part is
treated as a separate unit in the discussion of
7-24. Compressor Rotor and Blades.
Blade rework is limited to the outer 2/3 of
the blade. Vane rework is limited to the
inner 3/4 of the vane.
Repair of the compressor rotor and blades consists of
blending and polishing to remove nicks, dents,
scratches, corrosion, or erosion from the blades, blade
fillets and wheel hubs. Where blending is recom-
mended, use a medium grit stone. Where polishing is
recommended, use a fine grit stone or abrasive paper
(item 22, table 2-2), Blend and polish blades in a longi-
tudinal direction only with the repair forming a
smooth blend with the basic airfoil. No sharp edges,
burrs, cracks, or tears are acceptable after blending.
of blades or vanes which maybe reworked
is not limited. The limiting factor of blade or vane
rework is engine performance. Any reduction of blade
or vane area will decrease the efficiency of the com-
pressor and the performance of the engine. Remove as
little material as possible.
a. Leading and Trailing Edge Damage.
polish to remove damage on the outer 2/3 of the blade.
Replace compressor when: (1) the limits of figure 7-10 are
exceeded or (2) there is edge damage in the lower 1/3 of
b. Tip Damage. Blend and polish to remove tip
damage. Replace compressor when: (1) more than 1/3 (1/6 on
each side) of the original blade width requires rework
or (2) rework extends within the inner 4/5 of the blade
length. (See figure 7-11.)
c. Surface Damage. Blend and polish to remove
surface damage. Replace the compressor when any of the
limits of figure 7-12 are exceeded.
Figure 7-10. Compressor Rotor Blade Leading
and Trailing Edge Blend Limits
Figure 7-11. Compressor Rotor Blade Tip
If a crack is suspected, refer to TM 1-1520-254-23,
Technical Manual Aviation Unit Maintenance (AVUM)
and Aviation Intermediate Maintenance (AVIM)
Manual nondestructive inspection procedure
the OH-58 helicopter series. The number
Change 23 7-15