ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL
Rev.
7
MM-10-42
Aug
22/16
(4)
Drill aft coupling as follows: (see Figure 10-21)
(a)
Mark a line on driveshaft 7/8" from end of shaft.
(b)
Slide coupling on shaft until even with 7/8" line.
(c)
Mark and center-punch Point "A" of Figure 10-21 using dimensions given.
(d)
Drill through coupling and driveshaft with a "D" size drill (Ø.2460).
NOTE:
Drilling must be done in a drill press to assure that drilled hole is
perpendicular to driveshaft.
(e) Ream hole with a #2 tapered reamer to fit an AN386-2-8A taper pin very
carefully so as not to over ream.
NOTE:
If over-reaming of a tapered hole occurs, substitute the AN960 washer with
an AN975-3 cup washer or use P/N 28-13623-11 through -17 taper pins as
required.
(f)
Install taper pin through coupling. Install washer and nut, and torque.
(5)
Temporarily slide forward coupling half on forward end of driveshaft and place
driveshaft on tailcone.
(6)
Secure driveshaft couplings to gearbox couplings using an aluminum block
.235 inch thick between couplings. See Figure 10-22.
(7)
Mark location of forward coupling on driveshaft using a felt marker. Mark
location of pillow blocks on driveshaft.
(8)
Remove driveshaft from tailcone.
(9)
Remove forward coupling from driveshaft.
(10) Add 7/8" from mark on driveshaft and mark a new line for end of driveshaft. Cut
shaft to length.
NOTE:
Do not cut driveshaft at initial coupling position mark.
(11) Ream forward end of driveshaft with .640 reamer to remove paint.
(12) Loctite aluminum plug in bore of driveshaft.
(13) Drill forward coupling to driveshaft following procedure in step (4). See Figure
10-21.
(14) Install driveshaft on tailcone and connect both couplings to transmissions using
aluminum blocks. See Figure 10-22.
NOTE:
Taper pins on both main rotor and tail rotor gearbox sides of coupling are
AN-386-2-7A.
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