09/11/2018
RANS S-21 OUTBOUND
TEXT MANUAL
70
WING FUEL TANK ASSEMBLY
1.
Using a small piece of scrap aluminum sheet, make a drill guide as shown in
FIGURE 06-11
. The jigs purpose is to locate a center hole for the fly-cutter or
hole-saw. Make the screw holes about 1/4" outside of the small existing hole in
the tank to keep the jigs size down. If the jig is made too large it will interfere with
the fly cutter when the hole for the cap is cut.
2.
Screw the drill guide to the top of the tank, covering the center of the hole.
3.
Slide the fuel tank into position in the wing.
4.
Slide the Inside Root Rib into position and cleco to the front and rear spar. Make
sure the wing tank supports (top and bottom) are resting on the rib flange.
5.
Fabricate a sight gauge location tool as shown in
FIGURE 06-12
. Insert the Sight
Gauge Location Tool into the sight gauge locations in the Inside Root Rib and
use a long #11 bit to create a centering mark.
NOTE:
Drill only deep enough to create a mark and check to see that the
hole will be close to the center radius of the depression. Use a long #11
drill bit and drill a pilot hole for the sight gauge. Step drill to 1/2". A
1/2”
Unit-bit works well. Refer to
FIGURE 06-13
.
6.
Drill a #30 hole in the drill guide at the center of the hole in the top skin for the
cap. Mark the hole in the top skin to the top of the tank using a marker.
7.
Remove the tank from the wing.
8.
Cut a 3" hole for the wing tank cap using a fly-cutter or hole-saw and the
previously drilled hole as a guide.
9.
Debur the 3" hole.
10.
Remove the center of the fuel cap. Set the fuel cap flange into the hole with the
large drilled hole outboard. Center the cap assembly in the 3
” hole. Transfer drill
and cleco the holes in the cap assembly through the tank using a #11 drill. Do
NOT drill the outboard hole where the vent is located until after leak testing.
Remove the cap flange and debur the tank.
11.
Locate and pilot drill the hole for the AFT fuel withdrawal fitting as shown in
FIGURE 06-13.
Step drill
to 3/4". A 3/4” Uni-bit works well.
12.
Debur all holes and thoroughly clean any debris from the inside of the tank. A
shop vacuum works well.
13.
Insert a long piece of wire through the inside of the 3
/4” Bulkhead Fitting. Slide
the O-ring over the wire and onto the Bulkhead Fitting. Refer to
FIGURE 06-14
.
14.
Fish the wire through the hole at the rear of the tank for the AFT fuel withdrawal.
Pull the Bulkhead Fitting through the tank and into place.
15.
Install the rubber washer, 3/4" thick washer, and Reverse Thread Nut. Use blue
thread lock on the threads. DO
NOT
OVERTIGHTEN THE NUT. If the rubber
washer deforms past the washer, the fitting will leak.
