Great Planes SU-31 3D ARF - GPMA1412 - Manual (Page 38)

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a felt-tip pen to mark on the fi rewall the locations of the smooth
spots between the louvers on the cowl. If you have diffi culty
reaching through the front of the cowl to reach the fi rewall, tape
your pen to the end of a dowel rod or something similar.
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5. Center the cowl mounting blocks on the marks that
you made and trace around them onto the fi rewall. (Choose
one mark on each side of the plane that will not interfere with
anything.) The outside of the blocks should be fl ush with the
fuse sheeting. Mark the former behind the fi rewall at the top
of the plane for two more blocks. (These should be evenly
spaced apart and not interfere with the auxiliary battery tray
location.) The last two blocks should be placed near the
bottom of the fi rewall evenly spaced apart. When locating
the bottom two blocks, consider the size of the cooling hole
that will need to be cut out from the underside of the cowl
(look ahead in this manual for details).
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6. Remove the epoxy from the areas on the fi rewall beneath
the cowl mounting block locations with 220-grit sandpaper.
When satisfi ed, use 30-minute epoxy to glue the cowl blocks
in position. A small dot of medium or thick CA glue will hold
the blocks in place while the epoxy cures.
For added strength, after the cowl mounting blocks have
been securely epoxied in place, drill 1/8" [3.2mm] holes
through the center of each block and through the fi rewall.
Insert an appropriate length of 1/8" [3.2mm] dowel (not
included) into the holes and into the fi rewall. Glue the
dowels in place with CA and sand the dowels fl ush with the
face of the blocks. This modifi cation is especially important
when using a high vibration engine.
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7. Fuelproof the cowl mounting blocks with epoxy.
❏
8. Temporarily install the canopy hatch. Apply strips
of masking tape at least 6" [152mm] long from the cowl
mounting blocks back along the fuse as shown. (Make the
tape parallel with the length of the fuse.) Measure from the
center of each cowl mounting block 5" [127mm] back and
draw a straight line down the tape between your marks.