QuiQue's Aircraft Yak-54S Assembly Manual page 33

Figure 49
Figure 50
Use double-sided high strength tape
in between the plate and bottom of
the tank to prevent the tank from
forward motion.
Strap the tank using zip ties or
Velcro.
Figure 51
2. Another way is how Quique has
done his. Use two blocks of balsa
and sitting them on the floor of the
fuselage. One in front of the wing
socket and the other behind the wing
socket like below drawings. The
balsa blocks need to be flush with
top of the wing socket. Glue the
block to the wing socket using epoxy
and then glue a 1/16" plywood ply on
them. Best done if you have a band
saw to make the shape of the wing
socket on those balsa blocks. See
Figures below.
Between the plate and tank, you
need to have double-sided tape.
33