Sukhoi SU 31—2.75m/2.6m Page|21
Parts Required:
•
Carbon Tank Tray Mounting Rods
•
Plywood Tank Tray Discs
•
Fuel Tank DuBro 40oz
•
Tygon Fuel Line
Tools Required:
•
Steel Rule
•
Marking pen
•
CA and some Kicker
•
Hysol (or Epoxy with micro balloons)
The fuel tank tray is a pretty basic structure, comprising of two carbon
rods and 4 mounting plates. The round mounting plates are essential
for spreading the load over a wider area and keeping the tank tray
secured and in place. You may elect to use some of the ply pieces to
aid in keeping the tank in position. This is not completely necessary
as the tank can be held in place with some zip ties. However the op-
tion is yours. We used a Dubro 40oz (1200cc) fuel tank, however
there is plenty of room for most size tanks, or even a smoke tank.
You need to position the tank centrally over the top of the wing tube,
this is where the C of G is located. The carbon rods will need to be
cut down to suit, ours came in at 282mm and 276mm. However this
measurement may vary from model to model, so please take a cor-
rect measurement to meet your requirements.
As you an see from the pictures, when the carbon rods are held in
place with 4 ply discs, simply tack these discs in place with CA and
kicker , then when you are satisfied with the positioning, epoxy in
place. You may also want to add some ply strips to support the tank
if you wish (see picture), although this is not necessary.
You can also epoxy ply across the tank tray rails to mount you radio
equipment, please keep in mind that you need to be able to get your
hand through this area when attaching the forward wing retention
nuts.
Please note: if you are using one of the current lightweight en-
gines on the market such as the DA120, you will need to mount
the majority of your radio equipment as far forward as possible
to aid in obtaining the correct C of G. It may not be possible to
mount the batteries over the wing tube.
Fuel Tank Tray
