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Composite-ARF Yak 55 (2.1m/83")
techsupport@composite-arf.com
hook the spring over the sheetmetal screws - as shown in the photos.
Full-Length tuned pipe
A full length MTW tuned pipe and manifold for
the DA-50 is available from C-ARF as an option.
Please see the 'related products' link above
each color scheme photo on our website for part
numbers and prices.
To fit this you will need to cut the back off the
molded exhaust tunnel inside the plane and
extend it to match the pipe length. You could
make this extension with thin plywood or fibre-
glass sheet. For sufficient cooling you must
make sure that the outlet area for the warm air
to exit at the back of the pipe is at least as large
as the inlet area to the pipe tunnel.
Cooling
Depending on your choice of motor and exhaust system, mini-pipe or muffler you must make pro-
vision for enough cooling to all these components during flight. Depending on your engine con-
figuration you might even need to make a small balsa or ply baffle in the cowl to make sure that
cooling air entering the cowl passes through the engine cylinder head cooling fins before enter-
ing the exhaust tunnel.
Fuel Tank Base
Included in the kit are CNC milled plywood and balsa/composite parts to make up the fuel-tank
base, which also incorporates a receiver mount on the vertical back face. The photos show how
the parts are assembled, and the completed unit is then glued on top of the fibreglass wing spar
tube in the centre of the fuselage with epoxy and micro-balloons mix. Sand all the parts lightly
first, assemble with thin CA - and then reinforce all joints with a good fillet of epoxy and micro-
balloons mixture. It is also wise to seal all the bare balsa edges with a thin coating of epoxy -
just in case of a fuel leak, especially if fitting a methanol fuelled motor.
Reinforce the joint where the vertical balsa support is glued to top surface of the exhaust tunnel
with a short piece of 1" glassfibre tape and laminating resin. The tank base is designed for fitting
a Dubro 24 oz tank/700 ml (Part #424) and this is more than big enough, even for a DA-50. Glue
a scrap balsa block to the front to prevent your fuel tank moving forwards.
If you wish to mount your receiver on the vertical
support at the back of the tank base, then glue
the milled 3mm plywood stick to the inside sur-
face, centred on the 2 large holes, wrap the
receiver in thick foam and and fix it in place with
2 No.#80 rubber bands.
The fuel tank is held to the tank base with 3
cable-ties. Drill a hole in the motor firewall where
necessary for the fuel feed tube from the tank to
the carburettor, and protect it where it passes
through the fibreglass using a rubber grommet
or similar.
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