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Composite-ARF YAK 55SP (3m span)
Exhaust Cooling
Remove the canisters and turn the fuselage over so that
you can cut out the air exit holes underneath. These should
be minimum 150mm long and 45 wide, with radiused cor-
ners to prevent the composite sandwich tearing. Leave at
50mm space in between the 2 holes, where the carbon join-
ing tape is, for strength. If you fly in very warm ambient tem-
peratures, extend the length of the slots to 170mm (for-
wards to wards the pipe support bulkhead) to ensure suffi-
cient air exit flow.
Now you can glue the pipe support bulkhead into the fuse-
lage properly, using a slow epoxy and micro-balloons mix-
ture, reaching thru' the air exit holes to glue the rear face.
You will need to make 2 slots of about 25mm
wide and 40mm long for the muffler exits,
between the landing gear legs as shown.
For security, during final muffler installation,
install 2 of the small sheetmetal screws
though each the teflon joiners into the canister
entries and header ends to make sure that the
cans cannot slide forwards or backwards dur-
ing flight.
Tuned Pipes.
There is more than enough space to fit a pair
of tuned pipes in the muffler compartment, but
it is too short for full-length pipes. If you wish
to fit pipes then you will need to extend the
back of the compartment by about 150mm
(6"), and reposition the Rudder servo tray on
top of it. However, we have included a pair of
milled plywood tuned pipe supports in the
wood pack, to suit Ø 50mm pipes, such as the
Greve units.
In the near future we hope to manufacture a
molded muffler compartment extension for
customers who want to fit full-length tuned
pipes.
Motor Cooling
It is imperative that your chosen motor not
only receives sufficient air to cool it through
the opening in the front of the cowl, but that
the air is forced to go through the cooling fins
of the cylinders - otherwise the air will just take
the easiest route and exit the bottom of the
cowl without doing any cooling. In this case
techsupport@composite-arf.com
(above) MTW headers & canisters
are available as optional items from
C-ARF. Shown here are the TD110
cans and headers for the DA-150.
(below) Support bulkhead secure-
ly glued into position in the muffler
compartment with epoxy and
micro-balloon mixture.
(above) Make two small 40 x 25mm wide slots
for the muffler exits.
(below) 2 small screws thru' the Teflon joiners
prevent the cans moving in flight.
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