Turbine, Fuel Tank & Thrust Tube Installation
These 3 items are inter-depen-
dant on each other and need to
be installed together.
The Hawk is designed for tur-
bines of between 4.5 and 7kg
thrust. We flew the prototype
with a PST600, which is quite a
heavy motor, and even though
the completed plane weighted
almost 6.5kg (dry) it flew very
well indeed. Current production
Hawks are considerably lighter
than our prototype, and several
customers have flown the
Hawk with the excellent Wren
MW44, and it has sparkling
performance as the wing-load-
ing is reduced considerably.
IMPORTANT:
The Hawk is de-
signed for turbine of maximum 90mm diameter. If
you fit a larger motor the turbine may be too close to
the top surface of the wing, which could cause in-
sufficient airflow around it, and may even damage
the wing due to the heat. Maintain a minimum 10mm
gap between the outer case of the turbine and the
top surface of the wing in all circumstances.
The turbine should be mounted on the 2 milled ply-
wood plates provided, which are then bolted onto the
bottom of factory-installed fibreglass flanges in the
fuselage. These 2 plywood mounting plates also se-
cure the 2 conformal fuel tanks in place in the fuse-
lage, and make removal for maintenance very quick
and easy. A little patience taken in shaping the ply
plates to fit to the the fuel tanks nicely will reward
you with a neat and simple installation. The upper
surface of the wing and the curved inner surfaces of
the fuel tanks also serve to direct the air from the
inlet ducts into the turbine with minimal turbulence.
Thrustline
The bottom surface of the fibreglass mounting rails
that are bonded into the fuselage is nominally 3mm
above the centre of thrust tube (and centreline of the
turbine), to allow for the 3mm plywood mounting
plates. Therefore, if your turbine has a mounting
bracket that is offset from the centre (eg: Jetcat) you
Fox Composites Co., Ltd.
21
General view of completed turbine and fuel tank installation
from underneath. Note that ply engine mounts are shaped to
retain fuel tanks also. PST 600R turbine shown.
(above) Right hand tank/turbine mount-
ing plate sanded to final shape and
bolted to the fibreglass flange.
(below) Shape and sand the turbine/tank
mounts from the 3mm fibreglass/ply parts
provided in the kit. Left tank shown.
