Equipment and Accessories
In addition to the kit contents you will need some accessories, R/C, additional equipment and
small hardware items to complete your Sabre. The list below can act as a 'Check-list' to remind
you of the main items that will be needed, and our recommendations - based on our own experi-
ence, and that of several respected customers who have been operating our Sabre successfully.
Turbine
:
(4.5 - 6.5kg thrust) and installation kit with ECU, mounting strap, fuel pump and so-
lenoid valves etc. (eg: Wren MW44, MW54, PST600, Jetcat P60). This model is designed to op-
erate with turbines up to a
maximum
of 6.5kg (14lbs) thrust, and the fitting of a more powerful
turbine could cause excessive speed and structural failure, and consequentially injury or damage
to persons or property. No reference is made to EDF units in these instructions, but we know that
some customers have successfully flown our Sabre with Electric Ducted-Fan units.
Thrust Tube
: You will need to supply a suitable thrust tube for your turbine. A good source of
lightweight, well-designed, thrust tubes is Wren Turbines (UK). (www.wren-turbines.com)
Retracts
:
The kit was designed around Spring-Air 300 (or 700) series main gears (90 de-
gree) and Spring-Air 300 (100 degree) nose gear but, of course, many other units of a similar size
can be used. The main gear units cannot be higher than 30mm if you want the legs to fit fully into
the wings. A 100 degree retracting nosegear also allows the wheel to fully retract into the fuselage,
and retain the slight forward rake on the extended leg for a more scale-like appearance.
Wheels
:
We used a Ø 45mm nosewheel (1.75"). A soft foam type helps to prevent bounc-
ing during landing. Main wheels should be Ø 56 - 60mm (2.25 - 2.5"), and as thin as possible to
fit completely flush in the wing. The Robart type shown in the photos is Ø 66mm (2.75") and a lit-
tle too thick to fit totally flush.
Servos
:
For ease of installation we highly recommend that you use 4 'wing' servos such as
the 15mm thick digital JR3301 or Graupner 3328 for flaps and ailerons, as they have integrated
side-mounts on the servo case. In any case you should use digital types with a minimum torque
of 4kg. The horizontal stabiliser is quite thin, and therefore we recommend a pair of the 10.5mm
thick digital JR DS161's for the elevators. An alternative is the Hitech HS-5125 which is identical
in size, and has metal gears. Any mini-servo of minimum 4kg and 15mm thickness (eg: JR 3301,
3401 or Graupner 3328) will fit easily inside the vertical Fin for rudder control. A 'standard-sized'
servo easily fits in the nosegear bay for nose steering, preferably with metal output gear. Retract
valves, etc., can normally use any mini servos of at least 2kg torque.
Fuel System
:
A pair of fibreglass moulded main tanks (approx. 800cc each) are included in the
kit, which fit into bays in the wings. The tanks have an internal baffle installed during manufacture,
to prevent fuel surge. Included is basic stopper hardware, but you need to provide the brass tub-
ing (1/8" O.D), kerosene stoppers (Dubro part #400), clunks and I.D 3 - 3.5mm Tygon tube. If fit-
ting a turbine at the higher end of the thrust range you can fit an additional tank of about 300cc
(10 fl.oz) in the fuselage, just in front of, and below, the turbine.
We recommend a small 'hopper' tank between the main tanks and fuel pump, to prevent air bub-
bles getting to the turbine that could cause a 'flame-out'. Suitable tanks can easily be made from
any small 3 - 4oz tank, or you could use a BVM UAT, or the excellent small 'air-trap' from Intairco.
In addition you will need kerosene-proof fuel tube to suit your turbine, fuel filters etc.
Batteries/Switches
: The Sabre has a tendency to be slightly tail-heavy if fitted with a turbine at
Fox Composites Co., Ltd.
4