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11
it must supply power to the receiver from the flight battery. Switch
the motor on briefly, and check the direction of rotation of the
propeller once more. Hold the model very firmly before
switching the motor on, and remove any loose, lightweight
objects from the area behind the model before the propeller
does it for you.
Caution: even small motors and propellers constitute a
serious injury hazard!
17. Control surface travels and settings
The elevon travels must be set correctly in order to obtain a
balanced control response:
Up-elevator
(stick back towards you)
10 mm
Down-elevator
(stick forward)
8 mm
Aileron
travels
+8 / -11 mm
(negative differential)
If you cannot set these travels by making adjustments at the
transmitter, you will need to re-position the pushrod connectors
on the elevon horns.
The neutral position
The neutral position for the first flight should be
approximately 2 mm “up”. Once you have test-flown the
model, you may wish to increase the control surface travels
by about 20%.
During test-flying you will normally need to adjust the trims
slightly. After the first landing we suggest that you mark the
correct elevon setting on the fins using a waterproof felt-tip
pen. For the launch phase trim both elevons “up” by about 1
mm, i.e. 1 mm above the marked points.
Remove the up-trim again after the initial climb-out.
One little point to note for the perfectionists amongst you: as is
the case with all aeroplanes featuring this power configuration,
the model has a slight tendency to roll around the longitudinal
axis in reaction to motor torque. The FunJet ULTRA rolls slightly
to the left at full-throttle.
18. Default downthrust setting
The design of the motor mount provides an easy means of
varying the downthrust (inclination of the motor thrustline). For
the first few flights select the “0” setting. This is accomplished
by fitting the right and left locking screws loosely, holding the
motor bulkhead in place with your thumb, and setting the
adjustor screw (bottom) to “0”. The setting should always be
read off on the external scale, at the bottom of the motor mount.
Finally tighten the locking screws carefully until they rest against
the bulkhead, then tighten them by a further half-turn.
Caution: on no account tighten the screws more than this,
as the result will be a deformed motor bulkhead.
19. Balancing - Centre of Gravity
The FunJet ULTRA, like any other aircraft, must be balanced at
a particular point in order to achieve stable flying characteristics.
Assemble your model completely, ready to fly, and install the
flight battery.
You will find hemi-spherical markings in the underside of
the wing close to the change in leading edge angle.
Support the model at this point on two fingertips and it should
balance level; if not, adjust the position of the flight battery to
balance the model as described. Once you have established
the correct position, mark the location of the flight pack insidethe
fuselage to ensure that it is always replaced in the same
position.
Fig. 18
20. Fine-tuning
The FunJet ULTRA offers superb flying characteristics which
can be optimised by careful adjustment of the Centre of Gravity
(CG) and motor downthrust. The new design of motor mount
is very helpful here, as it enables you to adjust the downthrust
easily, and the set thrustline can simply be read off on a scale
(plastic bulkhead only).
Start by flying at full-throttle, and trim the model accurately, i.e.
straight and level “hands-off”. If you now switch the motor off,
the aeroplane should make a smooth transition to a steady
glide. If it climbs and slows down, the downthrust is too great
- reduce the downthrust angle. If the model goes into a dive,
the downthrust is insufficient - increase the downthrust slightly
and add a little up-trim before flying again. Repeat this
procedure until the model goes into a smooth descent when
you close the throttle, and responds to an open throttle by
spontaneously flying straight and level, with a slight tendency
to climb.
Fine-tuning the CG: fly straight and level at full-throttle, then
abruptly roll inverted. You will need to apply down-elevator to
maintain level flight, and this should be about 15 - 20% of full
travel. If you need less down-elevator to hold level inverted
flight, the CG is too far rearward; if you need more down-elevator,
it is too far forward. In almost all cases you will be able to
correct the CG by adjusting the position of the flight battery. If
not, add a little ballast to nose or tail as required. If you have to
alter the CG, you will need to re-check the downthrust setting.
21. Gilding the lily - applying the decals
The kit is supplied with two multi-colour decal sheets
2A + 2B
.
Cut out the individual name placards and emblems and apply
them to the model in the position shown in the kit box illustration,
or in an alternative arrangement which you find pleasing.
22. Preparing for the first flight
For the first flight wait for a day with as little breeze as possible.
The early evening is often a good time.
Be sure to carry out a range check before the first flight,
using the procedure recommended by your RC system
manufacturer.
Some ideas for improving reception conditions:
1. Install a separation filter between the speed controller and
the receiver.
2. Keep the speed controller / motor cables as short as
possible.
3. Avoid deploying servo leads - including the one attached to
the speed controller - parallel to the high-current motor cables.
If you are not sure about any aspect of the system, please do
not risk a flight. Instead pack up the whole system (including
battery, switch harness and servos) and send it to the
equipment manufacturer for testing.
The first flight ...
Do not attempt to hand-glide this model!
The FunJet is designed for hand-launching only - always launch
directly into wind.
If you are a beginner to model flying we strongly recommend
that you ask an experienced model pilot to help you for the
first few flights. The model should be launched at ½ to ¾-
throttle, with the wings level and the nose angled up at an
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