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model is when it is close to the ground, and hand launches
are therefore by their nature extremely hazardous. There
is hardly any time to correct the controls, and a hard landing
can easily damage the model.
Range testing (for experts too!)
Ensure that your transmitter and receiver batteries are
freshly charged according to the battery manufacturer's
recommendations. Before switching on your transmitter
make certain that your channel is vacant. The channel
pennant on your transmitter aerial is obligatory, and shows
other pilots what frequency you are using. If there are other
pilots present, tell them loud and clear what channel you
are on, and find out what frequencies they are using.
Before the first flight you should carry out a range check,
and we strongly recommend that you repeat the test before
the start of every day's flying. Hold the model in such a way
that your body cannot mask or otherwise influence the
receiver aerial.
A friend should collapse the transmitter aerial fully (but
leave it attached), then walk away from you carrying the
transmitter.
As the range increases your colleague should operate
one transmitter function constantly while you watch the
model's control surfaces. The servos not being moved
should remain motionless up to a range of about 80 m,
and the moving servo should follow the stick deflections
immediately and smoothly. Repeat the test with the motor
running. Even when close to the limit of ground range the
motor must respond immediately when you switch it off
from the transmitter.
This test can only be carried out successfully if the radio
band is not suffering interference, and if no other RC
transmitters are switched on - even on different channels!
Note that in high mountain areas extreme field strengths
and excessive range of other transmitters make such
checking procedures worthless.
If you are not sure the system is working correctly, please
don't risk a flight - even if you are dying to fly the new glider
and your mates are egging you on. Check first that your
channel really is vacant. If so, and if the problem persists,
pack up your entire RC system (complete with batteries,
switch harness and servos) and send it back to the
equipment manufacturer for checking.
Faults don't cure themselves!
The first flight
At the slope or at a flat field site
Set the motor running at full power and give your Alpina
4001 ELEKTRO a powerful hand-launch, with the wings
level and the nose angled slightly up. Immediately correct
the climb angle if necessary, and adjust the trims for a
straight climb. It may be necessary to mix in a little elevator,
depending on the power of the electric motor system you
have fitted.
At the slope you should wait for a period of reliable lift and
launch the model with the wings level and the nose down.
Don't worry if the model dives at first - it will pick up speed
rapidly, and speed is half the battle! If necessary adjust the
trims to achieve straight flight and a reasonable cruising
speed. The next step is to fly turns and circles in both
directions in order to test the model's turning
characteristics, the harmonisation between ailerons,
elevator and rudder, and the degree of aileron differential.
Be sure to try out the airbrakes or crow brakes at a
reasonable height so that you are ready for any pitch trim
change on the landing approach.
Checking the Centre of Gravity (always with motor switched
off)
The procedure for CG testing described here is a method
of fine-tuning the model's balance. It can only work when
air movements are slight, and when the initial CG position
is approximately correct. It is bound to fail if the model is
way out of balance and/or there is a strong wind. In windy
conditions it is difficult to set up the model for normal cruise
speed, as it is hard to judge the model's speed relative to
the surrounding air.
Trim the model carefully for normal cruising speed, which
should be comfortably above stalling speed. The model
should show no tendency to "hunt" up and down, or mush
along close to the stall. It should respond normally to all
controls. The camber-changing flaps should be at neutral.
Now - assuming that you have plenty of height in hand -
apply down-elevator briefly to place the model in a vertical
dive. Immediately centre the stick and watch the model
carefully. If it recovers to normal flight in a broad, gentle
curving arc (100 m) by itself, without ballooning up above
the horizontal, then the CG is correct.
If the model bounces up again immediately and climbs
strongly, the CG is too far forward.
Remove a small amount of lead ballast (min. 20 g, max.
40 g) from the nose, apply a little down-trim and repeat the
test.
If the model shows no tendency to recover by itself - the dive
may even become steeper - the CG is too far aft.
Immediately recover the model with gentle up-elevator.
Add a small amount of lead (min. 20 g, max. 50 g) to the
fuselage nose, fix it securely, and apply a little up-trim.
Repeat the test.
Once you have established the optimum CG position it is
best to remove any additional nose ballast and correct the
CG by adjusting the position of the flight battery.
Thermal flying
We assume that the electric motor is used just as a self-
launching aid, and that for the rest of the flight the model
will be flown as a pure glider.
Making the best use of flat field thermals is not particularly
easy, and calls for considerable skill and experience.
Areas of rising air are harder to detect and recognise at a
flat field because they tend to occur at higher altitude than
at the hillside, where it is often possible to find lift while the
model is cruising along the edge of the slope and then
circle away in it. A thermal at a flat field which occurs directly
overhead is very hard to recognise, and to exploit it to the
full requires a highly skilled pilot. For this reason it is
always best to go thermal seeking off to one side of where
you are standing.
You can recognise thermal contact by the model's
behaviour. Good thermals are obvious because the model
will climb strongly, but weak thermals take a practised eye
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