Multiplex Alpina 4001 ELEKTRO Notice De Construction page 24

to detect, and you will need a lot of skill to make use of them.
With a little practice you will be able to recognise likely
trigger points for thermals in the local landscape. The
ground warms up in the sun's heat, but heat absorption
varies according to the type of terrain and the angle of the
sun's rays. The air over the warmer ground becomes
warmer in turn, and the mass of warm air flows along close
to the ground, driven by the breeze. Strong winds usually
prevent thermal build-up. Any obstruction - a shrub or tree,
a fence, the edge of a wood, a hill, a passing car, even your
own model on the landing approach - may cause this
warm air to leave the ground and rise. Imagine a drop of
water on the ceiling, wandering around aimlessly, and
initially staying stuck to the ceiling. If it strikes an obstruction
it will fall on your head. A triggered thermal can be thought
of as the opposite of the drop of water.
The most obvious thermal triggers include sharply defined
snow fields on mountain slopes. The air above the snow
field is cooled, and flows downhill; at the edge of the snow
field, part-way down the valley, the cool air meets warm air
flowing gently uphill, and pushes it up and away as if cut
off by a knife. The result is an extremely powerful but bumpy
thermal bubble. Your task is to locate the rising warm air
and centre your model in it. You will need to control the
model constantly to keep it centred, as you can expect the
most rapid climb rate in the core of the thermal. Once
again, this technique does demand some skill.
To avoid losing sight of the model be sure to leave the
thermal in good time. Remember that a glider is always
easier to see under a cloud than against a clear blue sky.
If you have to lose height in a hurry, do bear the following
in mind:
The structural strength of the Alpina 4001 ELEKTRO is
very great, but it is not infinite. You can fetch your model
down from virtually any altitude at an angle of 45° with the
airbrakes extended. If you want to try speed runs in F3B-
style, then the camber-changing flaps must be kept at
neutral.
Set up your landing approach with plenty of height in hand,
and extend the airbrakes to achieve a steep final approach
so that the model is close to the ground for the minimum
period of time. The "regulation" square approach,
consisting of downwind leg away from you, cross-wind leg
and a straight approach with airbrakes extended or butterfly
system deployed and final flare will help preserve the
model, the pilot and any spectators.
Flying at the slope
Ridge soaring is an extremely attractive form of model
flying. Flying for hours on end in slope lift, without needing
any outside aid for launching, must be one of the finest of
modelling experiences. But to "milk" a thermal to the limits
of vision, bring it down again in a continuous series of
aerobatic manoeuvres, and then to repeat the whole show
- that must surely be the last word in model flying.
But take care - there are dangers for your model lurking at
the slope. Firstly, in most cases landing is much more
difficult than at a flat field site. It is usually necessary to land
in the lee of the hill where the air is turbulent; this calls for
concentration and a high-speed approach with last-minute
airbrake extension. A landing on the slope face, i.e. right
in the slope lift, is even more difficult. Here the trick is to
approach slightly downwind, up the slope, and flare at
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exactly the right moment, just before touch-down.
Safety
Safety is the First Commandment when flying any model
aircraft. Third party insurance should be considered a
basic essential. If you join a model club suitable cover will
usually be available through the organisation. It is your
personal responsibility to ensure that your insurance is
adequate.
Make it your job to keep your models and your radio control
system in perfect order at all times. Check the correct
charging procedure for the NC batteries used in your RC
set. Make use of all sensible safety systems and
precautions which are advised for your system. An excellent
source of practical accessories is the MULTIPLEX main
catalogue, as our products are designed and manufactured
exclusively by practising modellers for other practising
modellers.
Always fly with a responsible attitude. You may think that
flying low over other people's heads is proof of your piloting
skill; others know better. The real expert does not need to
prove himself in such childish ways. Let other pilots know
that this is what you think too. Always fly in such a way that
you do not endanger yourself or others. Bear in mind that
even the best RC system in the world is subject to outside
interference. No matter how many years of accident-free
flying you have under your belt, you have no idea what will
happen in the next minute.
The fascination of it all
Model flying is, and always has been, a fascinating hobby,
and a thoroughly enjoyable way of spending your leisure
hours. Take your time to get to know your new Alpina 4001
ELEKTRO really well. Plan to spend many hours in the
open air, where you will learn to appreciate the model's
outstanding performance and its docile handling. You can
join us in enjoying one of the few types of sport which
combine high technology, manual dexterity, and
sophisticated personal skills. You can fly alone or with
friends, and at the same time you can enjoy the pleasures
of nature - treats which have become rare in today's world.
We - the MULTIPLEX team - wish you many hours of
pleasure in building and flying your new model. Happy
landings!
MULTIPLEX Modelltechnik GmbH
Model Development Dept.