GREAT PLANES Spirit Select 사용 설명서 - 페이지 8
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ahead until you feel like you are in the strongest lift, fly a couple
of seconds farther (so your circle will be centered in the strongest
lift) and then start circling in a fairly tight but smooth turn. When the
sailplane is low the turns have to be tighter to stay in the strongest
lift. As the plane gains altitude, the turns can be larger and flatter.
The flatter the turn, the more efficient the plane is flying, but don't
be afraid to really "crank" it into a steep bank when you are low. If
you see the plane falling off on one side of the turn, move your
circle over into the stronger lift. Thermals move along with the wind
so as you circle you will be swept along with it. Be careful when
thermaling, that you don't get so far downwind you can't make it
back to the field to land.
If the sailplane is flying along straight and all of a sudden turns, let
the plane continue to bank (you may have to give it some rudder to
keep it banking) until it has turned 270-degrees (3/4 of a full circle).
Straighten out the bank and fly into whatever turned the plane. If
you encounter lift, and you won't every time, start circling just as
you did when flying directly into a thermal.
Thermals are generated all day long, but the strongest thermals
are produced when the sun is directly overhead. 10:00 am – 2:00 pm
seems to be the best time to get those "killer" thermals. Some of
these thermals can be very large and you may find it hard to get
out of them. If you find yourself getting too high, don't dive the
plane to get out of the lift. Sailplanes are very efficient aircraft and
they will build up a lot of speed and could "blow up" in the rough air
of a thermal. The easiest way to lose altitude is to apply full rudder
and full up elevator. This will put the plane into a tight spin that will
not over stress the airframe but it will enable it to lose altitude very
quickly. This is especially helpful if the sailplane gets sucked into a
cloud or it gets too high to see. The twirling action will give the sun
a better chance of flashing off of the wing and catching your
attention. When you are high enough and want to leave the
thermal, add a little down trim to pick up some speed and fly 90
degrees to the direction of the wind. If you are not real high and
want to find another thermal, you may want to look upwind of the
last thermal. The same source that generated this thermal is
probably producing another. Just watch out for "sink" which is often
found behind and between thermals.
As you might expect, with all this air rising, there is also air sinking.
This air is the sailplane pilot's nightmare that can really make
soaring challenging. "Sink" is usually not as strong as the thermals
in the same area, but it can be very strong. Down drafts of many
hundreds of feet per minute are common on a good soaring day.
These down drafts can make a sailplane look like it is falling out of
the air. Because of this, it is important that you do not let the
sailplane get too far downwind.
When encountering sink, immediately turn and fly 90 degrees to
the direction of the wind (towards you if possible). Apply a little
"down elevator" and pick up some speed to get out of the sink as
fast as possible. Every second you stay in the sink is precious
altitude lost.
POINTERS FOR CONTEST FLYING
Pay Attention! – Pay close attention to the sailplanes flying before
you, watch them and try to establish where and when the thermals
are being formed. Thermals are often formed in cycles and can be
fairly regular, so if you keep track of the time intervals you will have
a pretty good idea of when and where a thermal may be generated.
Watch The Birds! – Thermals suck up small insects that many
birds love to eat. A bunch of swallows flying around in one area
may indicate a thermal. Soaring birds (hawks, vultures, eagles
etc.) are the best thermal indicators. They not only show you where
the thermal is but they also show you where the center is. These
"Masters of the Sky" will often fly right along with sailplanes.
Practice Those Landings! – Most thermal contests are won or
lost during the landing. Establish a particular landing pattern and
try to stick to it for all landings. Learn to shift your pattern to
account for the wind and particular flying field characteristics.
Spoilers can be very useful during contest landings. They allow you
to bring the sailplane in for a landing higher or faster than normal
to guard against any last minute sink or gusts and dump the extra
altitude and speed at the last second. They can also be used to
help control your skid. Opening the spoilers will stop the plane from
sliding a little quicker. You can also "steer" the plane while it is
sliding along the ground. Don't expect to be able to "horse it
around" but you can gain valuable inches by using the rudder to
guide it toward the spot as it slides to a stop. Be very careful not to
"ground loop" the plane since you will lose your landing points if the
plane flips over.
Concentrate – Keep your eye on your sailplane during your
contest flights. Have a helper or your counter watch the other
sailplanes in the air. Sometimes your sailplane will wiggle so
quickly or gently that you may miss it if you are not paying close
attention. If you find a productive thermal, don't leave it because
your helper tells you that someone else has found a different one.
Know Your Sailplane! – Learn what your sailplane will and won't
do and fly within this envelope. This will allow you to ride thermals
downwind while knowing when you have to head back to make
your landing safely.
Learn From The Wind! – Keep track of which way the wind is
blowing. If the wind suddenly shifts, there is some thermal action
fairly close to you. The air is probably being either sucked up into
a thermal or falling out of some sink. In either case it is often a good
idea to fly in the direction the wind is blowing if your sailplane is in
the general area. This will take you towards a thermal if there is
one or away from the sink, both of which are desirable.
BALLASTING
In strong wind conditions, you may want to add ballast (weight) to
the sailplane to increase its wing loading which increases its
normal flying speed. Increasing the weight of your sailplane does
not change its "glide ratio" but it does make it fly faster which
makes it sink a proportional amount faster. Because of this faster
sink rate, you need to be very cautious when ballasting for a
thermal contest. In duration type contests only use ballast on very
windy days that also have a lot of thermal activity.
Add the weight as near as possible to the C.G. of the plane. Adding
6 – 8 oz. will make a noticeable difference in the sailplane's flying
speed and more can be added later, if needed. Make sure to
recheck the C.G. of the plane after adding ballast–it should remain
where it was.
Have a ball! Remember to always stay in control and fly in a
safe manner.
GOOD LUCK AND GREAT FLYING!