GREAT PLANES FLING Manuel d'instruction - Page 12

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Practice flying directly into the wind (upwind of yourself)

without letting the plane get off course, and then turn and

come downwind until the plane is even with you and try it

again. When you are comfortable with flying directly into the

wind, start letting the plane go behind you (downwind) a

little before you start back upwind. Continue this until you

can fly directly towards you from downwind without getting

disoriented. At this point you can start to establish a "landing

pattern" and bring the sailplane in for a landing from

downwind. This enables the plane to be flown as slowly

(ground speed) as possible for accurate landings.

Your First Hi-Start Launch

The included hi-start is the most popular way to launch your

Fling ARF. It consists of 30' of rubber tubing and 200' of

string with a streamer at the end. One end of the rubber is

staked down directly upwind of the launch point. One end of

the string is attached to the other end of the rubber. The end

of the string with the streamer has a loop or ring and is

attached to the tow hook on the sailplane. Lay the hi-start

out with the stake directly into the wind. Place the stake at

the far upwind edge of the flying field so the streamer will

blow back onto the flying field. Turn on your transmitter and

then your receiver and hook the ring onto your plane's tow

hook. Pull the plane back approximately 20 yards. More

tension can be used after you get acquainted with the

launching procedure. NEVER pull more than 30 yards. Hold

the plane above your head with the wings level and the

nose pointed slightly up and directly into the wind. Give

the plane a healthy push forward to get it flying and it will

climb up like a kite.You should not have to touch the elevator

during the launch but use the rudder stick to keep it going

straight up. As the rubber relaxes, the plane will fly off the hi-

start and the streamer will bring the end of the string back

towards you.

THERMAL FLYING

Thermal soaring is one of the most intriguing of all aspects

of flying and the Fling ARF was designed to excel at thermal

soaring even in the hands of a novice. It can be hard for the

average person to understand how a plane can fly for hours

and gain altitude without a motor!

Facts About Thermals

Thermals are a natural phenomenon that happen outside, by

the millions, every single day of the year. Thermals are

responsible for many things including forming several types of

clouds, creating breezes, and distributing plant seeds and

pollen. If you have ever seen a dust devil (which is nothing more

than a thermal that has picked up some dust), you have seen a

thermal in action. Their swirling action is very similar to that of a

tornado but of course much gentler. Most thermals have

updrafts rising in the 200 – 700 feet per minute range but they

have been known to produce updrafts of over 5,000 feet per

minute (that's over 50 miles/hour straight up!) These strong

thermals can rip a plane apart or carry the plane out of sight

before the pilot can get out of the updraft.

Thermals are formed by the uneven heating of the earth and

buildings, etc. by the sun. The darker colored surfaces

absorb heat faster than the lighter colors, which reflect a

great deal of the sun's energy back into space. These darker

areas (plowed fields, asphalt parking lots, tar roofs, etc.) get

warmer than the lighter areas (lakes, grassy fields, forests,

etc.). This causes the air above the darker areas to be

warmer than the air over the lighter areas and the more

buoyant warm air rises as the cooler, denser air forces its

way underneath the warmer air. As this warm air is forced

upward, it contacts the cooler air of the higher altitudes. This

larger temperature difference makes the thermal rise

quicker. The thermal is gradually cooled by the surrounding

cooler air and its strength diminishes. Eventually the thermal

stops rising and any moisture contained in the once warm

air condenses and forms a puffy cumulus cloud. These

clouds, which mark the tops of thermals, are usually

between 2000 and 5000 feet high.

Thermal Soaring

It takes a lot of concentration to thermal soar effectively. A

sailplane can fly along the edge of a thermal and unless the

pilot is carefully watching the model he may not realize the

opportunity to gain some altitude. Because most thermals are

relatively small (a couple hundred feet in diameter or less at

400' altitude) compared to the rest of the sky, the sailplanes

will rarely fly directly into the thermal and start rising.

Generally, the sailplane will fly into the edge or near a thermal

and the effects the thermal has on the plane may be almost

unnoticeable. As the sailplane approaches a thermal, the wing

tip that reaches the rising air first will be lifted before the

opposite wing tip. This causes the plane to "bank" and turn

away from where we would like the plane to go.

When you are thermal soaring, try to fly as smoothly and

straight as possible. Trim the plane to fly in a straight line

and only touch the controls when you have to. Watch the

sailplane carefully and it will tell you what it is encountering.

When the sailplane flies directly into a thermal it will either start

rising or stop sinking. Either case is reason enough to start