3. INTRODUCTION TO
GLIDERS
• Glider is a heavier-than-air aircraft that is supported in
flight by the dynamic reaction of the air against its lifting
surfaces, and free flight does not depend on an engine.
• routine operation without engines, though engine failure
can force other types of aircraft to become gliders.
• Some gliders have engines for extending their flight, and
some have engines powerful enough to launch into the
air.
4. THE ORIGINS OF SOARING
Public domain image of one of the Wright Brother’s gliders.
The Wright Brothers spent years experimenting with gliders
before attempting powered flight. Much of their effort was
spent developing more efficient airfoils and perfecting their
control system before building a powered plane.
5. THE ORIGINS OF SOARING
•With wingspans well over 20 feet and weighing well in
excess of 100 pounds, huge muscles would have been
required to maintain flapping flight.
• even with the denser air of that time providing more lift,
so it is thought these creatures flew exclusively in lift by
jumping off mountain tops.
In more recent times
large soaring birds
such as eagles and
hawks, rely on finding
lift for much of their
flight.
Paul Naton Image
6. GLIDER (SAILPLANE)
• It became a sail plane
for recreational
purpose.
• The pilot were sit
inside and glide the
glider.
• It develops high lift-
drag ratio.
7. HANG GLIDERS
• a hang glider is capable
of being carried,foot
launched
• landed solely by the use
of the pilot’s legs.
• In a hang glider the
shape of the wing is
determined by a
structure
8. ARF - ALMOST READY TO FLY
•High-quality gliders are available
at a reasonable cost.
• The Primers A.R.F. glider that I
am holding, came completely
constructed of wood and covered
with plastic covering, required
only minor assembly of major
components.
•Received third place in two-
meter division at 2001 Southwest
Classic flying this plane.
9. Glider Flown
It is best to fly at an approved soaring club field as a member.
If you must fly from private land.
Thermal Fields – need big enough area for high start or winch
and room to drift downwind over. As there is no glow fuel to
be spilled, often sailplane clubs are allowed to fly from sod
farms that power fliers can not.
Slope Sites - many concerns; access to the site, obstacles,
and will there be consistent lift for wind conditions.
Safety is a concern, although noise should not be. Do not fly
over populated areas.
10. Sailplane Stay Aloft
No matter how efficient a sailplane is, the glide path will
always be downward unless a source of lift is found. Lift is air
that is moving upward faster than the sailplane is descending,
(sink rate).
Lift is found in two majors ways; SLOPE LIFT - air moving
horizontal is deflected upward, or THERMAL LIFT - air rising
from the ground because it is warmer than surrounding air.
Slope Lift
Thermal Lift
11. Staying Aloft - Thermals
Thermals - sailplane enthusiasts have such a fondness
for the thermal lift that keep their sailplane’s aloft, many
sign their emails and letters with “Thermals” instead of
Sincerely.
As the ground is warmed by the
sun, thermal bubbles are formed
and break way from the ground.
These bubbles can combine and
mature to form thermal columns.
Thermals will normally drift with
the wind, so the pilot circles the
sailplane downwind adjusting to
stay within the thermal.
12. Staying Aloft - Slope Lift
Popular California Inland Slope
On large slopes such as this one, strong lift is
created when the wind blows straight into the
slope.
13. Winch Launching
Winch on the
left and
retriever on
the right.
Pilot holds some tension
as the winch line
stretches before pilot give
the plane a toss.
For most larger sailplanes, an
electric winch is the preferred
method for getting a sailplane to an
altitude of a few hundred feet.
Electric retrievers are also available
that pull back the winch line.
14. Electric Powered Sailplanes
Paul Naton photo of
Dieter Mahlein with
high-performance
electric powered
sailplane.
Sailplanes powered by electric motors are available in all sizes and
performance ranges. The weight of the motor and battery is not as much
of a handicap as it once was. Often it is helpful to be able to use electric
power to avoid landing off field.
15. Efficiency - L/D Glide Ratio
Half the drag results in
twice the glide ratio.
Steeper glide
angle result of
greater drag.
16. Slope Racing
Sailplanes race between poles on a course that
runs parallel to top of hill. Racing requires very
smooth flying.
