AERONAUTICAL ENGINEERING

GLIDERSGLIDERS

• PRESENTED BY

kvk

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.

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.

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

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.

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

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.

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.

Sailplane Stay AloftNo 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 LiftThermal Lift

Staying Aloft - ThermalsThermals - 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.

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.

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.

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.

Efficiency - L/D Glide Ratio

Half the drag results in twice the glide ratio.

Steeper glide angle result of greater drag.

Slope Racing

Sailplanes race between poles on a course that runs parallel to top of hill. Racing requires very smooth flying.

THANK YOU

• BY

kvk