**4.6 Ultralight Operations (gliders, motorized gliders, paragliders,
motorized paragliders, hangliders, ultralight aircraft):**

Special nature of ultralight flying

Hypoxia

Trapped gas expansion

Thermal stress

Noise

Vibration

Crash survival and crash worthiness

Ultralight operations include aircraft categorized as gliders or
sailplanes, motor gliders, paragliders, motorized paragliders, hang
gliders, and ultralights. The unique nature of the ultralight aircraft
category is that these aircraft are usually small, lightweight (under
1,000 pounds), and operated by a single pilot and occasionally a
passenger. A pilot\'s license is required for operating gliders and
motorized gliders.

![](media/image1.jpeg){width="6.206944444444445in"
height="2.615972222222222in"}

EARLY GLIDING IN AMERICA

Other categories of ultralight aircraft do not require a pilot\'s
license, and only gliders and motor gliders will require a medical
certificate if the pilot is performing commercial operations.
Instructors do not require medical certificates. These aircraft
generally operate in localized areas and relatively close to the ground
and frequently do not use runways or controlled airports. Their
instrumentation is basic and the most important of them is a strip of
yarn attached to the canopy: the yaw string. It indicates coordinated
flight, critical for smooth and efficient operation.

![](media/image2.jpeg){width="7.748611111111111in"
height="5.813888888888889in"}

VIEW FROM THE COCKPIT, NOTE THE YAW STRING ON THE OUTSIDE OF THE CANOPY,
ABOVE COMPASS.

Gliders and motorized gliders are larger aircraft and some of them have
extremely long wing span of up to 50 meters. They are characterized by
very high lift-to-drag ratios, as high as 70:1 or greater. This means
that for every foot of altitude lost the airplane will glide forward at
70 feet. The difference between a glider and the motor glider is that
the motor glider has an internal engine, which is used for brief periods
of time to launch the aircraft and climb to altitude. The engine is then
turned off, and in some cases can be withdrawn entirely within the
aircraft, after which, it functions as a glider. It requires a single
engine land pilot's license and medical certificate to operate.

![](media/image3.jpeg){width="6.0in" height="3.7916666666666665in"}

VIVAT MOTORGLIDER

Pure gliders much be launched. This can be done primarily through a tow
aircraft using a long tow cable to pull the other aircraft to the
release altitude. Special rules and training for towing and being towed
are part of the basic pilot education program, and are required for
certification as both a tow pilot or glider pilot.

![](media/image4.jpeg){width="4.9319444444444445in"
height="5.813888888888889in"}

The view behind a towplane.

Additional methods of launching gliders includes a winch, which consists
of a very long cable stretched along the runway, which rapidly winds up
the tow cable. The glider achieves flying speed, usually on the order of
35 to 40 miles per hour within the space of a few feet. The aircraft
then climbs at a 45 degree nose-up angle, until maximum altitude is
achieved, which is rarely more than 600 or 700 feet. The cable is then
released and descends to the ground via a small parachute while the
glider proceeds on its flight.

![](media/image5.jpeg){width="7.883333333333334in"
height="5.813888888888889in"}

WINCH LAUNCH OF A REBUILT T-2, WORLD WAR II TRAINING GLIDER.

A third method of launching is to use a tow car or automobile simply
driven down a runway with a tow cable behind it. Obviously, this is even
more limited than winch launches.

A final method of launching sailplanes, and the oldest, is called a
bungee launch, where the sailplane is on the side of the mountain or
hill, and is catapulted into the air by means of a short, elastic cable,
somewhat like a rubber band. Once the sailplane achieves flying speed,
one of the initial actions of the pilot is to prepare to land.
Sailplanes can only descend through the air. Therefore, the pilot must
immediately prepare to land and hope that rising air is found.
Sailplanes fly because air, under certain circumstances, rises, while
the plane itself is descending through the air mass, the air mass is
rising faster than the plane is descending.

Sailplanes can gain altitude under three circumstances. The first is
called a thermal. A rising column of warm air, usually in the
summertime, will begin to climb off a sun-heated area of ground.
Typically marked by birds, also circling in the thermal, a sailplane
will enter a thermal and spiral upwards. This requires constant flying
and delicate control. Sailplane pilots, unlike almost any other kind of
pilot, except a helicopter pilot, must fly their airplane constantly,
and cannot trim up the airplane and allow it to "fly itself" for even
the briefest periods of time.

One of the hazards of thermaling is that more than one airplane may
enter the same thermal. The rules of the air indicates that the first
plane into the thermal will dictate the direction of turning, either
right-handed or left-handed, and all other aircraft will follow that
convention. Sometimes, there may be so many birds in the thermal that
they will in turn dictate the direction of the turn, and it is not an
usual for a bird to fly formation on the wing tip of a sailplane in the
thermal, and ride the additional lift off the sailplane's wing tip
vortex.

A second type of lift is known as ridge lift. A constant wing blowing
across the land will strike raised terrain, such as a ridge or hillside.
The air will then rise on the upwind side of the ridge, and the
sailplane may enter this and gain altitude. Areas along seacoasts and
low mountains are famous for sustained ridge lift of many hours
duration. Sailplanes in the United States have literally flown from one
end of the Appalachians to the other and back, holding distance records
of several thousand miles in a single day.

![](media/image6.jpeg){width="8.801388888888889in"
height="5.813888888888889in"}

SOARING IN RIDGE LIFT

A third form is known as the mountain wave. This is a modification of
ridge lift where high-speed jetstream strikes a mountain and is
deflected upwards. Mountain waves may begin as low as 5,000 feet above
sea level in mountainous terrain and the updrafts created can be
extremely violent and moving at thousands of feet per minute. A
sailplane caught in such an updraft may find itself with no choice but
going up, and the current world record was set to 49,000 feet in this
manner.

The downwind side of mountain waves, however, is extremely violent, with
sharp, spinning vortices created, known as rotors, which create
extremely turbulent conditions on the downwind side. The aim of most
sailplane pilots is to either gain altitude, distance, or sustained time
aloft. Flight speeds of all sailplanes are relatively low and even under
the demands of racing conditions, will rarely exceed 100 miles per hour.

It is possible, particularly under mountain wave conditions, for
sailplanes to be carried to significant altitudes, where hypoxia and
oxygen requirements are necessary. Pilots of sailplanes, like those of
conventional aircraft, are required to use oxygen if flying above 12,500
feet. Thermal stress can be a significance factor in sailplane
operations, as most sailplanes have very large, glass canopies, and when
thermaling in the summertime, a significant greenhouse effect takes
place. Since sailplanes are unpowered, they are not air-conditioned, and
the only cooling factor will be venting of the air into the cabin.
Additionally, in a prolonged flight, high thermal load dehydration may
be a factor. The altitude gained on occasion may be significant enough
for trapped gas to expand particularly in the ears and sinuses.

Sailplanes operate out of any kind of airport. Often they utilize and
airfield dedicated only to glider operations. Many sailplanes will not
have radios, relying on hand signals to coordinate operations on the
ground. If they do operate at an airfield with a control tower, the same
rules of controlled airspace apply to them as any other aircraft.

Sailplanes fly extremely low speed, are very stable and are rarely
involved in accidents. The requirements for licensing and an FAA
Certificate are stringent and sailplanes are considered extremely safe.
Most problems occur during "outlandings", that is landings that occur
away from an airport, usually when lift is lost.

![](media/image7.jpeg){width="7.748611111111111in"
height="5.813888888888889in"}

OUTLANDING

Conversely, ultralights, paragliders, and hang gliders, do not require
an FAA Certificate or pilot\'s license. Such operations are haphazard
and often require only the price of the aircraft. Some of them may be
powered by small engines from 15 to 50 hp. The noise and vibration from
such engines can be extremely high. With little in the way of
certification or training required, and the smaller hang gliders,
usually simply launched off a hill or a cliffside, are used for
recreation by individuals with minimal training. The pilots are
suspended in an open cage and their personal protection may consist of
entirely a helmet, if worn or a parachute. Accidents are frequent and
there are many injuries associated with these aircraft. Some are braced
with a roll cage, but others may have no protection for the pilots,
whatsoever. And those that are foot launched, such as a hang glider,
provide no structural protection. There are literally hundreds of
different types of ultralight aircraft, which may look like anything
from a small conventional airplane to a powered parachute or a kite with
an engine.

![](media/image8.jpeg){width="4.301388888888889in"
height="2.696527777777778in"}

AMERICAN AEROLIGHT EAGLE

![](media/image9.png){width="6.4375in" height="4.634722222222222in"}

WEEDHOPPER

The accident and injury rate for hang gliders, paragliders, and other
ultralights is not known precisely, but is extremely high, at least in
order of magnitude greater than general aviation aircraft. Some
ultralights have even been equipped with parachutes to lower them safely
in an emergency.

Ultralights are relatively free from rules. Medical certificates and
pilot's licenses are not required. However there are some rules of the
road for these craft: No passengers are allowed, no flying over towns or
inhabited areas, no flying at night or in clouds, no flying in
controlled airspace and no commercial operations.

Sailplanes and ultralights have the right of way in the air over all
other aircraft except lighter-than-aircraft: blimps and balloons.

![](media/image10.jpeg){width="4.394444444444445in"
height="2.582638888888889in"}

WHO HAS THE RIGHT OF WAY?

Information source: Soaring Society of America