Flying Wires
Control Bar
Ground Wires
Figure 1-6. Simple structure added to the Rogallo wing allows wires to hold up the wings on the ground and support the wing in flight.
Figure 1-7. An original Rogallo wing, 1975.
Hang Glider
The WSC system and the good fl ying qualities of the Rogallo
wing and Dickenson wing, combined with its easy set-up
and portability, started the hang gliding craze in the early
1970s. [Figure 1-7] In 1967, the fi rst powered aircraft based
on the fl exible wing concept of Dr. Rogallo was registered
as amateur-built experimental. Flexible wing development
continued, and by the early 1970s several adventurous
entrepreneurs were manufacturing Rogallo wings for sport
use.
Another signifi cant step in wing design was an airfoil that
would change shape for optimum performance at slow and
fast speeds. It was the fi rst Rogallo wing with a lower surface
that could enclose the structure that holds the wings out.
Enclosing this cross bar tube and providing a thicker airfoil
similar to the airplane wing provided a jump in high speed
performance. This double-surface wing was quickly adopted
by manufacturers as the high performance standard and is
used on faster WSC aircraft today. [Figure 1-8]
Activity in the hang gliding community increased throughout
the 1970s, which resulted in the proliferation and development
of stable, high-quality modern hang gliders like the one
shown in Figure 1-9.
Motorized Hang Gliders
In the late 1970s, performance had increased enough to allow
motors to be added to hang gliders and fl own practically. It
was not until the wings had become effi cient and the engines
and propeller systems evolved that the fi rst commercial motor
for a hang glider was introduced in 1977, the Soarmaster. It
used a two-stroke engine with a reduction system, clutch, and
long drive-shaft that bolted to the wing frame. It had a climb
rate as high as 200 feet per minute (fpm) which was acceptable
for practical fl ight. However, during takeoff the wing would
overtake the running pilot, and launching was very diffi cult.
Also while fl ying, if the pilot went weightless or stalled under
power, the glider would shoot forward and nose down into
a dive. Overall, with the propeller pushing the wing forward
during takeoffs and in some situations while fl ying, this was
unsafe for a wide application. [Figure 1-10]
A Maturing Industry
Engines and airframe technology had made great advances
because the ultralight fi xed wing evolution was providing lighter
weight, higher power, and more reliable propulsion systems.
The propeller was moved lower for better takeoff and fl ight
characteristics, wheels were added, and the trike was born at
the end of the 1970s. A trike describes a Rogallo type wing
with a three wheeled carriage underneath (much like a tricycle
arrangement with one wheel in front and two in back). Trike
is the industry term to describe both ultralight vehicles and
Enclosed crossbar
Double or lower surface
Figure 1-8. The double-surface patented wing, 1978.
Figure 1-9. A modern high-performance hang glider soaring high
over the mountains from which it was launched.
Figure 1-10. First motorized system design sold as an add-on kit for a hang glider.
Engine
Propeller
Thrust at wing
Propeller guard
Propeller shaft
Light-Sport Aircraft (LSA) WSC aircraft. [Figure 1-11] The
major trike manufacturers were formed in the early 1980s
and continue to deliver trikes worldwide today.
New Challenges
By the 1980s, individuals were rapidly developing and
operating small powered trikes. This development failed
to address the sport nature and unique challenges these
new aircraft presented to the aviation community. In an
attempt to include these fl ying machines in its regulatory
framework, the FAA issued Title 14 of the Code of Federal
Regulations (14 CFR) part 103, Ultralight Vehicles, in 1982.
Aircraft falling within the ultralight vehicle specifi cations
are lightweight (less than 254 pounds if powered, or 155
pounds if unpowered), are intended for manned operation
Figure 1-12. Examples of LSA, from top to bottom: gyroplane,
airplane, powered parachute, and weight-shift control aircraft.
Figure 1-11. An ultralight vehicle trike: a Rogallo wing on a
modified undercarriage.
by a single occupant, have a fuel capacity of fi ve gallons
or less, a maximum calibrated airspeed of not more than 55
knots, and a maximum stall speed of not more than 24 knots.
Ultralight vehicles do not require pilot licensing, medical
certifi cation, or aircraft registration. Ultralight vehicles are
defi ned in more detail with their operating limitations in 14
CFR part 103.
Because training was so important for the single-place
ultralight vehicle pilots, the FAA granted an exemption that
allowed the use of two-seat ultralight vehicles for training,
and the sport of two-seat ultralight training vehicles grew.
Throughout the 1990s, worldwide sales of both single-
seat and two-seat ultralight vehicles soared, but it was the
proliferation of two-seat trainers that took the industry and the
regulators by surprise. Worldwide sales of two-seat ultralight
vehicle trainers vastly outnumbered the sales of single-seat
ultralight vehicles; and it became clear that the two-seat
trainers, which were intended to be operated as trainers only,
were being used for sport and recreational purposes. This
created a demand for increased comfort and reliability, which
resulted in heavier, more sophisticated machines.
Light Sport Aircraft (LSA)
To address the evolution of the ultralight vehicle and its
community of sport users, the FAA issued new rules on
September 1, 2004. These rules created a new category of
LSA and a new classifi cation of FAA pilot certifi cation to fl y
LSA, called Sport Pilot. Additional guidelines established by
the FAA can be found in 14 CFR part 61. [Figure 1-12] This
handbook focuses on the WSC aircraft.
Aircraft certifi cated as LSA exceed the limitations defi ned
for ultralight vehicles and require that the pilot possess, at a
minimum, a Sport Pilot certifi cate. The sport pilot rule defi nes
the limitations and privileges for both the sport pilot and the
Figure 1-13. Carriage and wing of a WSC aircraft.
Carriage
Wing
Figure 1-14. Wing folded and on top of a recreational vehicle with
the carriage in a trailer.
LSA. In addition, the regulations governing the sport pilot rule
defi ne the training requirements of prospective sport pilots
and the airworthiness requirements for their machines. For
instance, an ultralight vehicle must not exceed 254 pounds
or carry more than one person. Aircraft that carry more than
one person and weigh over 254 pounds but less than 1,320
pounds may be certifi ed as LSA provided they meet specifi c
certifi cation requirements. Therefore, many WSC ultralight
vehicles became LSA (provided they were properly inspected
and issued an airworthiness certifi cate by the FAA).
Weight-Shift Control Aircraft
WSC aircraft are single- and two-place trikes that do not meet
the criteria of an ultralight vehicle but do meet the criteria of
LSA. The defi nition for WSC can be found in 14 CFR part 1.
Flight control of the aircraft depends on the wing’s ability to
fl exibly deform rather than on the use of control surfaces.
The common acronyms for this LSA are WSC (weight-shift
control); WSCL (WSC land), which can be wheels or ski
equipped; and WSCS (WSC Sea) for water operations. A
LSA WSC used for sport and private pilot fl ying must be
registered with a FAA N-number, have an airworthiness
certificate, a pilot’s operating handbook (POH), and/or
limitations with a weight and loading document aboard. The
aircraft must be maintained properly by the aircraft owner
or other qualifi ed personnel and have the aircraft logbooks
available for inspection. Dual fl ight controls are required in
two-seat aircraft used for training.
The carriage is comprised of the engine and fl ight deck
attached by a structure to wheels, fl oats, or skis; it may also
be referred to as the fuselage. The wing is the sail, structure
that supports the sail, battens (ribs) that form the airfoil, and
associated hardware. [Figure 1-13]
There are several unique features of the WSC aircraft:
• The wing structure is in the pilot’s hands and is used
to control the aircraft. There are no mechanical devices
between the pilot and the wing. The pilot can directly
feel the atmosphere while fl ying through it because the
pilot is holding the wing. This is a direct connection
between the wing and the pilot like no other aircraft.
• The pilot can feel the wing as the wingtips or nose
moves up and down, but the carriage and passenger
are more stable. Turbulence is not felt as much as in
a fi xed-wing aircraft.
• Different wings can be put on a single carriage. This
allows the pilot to have a large wing that can take off
in short distances, which would be good for low and
slow fl ying. A large wing with a lightweight carriage
can also be used for soaring and is capable of fl ying
at speeds below 30 miles per hour (mph). At the other
extreme, a smaller high performance wing can be
used for fl ying long distances at high speeds. With a
small wing and a larger motor, WSC aircraft can fl y
at speeds up to 100 mph.
• The wing can be taken off the carriage and folded up
into a tube that can be easily transported and stored.
This allows owners to store the WSC aircraft in a
trailer or garage, transport the WSC aircraft to a local
site, and set it up anywhere. [Figure 1-14]
Figure 1-15. WSC aircraft with struts similar to those on an airplane
(top) and WSC aircraft operating on water (bottom).
Figure 1-16. Federal Aviation Regulations (FAR) and Aeronautical
Information Manual (AIM).
• Since the WSC aircraft is designed without the weight
and drag of a tail, the performance is signifi cantly
increased. The aircraft can take off and land in short
fields, has good climb rates, can handle a large
payload, has a good glide ratio, and is fuel effi cient.
The WSC LSA typically can carry 600 pounds of
people, fuel, and baggage.
Besides having large and small wings for different speeds,
the WSC aircraft wings can have wires for bracing, struts,
or a combination of both. Throughout this handbook, both
are used in diagrams and pictures. WSC aircraft are typically
on wheels, but there are models that can land and take off on
water and snow. [Figure 1-15]
Weight-Shift Control LSA Requirements
A WSC LSA must meet the following requirements:
1. A maximum takeoff weight of not more than—
• 1,320 pounds (600 kilograms) for aircraft not
intended for operation on water; or
• 1,430 pounds (650 kilograms) for an aircraft
intended for operation on water
2. A maximum airspeed in level fl ight with maximum
continuous power (V H) of not more than 120 knots
calibrated (computed) air speed (CAS) under standard
atmospheric conditions at sea level.
3. A maximum stalling speed or minimum steady fl ight
speed without the use of lift-enhancing devices
(VS1) of not more than 45 knots CAS at the aircraft’s
maximum certifi cated takeoff weight and most critical
center of gravity.
4. A maximum seating capacity of no more than two
persons, including the pilot.
5. A single reciprocating engine.
6. A fi xed or ground-adjustable propeller.
7. Fixed landing gear, except for an aircraft intended for
operation on water.
8. Fixed or retractable landing gear, or a hull, for an
aircraft intended for operation on water.
Flight Operations and Pilot Certifi cates
The FAA is empowered by the United States Congress to
promote aviation safety by prescribing safety standards for
civil aviation programs and pilots. Title 14 of the Code of
Federal Regulations (14 CFR), formerly referred to as Federal
Aviation Regulations (FAR), is one of the primary means of
conveying these safety standards. [Figure 1-16] 14 CFR part
61 specifi es the requirements to earn a pilot certifi cate and
obtain additional WSC privileges if already a pilot. 14 CFR
part 91 is General Operating and Flight Rules for pilots. The
Aeronautical Information Manual (AIM) provides basic fl ight
information and operation procedures for pilots to operate in
the National Airspace System (NAS).
Figure 1-17. Sport Pilot Practical Test Standards for Weight Shift
Control, Powered Parachute, and Flight Instructor.
Basic Pilot Eligibility
Title 14 CFR, part 61 specifi es the requirements to earn a
pilot certifi cate. This regulation also states the pilot applicant
must be able to read, speak, write, and understand the English
language. The FAA Practical Test Standards (PTS) establish
the standards for the knowledge and skills necessary for the
issuance of a pilot certifi cate. It is important to reference both
of these documents to understand the knowledge, skills, and
experience required to obtain a pilot certifi cate to fl y a WSC
aircraft. [Figure 1-17]
Pilot applicants and students fl ying solo must have a valid
driver’s license or a current third-class medical certifi cate
issued under 14 CFR part 67. In addition to a valid driver’s
license or a medical certifi cate, each pilot must determine
before each fl ight that he or she is medically fi t to operate
the aircraft in a safe manner. If using a valid driver’s license
to exercise the privileges of a sport pilot certifi cate, then
all restrictions on that driver’s license are also upheld. A
current FAA third-class medical certifi cate must be obtained
to exercise the privileges of a WSC private pilot certifi cate.
Existing pilots, including previous student pilots, who have
had their FAA medical certifi cate or most recent application
denied, revoked, withdrawn, or suspended by the FAA, are
not allowed to operate using a driver’s license until the denial
on the airman record is cleared by having a valid third class
medical certifi cate issued.
Flight Safety Practices
In the interest of safety and good habit pattern formation,
there are certain basic fl ight safety practices and procedures
that must be emphasized by the fl ight instructor and adhered
to by both instructor and student, beginning with the very
fi rst dual instruction fl ight. These include, but are not limited
to, collision avoidance procedures including proper scanning
techniques and clearing procedures, runway incursion
avoidance, and positive transfer of controls.
Collision Avoidance
All pilots must be alert to the potential for midair collision
and near midair collisions. The general operating and
fl ight rules in 14 CFR part 91 set forth the concept of “see
and avoid.” This concept requires that vigilance shall be
maintained at all times by each person operating an aircraft.
Most midair collision accidents and reported near midair
collision incidents occur in good visual fl ight rules (VFR)
weather conditions and during the hours of daylight. Most of
these accident/incidents occur within fi ve miles of an airport
and/or near navigation aids.
The “see and avoid” concept relies on knowledge of the
limitations of the human eye, and the use of proper visual
scanning techniques to help compensate for these limitations.
The importance of, and the proper techniques for, visual
scanning should be taught to a student pilot at the very
beginning of fl ight training. The competent fl ight instructor
should be familiar with the visual scanning and collision
avoidance information contained in Advisory Circular
(AC) 90-48, Pilot’s Role in Collision Avoidance, and the
Aeronautical Information Manual (AIM).
It should be noted that any turn or maneuver must be
cleared before initiating. This is a most important concept
in fl ying any aircraft. Look and clear the area of any aircraft
or obstructions before any maneuver is performed. As an
example, if a right hand turn is to be performed, the pilot
must look right and clear the area before initiating any turn
to the right. This “clearing procedure” must be done before
performing any maneuver.
This is an important habit for any student for safety purposes
and is incorporated into the pilot certifi cation process. The
pilot must be trained by a CFI in effectively clearing the area
before any maneuver is performed.