ered parachute wing should become too porous, more
groundspeed may be needed to pressurize the wing,
takeoff distance may increase, more RPM may be
required to hold altitude, and fuel consumption may
increase.
At first sight, the suspension lines on the powered
parachute wing might appear like an unorganized wad
of strings. On the contrary, each line has a distinct
purpose and each line has distinct properties. The sus-
pension lines are sometimes designated A through D
and differ between manufacturers; check your POH to
know the line labels for your PPC. [Figure 3-12] The
front suspension lines are located at the leading edge
and the steering lines connect to the trailing edge. The
Figure 3-11. Airflow into the wing.
Figure 3-12. Front and rear suspension lines.
Figure 3-10. Canopy cross-section.
suspension lines come together at a point where they
connect with the riser. (The risers are the connection
between the suspension lines and the cart.) Many
manufacturers color-code the wing suspension lines
to assist the pilot in their preflight inspection and lay-
out of the wing prior to inflation. [Figure 3-12]
Suspension lines must be constructed of very strong
materials, yet remain very small in profile to reduce
parasite drag. The most commonly used materials are
polyaramid and polyethelene, which are both carbon
based.
Kevlar® is a common polyaramid used for suspension
lines. Its properties render it extremely strong, as well
as resistant to stretching or shrinking, and it is not sus-
ceptible to temperature changes. However, one criti -
cal drawback of polyaramids is that they tend to kink
or knot when looped around. When polyaramids are
used to construct suspension lines, they are encased in
a skin of a terylene product, like Dacron® or a product
with similar properties. Polyethelene materials, such
as Spectra®, Dyneema® or Technora®, are very strong
as well as more flexible than polyaramids, which
makes them more durable under hard use. However,
polyethelene materials are more likely to stretch or
shrink, and they are more susceptible to temperature
changes. If your wing is equipped with polyethelene
suspension lines, it is imperative you do not store your
equipment in a place that might experience extreme
temperatures. The POH or owner manual provided by
the chute manufacturer will specify limits for tempera-
ture and storage.
Every line on the powered parachute wing is precisely
measured and fitted to a specific location. Therefore,
it is imperative to inspect the wing during preflight,
in addition to having the wing and its lines inspected
periodically by qualified technicians. The technician
will conduct strength tests as well as look for wear
and compromised attachment points; refer to your
wing manufacturer’s specifications for inspection
parameters. Under no circumstances should powered
parachute suspension lines be spliced or tied if sev -
ered! Each line’s length and strength is specifically
calibrated. If you tie a knot in the line you will change
the specifically-engineered flight characteristics of the
wing, rendering it unairworthy.
Risers
Also known as “V lines,” the risers are the intermedi-
ate link between the suspension lines and the airframe
or the attachment point of the wing to the airframe.
The risers are generally constructed of webbing,
which takes on the appearance of two straps that in -
corporate a main cable and a safety cable as one unit.
[Figure 3-13] Some of the older designs of wings may
have braided wire cables serving as their risers. The
risers are connected to the suspension lines and to the
aircraft with various connections such as with D-rings
and eyebolts.
During flight, as discussed in Chapter 2, propeller-
driven aircraft are affected by the rotation of engine
components and the propeller. This is commonly
referred to as the “ left turning tendency,” which in -
cludes torque and sometimes P factor. There are sev-
eral design features that have been incorporated into
airplanes to counteract the left turning tendency from
a clockwise turning propeller. Powered parachute de-
signers can counteract the turning effect by chang -
ing the length of the riser cables on one side of the
airframe. By decreasing the length of the right riser
cable, the wing is given a slight right turn, just enough
to cancel the effects of torque at cruise thrust settings.
This design feature of the powered parachute wing
risers makes it imperative not to mistakenly attach the
different length riser cables on the wrong side of the
airframe. Remember: the left main and the left safety
cables, from the pilot’s seat, are longer than the right
main and the right safety cables. Mixing the right and
the left cables will result in a pronounced left turn;
especially during takeoff when the engine is at full
throttle, which could jeopardize the safety of all con-
cerned.
Engine installations with a counterclockwise rotating
propeller require opposite adjustments. It is important
to know which direction the propeller turns for your
PPC to accurately counter turning tendencies.
Alternately, the wing could have the same length ris-
ers, and the cart could have a higher attachment point
for the left riser. This is why each wing is designed
for each cart and should not be interchanged: the wing
and the cart is a complete system.
The Fuel Tank
The powered parachute is usually equipped with fuel
tanks ranging in capacity from 5 to 20 gallons. As
with any aircraft, knowing how much fuel your fuel
tank holds is crucial to flight operations. The light-
sport aircraft powered parachute has no limitations as
to the size of the fuel tank, unlike its ultralight vehicle
predecessor. Most PPC powerplants require auto fuel
mid-grade or higher to be burned (see the powerplant
Figure 3-13. The risers are constructed of nylon webbing
that takes on the appearance of two straps incorporating a
main cable and a safety cable as one unit.
operating handbook for specific engine specifica -
tions).
Generally, the fuel tank is located close to the center
of gravity, so fuel burn does not affect the balance of
the aircraft. Some fuel tanks are clear for visual in -
spection of the amount of fuel on board while others
are dark. Dark tanks or hidden tanks generally have a
sight tube to assist the pilot in determining the actual
amount of fuel. [Figure 3-14] Some powered para -
chute manufacturers offer optional fuel level probes
and instrument panel analog gauges or incorporate
this information into the EIS. As fuel is used by the
engine, air needs to enter the tank and take its place;
otherwise a vacuum will form inside the fuel tank
preventing the fuel pump from drawing fuel. This is
usually accomplished with a fuel venting system. This
can be a vent in the fuel cap or some other means that
vents elsewhere, providing the ability for the fuel tank
to breathe. Any vent system must be free of debris or
it will cause fuel starvation in flight. This is especially
true when a small hole is in the fuel cap that can be
easily plugged. Check the fuel venting system during
each preflight inspection.
The Powerplant
The typical powered parachute engine can be two- or
four-stroke, liquid- or air-cooled, 50 to 100 horsepow-
er. Some engines have electric starters and some have
pull starters. Most PPC engines have reduction drives
that, when attached, reduce the propeller RPM to half
to one quarter the engine RPM. [Figure 3-16] The en-
gines are as varied as the powered parachutes they
power. Modern technology has allowed the powered
parachute engine to become lighter, more efficient
and, most importantly, dependable. Chapter 4 covers
the powerplant in more detail.
The Propeller
Propellers are “power converters” that change the
engine horsepower into “thrust.” Thrust is the force
that propels the aircraft through the air by pushing
the powered parachute forward. Aerodynamically
speaking, a propeller is a rotating airfoil and the same
principles that apply to the wing will apply to the pro-
peller. [Figure 3-17] Engine power is transferred to the
propeller through a rotating crankshaft that turns the
propeller through the air, producing thrust in the same
way as wings produce lift. The shape of the blade cre-
ates thrust vectors because it is cambered like the air-
foil of a wing. Consequently, as the air flows past the
propeller, the pressure on one side is less than that on
the other. As in a wing, this produces a reaction force
in the direction of the lower pressure. In the case of
the propeller, which is mounted in a vertical plane, the
Figure 3-15. Powered
parachute throttle.
Figure 3-16. Reduction drives
reduce the propeller RPM from
the engine RPM by about half.
Figure 3-14. Fuel tank with sight tube.
The fuel shut-off valve can be located anywhere in the
fuel line. It is important to make sure the fuel valve
is open and stays open for normal operation. Most
designs have a fuel tank sump drain valve to remove
water and solid contaminants. Each design is differ -
ent and the PPC POH will specify how to conduct
this check.
Throttle System
The throttle is the pilot’s hand control to regulate the
power provided by the engine. The configuration of
the throttle control varies from one cart manufacturer
to another. Refer to the POH of each individual PPC
for function reference. [Figure 3-15]
area of decreased pressure is in front of the propeller,
and the force (thrust) is in a forward direction. Aero -
dynamically, the thrust is the result of the propeller
shape and the angle of attack of the blade.
The typical powered parachute has a ground adjust-
able propeller. The adjustment of the propeller should
only be conducted to meet the engine manufacturer’s
maximum recommended RPM target. Pilots who are
not familiar with adjusting the propeller and how it
will affect the PPC performance should consult with
a knowledgeable source prior to making any propeller
adjustments.
The engine mount is designed by individual manu -
facturers for each cart configuration. The majority of
the total aircraft weight is determined by the engine
and mounting configuration. When trailering the PPC
over bumpy terrain or over long trips, the bouncing
of the cart in the trailer can put extreme stress on this
mounting system. In addition, repeated hard land -
ings of the cart can also stress the welds of the engine
mount. Consistent detailed inspections of the engine
mount should be an important part of every preflight
and post-flight inspection.
Just like an airplane propeller, the powered parachute
propeller turns at such great speeds that it becomes
invisible when in motion. The dangers of a turning
propeller require every pilot to maintain the highest
level of safety and respect for the consequences of
body parts, pets, and debris coming in contact with a
rotating propeller. Always treat the propeller as if the
ignition were on. Debris on the takeoff/landing field
is a danger to the propeller as well as to the people
who may be in the prop-wash area behind the pro -
peller. Stones, small pieces of metal, and sticks can
become dangerous projectiles if kicked into the pro -
peller during takeoff and landing. Just as with any
airframe or wing component of a powered parachute,
if the propeller becomes damaged, nicked or dinged,
the aircraft’s performance can be greatly affected.
Some pilots elect to use tape or rock deflector guards
to protect the leading edge from rock/debris damage.
Regardless, taking proper care of the PPC propeller is
as critical as proper engine and wing care.
Axle and Wheel Assembly
The rear and front wheels of the powered parachute
are an assembly and consist of a tire, a rim, and an
inner and outer set of wheel bearings. The wheel is
secured on a spindle and held in place by a nut and
a cotter pin. Each spindle is typically mounted on a
suspension system which provides elasticity and at
the same time is very strong. [Figure 3-18] The sus-
pension system varies by manufacturer from one cart
to another; refer to the POH for exact configuration
and components. Some powered parachute tires are
heavily treaded while others are smooth; pilot prefer-
ence and the terrain type are determining factors in
choice of tire profiles. [Figure 3-19] Tire sealant or
thorn guards can be used to minimize flat tires.
Figure 3-17. Airfoil sections of a propeller blade.
Figure 3-18. Suspension system.
Figure 3-19. Some powered parachute tires are heavily
treaded while others are smooth.