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Chapter 7 — Takeoffs and Departure Climbs
Before Takeoff Check
The before takeoff check is the systematic procedure
for making a final check of the engine, controls, systems,
instruments, and avionics prior to flight. In addition,
it gives the pilot an opportunity to establish a
go or no-go decision. The engine temperatures should
be rechecked, especially if any considerable amount
of time has passed since the engine warm-up was
completed, to make sure the engine and fluids are still
within the manufacturers’ recommended minimums.
If the air temperature is cold, the engine will cool
down faster than when the air temperature is warmer;
take a few minutes to bring the engine temperature
back up to minimums. Recheck the wind direction. If
the wind has changed, adjust your takeoff position so
you remain into the wind. Double check the steering
and suspension lines are not in the way of the forward
movement of the tires and the steering lines are not
tangled in the riser cables.
Start the Engine/Initial Rollout
Prime the engine, if so equipped, switch magnetos to
the ON position, recheck that the throttle is not open
beyond idle, and turn the electric master switch to the
ON position. Visually check the area, shout “CLEAR
PROP” and start the engine. Monitor the engine temperatures
and check security of harnesses and helmets.
Check that the strobe lights are ON, electric
fuel pump is ON (if applicable), oil pressure is within
limits (if applicable), and complete a final ignition
system check.
Once again, the pilot has this opportunity to establish
a go or no-go decision point. Check the intended runway
and traffic pattern for existing traffic, and if radio
equipped and a nontowered airport, announce field,
type of aircraft, runway heading, and flight intentions;
if a tower-controlled airport, contact ground or tower
control to request a departure clearance. By adding
thrust smoothly to about half to three-quarter throttle,
the powered parachute will begin the takeoff roll.
Wing Inflation and Kiting
During the takeoff roll of an airplane, the goal is to
build sufficient airflow over the wing to generate the
lift required to lift the aircraft off the ground. Powered
parachutes have two goals during the takeoff roll: to pressurize and raise the wing overhead making sure
proper inflation exists for takeoff, and to create the
airflow over the wing to generate the necessary lift.
[Figure 7-3]
Make a final check to confirm that the cart is pointed
in the right direction and nothing has moved into the
way. Look over your shoulder to observe the canopy
inflation. Advance the throttle smoothly and firmly
to about one-half to two-thirds takeoff power. Too
abrupt an application of power may cause the cart to
yank the wing too roughly forward. This can damage
the riser system and shorten wing life. This is more
of a problem with higher horsepower engines than in
lower powered aircraft. As the cart starts to roll forward,
make sure both feet are on the steering bars to
begin steering the parachute immediately.
As the wing starts to rise off the ground and climb, it is
acting like a parachute with lots of drag; the cart does
not move forward much. As soon as the wing passes
through the 50° angle to the ground, the drag dramatically
decreases as the parachute becomes a wing and the cart will begin to pick up forward speed very rapidly.
You must reduce the engine thrust enough at this
point to prevent the powered parachute from becoming
airborne prematurely. If the initial thrust reduction
is too great, the wing will begin to lose pressurization
and settle back to the ground. If the thrust reduction
is not adequate, the powered parachute will continue
to accelerate and become airborne. On occasion the
wing can become locked-out, or stuck in the prop
wash; easing back on the throttle will allow the wing
to settle out of the prop wash. Once again, easing
the throttle smoothly forward will assist the wing in
climbing through the prop wash and climb overhead
above the fuselage.
As the wing is coming up in back of the cart, one side
of the wing may inflate and rise faster than the other
side. That higher side should be given a little bit of
steering control to allow the other side of the wing
to catch up. If you don’t make the correction early,
the wing will want to fly over to the slower-inflating
side. This may create wing oscillations, especially if
combined with too slow a takeoff speed. While it is
important to not over-control, remember that wing
controls during kiting are sluggish and more control
inputs are needed than during flight.
Now is the most critical point during takeoff and possibly
during the entire flight. While the parachute is
inflating and rising overhead, most of the powered
parachute’s weight is still being carried by the wheels
and the suspension system. The goal is to get the wing
overhead and then transition the load from the wheels
to the wing.
During the inflation and takeoff roll, you need to divide
your attention between the direction the cart is going
and the wing. When the wing is overhead, perform
the “rolling preflight.” You need to quickly inspect the
wing to make sure it is fully inflated and there are no
line-overs, end cell closures, pressure knots, or huge
oscillations before adding full power for takeoff. This
all has to be done with quick glances.
Line-overs are very easy to detect because the wing
will be obviously deformed and look like it is pinched
by the line that is over the top of the wing. If you see
a line-over, shut down and set up again.
End cells of the wing not inflating are something additional
to watch for. Most powered parachute wings
have large cross-venting in the cells to allow the
entire wing to pressurize evenly. Generally, the wing
will pressurize in the middle first. As the pressure
evens out across the wing sometimes the end cells of the wing simply do not want to inflate. It is imperative
that the pilot visually sees end cells inflate before
taking off. Sometimes all you have to do is wait for
the end cells to open. On some wing configurations it
is recommended that the steering tubes be “pumped”
lightly to help open the end cell openings.
Pressure knots are harder to determine during a rolling
preflight. It may be very hard to see what is going on
with the lines themselves, so the pilot may find it better
to look for deformations on the bottom surface of
the wing caused by one line being pulled more than it
should be. Trying to take off with a pressure knot will
result in the powered parachute turning very sharply
to the side of the pressure knot. It will be nearly impossible
to correct for that turn without nearly stalling
the wing with the input on the other side. The engine
will have to be kept at a very high setting just to maintain
what little altitude is gained.
Wing oscillations occur for several reasons. There
may not have been enough power added initially to
kite the wing, or the pilot may have waited too long
to correct for a wing that was flying to one side. Some
light oscillation is okay, and will merely lift one side
of the powered parachute into the air before the other.
On the other hand large oscillations will actually
change the lift from a straight upward vector to an
upward and side-pulling force. An oscillating wing
forced into takeoff will most likely roll the airframe,
which is an undesirable cause and effect.
Oscillations are easier to prevent with good inflation
techniques than they are to correct. However, if a
wing is oscillating, it is possible to correct by steering
the wing opposite to the side that the wing is drifting
towards. In other words, manage the wing, steer
it straight. The wrong inputs can make the problem
worse. If the oscillations become too severe, it is best
to abort the takeoff and set up again.
It is critical for the wing and lines to become verified,
or fully inflated, directly overhead and centered, with
the lines free of tangles. An acronym of LOC is often
used to verify the wing is ready for takeoff: L – Lines
Free, O – Cells Open, C – Wing Centered. Once the
wing is fully pressurized, centered above the cart and
the suspension and steering lines are free of tangles,
slowly increase the throttle to takeoff thrust. The increased
thrust accelerates the powered parachute forward
until the airflow over the wing generates enough
lift to get the PPC airborne. Continue to increase
throttle gradually to the desired pitch attitude. Your
feet have been resting on the steering bars throughout
all the ground operations, and can be used to steer.
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