38
❏
21. Cycle your receiver battery pack (if necessary) and
make sure it is fully charged.
❏
22. Range-check your radio at the field at the start of
each flying day. Check it with the engine operating.
FLYING
The Waco YMF-5 is a great-flying model that flies smoothly
and predictably. The Waco YMF-5 does not, however,
possess the self-recovery characteristics of a primary R/C
trainer and should be flown only by experienced R/C pilots.
Fuel Mixture Adjustments
A fully cowled engine may run at a higher temperature than
an un-cowled engine. For this reason, the fuel mixture should
be richened so the engine runs at about 200 rpm below
peak speed. By running the engine slightly rich, you will help
prevent dead-stick landings caused by overheating. Keep
in mind also that an engine runs more rich on the ground.
Leaning to peak rpm on the ground can cause overheating
in the air.
CAUTION (THIS APPLIES TO ALL R/C AIRPLANES): If,
while fl ying, you notice an alarming or unusual sound such
as a low-pitched "buzz," this may indicate control surface
fl utter. Flutter occurs when a control surface (such as an
aileron or elevator) or a fl ying surface (such as a wing or
stab) rapidly vibrates up and down (thus causing the noise).
In extreme cases, if not detected immediately, fl utter can
actually cause the control surface to detach or the fl ying
surface to fail, thus causing loss of control followed by
an impending crash. The best thing to do when fl utter is
detected is to slow the model immediately by reducing
power, then land as soon as safely possible. Identify which
surface fl uttered (so the problem may be resolved) by
checking all the servo grommets for deterioration or signs of
vibration. Make certain all pushrod linkages are secure and
free of play. If it fl uttered once, under similar circumstances
it will probably fl utter again unless the problem is fi xed.
Some things which can cause fl utter are; Excessive hinge
gap; Not mounting control horns solidly; Poor fi t of clevis
pin in horn; Side-play of wire pushrods caused by large
bends; Excessive free play in servo gears; Insecure servo
mounting; and one of the most prevalent causes of fl utter;
Flying an over-powered model at excessive speeds.
Takeoff
Before you get ready to takeoff, see how the model handles
on the ground by doing a few practice runs at low speeds on
the runway. Hold “up” elevator to keep the tail wheel on the
ground. If necessary, adjust the tail wheel so the model will
roll straight down the runway. If you need to calm your nerves
before the maiden flight, shut the engine down and bring
the model back into the pits. Top off the fuel, then check all
fasteners and control linkages.
Remember to takeoff into the wind. When you’re ready,
point the model straight down the runway, hold a bit of up
elevator to keep the tail on the ground to maintain tail wheel
steering, then gradually advance the throttle. As the model
gains speed, decrease up elevator allowing the tail to come
off the ground naturally. One of the most important things to
remember with a tail dragger is to always be ready to apply
right rudder to counteract engine torque. Gain as much
speed as your runway and flying site will practically allow
before gently applying up elevator, lifting the model into the
air. At this moment it is likely that you will need to apply more
right rudder to counteract engine torque. Be smooth on the
elevator stick, allowing the model to establish a gentle climb
to a safe altitude before turning into the traffic pattern.
Flight
For reassurance and to keep an eye on other traffic, it is a
good idea to have an assistant on the flight line with you. Tell
him to remind you to throttle back once the plane gets to a
comfortable altitude. While full throttle is usually desirable for
takeoff, most models fly more smoothly at reduced speeds.
Take it easy with your airplane for the first few flights, gradually
getting acquainted with it as you gain confidence. Adjust the
trims to maintain straight and level flight. After flying around
for a while, and while still at a safe altitude with plenty of fuel,
practice slow flight and execute practice landing approaches
by reducing the throttle to see how the model handles at
slower speeds. Make a few more runs minding your field’s
current traffic pattern and try executing a few straight-ahead
stalls. Add power to see how she climbs as well. Continue to
fly around, executing various maneuvers and making mental
notes (or having your assistant write them down) of what trim
or C.G. changes may be required to fine tune the model so
it flies the way you like. Mind your fuel level or batteries, but
use this first flight to become familiar with your model before
landing.
Landing
To initiate a landing approach, lower the throttle while on the
downwind leg. Allow the nose of the model to pitch downward
to gradually bleed off altitude. Continue to lose altitude, but
maintain airspeed by keeping the nose down as you turn onto
the crosswind leg. Make your final turn toward the runway
(into the wind) keeping the nose down to maintain airspeed
and control. Level the attitude when the model reaches the
runway threshold, modulating the throttle as necessary to
maintain your glide path and airspeed. If you are going to
overshoot, smoothly advance the throttle (always ready on
the right rudder to counteract torque) and climb out to make
another attempt. When you’re ready to make your landing flare
and the model is a foot or so off the deck, smoothly increase
up elevator until it gently touches down. Once the model is
on the runway and has lost flying speed, hold up elevator to
place the tail on the ground, regaining tail wheel control.
Summary of Contents for Waco YMF-5
Page 40: ......
