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20. If you are flying this plane with electric power be sure
you properly charge the batteries following the
instructions with your batteries and charger.
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20. If you wish to photograph your model, do so before
your first flight.
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21. Range check your radio when you get to the flying field.
The RV-4 is a great-flying model that flies smoothly and
predictably. The RV-4 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 200RPM
below peak speed. By running the engine slightly rich, you
will help prevent dead-stick landings caused by overheating.
CAUTION (THIS APPLIES TO ALL R/C AIRPLANES): If,
while flying, you notice an alarming or unusual sound
such as a low-pitched "buzz," this may indicate control
surface flutter . Flutter occurs when a control surface (such
as an aileron or elevator) or a flying surface (such as a
wing or stab) rapidly vibrates up and down (thus causing
the noise). In extreme cases, if not detected immediately,
flutter can actually cause the control surface to detach or
the flying surface to fail, thus causing loss of control
followed by an impending crash. The best thing to do
when flutter is detected is to slow the model immediately
by reducing power, then land as soon as safely possible.
Identify which surface fluttered (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 fluttered
once, under similar circumstances it will probably flutter
again unless the problem is fixed. Some things which can
cause flutter are; Excessive hinge gap; Not mounting
control horns solidly; Poor fit 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 flutter; Flying an over-
powered model at excessive speeds.
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
FLYING
Takeoff
bring the model back into the pits. Top off the fuel, and then
check all fasteners and control linkages for peace of mind.
Though this airplane has flaps they are not required for
takeoff. For your first flight it is recommended you do not use
flaps. After the plane has been properly trimmed you may
wish to try flaps for takeoff by starting with 1/2 flaps.
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. One of the most important things to remember with
a taildragger 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.
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 the RV-4 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. 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. You will find that the
airplane does very nice loops, spins, inverted flight, etc. The
plane has a fairly slow roll rate. Setting up aileron differential
either mechanically or through your radio can increase the
speed of the roll. Mind your fuel level, but use this first flight to
become familiar with your model before landing.
The flaps on this airplane are very effective but if you are not
familiar with flaps it is suggested that you do your first landings
without them. The RV-4 lands slowly with or without the use of
the flaps. 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
29
Flight
Landing
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