Flying; Engine Setup; Takeoff; Flight - GREAT PLANES Profile 38 Instruction Manual

13. Make sure any servo extension cords you may have
used do not interfere with other systems (servo
arms, pushrods, etc.).
14. Secure the pressure tap (if used) to the muffler with
high temp RTV silicone, thread locking compound
or J.B. Weld.
15. Make sure the fuel lines are connected and are
not kinked.
16. Use an incidence meter to check the wing for twists
and attempt to correct before flying.
17. Balance your propeller (and spare propellers).
18. Tighten the propeller nut and spinner.
19. Place your name, address, AMA number and
telephone number on or inside your model.
20. Cycle your receiver battery pack (if necessary) and
make sure it is fully charged.
21. If you wish to photograph your model, do so before
your first flight.
22. Range check your radio when you get to the flying field.

FLYING

The Profile 38 is a great-flying model that flies smoothly and
predictably. The Profile 38 does not, however, possess the
self-recovery characteristics of a primary R/C trainer and
should be flown only by experienced R/C pilots.
CAUTION (THIS APPLIES TO ALL R/C AIRPLANES): If,
while flying, you notice any unusual sounds, such as a
low-pitched "buzz," this may indicate control surface
flutter . This means that the control surface is moving back
and forth very rapidly. Because flutter can quickly destroy
components of your airplane, any time you detect flutter
you must immediately cut the throttle and land the
airplane! Check all servo grommets for deterioration (this
may indicate which surface fluttered), and make sure all
pushrod linkages are secure and free of play. If the control
surface fluttered once, it probably will flutter again under
similar circumstances unless you can eliminate the free-
play or flexing in the linkages. Here are some things
which can cause flutter: Excessive hinge gap; Not
mounting control horns solidly; Poor fit of clevis pin in
horn; Side-play of pushrod in guide tube caused by tight
bends; Poor fit of Z-bend in servo arm; Excessive play or
backlash in servo gears; and Insecure servo mounting.

Engine Setup

For the Profile 38 to fly straight at all throttle settings, the
engines must be synchronized (the props turning close to
the same rpm at idle and at full throttle). This will require
adjustments of the throttle linkage and the needle settings
on the engines. We try to get our engines within 200 rpm. It
is also a good idea to run a full tank of fuel through the
engines while the plane is on the ground to make sure both
engines remain running at different throttle settings and
remain synchronized. If the engines get out of synch in the
air, some rudder trim can be added to compensate for the
difference.
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. If necessary, adjust the nose wheel so the
model will roll straight down the runway. If you need to calm
your nerves before the maiden flight, shut the engines down
and bring the model back into the pits. Top off the fuel, then
check all fasteners and control linkages for peace of mind.
Remember to takeoff into the wind. When you're ready, point
the model straight down the runway, then gradually advance
the throttle. 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 Profile 38 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. Mind your fuel level, but use this first flight to become
familiar with your model before landing.

What to Do if One Engine Quits

If you installed two .25-size engines on your plane, and one
engine quits, the plane can maintain altitude with only one
engine running. You may need to apply a small amount of
rudder to continue flying straight. Try to keep the plane flat
in turns and don't turn into the dead engine. Keep your
airspeed up. If the nose does drop because of lack of
airspeed, don't fight it. Let the nose drop and gain speed.
Land the plane as soon as possible.
45

Takeoff

Flight