Great Planes SU-31 3D ARF - GPMA1412 - Manual (Page 47)

47
The use of anti-glitch devices for long leads is recommended.
There is no maximum engine displacement limit, as it is the
position of this body that an underpowered aircraft presents
a greater danger than an overpowered aircraft. However, the
selections of engine size relative to airframe strength and
power loading mandates good discretionary judgment by
the designer and builder. Current AMA maximums for engine
displacement are 6.0 cu. in. for two stroke and 9.6 cu. in. for
four stroke engines. These maximums apply only to AMA
Sanction competition events (such as 511, 512, 515 and
520). All non competition events should be sanctioned as
Class “C” events, in which these engine size maximums do
not apply.
Generally, it is recommended that no attempt should be made
to fl y a radio controlled model aircraft with a gasoline engine
in which the model aircraft weight would exceed 12 pounds
per cubic inch of engine displacement (underpowered), or
be less than 5 pounds per cubic inch of engine displacement
(overpowered). Example: Using a 3 cu. in. engine, a model
would likely be underpowered at an aircraft weight greater
than 36 pounds. With the same engine, an aircraft weighing
less than 15 pounds would likely be overpowered.
Servo arms and control horns should be rated heavy-duty. Glass
fi lled servo arms and control horns are highly recommended.
Control surface linkages are listed in order of preference:
1. Cable system (pull-pull). A tiller bar is highly recommended
along with necessary bracing.
2. Arrow-shaft, fi berglass or aluminum, 1/4" or 5/16" O.D.
bracing every six (6) to ten (10) inches is highly recommended.
3. Tube-in-tube (nyrod). Bracing every few inches is highly
recommended. Inner tube should be totally enclosed in
outer tube.
4. Hardwood dowel, 3/8" O.D. Bracing every six (6) to ten
(10) inches is highly recommended.
Hinges should be rated heavy-duty and manufactured
primarily for use in giant-sized aircraft. Homemade and
original design hinges are acceptable if determined to be
adequate for the intended use.
Clevis (steel, excluding heavy duty ball links) and attachment
hardware should be heavy duty 4-40 threaded rod type.
2-56 threaded size rod is acceptable for some applications
(e.g. throttle). Clevises must have lock nuts and sleeve (fuel
tubing) or spring keepers.
Propeller tips should be painted or colored in a visible and
contrasting manner to increase the visibility of the propeller
tip arc.
CHECK LIST
During the last few moments of preparation your mind may
be elsewhere anticipating the excitement of the fi rst fl ight.
Because of this, you may be more likely to overlook certain
checks and procedures that should be performed before the
model is fl own. To help avoid this, a check list is provided to
make sure these important areas are not overlooked. Many
are covered in the instruction manual, so where appropriate,
refer to the manual for complete instructions. Be sure to
check the items off as they are completed.
❏
1. Fuelproof all areas exposed to fuel or exhaust residue
such as the cowl mounting blocks, wing saddle
area, etc.
❏
2. Check the C.G. according to the measurements
provided in the manual.
❏
3. Be certain the battery and receiver are securely
mounted in the fuse. Simply stuffi ng them into place
with foam rubber is not suffi cient.
❏
4. Extend your receiver antenna and make sure it has
a strain relief inside the fuse to keep tension off the
solder joint inside the receiver.
❏
5. Balance your model laterally as explained in
the instructions.
❏
6. Use threadlocking compound to secure critical
fasteners such as the set screws that hold the wheel
axles to the struts, screws that hold the carburetor arm
(if applicable), screw-lock pushrod connectors, etc.
❏
7. Add a drop of oil to the axles so the wheels will
turn freely.
❏
8. Make sure all hinges are securely glued in place.
❏
9. Reinforce holes for wood screws with thin CA where
appropriate (servo mounting screws, cowl mounting
screws, etc.).
❏
10. Confi rm that all controls operate in the correct direction
and the throws are set up according to the manual.
❏
11. Make sure there are silicone retainers on all the
clevises and that all servo arms are secured to the
servos with the screws included with your radio.
❏
12. Secure connections between servo wires and
Y-connectors or servo extensions and the connection
between your battery pack and the on/off switch with
vinyl tape, heat-shrink tubing or special clips suitable
for that purpose.
❏
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 muffl er with
high temp RTV silicone, threadlocking compound or
J.B. Weld.
❏
15. Make sure the fuel lines are connected and are
not kinked.
❏
16. Balance your propeller (and spare propellers).
❏
17. Tighten the propeller nut and spinner.
❏
18. Place your name, address, AMA number and telephone
number on or inside your model.