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CHECK LIST
During the last few moments of preparation your
mind may be elsewhere anticipating the
excitement of the first flight. Because of this, you
may be more likely to overlook certain checks
and procedures that should be performed before
the model is flown. To help avoid this, a
checklist 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
stuffing them into place with foam rubber
is not sufficient.
4. Extend your receiver antenna and make sure it
has a strain relief inside the fuselage 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, 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. Confirm 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
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. 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.
19. Cycle your receiver battery pack (if necessary)
and make sure it is fully charged.
20. If you wish to photograph your model, do
so before your first flight.
21. Range check your radio when you get to
the flying field.
FLYING
The Hobbico Sukhoi SU31 is a great-flying model
that flies smoothly and predictably. The Hobbico
Sukhoi 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.
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.
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