4. I will operate my model using only radio control
frequencies currently allowed by the Federal
Communications Commission...
Since the Great Planes Pitts Special S2S ARF qualifies
as a “giant scale” model and is therefore eligible to fly
in IMAA events, we’ve printed excerpts from the IMAA
Safety Code which follows.
Definition:
For the purpose of the following IMAA Safety Code, the
term Giant Scale shall refer to radio controlled model
aircraft, either scale or non-scale, which have a wingspan of
80 inches or more for monoplanes and 60 inches or more
for multi-winged model aircraft and have a ramp weight
(fueled and ready to fly) of 55 lbs. or less.
Section 1.0: SAFETY STANDARD
1.1 Adherence to Code:
This safety code is to be strictly followed.
1.2 The most current AMA Safety Code in effect is to be
observed. However, the competition sections of the code
may be disregarded.
Section 3.0: Safety Check
3.4 Flight Testing: All Giant Scale R/C aircraft are to have
been flight tested and flight trimmed with a minimum of six
flights before the model is allowed to fly at an IMAA
Sanctioned event.
3.5 Proof of Flight: The completing and signing of the
Declaration section of the Safety Inspection form by the pilot
(or owner) shall document as fact that each aircraft has
been successfully flight-tested and proven airworthy prior to
an IMAA event.
Section 5.0: EMERGENCY ENGINE SHUT OFF (kill
switch)
5.1 All magneto spark ignition engines must have a coil
grounding switch on the aircraft to stop the engine. This will also
prevent accidental starting of the engine. This switch shall be
readily available to both pilot and helper. This switch is to be
operated manually and without the use of the radio system.
5.2 Engines with battery power ignition systems must have a
switch to turn off the power from the battery pack to disable the
engine from firing. This will also prevent accidental starting of
the engine.This switch shall be readily available to both pilot and
helper. This switch shall be operated manually and without the
use of the Radio System.
5.3 There must also be a means to stop the engine from the
transmitter. The most common method is to close the
carburetor throat completely using throttle trim, however,
other methods are acceptable. This requirement applies to
all glow/gas ignition engines regardless of size.
Section 6.0: RADIO REQUIREMENTS
6.1 All transmitters must be FCC type certified.
6.2 FCC Technician or higher-class license required for 6
meter band operation only.
Additional IMAA General Recommendations
The following recommendations are included in the Safety
Code not to police such items, but rather to offer basic
suggestions for enhanced safety.
Servos need to be of a rating capable to handle the loads
that the control surfaces impose upon the servos. Standard
servos are not recommended for control surfaces. Servos
should be rated heavy-duty. For flight-critical control
functions a minimum of 45 inch/ounces of torque should be
considered. This should be considered a minimum for
smaller aircraft and higher torque servos are strongly
encouraged for larger aircraft. The use of one servo for each
aileron and one for each elevator half is strongly
recommended. Use of dual servos is also recommended for
larger aircraft.
On-board batteries shall be 1000 mAh up to 20 lbs., 1200
mAh to 30 lbs., 1800 mAh to 40 lbs. and 2000 mAh over 40
lbs. flying weight. The number and size of servos, size and
loads on control surfaces, and added features should be
considered as an increase to these minimums. Batteries
should be able to sustain power to the onboard radio
components for a minimum of one hour total flying time
before recharging.
Redundant and fail-safe battery systems are recommended.
The use of anti-glitch devices for long leads are 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 selection of engine size relative to airframe strength and
power loading mandates good discretionary judgments 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 Sanctions concerning competition events (such as
511, 512, 515 and 520) and, as such, the maximums apply.
All IMAA (non competition) events should be sanctioned as
Class “C” events; in which these engine size maximums do
not apply.
IMAA Safety Code (excerpts)
37
