Great Planes PT-E Trainer Electric Kit - GPMA0110 - Manual (Page 42)

THRUST
There are several factors that contribute to the way
an airplane flies, but the most important things you have
control of are WEIGHT and THRUST Here are some ways
you can insure maximum thrust.
Battery: A 7-cell 1200 mAh battery is 1 or 2 ounces heavier
than a 6-cell 1200 mAh battery, but the additional thrust
provided by a 7-cell battery more than offsets the increased
weight For best results with 6- cells, we recommend using
a battery pack that has matched cells, such as the Kyosho
6-cell 1200 mAh racing battery If you are not satisfied
with the performance of your airplane with the battery
you are using, you may either switch to a 7-cell pack, or
you may purchase a "7th cell" that plugs into your switch
harness in series with your existing 6-cell pack.
Propellers: The Thrustmaster electric motor was de-
signed especially for powering airplanes by direct-drive.
It is well suited for this application because it turns a
relatively large (8x4 or 9x4) propeller at an RPM that
provides sufficient thrust for this airplane Because it has
a relatively low no-load RPM (compared with some car
motors), you will not benefit by using a smaller diameter
prop We have tested many props and have found the Gnsh
8x4 (nylon) to be about the best The Taipan 8x4 (nylon)
and the Zinger 8x4 (wood) are about equal to the Gnsh The
only prop we found to give slightly increased thrust is the
Top Flite 9x4 Super-M (wood).
Motor Break-in: Be sure to run your motor with no load
(prop removed) for at least 1/2 hour before using it in your
airplane Because of the special design of the brushes, your
Thrustmaster's performance will continue to improve dur-
ing the first couple hours of operation
Peak Battery Charging: A fully charged battery pack
will provide an initial "surge" of power during the first 15
to 30 seconds of the motor run, then the power curve stays
fairly level for the next several minutes If you do not
charge your battery fully it will not deliver that surge
necessary for a good takeoffand climb-out There are three
easy ways to "peak-charge" your battery pack:
CAUTION! Regardless of which method you use, you must
never charge the battery unattended. NiCad batteries
have enough power to start a fire' Some modelers have
burned down houses or burned family cars by leaving them
unattended' If you fully charge a battery, then forget you
have done so, then fully charge the battery again, this
will cause the battery to get extremely hot and may cause
a fire or explosion If the timer on your charger sticks, it
will charge too long causing the same results If the insu-
lation on your wiring is cracked or missing and the red
and black wires touch, shorting the battery, much heat
will be produced which could easily start a fire or explosion
Always follow the charging instructions included with
your battery and charger.
D 1. Use a "peak-detecting" battery charger This
type charger will automatically charge your battery
until it is fully charged Unfortunately, this type
charger is not yet available for use with AC current,
but it works very well when connected to a 12-volt
car battery
42
D 2 You can monitor the voltage of your charging bat-
tery with a voltmeter Your charger may have soc-
kets into which you may plug a voltmeter If not,
you may insert the probes from the voltmeter into
the rear of the battery plug, making contact with
the metal portions As your battery charges, the vol-
tage will gradually increase When the battery is
fully charged, the voltmeter will show a slight drop
in the battery voltage At this point your battery is
fully charged.
D 3 The third method of "peaking" your battery is by
checking its temperature As the battery charges
it will remain cool until it is almost fully charged.
When it reaches the fully charged state it will rapidly
build up heat You can feel this heat with your hand
As soon as the pack starts to noticeably warm up,
disconnect it from the charger Do not continue
charging until the pack is hot! Overcharging will
damage your battery pack and can result in a fire
or explosion
Exercise Your Batteries: A new battery pack should be
"cycled" for best results You should peak charge the bat-
tery, then discharge it almost completely by actually run-
ning your motor with the propeller attached Do this 3 or
4 times on the ground before actually flying Be sure you
remove the battery from the airplane between each cycle
and allow it to cool before recharging
Switch Harness: The standard "Kyosho"-type battery
connectors supplied with your switch harness are normally
adequate for most installations However, if you are look-
ing for maximum performance, you may want to consider
installing high-performance battery connectors, such as
"Sermos R/C Snap Connectors" Replacing all the standard
switch harness wire with ultra high performance wire,
such as Jomar 12 gauge (665 strand) wire will also provide
a slight increase in performance
OTHER FACTORS
There are several other things that can reduce per-
formance considerably Check for the following conditions
and correct as necessary.
D 1 Make sure there is plenty of clearance between
the front of the fuse sides and the propeller If the
prop is very close to the front end of the fuse sides,
it may rub slightly during operation (due to vibra-
tion), and this will reduce performance significantly.
D 2 Examine your propeller for irregularities caused
by the injection molding process Carefully remove
these imperfections with fine sandpaper.
D 3 Most nylon propellers balance quite well as they
come from the factory, but we have found several
that require balancing You can improve the per-
formance of your Thrustmaster by balancing the
prop, using an inexpensive prop balancer available
at your local hobby shop
D 4 To takeoff from a hard-surfaced runway the wheels
of your airplane must spin freely, with very little
friction Check the wheels for possible binding when