Power Switch: JR X9303 2.4 GHz Helicopter Radio System

Power Switch: JR X9303 2.4 GHz Helicopter Radio System
Thumb fliers will appreciate the knurled grips on the back side of
the X9303 transmitter. This is a dedicated 2.4 GHz system—not
an upgrade.
TOM SCHWYN
Based on the world-class 9303
computer system, JR brings spread
spectrum to a high-end radio
Pro vs. Joe: The X9303 2.4 radio is all pro, with smooth actuating rocker switches and
precision gimbal movement. Isopropyl alcohol is the best cleaner for the chrome-plated
case.
THE “HIGH-END” radio market has
always had two advantages: a great deal of
programming capability and a significant
number of channels to use with almost
every aircraft you could imagine. JR has
added to all this the precision, convenience,
and safety of spread spectrum.
The JR line of radios has always been
recognized for its user-friendly
programming, and the X9303 2.4 GHz
system is no exception. If you want virtually
unlimited programming options, this radio
delivers that and then some!
The X9303 2.4 contains all the software
you need to operate helicopters, airplanes,
and sailplanes. The only things separating
the mechanical layout of the helicopter and
airplane variations of the transmitters are the
labeling and location of switches such as
throttle hold and flight mode and removal of
the detent feature on the throttle/collective
pitch stick. This system even offers
reprogramming of some switch locations as
you select the type of aircraft you want to
fly.
The X9303 2.4 is certainly aimed at the
intermediate to advanced pilot from the
standpoint of features and capability. I’m
going to go into some depth regarding the
helicopter software features, but this radio is
certainly no slouch in the airplane- and
sailplane-software area.
Airplane software includes such features
as multiple flight modes, switch assignment,
dual rates and exponential (expo), flap
system, servo speed, and six programmable
June 2008 65
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June 2008 67
+
• High-end radio without the high-end price.
• Friendly programming with many automatic features.
• High-capacity batteries included with charger.
• Finite feature control offers customization to suit
individual pilot taste.
• Fast and precise system response.
• Control of all channels in fail-safe mode.
-
• Neck-strap users might require offset connection
accessory.
• Switch locations may not suit users who are looking
for one airplane/helicopter transmitter.
Pluses and Minuses
The X9303 includes high-capacity NiMH batteries for the
transmitter and flight pack. All wiring is heavy-duty like the
included power switch.
Who needs a nine-channel radio?
The idea of all those channels is
daunting at first. After all, most of my
airplanes use only four or six channels.
What can a system with nine channels
offer besides bling and bragging rights?
The JR X9303 2.4 has plenty to
offer, not to mention that it is a comfort
to use even if all I want to fly is a threechannel
sailplane. What convinced me
to buy a high-end radio in the first place
was the need to suit my growth pattern
as an RC pilot; I needed more
adjustability options.
If you’re as tired of codes, channel
numbers, and acronyms as I am, you
might appreciate that with the X9303
2.4 you don’t have to live with AUX1
and AUX2 as the assigned names for
channels 6 and 7. This system will
allow you to rename those channels. I’d
much rather refer to right aileron as
For Airplane People ...
AILR than AUX1 any day. The X9303 2.4
will make sure that the other menus in the
radio feature that new name for the channel.
(The “X9303” code is for X, as in the
latest JR series; nine channels; 30-model
storage; and three model types. The 2.4
denotes the 2.4 GHz radio frequency it
uses.)
That condition when an aircraft is rolled
inverted and the nose wants to drop can be
easily adjusted through the radio
programming. I don’t want to have to give
the model more control in any direction,
because that extra amount of movement
required makes it harder to time segments of
a maneuver. I call it “stick harmony”—
where the control stick’s sensitivity is the
same in all axes.
To coordinate a roll maneuver, for
instance, I want the down-elevator input to
have the same effectiveness as the upelevator
input. More down-elevator pressure
is typical; however, there are many ways to
harmonize the stick.
The endpoint adjustments, dual rate, or
exponential programming features will be
able to control the stick input’s
effectiveness. With the X9303 2.4, I can
adjust the distance, rate, and feel of both
sides of the control stick. Custom pilot
programming is an obvious reason why a
high-end radio is beneficial.
In this case I want to change the feel of
the control input. So I’ll access the
exponential menu and reduce the value to
make the down-elevator stick input more
sensitive. Most basic computer radios in
the four- to six-channel range don’t have
this option. I’ll adjust the expo until the
amount of down-stick travel feels the same
as up.
When pilots invest in radio systems,
they rarely regret having too many options.
But they often wish they could have done
something different if they had had the
tools. I’ll never regret spending good
money on the improved feel and
response that digital spread spectrum
systems offer.
The first thing I did to test my radio
was switch everything on and wiggle
the control stick. The servos responded
so precisely and quickly that the
airplane rocked back and forth. All I did
was change the transmitter and receiver;
it was as if I upgraded the servos and
battery.
Not that I look for super sensitivity
on all my models, but the confidence
upgrade I get as a pilot to see my
equipment work so well is a boost to my
skills and satisfaction in participating in
the hobby. Add to that the exclusive
ModelMatch and fail-safe features of
the DSM2 programming, and I’m more
confident than ever that the investment I
make in a sophisticated airplane or
helicopter is less likely to be lost
because of a glitch or operator error.
I need a nine-channel radio because I
want the radio system to support my
growing interests. Now that I have a
better radio, flying the models in my
fleet will be a better experience. MA
—Michael Ramsey
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68 MODEL AVIATION
Nearly the only
suggestion I have is
to substitute a smaller
receiver—such as the
Spektrum AR6100e—
for the included
Spektrum R921. It is
a tight squeeze and
adds a few ounces to
the helicopter.
The R921 is a fullrange
receiver, which
is a bonus to have if you ever decide to fly the 450SA until it’s
a speck in the sky and test its tailslide endurance. The small
AR6100 package weighs only 3.5 grams and is specifically
designed for park flyers’ short-range requirements. You should
not use this receiver in larger aircraft that need full range.
The other nice thing about the T-Rex is that dealers and
hobby shops across the country do a good job of supporting it.
Parts are easy to find, which means that a push too far outside
the envelope won’t mean a long wait to get the machine back
together.
Many frugal helicopter pilots will appreciate that the 450SA
costs considerably less than the T-Rex 450SE V.2, which has
composite frames instead of aluminum. The metal frame is
only slightly heavier, and there is little difference in flight-load
strength endurance. MA
—Michael Ramsey
The R921 DSM2 receiver includes one remote and one spare port
for a third remote receiver, to offer more RF link path diversity.
Align T-Rex 450SA ARF at a Glance
Digital servos will quickly spoil any pilot. The DS821 has precise
centering and strength, even though it has an economical threepole
motor and single BB design.
Features:
• Extreme 3-D capability right out of the box
• 95% assembled at the factory
• Direct swashplate CCPM linkages
• Belt-driven tail rotor
• Autorotation system
• Brushless 3550 Kv motor (included)
• 35-amp brushless ESC with governor (included)
Chosen to show off the
intense programming
options a high-end radio
such as the JR X9303 2.4
offers, the T-Rex 450SA
presents the opportunity to
get a helicopter into the air
in the shortest amount of
time. Because it is an ARF,
it goes together quickly
using the recommended
Horizon Hobby equipment.
The 450SA is a tight
enough machine for its size
to display the nuances and
finite control a high-end
radio system offers the
discerning pilot.
I used an Align T-Rex 450SA to test the X9303 2.4. This
helicopter is a great buy; it comes as an ARF, 95% assembled,
and will perform just about any 3-D maneuver the pilot can
imagine.
The T-Rex includes a swashplate system using Cyclic
Collective Pitch Mixing (CCPM). This type of control offers one
of the most precise “feels” you can get to control the head of a
helicopter, and it takes advantage of the multiple software options
the X9303 2.4 offers. The T-Rex 450SA requires the addition of
servos, receiver, gyro, ESC, motor, and battery.
The helicopter special interest has grown tremendously in the
last few years, and it now offers a larger variety of aircraft in
glow and electric configurations. The models offer several
features that are common to both power sources, such as gyros,
governors, and, in many cases, CCPM swashplate systems that the
X9303 2.4 is more than capable of managing. And the T-Rex
450SA will show them off for this review.
Let’s get started by installing the radio and looking at some of the
more sophisticated features it offers. I used the JR DS285 Digital
Hi-Speed Sub-Micro servos. These little gems are very fast and
ultraprecise—all in a package that is incredibly small for its power
and size.
The JR R921 receiver will fit in the 450-size helicopter but is a
bit large for a model this size. I’m using the R921 because it came
with the system. The typical receiver for this size of helicopter is the
Spektrum AR6100 DSM2: a compact, six-channel, park flyer-range
unit that can also use all the X9303 2.4’s features.
Basic setup for the X9303 2.4 begins in the System Menu. To
access this, hold down the ENT button and power up the transmitter.
From there you can choose model type, model name, Swashplate
Type, and Device Select.
Device Select and Swashplate Type are the more advanced
features within the System Menu. Device Select allows you to
activate and deactivate two additional flight modes, switch
06sig3.QXD 4/24/08 11:11 AM Page 68
assignments, hover throttle, hover pitch,
and governor functions.
Horizon Hobby, which imports both the
JR X9303 2.4 radio and the Align T-Rex
450SA ARF, does a great job of outlining
setup details in both manuals. Everything
from linkage lengths to swashplate settings
to tail setup was accurate. My machine flew
off the bench and required almost no trim
adjustments.
The T-Rex uses a three-servo 120°
CCPM system, so I selected that option in
the System Menu/Swashplate Type. New
JR users should keep in mind that the
channel numbers assigned to CCPM are
different from in other radio systems and
may need to be plugged into a different
channel number on the receiver. The
manual shows this clearly and includes
cross-references by brand.
Once you have chosen the basic
helicopter settings in the System Menu, it’s
time to go to the Function List. Operations
that can be controlled using this list include
dual rate/expo, servo reversing, travel
adjust, swashplate mixing, throttle/pitch
curves, gyro/governor settings, and
programmable mixing. Because this
helicopter can be set up from mild to wild,
the dual rate/expo feature is extremely
handy.
Aerobatics and hard 3-D pilots should
set the total throw values on the swashplate
using CCPM exponential to the desired
percentage. I like to use roughly 75%—
75% and 70% respectively for hard 3-D—
and then set expo rates in the 25%-30%
range as a starting point to soften the
response of the helicopter while hovering.
Set the Throttle Hold to ACT (activate)
from INH (inhibit) in the Function List to
allow safe operation of the helicopter by
flipping on the throttle-hold switch.
The X9303 2.4’s default is with the
throttle-hold switch on the right rear corner
of the transmitter case. Many pilots
consider normal to be the top right front of
the case. You can change the switch
location in the System Menu, using the
Switch Selection function.
Most electric-powered helicopters in this
size range are set with the pitch curves
basically flat. The throttle is usually set in a
70 MODEL AVIATION
normal range of low, 0%; mid, 80%; and
high, 100%. And idle up/stunt of low,
100%; mid, 85%; and high, 100%. The
amount of curve points between low to
high varies depending on your radio. The
X9303 2.4 has seven.
The tail rotor/gyro is the last major
component in a helicopter’s setup. The
X9303 2.4 has a manual and automatic
mode, selectable under the Function List
for gyro. I used an Align 500X dual-mode
gyro, which plugs into the receiver and
allows me to remotely select varying gain
percentages from the transmitter.
Using the automatic mode, a pilot can
select different gain percentages for each
individual flight mode. I averaged 53%
gain in Stunt 2 flight mode for the gyro
gain percentage.
With gear installed and the Thunder
Power 2100 mAh, 11.1-volt Li-Poly
battery charged, the T-Rex 450SA lifted
off in a smooth and true manner. After
feeling it out in a hover and checking
main blade tracking, it was time to do a
few circuits to feel the X9303 2.4
system’s response.
To say it was tight and precise is a
gross understatement. This combination
of machine and radio in a helicopter is the
tightest I have ever experienced.
Pilots who haven’t flown with the
latest digital spread spectrum technology
(this one has 2048 resolution) are in for a
surprise! Some fliers may actually have to
“retime” some of his or her favorite
maneuvers because the speed and
response are that quick!
The JR X9303 2.4 is a great high-end
radio that boasts user-friendly
programming, plenty of channels, stateof-
the-art response, and the worry-free
benefit of spread spectrum to top it all
off. MA
Manufacturer/Distributor:
Horizon Hobby, Inc.
4105 Fieldstone Rd.
Champaign IL 61822
(800) 338-4639
www.jrradios.com
Items Used in Review:
Align helicopter, accessories:
Horizon Hobby, Inc.
Thunder Power batteries:
Thunder Power RC
(702) 228-8883
www.thunderpowerrc.com
Other Reviews:
Quiet Flyer: July 2007
Model Airplane News: August 2007
Fly RC: August 2007, May 2008
R/C Report: November 2007
Rotory Modeler: January 2008
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