FEATURES
• Compact integrated design for easy installation/connection
• No moving parts for a nearly unlimited service life
• Linear dynamic range up to 720 degrees per second
• 10 times faster response time than mechanical gyro s
• Manual gain control for easy set up
• Patented offset drift canceler
• New silver/chrome finish to isolate RF & dissipate heat
• Compatible with JR and other brand radio systems
SPECIFICATIONS
Operating Voltage: 4 . 8 V – 6 . 0 V
Operating Current: 28 mAh
Dimensions: 37H x 28W x 36L
Weight: 3 5 g
Dynamic Range: 0 – 720° per second
B a t t e ry Requirements: 4.8 – 6.0V 1000ma minimum
INTRODUCTION
J R ’s latest Piezo gyro, the G400, utilizes a new state-of-the-art integrated
design for easy installation, while retaining the same perf o rmance levels found in
m o re expensive gyros like JR’s G450 Piezo gyro .
Unlike standard mechanical type gyros that use a motor, flyweights, bearings,
etc., the G400 Piezo gyro system is totally free of moving parts that in time
w e a rout, giving the G400 a nearly unlimited service life.
The G400 offers a true linear response of up to 720 degrees per
second. The G400 is also 10 times more sensitive and has a faster response time
than any current mechanical type gyro, making the G400 one of the highest perf o r-
mance entry level gyros available.
It is important to note that the operational features of the G400 Piezo gyro are
v e ry diff e rent than that of a mechanical type gyro system. Many current settings,
including the travel volume, exponential, dual rates, and tail rotor revolution mixing
values, must all be changed from their previous normal settings in order to achieve
the correct tail ro t o r / c o n t rol surface response and maximum perf o rmance that the
G400 has to off e r.
It is not recommended that the G400 be installed and flown in a model that
was previously set up using a mechanical type gyro without first readjusting the
function values as described in these instru c t i o n s .
C a refully read these instructions so you will fully understand and become
c o m f o rtable with the functions and operating characteristics of the G400 prior to
installation and initial test flights.
CONNECTIONS
Radio Type Connections
Please note that if the system is connected incorre c t l y, the G400 will not func-
tion, but no damage will occur to any of the radio components. After successful
connection, secure the gyro to the servo connection with a small piece of tape to
p revent possible disconnection during use.
Servo Selection
The G400 Piezo gyro offers greatly improved response time, sensitivity and
p e rf o rmance as compared to other Piezo gyros. However, in order to realize these
i m p rovements, great care and consideration must be taken in the selection of the
s e rvos to be used.
In general, the quicker the transit time and the more accurate the centering
tendencies of the servo, the better the gyro will perf o rm .
If a servo with a slow transit time is used, the G400 may become too quick for
the servo, resulting in a “wag” or “hunting” situation which will re q u i re the user to
reduce the percentage of gain. This reduction in gain will also reduce the holding
power and, there f o re, the perf o rmance of the G400. The following JR servos are
recommended for use with the G400:
INSTALLATION AND HOOK-UP
T h e re are three important criteria that must be considered in deciding on the
position you should mount the G400.
#1 Heat. The Piezo sensor is sensitive to drastic temperature changes; in
some cases a neutral drift will occur.
When mounting the Gyro, be sure it is located away from the engine and
exhaust system so none of the heat will transfer to the Gyro from these or any
other helicopter parts that might change temperature during operation.
Also, when subjecting your helicopter to temperature diff e rentials (e.g., going
f rom your warm car to the cold outside), allow the gyro ’s temperature to
stabilize for about 10 minutes before flying.
#2 Vi b r a t i o n . The Piezo gyro is 10 times more sensitive to ro t a t i o n a l
motion than a standard mechanical type gyro. Plus, it has a 10 times faster
response time (the time it takes the gyro system to react to motion).
Because vibration is motion, the Piezo gyro senses even minute vibrations
and acts upon them (sending the servo an opposing command) 10 times
faster than a standard gyro .
It is, there f o re, important to reduce the vibration of your model to a
minimum by making sure that everything is balanced, straight and pro p e r l y
a d j u s t e d .
The Gyro should be mounted away from inherent high vibration are a s
(e.g., engines).
#3 Location. The Gyro should be mounted as close to the center of
gravity (normally the main shaft) as possible while taking into account the
points made in #1 and #2 above. Many helicopters provide mounting bases
near the main shaft. Use them only if they are positioned away from heat-
generating sources. If it is not possible to locate the Gyro near the main
shaft, an alternate location to consider is up front on the servo tray.
When choosing a mounting location for the G400, make sure you
position the gyro so that you have easy access to the manual gain adjuster, located
on the back side of the gyro. On initial flights, it will be necessary to access this
gain adjuster to fine tune the gain value setting.
Installing the G400
Refer to the following diagrams for proper Gyro
positioning. Mount the G400 with the label facing
u p w a rd as shown in the diagram at right. Please note
that the unit must be mounted so the sides of the unit
a re parallel to the main rotor shaft.
Be sure to thoroughly clean the G400’s mounting
a rea and the airc r a f t ’s mounting location with ru b b i n g
alcohol prior to attachment. Use one layer of the sup-
plied double-sided tape to secure the unit in place. It is
not recommended that “thick” foam tape be used as
this could reduce the eff e c t i v e n e s s / p e rf o rmance of the G400.
Final Connections
Step 1: Connect the RX Rudd connector to the rudder channel/function of the
re c e i v e r.
If the G400 is located away from the re c e i v e r, an optional servo extension
( p u rchased separately) may be used.
Step 2: Connect the desired servo to be used into the SV Rudd lead of the
G 4 0 0 .
SET-UP AND ADJUSTMENT
The G400 Piezo gyro gives true linear feedback and response of rotation rates
up to over 720 degrees per second (standard gyros are limited to appro x i m a t e l y
250 degrees per second).
Thus, the gyro is still sensing at high rotation rates, giving appropriate feed-
back to the servo. This allows for more consistent pirouettes in the wind and
i m p roved 540 stall turns with aggressive stops.
Because of this high rate of rotation sensing, the adjustment values (i.e., travel
adjust, dual rates, exponential, tail rotor compensation) will be very diff e rent than
what you’re used to.
Following on the next page is the set-up and adjustment pro c e d u re that must
be followed to achieve the highest level of perf o rmance from your system.
G 4 0 0
PIEZO GYRO
S Y S T E M
G 4 0 0
PIEZO GYRO
S Y S T E M
Helicopter Use Only
J R P G 4 0 0
R e c e i v e r
Sensor/Amplifier
S e rvo Lead –
Connect to
SV ru d d e r
D i re c t i o n
R e v e r s i n g
S w i t c h
JR
“ S t a n d a r d” or “Digital” Ser v o s
Connect to S
e rv o
* Rx Rudd – Connect to
the desired contr o l
s u rface as shown
b e l o w
M a n u a l
G a i n
A d j u s t e r
J R F u t a b a / H R C A i rt ronics Z
red to re d red to re d red to re d
b rown to brown b rown to black b rown to black
orange to orange orange to white orange to white
S TANDARD SERV O S TRANSIT TIME
JRPS4735 Ultra Speed Serv o .15 sec/60°
JRPS4721 Ultra To rque Servo .22 sec/60°
JRPS4131 Ultra Precision Serv o .23 sec/60°
JRPS531 P remium Sport Serv o .21 sec/60°
JRPS517 S t a n d a rd BB Serv o .26 sec/60°
L a b e l
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