JR G400 User manual

FEATURES
• Compact integrated design for easy installation/connection
• No moving parts for anearly unlimited service life
• Linear dynamic range up to 720 degrees per second
• 10 times faster response time than mechanical gyros
• 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: 4.8V–6.0V
Operating Current: 28 mAh
Dimensions: 37H x 28W x 36L
Weight: 35g
Dynamic Range: 0 – 720° per second
Battery Requirements: 4.8 – 6.0V 1000ma minimum
INTRODUCTION
JR’s latest Piezo gyro, the G400, utilizes a new state-of-the-art integrated
design for easy installation, while retaining the same performance levels found in
more 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
wearout, 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 perfor-
mance entry level gyros available.
It is important to note that the operational features of the G400 Piezo gyro are
very different 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 rotor/control surface response and maximum performance that the
G400 has to offer.
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 instructions.
Carefully read these instructions so you will fully understand and become
comfortable 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 incorrectly, 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
prevent possible disconnection during use.
Servo Selection
The G400 Piezo gyro offers greatly improved response time, sensitivity and
performance as compared to other Piezo gyros. However, in order to realize these
improvements, great care and consideration must be taken in the selection of the
servos 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 perform.
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 require the user to
reduce the percentage of gain. This reduction in gain will also reduce the holding
power and, therefore, the performance of the G400. The following JR servos are
recommended for use with the G400:
INSTALLATION AND HOOK-UP
There 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 differentials (e.g., going
from your warm car to the cold outside), allow the gyro’s temperature to
stabilize for about 10 minutes before flying.
#2 Vibration. The Piezo gyro is 10 times more sensitive to rotational
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, therefore, important to reduce the vibration of your model to a
minimum by making sure that everything is balanced, straight and properly
adjusted.
The Gyro should be mounted away from inherent high vibration areas
(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
upward as shown in the diagram at right. Please note
that the unit must be mounted so the sides of the unit
are parallel to the main rotor shaft.
Be sure to thoroughly clean the G400’smounting
area and the aircraft’s mounting location with rubbing
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 effectiveness/performance of the G400.
Final Connections
Step 1: Connect the RX Rudd connector to the rudder channel/function of the
receiver.
If the G400 is located away from the receiver, an optional servo extension
(purchased separately) may be used.
Step 2: Connect the desired servo to be used into the SV Rudd lead of the
G400.
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 approximately
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
improved 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 different than
what you’re used to.
Following on the next page is the set-up and adjustment procedure that must
be followed to achieve the highest level of performance from your system.
G400
PIEZO GYRO
SYSTEM
G400
PIEZO GYRO
SYSTEM
Helicopter Use Only
JRPG400
Receiver
Sensor/Amplifier
Servo Lead –
Connect to
SV rudder
Direction
Reversing
Switch
JR “Standard” or “Digital” Ser vos
Connect to S ervo
* Rx Rudd – Connect to
the desired contr ol
surface as shown
below
Manual
Gain
Adjuster
JR Futaba/HRC Airtronics Z
red to red red to red red to red
brown to brown brown to black brown to black
orange to orange orange to white orange to white
STANDARD SERVOS TRANSIT TIME
JRPS4735 Ultra Speed Servo .15 sec/60°
JRPS4721 Ultra Torque Servo .22 sec/60°
JRPS4131 Ultra Precision Servo .23 sec/60°
JRPS531 Premium Sport Servo .21 sec/60°
JRPS517 Standard BB Servo .26 sec/60°
Label

Set-Up
Step 1: Unhook the tail rotor linkage from your rudder servo and swing the
servo arm out of the way. Lightly grasp the tail rotor pushrod at the servo end and
run the tail rotor through its entire pitch range. The tail rotor linkage should move
through its entire range smoothly with very little friction and no rough spots. Work
on the linkage system until this is achieved.
Step 2: On your transmitter, set all rudder trimmers (sub-trim, trim offset,
mechanical trim, etc.) to zero. Set the throttle/pitch stick at exactly the hover posi-
tion (standard hover position is 50%). Turn off or zero out both the revolution mix-
ing up and down and the acceleration mixing.
Step 3: Turn on your receiver and allow the helicopter to remain totally
motionless for 3 seconds. This procedure is necessary to allow the G400 time to
establish and record the center or neutral positions.
Step 4: Remove
the servo arm and
replace it so that it is
exactly 90 degrees to
the tail rotor pushrod
(see diagram). You may
find that the splines in
the screw output shaft
are just offset enough
on your servo arm so as to
not allow 90 degree posi-
tioning. Rotate the servo
arm to another arm and try again. Find the arm that is closest to 90 degrees and
secure it in place with the provided screw.
Control Rod Ball Placement
For best performance, attach the tail control rod ball to the servo arm at a dis-
tance of approximately 16–18mm from the center mounting screw of the servo
arm. The performance of the G400 will be greatly reduced if the tail control rod ball
is attached at a distance of less than 16mm, as this position will not make full use
of the G400’s sensing abilities.
Step 5: Be sure the rudder servo is moving in the proper direction. A right
servo command should move the nose to the right (if you’re unsure, seek help
from someone more experienced). Reverse the servo direction in the transmitter if
necessary.
Step 6: Give a right rudder command and note the direction the rudder servo
moves (clockwise or counterclockwise). Now pick up the helicopter and quickly
move the nose to the left. The servo should move in
the same direction. If it moves in the opposite direc-
tion, switch the small reverse switch located on the
gyro sensor/amplifier in the opposite direction.
Step 7: To verify that the G400 is compensating
in the correct direction, please refer to the diagram at
right for clarification:
With a quick motion, rotate the nose of the heli-
copter to the left while viewing the servo arm/tail
rotor blades. If correct, the leading edge (front) of
the tail rotor blades should pitch to the left as
shown. Reverse the direction of the gyro compensa-
tion if necessary using the Direction Reversing
Switch located on the Sensor/Amplifier Unit.
Overdriving the Tail Rotor
As illustrated above, the transmitter gives a command to the servo to find a
specific position (e.g., full right rudder). The gyro senses the right rotation and
gives the opposite command (left) to the servo. The final servo position (and hence
the rotation rate) is based upon the transmitter’s command versus the gyro’s gain
setting versus the rotation rate.
In order to get really rapid rotation rates with some helicopters, it may be nec-
essary to use a travel adjustment that on the ground (no rotational feedback from
the gyro) actually exceeds the mechanical limitations of the tail rotor mechanism. In
flight, the Piezo gyro will reduce the travel so binding will not occur. But be very
careful on the ground to ensure that you don’t give hard over rudder commands.
Transmitter Adjustments
Travel Adjust
Set the rudder travel adjustment to maximum right and left. If you are using a
JR XP642, XP652, XP783 or XP8103, set this adjustment to 125% left and 125%
right. Note: This may overdrive the tail rotor mechanism on the ground. However,
in flight, the gyro will reduce the throw, preventing binding at the extremes. You
can test this by physically spinning the helicopter as described previously.
Dual Rates
The recommended starting points for dual rates are:
Maneuver Dual Rate Flight Mode
Hover 80% Normal
540 Stall Turn100% Flight Mode 1
Standard Aerobatics 80% Flight Mode 2 (optional)
After some experience and flight time is gained, these values can be adjusted
to suit your preference. We recommend adjusting the dual rate values to obtain the
desired maximum rotational rate during a maneuver.
Example:
If a 100% dual rate yields too high of a rotation rate in the 540 stall turn when
the rudder stick is fully displaced, reduce the dual rate value until the desired rota-
tion rate is achieved.
Exponential
Because a very large servo stroke is utilized (125% L, 125% R), the control
sensitivity around neutral is very high. Exponential is recommended to reduce this
over-sensitivity around neutral. Following are the recommended expo settings:
Maneuver Exponential V alue Flight Mode
Hover 30% Normal
540 Stall Turns 30% Flight Mode 1
Std Aerobatics 40% Flight Mode 2 (optional)
After some experience and flight time is gained, these values can be changed
to suit your preference.
We recommend using exponential to adjust the control sensitivity from neutral
to approximately 1/3 stick position.
Revo Mixing
The G400 actually increases the total servo stroke by approximately 35%.
Compared with previous gyro systems, the Piezo gyro will require that you reduce
the revo mixing and stunt trim values by approximately 35%.
Below are some basic starting values to work with.
Note: Because of the variables involved with each different helicopter
(e.g., engines, fuel, blades, exhaust systems, aerodynamics, gear ratios, etc.), the
optimum can only be achieved with careful tuning and adjustment to your particular
helicopter.
XP642, XP652, XP783, XP8103 MIXING VALUES
Stunt Trim
Test fly and adjust until the tail follows exactly behind the body in fast forward
flight, full throttle/pitch.
Gain Value Adjustments
Hover
On initial test flights it will be necessary to adjust the mechanical control link-
age/tail rotor blade pitch so the helicopter will have no tendency to rotate while in
the hover position. Minor “fine tuning” adjustments can be made with the rudder
trim lever. Once this has been achieved, increase the hover gain (pre-set at 65%)
until the helicopter starts to oscillate (hunt). Back down the value just below the
hunting point. The value should be between 65 and 95 percent. If so, proceed to the
next step. If not, do the following:
Hunting occurs at less than 65% gain in hover—move the rudder pushrod
connection at the servo inward one hole on the servo arm.
No hunting occurs even at 100% gain in hover—move the rudder pushrod
connection at the servo outward one hole on the servo arm.
Forward flight the helicopter in fast forward flight (if you are comfortable) and
increase the low gyro gain value until oscillation (hunting) occurs. Reduce the value
slightly, just below the point of hunting. Try a few rolls and see if hunting occurs.
Reduce the gain if necessary.
Now go back and fine tune your revo mixing, stunt trim, using your standard
method or the method given in your specific radio’s instruction manual.
WARRANTY COVERAGE
Your new equipment is warranted to the original purchaser against manufac-
turer defects in material and workmanship for 1 year from the date of purchase.
During this period, Horizon Service Center will repair or replace, at our discretion,
any component that is found to be factory defective at no cost to the purchaser.
This warranty is limited to the original purchaser of the unit and is not transferable.
This warranty does not apply to any unit which has been improperly installed,
mishandled, abused, or damaged in a crash, or to any unit which has been repaired
or altered by any unauthorized agencies. Under no circumstances will the buyer be
entitled to consequential or incidental damages. This limited warranty gives you
specifc legal rights; you also have other rights which may vary from state to state.
As with all fine electronic equipment, do not subject your unit to extreme tempera-
tures, humidity or moisture. Do not leave it in direct sunlight for long periods of
time.
REPAIR SERVICE INSTRUCTIONS
In the event that your equipment needs service, please follow the instructions
listed below:
1. Return your system components only. Do not return your system installed
in a model helicopter, plane, etc.
2. Use the original carton/packaging (molded foam container), or equivalent, to
ship your unit. Do not use the carton itself as a shipping carton; you should pack-
age the equipment carton within a sturdy shipping container using additional pack-
ing material to safeguard against damage during transit. Include complete name
and address information inside the carton, as well as clearly writing it on the outer
label/return address area. Ship your equipment fully insured and prepaid. Horizon
Service Center is not responsible for any damages incurred during shipping.
3. Include detailed information explaining your operation of the equipment and
problem(s) encountered. Provide an itemized list of equipment enclosed and identi-
fy any particular area/function which may better assist our technicians in address-
ing your concerns. Date your correspondence and include your name, mailing
address, and a phone number where you can be reached during the business day.
4. Warranty Repairs. To receive warranty service you must include a legible
photocopy of your original dated sales receipt to verify your proof-of-purchase date.
Providing that warranty conditions have been met, your radio will be repaired with-
out charge.
5. Normal Non-Warranty Repairs. Should your repair cost exceed 50% of the
retail purchase cost, you will be provided with an estimate advising you of your
options.
Within your letter, advise us of the payment method you prefer to use. Horizon
Service Center accepts VISA, MasterCard, or money orders. Please include your
card number and expiration date.
Mail your system to: Horizon Service Center
4105 Fieldstone Road
Champaign, Illinois 61822
[phone] www.horizonhobby.com
Left Right
ail Rotor)
Rudder Servo
Ball Position
16-18mm
90°
Remove unused servo horn
arms to prevent obstruction.
Right Rudder Command
(tail blades pitch left)
Step 7
Diagram
Normal Up 20% Down 15%
Flight Mode 1 Up 5% Down 5%
Flight Mode 2 Up 5% Down 5%