JR G400 - User Manual

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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

“ 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

Need help?

Do you have a question about the JR G400 and is the answer not in the manual?

Summary

Connections

Radio Type Connections

Details on connecting the gyro to different radio systems.

Servo Selection

Guidance on choosing compatible servos for optimal gyro performance.

Installation and Hook-Up

Mounting Considerations

Discusses heat, vibration, and location for gyro mounting.

Installing the G400

Instructions for physically mounting the gyro unit with proper orientation.

Final Connections

Steps for connecting the receiver and the servo to the gyro.

Set-Up and Adjustment

Set-Up

Initial setup procedures including servo centering and direction verification.

Transmitter Adjustments

Settings for travel adjust, dual rates, exponential, and revo mixing.

Gain Value Adjustments

How to adjust gain values for stable hover and flight performance.

Summary

Connections

Radio Type Connections

Details on connecting the gyro to different radio systems.

Servo Selection

Guidance on choosing compatible servos for optimal gyro performance.

Installation and Hook-Up

Mounting Considerations

Discusses heat, vibration, and location for gyro mounting.

Installing the G400

Instructions for physically mounting the gyro unit with proper orientation.

Final Connections

Steps for connecting the receiver and the servo to the gyro.

Set-Up and Adjustment

Set-Up

Initial setup procedures including servo centering and direction verification.

Transmitter Adjustments

Settings for travel adjust, dual rates, exponential, and revo mixing.

Gain Value Adjustments

How to adjust gain values for stable hover and flight performance.

The document describes the JR G400 Piezo Gyro System, a helicopter-specific device designed to enhance flight stability and control.

Function Description

The G400 Piezo Gyro System is a compact, integrated device that utilizes a piezo sensor to detect rotational motion and provide feedback to the tail rotor servo, thereby stabilizing the helicopter's yaw axis. Unlike traditional mechanical gyros that rely on moving parts, the G400's piezo technology offers a nearly unlimited service life and significantly faster response times. It provides true linear feedback and response of rotation rates up to over 720 degrees per second, which is a substantial improvement over standard gyros typically limited to around 250 degrees per second. This high-rate sensing allows for more consistent pirouettes in windy conditions and improved performance during aggressive maneuvers like 540 stall turns with sharp stops. The system also features a patented offset drift canceler to maintain neutral stability.

Important Technical 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
Response Time: 10 times faster than mechanical gyros
Sensitivity: 10 times more sensitive to rotational motion than mechanical gyros

The G400 is compatible with JR, Futaba/HRC, and Airtronics Z radio systems, with specific wiring instructions provided for each. Recommended JR servos for optimal performance include:

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°

Usage Features

The G400 is designed for helicopter use only and requires careful setup due to its advanced performance characteristics. Key usage features and setup procedures include:

Installation:
- Heat Management: The piezo sensor is sensitive to temperature changes. The gyro must be mounted away from the engine and exhaust system to prevent heat transfer. It's also advised to allow the gyro's temperature to stabilize for about 10 minutes when moving from extreme temperature differentials (e.g., warm car to cold outside).
- Vibration Reduction: The G400's high sensitivity means it will react to even minute vibrations. Therefore, the model must be balanced, straight, and properly adjusted to minimize vibration. The gyro should be mounted away from high-vibration areas like engines.
- Location: Ideally, the gyro should be mounted as close to the helicopter's center of gravity (main shaft) as possible, ensuring it's away from heat sources. If not possible, the servo tray upfront is an alternative. The manual gain adjuster on the back of the gyro must be easily accessible for initial fine-tuning.
- Mounting: The G400 should be mounted with the label facing upward, parallel to the main rotor shaft. The mounting surface must be thoroughly cleaned with rubbing alcohol, and one layer of the supplied double-sided tape should be used. "Thick" foam tape is not recommended as it can reduce effectiveness.
- Connections: Connect the RX Rudd connector to the receiver's rudder channel. Connect the desired servo to the SV Rudd lead of the G400. Incorrect connection will not damage components but will prevent function.
Set-Up and Adjustment:
- Pre-flight Checks: Ensure tail rotor linkage moves smoothly without friction. Set all rudder trimmers to zero and throttle/pitch stick to hover position (50%). Turn off or zero out revolution mixing and acceleration mixing.
- Neutral Position: Turn on the receiver and keep the helicopter motionless for 3 seconds to allow the G400 to establish its center/neutral position.
- Servo Arm Placement: The servo arm must be replaced so it is exactly 90 degrees to the tail rotor pushrod. The tail control rod ball should be attached 16-18mm from the center mounting screw of the servo arm for optimal performance.
- Servo Direction: Verify the rudder servo moves in the proper direction (right command moves nose to the right). Reverse servo direction in the transmitter if needed.
- Gyro Compensation Direction: Quickly move the helicopter's nose to the left. The servo should move in the same direction. If not, switch the small reverse switch on the gyro sensor/amplifier. For verification, with a quick motion, rotate the nose to the left; the leading edge of the tail rotor blades should pitch to the left.
- Overdriving the Tail Rotor: The G400 may require travel adjustment values that, on the ground, exceed the mechanical limitations of the tail rotor. In flight, the gyro will reduce travel to prevent binding. Caution is advised to avoid hard over rudder commands on the ground.
- Transmitter Adjustments:
  - Travel Adjust: Set rudder travel adjustment to maximum (125% L/R for JR XP642, XP652, XP783, XP8103). The gyro will reduce throw in flight to prevent binding.
  - Dual Rates: Recommended starting points are 80% for Normal/Standard Aerobatics, and 100% for 540 Stall Turn. These values can be adjusted to achieve the desired maximum rotational rate.
  - Exponential: Recommended expo settings are 30% for Hover/540 Stall Turns and 40% for Std Aerobatics to reduce control sensitivity around neutral, especially with the large servo stroke utilized (125% L/R).
  - Revo Mixing & Stunt Trim: The G400 increases total servo stroke by approximately 35%, requiring a reduction of revo mixing and stunt trim values by approximately 35% compared to previous gyro systems. Basic starting values are provided (e.g., Normal: Up 20% / Down 15%). Fine-tuning is essential for each specific helicopter setup.
- Gain Value Adjustments:
  - Hover Gain: Adjust mechanical control linkage/tail rotor blade pitch to eliminate rotation in hover. Increase hover gain (pre-set at 65%) until oscillation (hunting) occurs, then reduce slightly below that point (typically 65-95%). If hunting occurs below 65%, move the rudder pushrod connection inward. If no hunting at 100%, move it outward.
  - Forward Flight Gain: Increase low gyro gain until oscillation occurs, then reduce slightly below that point.

Maintenance Features

The G400 Piezo Gyro System is designed with "no moving parts for a nearly unlimited service life," which inherently reduces maintenance requirements compared to mechanical gyros. The robust design, featuring a new silver/chrome finish, helps isolate RF interference and dissipate heat, contributing to its longevity.

Warranty Coverage: The G400 comes with a 1-year warranty against manufacturer defects in material and workmanship from the date of purchase. Horizon Service Center will repair or replace defective components at no cost. The warranty is limited to the original purchaser and is not transferable. It does not cover units that have been improperly installed, mishandled, abused, damaged in a crash, or repaired/altered by unauthorized agencies. The warranty does not cover consequential or incidental damages. Users are advised not to expose the unit to extreme temperatures, humidity, or moisture, or leave it in direct sunlight for extended periods.

Repair Service Instructions: In case of service needs, users should return only the system components (not the entire model helicopter). Use the original carton/packaging or equivalent, packed within a sturdy shipping container, fully insured and prepaid. Include complete name, address, phone number, and detailed information explaining the equipment's operation and problems. For warranty repairs, a legible photocopy of the original dated sales receipt is required. For non-warranty repairs, an estimate will be provided if the cost exceeds 50% of the retail purchase cost. Payment methods accepted are VISA, MasterCard, or money orders.