Detrum SR86A Instruction Manual V1.1

Quick Start

Before installing, make sure:

• All surfaces are well connected to the servos by the linkage rods.
• Bind the receiver to your transmitter in advance.
• All channel directions and trims are set to the correct position.

Follow these steps to complete your first-time installation:

1. Power on the transmitter and create a new airplane model. Assign a 3-position switch for the flight mode control and ensure this switch has no other function.
2. Mount the SR86A on the airframe and connect its required channels to corresponding control surfaces.
3. Place the airplane on the ground and power it on. The LED on SR86A will start fast green flashing, indicating gyro and stick calibration. Do not move the airplane or sticks during this period. After successful initialization, the LED displays the current flight mode.
4. After successful initialization, use the transmitter to set programmable items (mounting direction, wing type, etc.).
5. Switch to Gyro Off Mode. Adjust the neutral position for all servos. Check servo movement by moving each stick. If a servo moves in the opposite direction, reverse it on your transmitter (refer to the transmitter's instruction manual for details). CAUTION: If trims were set in this step, redo Step 3 for SR86A initialization.
6. Switch to Normal Mode, check gyro direction for each axis, and reverse if necessary.
7. Use the transmitter again to set programmable items (assigning flight mode to the 3-position switch, adjusting gain, etc.). After all settings are complete, begin your first flight.

Introduction

The SR86A is an 8-channel 2.4GHz receiver integrated with a 6-axis gyro, providing four different flight modes: Gyro Off, Normal, Aerobatic, and Auto-Recovery (Auto Balance). It can be programmed from the matched transmitter.

The port descriptions of SR86A are listed below. For each channel, the signal wire is close to the top of SR86A, middle is VDD, and bottom is GND.

Note: For delta-wing airplanes, the left and right aileron servos are connected to the AILE and ELEV channels. For V-tail airplanes, the left and right rudder servos are connected to ELEV and RUDD channels.

Installation

SR86A should be mounted on the platform inside the airframe using one of the provided double-sided tapes. Follow these installation principles:

Installation precaution:

• Use only one piece of the double-sided tape at a time. Soft or thick mounting may hinder gyro performance.
• Use the double-sided tape provided with SR86A; do not use hot-melt glue or belt.
• Ensure sufficient space around SR86A, away from motors, ESCs, and batteries. Avoid contact with servo horns, linkages, or other movable parts.
• Place antennas in an open space, do not block them. Position the heads of the two antennas at a 90-degree angle. Do not place the antennas twisted together or in parallel.

Binding

To enable communication between the transmitter and receiver, they must be paired or bound. This procedure is necessary when using the R/C system for the first time or when changing transmitters. Each transmitter has a unique ID code. Once bound, the ID code is stored in the receiver, eliminating the need for further binding after restarting.

Preconditions:

• Move the throttle stick to the lowest position and ensure the transmitter is powered off.
• Place the transmitter and receiver close to each other, within approximately 1 meter.

Steps:

1. Power on SR86A. The LED indicator will flash red rapidly, indicating the transmitter is off.
2. Press and hold the Bind button for more than 2 seconds. The LED indicator will flash red slowly, indicating the receiver is in bind mode.
3. Put the transmitter in bind mode; the system will begin binding.
4. Once the SR86A LED turns solid green, the receiver is bound to the transmitter. After 1 second, the LED will flash green rapidly, indicating the initialization process has begun.

Initialization

After powering on the RC system or binding, SR86A enters the initialization process, indicated by a fast green flashing LED. This calibrates the gyro and sticks. Do not move the airplane or sticks during this period, as it may cause repeated recalibration (up to 10 seconds).

• If calibration is successful, SR86A switches to flight mode, and the LED displays the current flight mode.
• If calibration fails, the LED remains red, indicating the gyro is unavailable. SR86A will function only as a receiver. Restart the power to re-initialize SR86A.

Flight Mode

Use a 5-channel or higher transmitter and assign a 3-position switch for flight mode control. Ensure this switch has no other function. This allows switching between flight modes.

SR86A offers four flight modes indicated by the LED (refer to LED Descriptions for details).

Flight Mode Descriptions:

• Normal Mode: The gyro senses angular velocity on each axis and reacts momentarily. This mode is suitable for all airplane types and improves stability, especially in windy conditions.
• Aerobatic Mode: With attitude hold functionality, the gyro locks the airplane's previous attitude if no transmitter command is sent. This mode aids in accomplishing aerobatic maneuvers. SR86A does not interfere with stick inputs in this mode but improves stability. Upon releasing the sticks, SR86A saves the previous flight attitude and locks the airplane. When flying in Aerobatic Mode, avoid drastic trim adjustments, as excessive trims can affect the transmitter's neutral position judgment. Set trims during testing, then power cycle.
• Gyro Off Mode: Disables gyros for all channels. The airplane is fully controlled by the transmitter, and SR86A acts solely as a receiver. This mode is typically used for testing.
• Auto-Recovery Mode (Auto Balance): Locks tilt angles on pitch and roll axes, allowing the airplane to maintain level flight automatically. In emergencies, switching to this mode from any other mode will automatically recover the airplane to level flight (one-click rescue). This mode is suitable for beginners or FPV applications.

Setting the Programmable Items

After installation and initialization, set SR86A's programmable items using the matched transmitter. Programmable items include mounting direction, wing type, roll/pitch/yaw gain, flight mode, and offset on roll/pitch. Refer to the transmitter's instruction manual for detailed setting methods.

Appendix

LED Descriptions

Flight Mode

Specifications

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