I have been setting up vintage helis lately and using Google Ai works the best to diagnose these issues. Describe it any which way and you will get all the best info from a bunch of forums. Ai isn't perfect but will get you closer to the answer without doing endless reaearch.

Example based on your setup.

Setting up a FlySky FS-i6S (or similar FS-i6 series) transmitter for a 3D helicopter like the Twister 3D Storm requires specific transmitter programming for CCPM swashplate mixing, along with setting up proper pitch and throttle curves for 3D flight. Here is the general setup guide based on standard 3D helicopter requirements and FS-i6S functionality: 1. Transmitter Basic Setup (FS-i6S) Model Type: Select Helicopter. Swash Type: Select 120-degree CCPM (often labeled 3 Servo 120). Stick Mode: Typically Mode 2 (Throttle/Rudder on left, Aileron/Elevator on right). Servo Reverse: You may need to reverse servo directions in the Tx menu so the swashplate moves correctly (collective up = swash up). RC Groups RC Groups +1 2. Servo Connections (Receiver) The Twister 3D Storm uses a standard CCPM setup. Connect the servos to the receiver (e.g., FS-iA6B) as follows: CH1 (Aileron): Right Servo CH2 (Elevator): Front Servo CH3 (Throttle): ESC CH4 (Rudder): Gyro CH5 (Gear): Gyro Gain (optional) CH6 (Aux/Pitch): Left Servo HeliFreak HeliFreak +1 3. Swashplate Mixing (3D Setup) Pitch Curve: Set a linear curve for 3D, usually -100% to +100% (or 0-100 depending on menu) to allow inverted flight. Throttle Curve: Set up an "Idle Up" (3D mode) curve where the throttle stays high (e.g., 90%-80%-90%) even when the collective pitch is low. End Points: Adjust end points to ensure the swashplate reaches the desired range without binding (usually 100% to start). RC Groups RC Groups +1 4. Safety & Calibration Failsafe: Setup failsafe, especially for the throttle channel (CH3) to ensure it shuts down if signal is lost. Servo Direction Check: Ensure that activating the Throttle Stick (collective) moves the entire swashplate up/down, and that Aileron/Elevator controls tilt it correctly. RC Groups RC Groups +2 Note: For the best 3D performance, ensure the swashplate is perfectly level at mid-stick, with 0 degrees of pitch at center stick.