Why the Syma S107G Spinning in Circles Happens
The Syma S107G is a compact coaxial helicopter, so it depends on balanced rotor thrust and a working gyro system to stay steady.
When it starts spinning in circles, the problem is usually mechanical, electrical, or related to trim and calibration.
This issue is common enough that most owners can trace it to a few repeatable causes.
The good news is that many fixes take only a few minutes and do not require replacement parts.
How the Syma S107G Controls Yaw
Yaw is the rotation of the helicopter around its vertical axis.
On the Syma S107G, yaw control comes from the difference in lift between the upper and lower rotors, plus the tail or gyro-assisted stabilization logic built into the board.
If that balance is off, the aircraft will rotate left or right instead of holding a stable heading.
Understanding this makes troubleshooting much easier because the spinning usually points to one side that is overpowering the other.
Most Common Reasons It Spins in Circles
1. The trim is set incorrectly
Improper trim is one of the most frequent reasons the Syma S107G spins in circles.
If the yaw trim is too far left or right, the helicopter will continuously rotate even when the stick is centered.
2. The rotor blades are damaged or mismatched
Cracked blades, bent blade shafts, or a mismatched top and bottom rotor can create unequal thrust.
Even a small imbalance can make the helicopter drift into a spin.
3. The battery is weak or undercharging
A weak battery can reduce motor output unevenly.
Since the Syma S107G relies on consistent rotor speed, low voltage often causes unstable flight and an inability to hold yaw.
4. The motors are wearing out
Mini brushed motors lose efficiency over time.
If one motor is weaker than the other, the helicopter may rotate because the lift balance between the coaxial rotors is no longer correct.
5. The frame is bent or the shafts are out of alignment
If the helicopter has had a hard landing, the main shaft, rotor mast, or landing gear may be slightly bent.
That can change how the rotors interact with the air and cause persistent spinning.
6. The gyro or flight board is malfunctioning
The Syma S107G uses onboard stabilization electronics.
If the gyro sensor or control board is failing, the helicopter may keep correcting in the wrong direction and spiral into a continuous turn.
Quick Fixes to Try First
Reset the yaw trim
Set the helicopter on a level surface and power it on fully before making adjustments.
Return the yaw trim to center, then test hover flight and make small corrections only after liftoff.
Check the rotor blades for damage
Inspect both rotors carefully.
Replace any blade that is cracked, warped, or loose, and make sure the top and bottom blades are installed correctly and rotate freely without rubbing.
Charge the battery fully
Use a known-good charger and allow the battery to reach a full charge before testing.
If flight time is short and spinning starts as soon as throttle is applied, battery voltage may be the simplest explanation.
Test on a calm indoor surface
The Syma S107G is light and sensitive to airflow.
Fans, open windows, and air conditioning vents can make it appear unstable, so always test in a calm indoor environment first.
How to Calibrate the Syma S107G
Calibration can reduce or eliminate a circular spin when the gyro needs a fresh reference point.
To do this properly, place the helicopter on a flat surface, turn on the transmitter first, then connect the helicopter battery and let it initialize without touching the controls.
Wait until the lights indicate readiness, then perform a brief hover test.
If it still rotates, apply a small trim adjustment and retest.
Avoid making large changes all at once because that can mask the underlying issue.
Trim Adjustment Strategy That Actually Works
Many beginners overcorrect the trim.
The better approach is to make one small change, lift off, observe the direction of rotation, then stop and adjust again only if needed.
- If the nose turns left, add a small right yaw trim correction.
- If the nose turns right, add a small left yaw trim correction.
- If the spin changes speed but never stops, inspect the mechanical and electrical components next.
If trim adjustments do not produce a noticeable improvement after several attempts, the cause is likely not trim alone.
What to Inspect Inside the Helicopter
If you are comfortable opening the shell, inspect the connectors, motor mounts, and shaft alignment.
Look for loose wiring, dirt near the gears, or signs that a motor is not responding consistently.
Pay close attention to the main gear and rotor connection points.
A small amount of slippage or wobble can disrupt the lift balance enough to trigger constant spinning.
When the Motors Are the Real Problem
Motor wear often shows up as reduced lift, delayed throttle response, or inconsistent speed between the two rotors.
If the helicopter spins more aggressively after a few flights, the motors may be losing torque under load.
Replacement brushed motors are usually inexpensive, but matching the correct part matters.
Use the exact Syma S107G-compatible motor type and verify that each motor spins in the proper direction after installation.
Signs the Gyro or Board Needs Replacement
Not every spinning problem can be fixed with trim or blades.
If the helicopter spins immediately after takeoff, ignores trim changes, and behaves the same with a fully charged battery, the gyro or control board may be failing.
- The helicopter spins even on a level, wind-free surface.
- Trim changes produce little or no response.
- The problem started after a crash or water exposure.
- Motor and blade checks show no obvious damage.
In that case, replacing the board is often the most practical repair.
Preventing Future Spinning Problems
Good maintenance reduces the chance of repeat yaw issues.
Store the helicopter without battery pressure on the frame, inspect blades after every crash, and avoid flying until a damaged rotor is replaced.
It also helps to let the battery cool before recharging and to avoid repeated hard landings.
Small RC helicopters are sensitive to cumulative wear, and preventing damage is easier than chasing unstable flight later.
Step-by-Step Troubleshooting Checklist
- Fully charge the battery.
- Reset yaw trim to center.
- Test in a still indoor environment.
- Inspect blades for cracks or bending.
- Check for bent shafts or loose parts.
- Observe whether one motor sounds weaker than the other.
- Recalibrate by powering on correctly and allowing initialization.
- If none of the above works, consider motor or board replacement.
Following this order saves time because it checks the easiest and most common causes first.
For most owners, that sequence is enough to identify why the Syma S107G spinning in circles problem is happening and what to do next.