Apr 192015
 

 
It’s downright frustrating when you take your remote control (RC) helicopter outside for a short flight, only to discover that it won’t stop spinning in circles. You may attempt to adjust the throttle, tail rotor and elevator, all to no avail. So, what causes this phenomenon and how do you fix it?

The Toilet Bowel Effect

Known as the Toilet Bowel Effect (for obvious reasons), this is an all-too-common phenomenon experienced with RC helicopters. It lives up to its namesake by mimicking the characteristics of a flushing toilet, continuously spinning the RC helicopter around in circles. Rather than flying forwards, backwards, or from side-to-side, it remains in a constant state of uncontrolled spin.

While the toilet bowel effect is far more common in models with a flybar (AKA stabilizer bar), the truth is that any RC helicopter can experience this issue.

rc heli in flight

What Causes The Toilet Bowel Effect?

Now for the million-dollar question: what causes the toilet bowel effect? There are several different possible causes, which we’re going to discuss further in this post.

Gyro Sense

One possible reason why your RC helicopter is experiencing the dreaded toilet bowel effect is that it has a malfunctioning gyro sense. If it’s set incorrectly, your helicopter will spin rapidly upon taking off. But if it’s set correctly, it will detect the normal clockwise rotation, applying the necessary adjustments to the tail rotor so the helicopter will turn just slightly in the opposite direction (counter-clockwise); thus, stabilizing its heading.

Gyro only detects rotational movement, so you can place it practically anywhere on your helicopter without causing any adverse effects.

Flybar

Yep, a stiff flybar may also cause your RC helicopter to experience the toilet bowel effect. A stiff flybar will make your helicopter take longer to tilt and change rotor pitch, resulting in uncontrolled spinning. Assuming your helicopter has a flybar, try loosing the ball bearings to give it a little bit of wiggle room.

Tail Rotor

Another possible cause is the tail rotor is setup incorrectly. The tail rotor counteracts torque created by the main rotor blades. In RC helicopters the main rotor spins clockwise. So, the helicopter wants to spin counterclockwise – the tail rotor compensates for that.

If it was attached in a manner that causes it to spin rather than maintaining control, your RC helicopter may experience the toilet bowel effect. If you haven’t done so already, check the tail rotors to make sure they are secured correctly. Remember, they should be pitched in a manner that keeps the helicopter still when in flight.

Many large RC helicopters have a direct drive – the tail rotor is controlled by the main rotor by means of a belt. So if you have one of these large copters, the problem could be several things, such as stripped tail gears, a bad belt, or a faulty tail servo.

If your large helicopter was assembled from a kit, and is experiencing the spinning problem, it may have been assembled incorrectly. In this case you would have to take your heli apart and reassemble it piece by piece.

In smaller RC helicopters the tail rotor is driven by a small motor. In many cases of RC helicopter spinning, the tail motor is burned out and simply needs to be replaced.

Trim

I know this probably sounds like common sense to most seasoned RC helicopter pilots, but did you check the trim on your controller? Ideally, it should set in the very center of the controller stick. Try moving it around to the left and right to see if it has any effect on your helicopter’s spinning. Sometimes a stuck trim control will result in this.

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 Posted by at 10:44 am