What Is Toilet Bowl Effect And How To Fix It?

“What is toilet bowl effect?” If you have ever played with a micro RC helicopter with fly bars, you might have come across this intriguing term.

The toilet bowl effect, commonly abbreviated as TBE, is a distinctive flight condition that impacts small-scale helicopters, particularly micro coaxials. As the name suggests, TBE leads the helicopter to mimic the motion of being caught in a whirlpool or flushed down a toilet. The effect traces out circular flight paths instead of flying smoothly.

For a deeper explanation, I will give a comprehensive understanding of this curious phenomenon. I will also explore the causes and characteristics of the toilet bowl effect.

What Is Toilet Bowl Effect And How To Identify It?

The “toilet bowl effect” is a flight condition that affects micro-RC helicopters or drones equipped with fly bars. It is also known as TBE for short.

While all micro helicopters come with fly bars, micro coaxials are particularly prone to it. For instance, the Blade mSR or Blade 120 SR can highly experience TBE.

Read More: How To Increase The Water Level In A Toilet Bowl

Actually, the name “toilet bowl effect” arises from the behavior exhibited by a micro helicopter experiencing this condition. It resembles what might happen if the helicopter were caught in a whirlpool or flushed down a toilet. Yet, some experts don’t agree with this description.

In reality, a more precise way to describe the effect would be the “cyclic circle effect.” When a micro helicopter experiences TBE, it behaves as if it is receiving rotating cyclic commands. This can trace out a circular flight path.

However, in the meantime, the nose of the helicopter remains relatively stable and pointing forward.

Remember, the toilet bowl effect is not similar to other issues, such as yawing, spinning, or getting a rudder input. These indicate different problems for the micro helicopter or drone.

If a coaxial helicopter yaws as if receiving rudder commands, it may indicate trimming, mixing, or binding rotor shaft issues. In contrast, if the helicopter is consistently tracing out a cyclic circle in flight, it is experiencing the toilet bowl effect.

Read: What Causes Black Ring In Toilet Bowl

What Causes The Toilet Bowl Effect?

The micro RC helicopters with fly bars are susceptible to toilet bowl effects. The fly bar is responsible for automatically adjusting the pitch angles of the rotor blades to stabilize the helicopter when it pitches or rolls in any direction. Such an effect is caused by a discrepancy in the response of the fly bar. Usually, it occurs on the upper rotor of a micro coaxial or the fly bar on a single rotor head.

The main reason for TBE is when the fly bar and its linkages become stiff. During that time, they bind on the pivot points in the head or on the ball links connecting the fly bar to the rotors.

As a result, it will take a longer time for the fly bar to tilt and change the pitch angle of the rotors to self-correct the helicopter’s movement.

Then, the fly bar can’t stabilize the helicopter effectively. For example, if the helicopter is tilting forward, a stiff fly bar may correct it later in the rotor cycle.

This will cause a right roll instead of a backward pitch movement, leading to an unstable flight. The toilet bowl effect results from this continuous catch-up process.

The helicopter will continue to trace out a cyclic circle instead of flying steadily. The stiffness of the fly bar determines the degree of the effect. The larger and more pronounced toilet bowl or cyclic circle will be with a stiffer fly bar.

Moreover, a slow-reacting fly bar can also be caused by stiff or binding upper blade pivots. If the blades are slow to pivot on the headpins, it can have the same effect as a binding fly bar pivot. This will contribute to the toilet bowl effect.

The phenomenon is more common in micro coaxial RC helicopters with counterclockwise rotating upper rotors. In such cases, a clockwise toilet bowl effect can be generated easily. Conversely, if the upper rotor rotates clockwise, the TBE encountered would produce a counterclockwise circle.

Overall, the cause of the toilet bowl effect involves complex dynamics and physics. TBE is the result of the complex interactions between the fly bar, rotor blades, and the helicopter’s stability during flight.
Read: How Does A Toilet Fill Valve Work?

Examples of The Toilet Bowl Effect

Honestly speaking, it can be challenging to picture what toilet bowling looks like with various micro-RC helicopters or drones. Here are some examples that you can use to measure how your own experience compares.

Example 1:

In this example, a man is flying a Hubsan H501 drone. Watch the following video and compare if you have encountered a similar toilet bowl effect or not.

Example 2:

This example also demonstrates how a Hubsan H501 drone deals with the toilet bowl effect. However, the scenario is slightly different from the previous example. Please watch:

How To Fix The Toilet Bowl Effect?

Now that you have some idea of what is toilet bowl effect, you need to learn how to fix it. For that, you have to address the stiffness and binding of the fly bar and ball links to fix the toilet bowl effect in micro RC helicopters with fly bars or drones. Here are a few steps to follow:

Check the fly bar Pivot

Disconnect the fly bar linkages and pivot the fly bar up and down. The fly bar should pivot freely and smoothly in the upper rotor head or on the rotor shaft.

If it feels tight, use 400-600 grit sandpaper to gently polish the plastic pivot points of the fly bar or the inside of the fly bar head. Apply a little silicone spray for lubrication.

However, avoid using heavy or petroleum-based lubricants like WD-40.

Address Stiff Ball Links

The most common cause of a stiff fly bar is tight and stiff ball links. Polish the link balls on both the fly bar and the rotor blade with 400-600 grit sandpaper to remove any ridges or imperfections. A little looseness in the fly bars is desirable to eliminate the toilet bowl effect.

Perform “Sizing”

Use needle-nose pliers to gently squeeze the ball links while moving them around on the ball. This “sizing” process ensures the links move freely on the ball. Apply a bit of silicone spray on the link and ball for a friction-free fit.

Check Upper Blade Pivots

Ensure the upper blade pivots rotate easily on the headpins, just like the fly bar pivot. Clean the pins with isopropyl alcohol to remove any dirt or gummy residue that may cause binding. Re-lube the pivot pins with a light lubricant like light silicone oil or silicone spray.

Test Flight

After performing the above steps, go for a test flight and observe the improvement. If you still notice a slight toilet bowl effect, there might still be something too tight or dragging. It is best to be conservative to avoid any adverse effects during flight.

Allow for Natural Loosening

Sometimes, flying the helicopter a few times will naturally loosen up the components. Hence, any remaining toilet bowl effect may fade away over time.

Wrapping Up

So, I bet you have found the answer to what is toilet bowl effect. This effect poses a challenge for micro RC helicopter pilots relying on fly bars. Throughout this exploration, we have unveiled the key factors contributing to this intriguing flight condition.

Now, you are armed with the know-how to combat the toilet bowl effect. So, you can confidently take action to rectify the issue and achieve stable flights. Let us know if you still have any confusion regarding the toilet bowl effect, I will be happy to help.

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