● Tips for RC Helicopter Users (2)

[laodan]

          A problem frequently encountered by RC helicopter users is related to the tail. These issues include the tail slowly drifting in one direction, wagging or shaking up and down / left and right, or suddenly losing its hold and spinning out of control.It is incredibly frustrating and alarming when the fuselage spins uncontrollably like this. Let's look into what needs to be checked and how to resolve these issues.

          (1) First, if the tail shakes up and down, it is nine times out of ten caused by low motor RPM. If your blade pitch angle is around +5 degrees at 50% throttle, lowering it to +4 or +3 degrees should improve the situation.If the tail wags left and right, it is highly likely due to play or slop in the tail blade components.Additionally, a tail that slowly drifts to one direction occurs when the receiver's signal quality cannot keep up with the gyro's performance capability—meaning the receiver's performance is subpar. This commonly happens when using counterfeit rather than genuine parts. Since gyros utilize semiconductor-based MEMS (Micro-Electro-Mechanical Systems/detail) technology, which is generally reliable, the root cause is very likely an issue with either the tail servo or the receiver.

          (2) The second issue is when the tail spins uncontrollably. If the tail servo is a coreless type rather than a brushless type, it will draw a large amount of power due to internal friction and heat. If you draw power directly from the receiver in this setup, a conflict arises: the three swashplate servos are already drawing power from the receiver, and when the tail servo demands additional high current, the receiver's voltage instantly drops below its operational threshold. This directly affects the gyro, which also relies on the receiver for power. When the gyro falls below its required operational voltage, its internal processing chip (MCU) instantly resets. This phenomenon is known as a BROWN-OUT, and it is highly likely caused by a power bottleneck at the receiver's input. To fix this, you must widen the path for the power entering the receiver.A single power plug connected to a receiver has a continuous/burst rating of only about 3A to 5A, which is barely enough to handle the peak current drawn by a tail servo on a medium-sized helicopter (500 class or larger).If you examine the internal circuit board of a typical receiver, you will find that all positive (+) terminals (red) and negative (-) terminals (black/brown) are bused together on a single rail, excluding the signal lines (usually channels 1, 2, and 6). Therefore, you can prevent this power starvation (bottleneck) by delivering the output power through 2 to 3 unused slots on the receiver simultaneously using multiple power leads.▮