Thread: Tail Wag Cures
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Old 01-09-2011, 08:59 AM   #1 (permalink)
Steve Joblin
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Default Tail Wag Cures

Seems that every few days a new T-REX 250 owner completes his (or her) build and prepares themselves for the maiden flight of their new heli.... only to find out that once the heli spools up and settles into a hover, the tail wags back and forth Whilst some may say that it is just the sign of a happy 250 (like a dog that sees his master), most are disapointed and land their heli in frustration. Some may find a quick cure to TWS (Tail Wag Syndrome), others seem to need weeks or months to find a cure, and there are an unlucky few that never get better. I was one of those folks that had a bad case of TWS and it lasted for many, many weeks until my 250 was cured. In the end, I was never really cured... I just found a solution that masked my syptoms.

Here is the journey I took to find a cure... if others have other ideas or suggestions, please add them!

1. Inspect, re-inspect, then double check that there is no binding in the tail mechanism

2. Position the servo ball on tail servo arm to 4.5mm (or even closer) from the center.

3. Install a Kevlar Belt (see my video showing how a belt can be damaged, but not broken)

4. Try different size tail rotor blades:
  • 42mm Straight Cut Blades
  • 40mm Batwing Blades
  • 37mm Batwing Blades
  • 35mm Straight Cut Blades (home made by simply cutting a blade down to size)
  • 32mm Straight Cut Blades (home made by simply cutting a blade down to size)
5. Install a CF Carbon pushrod (a fun project that you can make your own)... the idea is that you remove any friction in the rod guides.

6. CF Boom (maybe there is a slight bend in the aluminum boom that is affecting things?)

7. Install a Metal Tail Rotor Control Arm

8. Remount the Gyro on two layers of foam tape

9. Set the Gyro Delay to 100%

10. Change the ESC BEC voltage to 5.0

11. Change the GP780 Gyro Analog/Digital Servo Setting from "DS" to "AS"
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