Blade CP Pro Sudden Drops & Glitches

This page shares some of my progress as I learn to fly a 3D Helicopter.

Sudden Drop in Altitude during Hover

I have now experienced a few sudden drops or glitches during my hover practice. Usually these are small enough that I'm not overly concerned. However, today I had a sudden drop of over 2' while hovering just out of ground-effect. This momentary glitch caused my Blade CP Pro to drop to the ground, with the training gear absorbing much of the fall.

So far, I have observed the following (on occasion):

  • Sudden drop in altitude
  • Sudden right rotation (yaw)

Overall, I would say that I am now experiencing these symptoms about once every few flights, whereas I don't believe I have so much in the past. So far, none of these have caused a crash, but I could imagine that it could get me into trouble with low-altitude hover practice.

Related articles on the Web

Possible Causes

According to the a number of sources on the web, it seems that there are a few different causes that can be the source of this sudden drop behavior:

  • Radio Glitch - I'm inclined to think this is the cause. Unfortunately, replacing the transmitter (TX) on a Ready-To-Fly (RTF) heli means a fair amount of work setting up the new radio, receiver, electronics, etc. I don't think I'm quite at the stage where I'll be replacing my TX, but it certainly has crossed my mind. Someday, when I do upgrade my radio, I'd likely go for a Spektrum DX7 (~ $350). The nice thing about investing in a good radio is that you can generally transfer it to new aircraft as you go. Most modern radios have a "Model Memory" which can accommodate the settings for dozens of different aircraft you may own.
  • Aluminum Swashplate Separating - Not the cause of my problems, as I have stock plastic swashplate.
  • Vertical play in Main Shaft
  • Dirty Potentiometers (pots) in Transmitter - Apparently this becomes an issue on the Blade radios fairly quickly (I have just under 40 flights on my radio at this point). The contacts under the "sticks" should be providing a continuously-varying voltage as you fly your heli. However, if there is a momentary loss of contact (due to dirt or poor contact), the potentiometer might interpret the position as being full-left, full-down, etc. One should be able to rule this cause out by opening up the TX, connecting a multimeter to the pot outputs and verifying that the resistance is smoothly varying over range.
  • Bent Spindle Shaft / Feathering Shaft - Considering how my rotor head seems to be in perfect alignment (following my re-alignment of the blades and paddles), I doubt this to be the case.
  • Tight/Sticky Ball Links - The idea behind this as a possible cause is that as the collective tries to move in a certain direction, it binds or sticks. At some point it breaks past the sticking point and you may have an overcorrection in the motion that quickly recovers again. I haven't checked on this yet. Apparently, this particular issue is worsened by some aftermarket ball links.
  • Other Electronics (ESC, 3-in-1, Speed Control, Servos, etc.)

Because I have also experienced the sudden yaw motion as well (particularly when I've flown near my work), which I don't believe to be the result of anything other than a radio glitch, I'm still inclined to think that the radio could be the source of the problem.

 

 

 

 


Reader's Comments:

Please leave your comments or suggestions below!
2014-04-11 
 The tip about the gear just saved me a trip to the hobby store. I was getting that fltteur that you were and it was really messing with the gyro. After fixing the alignment and gap it now flies great. Thank you!

 


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