DynaVibe Balancing Tips

Tach Readings

  • Be sure you have a stable tach reading. A tach error will show up in the IPS reading!
  • If the tach reading is jumping around, try to double the width of the tape and check the alignment of the optical sensor.
  • Mounting the reflective tape on a polished spinner back plate can give extra reflections. Relocate the tape or paint the back of the plate.
  • The optical pickup must be at least 6 inches from the reflective tape to get a good signal.
  • You can test the tape/pickup alignment by wiggling your finger between the tape and sensor. The tach reading should become live if your accelerometer is also plugged in. Also note that when aligned, a red light will glow on the back of the optical pickup.
  • Remove the tape from metal props when finished to avoid corrosion under the tape. Use as little tape as possible (i.e. 1 inch strip) and mount the tape inboard toward that hub so the balance is not affected by removing the mass.

Accelerometer Mounting

  • The accelerometer mount MUST be short, and rigid. If the results after weight additions don't make sense, your accelerometer/mount may be resonating.
  • If the accelerometer cable is pointing away from the center of the hub, then the angle reported by the DynaVibe is the HEAVY spot (where to remove weight, or 180 degrees from where to add weight). If you flip it so the accelerometer cable is pointing toward the hub, then the reading will indicate the light spot (where to ADD weight).
  • If possible, align the axis of the accelerometer so it goes through the center of the hub. If you have to shift it more than an inch, review the DynaVibe manual for interpreting the phase angle.
  • If a long mount is needed for the tach, make two mounts and keep the accelerometer mount short and stiff.

Inconsistent Readings

  • As indicated above, if the results after weight additions don't make sense, your accelerometer/mount may be resonating. Keep the mount short.
  • Be sure something isn't moving! A common example is the spinner. If not securely mounted it can relocate during each runup. In that case, multiple readings during one runup may be consistent. After shutting down and restarting the angle could move due to the spinner shift. Also, if the spinner has packing, it may be shifting as well.
  • If you're trying to get below 0.10 IPS, the reading may become "noisy". Take multiple readings, throw out any anomalies, then average the results.
  • It doesn’t matter if you measure the angle while standing in front of or behind the prop. This ambiguity is eliminated by simply measuring in the direction of prop rotation.
  • The engine RPM must be stable for a valid vibration reading. Hold RPM as stable as possible when balancing.
  • The engine should be running smoothly from idle to max RPM. Do NOT try to balance a prop with a rough engine!
  • Route all of the DynaVibe wires well away (4" or more if possible) from spark plug wires or other sources of electrical noise.

Good Readings, Still have Vibrations

  • Check blade tracking and pitch. Aerodynamic imbalance will change the vibration magnitude with RPM.
  • Be sure other mounts, such as the alternator etc., are not vibrating.
  • There are many sources of vibrations. The DynaVibe will zero in on the prop frequency. Balancing will not correct aerodynamic imbalances, vibrations at other frequencies, or vibrations from an unbalanced engine.

Batteries

  • When in doubt, change the batteries! The unit takes two 9V batteries that can be accessed by removing the two screws on the back of the unit.

Error Messages

  • "Sensor Error" - This indicates that there is a problem with the accelerometer signal. Check the cables and be sure the accelerometer is completely plugged into the DynaVibe.
  • "No Tach" - This means that the DynaVibe is not receiving tach pulses. Note that a continuous signal will generate this message. To test the optical pickup, reflect the light from a piece of reflective tape that is statically positioned at least 6 inches from the optical pickup. The red light on back of the pickup should come on. Then pass your finger back and forth quickly to break the beam. The tach reading should become live. Note that the accelerometer MUST be plugged in for this procedure.

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