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Old 12-15-2015, 07:18 PM   #14 (permalink)
hANDYman
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Quote:
Originally Posted by Brian Bremer View Post
Checking that the swash plate is level;

Simply follow the procedure outlined in the product manual (page 14, Servo Adjustment Mode). Once you have entered the adjustment mode the servos will be in the neutral position and the flight controller will be disabled so the helicopter can be moved around.

The back two servo arms should be parallel to the servo case and the front arm should be parallel with the back two servo arms.

Verify that the swash plate is level. Fold both main blades back and if the tips of the blades line up with each other as you slowly rotate the head 360 degrees. If the main blade tips remained aligned with each other then your swash is level and the swash is at the proper height to have 0 degrees of collective at center stick.

To exit servo adjustment mode simply hold the panic button down for 4 seconds and the servos will jump to indicate the values have been saved.
Hi Brian. I must say that I'm truly surprised that someone at Horizon Hobby is suggesting folding the blades to check for a level swash plate. That is not a valid test.

If you fold the blades to the same side then they will tell you when you are at zero degrees collective pitch , but they tell you nothing about whether or not the cyclic pitch is at zero degrees (i.e. if the swash is tilted or level).

When the blades are folded, the collective input (swash plate moving up and down along the shaft) will determine whether the blades are split or side-by-side. If the collective is set at zero degrees and the folded blades are lined up with each other, they will continue to line up as the main shaft is rotated even if the swash plate is tilted. The only thing that will make the blade tips split is moving the collective away from 0 degrees pitch.

Here is the distinction... If the blade tips are lined up, and the swash plate is perfectly level, then the path that the blade tips follow as the main shaft is rotated will be perfectly perpendicular to the main shaft in both the fore/aft direction as well as the side/side direction. If the swash plate is not level, then the folded blade tip path will be tilted in relation to the main shaft.

To prove this point, take a properly setup heli, and with TH applied, play with the controls while rotating the rotor head by hand with the blades folded. At zero degrees collective, apply full cyclic in any direction. The folded blade tips will remain aligned, but they tilted blade tip path will be very evident.

I've seen this method suggested a number of times in the past and it seems to be one of those myths that won't go away unfortunately.

Regards,

Andrew
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