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01-10-2013 01:26 PM  7 years ago
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MikeyD_From_Indy

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Carmel, In

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RC Logger 1
I have one of the older RC Loggers. I always thought this was spot on, but last night I was checking blade pitch, and noticed that once I zero (motor as reference) and then turn the logger 180% on the motor (LCD front is now in the back)the logger reads a full degree different.

Any body else have this going on?

I have followed to the letter the work instructions for calibration, and have taken the battery's out and replaced with new ones. I also tried this last night on a friends slate pool table. After calibration and turning it 180 degrees same spot same reference it is still a full degree off.

Curious?

Mikey D
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01-10-2013 01:59 PM  7 years ago
thefrog

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Johannesburg, South Africa

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The logger is fine - if you zero it in one orientation it will provide different numbers when you change the device's orientation.
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01-10-2013 02:39 PM  7 years ago
MikeyD_From_Indy

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If the reference is the same in all directions, your statement makes no sense to me.

Can you please explain your thoughts?

Thanks
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01-10-2013 04:49 PM  7 years ago
Cavnatkguy

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Puyallup, WA

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Here my random thought -

The case is not perfect, thus when you set down for ref 0 and turn it 90 and the case is off by 1 your going to see 89 or 91. This gauge hangs on the blades with the ref 0 and your going to get good numbers on the -/+ pitch. It a theory not a fact!
Charles
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01-10-2013 05:13 PM  7 years ago
JKos

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Redondo Beach, CA

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MikeyD,
Think of it this way... If you zero the logger on something obviously not level, say 10 deg negative slope, and then turn the device around it will read 20 degs. Why? Its reference is -10 deg slope as "zero." Turn the device around and it is now on a +10 deg slope which is a 20 deg difference.

- John
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01-10-2013 05:38 PM  7 years ago
MikeyD_From_Indy

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Forget about the Heli for the moment. If I have known level surface like a pool table, and I zero the Rc logger to reference zero to the table, and turn it 180 degrees it should read the same, it has to or it's off.

Back to the Heli. If I reference my motor as zero, and I know the Heli is level, and my swash is level I would expect to see zero on pitch gauge. If I turn the blades 180degrees I would expect the same not a full degree off.

The reason i went to the pool table was to eliminate the swash and anything else on the Heli as a possible cause.

What am I missing?
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01-10-2013 06:19 PM  7 years ago
JKos

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MikeyD,
You will only get zero both ways IF the sensor is installed perfectly in the device (or the calibration routine is robust and can account for any sensor installation issues) and IF the surface used to zero the logger is exactly, perfectly level.

Are you doing the full calibration on the pool table surface?
Back to the Heli. If I reference my motor as zero, and I know the Heli is level, and my swash is level I would expect to see zero on pitch gauge. If I turn the blades 180degrees I would expect the same not a full degree off.
Only if the mainshaft was exactly plumb and the swash was exactly level.

Try something to show yourself what is happening. Zero the logger to the motor. With the swash perpendicular to the mainshaft (no cyclic), put a few degrees of collective pitch on the blades, say 5 degs. Rotate the head 180 degs and note what the logger says. Rotate the head back to the original position.

Now, change the angle of the heli a bit (perhaps put something under the rear of the skids), and repeat the above steps (zero on the motor, etc.).

Finally, with the heli still angled, check the reading with the blade in the starting orientation, rotate the head 180 degs, turn the logger around on the blade so that it is facing the original direction and note the reading.

Let us know what you get in each of those cases.
What am I missing?
How do you know the pool table is perfectly level?

How do you know the top of your motor is exactly perpendicular to the mainshaft?

The logger is always referencing the acceleration due to gravity. Zeroing the logger on a particular angle does not change that fact. The logger does not know the orientation of the mainshaft/helicopter. This is why my example of zeroing the logger on a slope and then turning it around will yield twice the slope.

This is a hobby grade device. It is neither highly precise nor highly accurate and will show slight oddities at times.

Thanks,
John
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01-10-2013 07:00 PM  7 years ago
MikeyD_From_Indy

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Thanks John
Appreciate your perspective. I'll keep working with it. It's not a big deal, in the end it's how the Heli flies.

The pool table is flat because I referenced it with 4ft level. My friend tells me the installers leveled the tables when it was received as well.

BTW, I have a message out to RC Logger as well.
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