Gyro Placement for Best Results
02-03-2015, 03:00 PM
#26
My Feedback: (1)
Again, another Whatever!
You guys are missing the point, it works for me and I could care less that it doesn't follow your logic and Science based knowledge, so you can place your Gyro where you want and I will place mine where it works best for me and that is inline with the main gear!
You guys are missing the point, it works for me and I could care less that it doesn't follow your logic and Science based knowledge, so you can place your Gyro where you want and I will place mine where it works best for me and that is inline with the main gear!
Add one for me. Have a gyro in my Gold Berg Cub mounted just behind the fuel tank and setting next to the receiver. Not exactly on centerline but it does what I need it to do and that is get me down the runway nice and straight.
Gary
02-03-2015, 11:28 PM
#28
Senior Member
"Wrong.
It measures rotation rate about an axis.
That doesn't change no matter where you mount it. And assuming what you're saying is true, do you think the distance we could change that in a model is significant?"
RC Gyros measure using accelerometers.
They, to the best of my knowledge are not "ring gyros"
You can measure the raw or pulse train outputs with an oscilloscope.
As you move a heli tail rotor gyro towards the tail,. the gain setting changes,
or the tail hunts. Fortunately, Model AC gyros have a decent adjustment range.
It measures rotation rate about an axis.
That doesn't change no matter where you mount it. And assuming what you're saying is true, do you think the distance we could change that in a model is significant?"
RC Gyros measure using accelerometers.
They, to the best of my knowledge are not "ring gyros"
You can measure the raw or pulse train outputs with an oscilloscope.
As you move a heli tail rotor gyro towards the tail,. the gain setting changes,
or the tail hunts. Fortunately, Model AC gyros have a decent adjustment range.
02-04-2015, 09:10 AM
#32
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There is obvious 2 opinions to Gyro placement, some say it doesn't matter and a significant amount of other folks say it does. I had a simple experiment that showed it does matter and the experts say my experiment is flawed.
I will agree that a Gyro will react where ever it is placed; However, placement dictates how quickly a Gyro reacts and how much Rudder throw or control is given. My experiment demonstrated this, and yet I am discredited.
Please explain; how is it that if you place a plane on the bench and hook an un-mounted Gyro to the RX and Rudder and with the Gyro between your fingers you slightly spin or rotate the actually Gyro no more than 10 to 25 degrees in either direction you get immediate response and rudder movement to counter the rotation; you then take the same Gyro and instead of rotating or spinning it, you move it in an arch from side to side the response is slower and the rudder movement is less.
You will get the same results or effect if the Gyro is mounted inline with the main gear serving as the Axis or Pivot point the reaction is immediate when you swing the tail left to right using the main gear as the pivot versus mounting it further down the fuselage away from the pivot point or axis. I am only talking about using a Gyro for takeoffs with the main wheels in contact with the ground acting as the pivot point, I will contend that the results could be different once in the air and placement may not matter at all, but I turn the Gyro off once in the air, I only need it on the ground for takeoffs.
Don't believe me, try my experiment yourself!
I will agree that a Gyro will react where ever it is placed; However, placement dictates how quickly a Gyro reacts and how much Rudder throw or control is given. My experiment demonstrated this, and yet I am discredited.
Please explain; how is it that if you place a plane on the bench and hook an un-mounted Gyro to the RX and Rudder and with the Gyro between your fingers you slightly spin or rotate the actually Gyro no more than 10 to 25 degrees in either direction you get immediate response and rudder movement to counter the rotation; you then take the same Gyro and instead of rotating or spinning it, you move it in an arch from side to side the response is slower and the rudder movement is less.
You will get the same results or effect if the Gyro is mounted inline with the main gear serving as the Axis or Pivot point the reaction is immediate when you swing the tail left to right using the main gear as the pivot versus mounting it further down the fuselage away from the pivot point or axis. I am only talking about using a Gyro for takeoffs with the main wheels in contact with the ground acting as the pivot point, I will contend that the results could be different once in the air and placement may not matter at all, but I turn the Gyro off once in the air, I only need it on the ground for takeoffs.
Don't believe me, try my experiment yourself!
Last edited by dasintex; 02-04-2015 at 09:13 AM.
02-04-2015, 11:19 AM
#35
Here is some reading for you.
http://www.differencebetween.net/tec...accelerometer/
You decide.
Rafael
http://www.differencebetween.net/tec...accelerometer/
You decide.
Rafael
02-04-2015, 11:28 AM
#36
There is obvious 2 opinions to Gyro placement, some say it doesn't matter and a significant amount of other folks say it does. I had a simple experiment that showed it does matter and the experts say my experiment is flawed.
Please explain; how is it that if you place a plane on the bench and hook an un-mounted Gyro to the RX and Rudder and with the Gyro between your fingers you slightly spin or rotate the actually Gyro no more than 10 to 25 degrees in either direction you get immediate response and rudder movement to counter the rotation; you then take the same Gyro and instead of rotating or spinning it, you move it in an arch from side to side the response is slower and the rudder movement is less.
Please explain; how is it that if you place a plane on the bench and hook an un-mounted Gyro to the RX and Rudder and with the Gyro between your fingers you slightly spin or rotate the actually Gyro no more than 10 to 25 degrees in either direction you get immediate response and rudder movement to counter the rotation; you then take the same Gyro and instead of rotating or spinning it, you move it in an arch from side to side the response is slower and the rudder movement is less.
Rafael
02-04-2015, 11:35 AM
#37
Senior Member
It is always interesting when arguments like this begin. Both sides seem so very convinced of their position that there must be some element of truth in both sides. On the one hand, I do agree 100% with Barracuda's assertion that a true gyro can be placed anywhere on a rigid structure and give the same output. On the other hand, I believe that dasintex truly did experience the variation in output depending upon the location of his "gyro". So ----- How do we reconcile this?
I went out to my shop where I have a lot of parts and pieces of airplanes in various stages of construction or repair. In my parts box I found an old Ikarus Tele-Gyro that I had removed from one of my son's airplanes. Since I have no plan to ever install this item, I decided to take it apart to see how it works. I took the housing apart, removed the circuit board, and then removed the metal cover from the part labeled 'gyro'. Then, with everything exposed, I connected this unit in line with the rudder control of one of my planes. When I turned on the power, I expected to see the tiny little rod inside the gyro unit to start spinning - but - it did not. I rotated the circuit board in my hand and the rudder moved. I touched the tiny little rod inside the gyro unit - and the rudder moved. That's as far as I went. I actually got a little excited that this old unit might still be functioning correctly and maybe I should try it in one of my aircraft.
Here are my conclusions: chuckk2 said it correctly - "RC Gyros measure using accelerometers. They, to the best of my knowledge are not 'ring gyros'".
This is one conclusion in which assertions by both Barracuda and dasintex can be true. I would also add that whether or not the 'gyro' is located on the CG or some distance from the CG is irrelevant except for the required change in gain setting and that gain adjustment can be made to make any installation location behave acceptably.
Of course ------- I could be wrong.
I went out to my shop where I have a lot of parts and pieces of airplanes in various stages of construction or repair. In my parts box I found an old Ikarus Tele-Gyro that I had removed from one of my son's airplanes. Since I have no plan to ever install this item, I decided to take it apart to see how it works. I took the housing apart, removed the circuit board, and then removed the metal cover from the part labeled 'gyro'. Then, with everything exposed, I connected this unit in line with the rudder control of one of my planes. When I turned on the power, I expected to see the tiny little rod inside the gyro unit to start spinning - but - it did not. I rotated the circuit board in my hand and the rudder moved. I touched the tiny little rod inside the gyro unit - and the rudder moved. That's as far as I went. I actually got a little excited that this old unit might still be functioning correctly and maybe I should try it in one of my aircraft.
Here are my conclusions: chuckk2 said it correctly - "RC Gyros measure using accelerometers. They, to the best of my knowledge are not 'ring gyros'".
This is one conclusion in which assertions by both Barracuda and dasintex can be true. I would also add that whether or not the 'gyro' is located on the CG or some distance from the CG is irrelevant except for the required change in gain setting and that gain adjustment can be made to make any installation location behave acceptably.
Of course ------- I could be wrong.
02-10-2015, 08:13 AM
#38
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Not that critical within reason. Usually ends up close to the CG at any rate as that's where the rcvr usually ends up. Gyro really works well on rudder keeping the plane in line on takeoff. Great for warbirds and such that need a lot of care. 
02-13-2015, 01:08 AM
#39
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A gyro system only containing pure gyro sensors does not care about where it is mounted at all, as it meassures angles, no acceleration or anything. And angle change all the same, anywhere on the plane (except the moving surfaces of course....just kidding 
).
This being said, if a gyro system additionally makes use of accelerometers, this fact of course changes the situation a bit. But still, these days even then it is not really relevant, but would make you prefer a mounting position more outside the CG for better feedback.
).This being said, if a gyro system additionally makes use of accelerometers, this fact of course changes the situation a bit. But still, these days even then it is not really relevant, but would make you prefer a mounting position more outside the CG for better feedback.
Last edited by DEMONjoe; 02-13-2015 at 01:18 AM.
