Gyro's
04-30-2008 | 05:06 PM
#1
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From: london, UNITED KINGDOM
Gyro's
Hiya all
I'm having trouble getting my head round gyro settings 0 66.5% 1 64.0% and how to set it up i have upgraded tail to a robbe fs61bb and switched gyro from norm to digital
My servo arm is centered , tail slider centered
Tried to hover tonight but nose seems to wander all over the place if i turn the gyro up it starts to spin constantly and if i turn it down i dont seem to have any rudder input ( even with hard left / right )
Am i doing something wrong or do i have a servo/gyro problem ?
I have read that u need to set up gyro in rate mode, What do i need to do ?? (does this mean i have to turn the gyro down to below 50% to put it rate mode ) i'm getting quite frustrated now as this is the area i don't understand (i can rebuild without any probs now and all cyclic's are 65mg's
I'm having trouble getting my head round gyro settings 0 66.5% 1 64.0% and how to set it up i have upgraded tail to a robbe fs61bb and switched gyro from norm to digital
My servo arm is centered , tail slider centered
Tried to hover tonight but nose seems to wander all over the place if i turn the gyro up it starts to spin constantly and if i turn it down i dont seem to have any rudder input ( even with hard left / right )
Am i doing something wrong or do i have a servo/gyro problem ?
I have read that u need to set up gyro in rate mode, What do i need to do ?? (does this mean i have to turn the gyro down to below 50% to put it rate mode ) i'm getting quite frustrated now as this is the area i don't understand (i can rebuild without any probs now and all cyclic's are 65mg's
04-30-2008 | 09:19 PM
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From: Lincoln,
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RE: Gyro's
Yeah you go under 50% and it is in rate mode. Setting up the tail is what you did to get things centered. With the motor unplugged pull the tail really fast in one direction and see what way the tail blades pitch to. I am thinking you need to reverse the gyro and the rudder channel in the transmitter, but with out testing which way the tail blades pitch to that is all I can think of right now.
Nick
Nick
05-01-2008 | 05:10 AM
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From: Sunshine Coast,Sunny Queensland, AUSTRALIA
RE: Gyro's
Ummm... Wolf, unless I am mistaken, the discussion in that link has the servo moving in reverse to that of the Blade... It says servo horn toward the front for nose left - in the blade the servo moves to the rear for nose left... (EDIT: Just looked through the build info on that X400 and it has trailing edge control for the tail blades, where as we have leading edge control, hence the reverse direction on the servo)
This is a copy/paste of a PM I sent someone a while ago on the gyro setup. The only thing missing for you will be that you will need to reverse (most likely, since you have replaced the servo and most servos are reversed to the eflite ones) the rudder channel in the TX and the nor-rev switch on the gyro. To check, stick the gain down to about 30 (this is 40% in Rate Mode) and give it left stick, the trailing edge of the tail blades should move to the left, if not, reverse the rudder channel in the TX. Then center the stick again and push the tail to the left (nose right) and the blades should move in the same direction they did when you gave it left stick, if they dont, reverse the nor-rev switch on the gyro.
Then........
This is a copy/paste of a PM I sent someone a while ago on the gyro setup. The only thing missing for you will be that you will need to reverse (most likely, since you have replaced the servo and most servos are reversed to the eflite ones) the rudder channel in the TX and the nor-rev switch on the gyro. To check, stick the gain down to about 30 (this is 40% in Rate Mode) and give it left stick, the trailing edge of the tail blades should move to the left, if not, reverse the rudder channel in the TX. Then center the stick again and push the tail to the left (nose right) and the blades should move in the same direction they did when you gave it left stick, if they dont, reverse the nor-rev switch on the gyro.
Then........
In the Gyro menu, the original settings had the top line on the right as SW-GYRO. This means the two settings below it on the left (0 and 1) are the percentages of gain applied to the gyro depending on the position of the Flap/Gyro switch.
However, if that top line in the Gyro menu is changed to SW-F.MODE, then you still have the two figures for the gain at 0 and 1 on the left hand side, but now on the right hand side of the screen you have the Norm and Stunt settings, with the editable option of 0 and 1 beside them.
What this means is if you have Norm = 0 and Stunt = 1, then in Norm flight mode the gyro will have the gain that you set on the left of the screen for setting 0, and in Stunt mode the gyro will have the gain set on the left for setting 1.
Why you can edit the 0 and 1 is a bit strange, since you could just as easily change the gain settings anyway. Hope that makes sense. The idea is in this setup you can have the gyro gain automatically change to suit the flight mode if you wish, rather than have a seperate gyro switch to throw as well (mind you the gyro switch will now do nothing).
As for the actual settings on the left under Rate for 0 and 1, these are the gains applied to the gyro. They are as follows: (this is the easiest way to explain it)
0=100% gain in rate mode
0.5=99% " " "
1=98% " " " "
5=90% " " " "
10=80% " " " "
20=60% " " "
25=50%
40=20% " " " "
45=10%
50=no gain
51=2% gain in Heading Hold
55=10% " " " " "
60=20% " " " " "
75=50%" " " "
90=80% " " " "
100=100%" " " " "
(and all the numbers inbetween)
Now, how to actually setup the gyro. First, set the gyro for very low gain in rate mode (ie, settings of around 48 or so) then the servo will centre properly (and not travel very far with stick movement) then place the servo arm as close to 90 degrees to the pushrod as possible with no trim or subtrim on the radio. Then, adjust the control rod to make the tail pitch slider as close to center of travel as possible. This will give around 5 to 8 degrees of pitch to the tail blades. You may have the move the linkage one hole closer to the centre of the servo to avoid the servo pushing the pitch slider too far at higher gain settings (bump the gain in rate mode higher to test, such as around 10 on the settings), as this gyro has no endpoint/travel adjustments (the servo endpoint only adjust how fast the heli will pirouette, it will not limit the servo travel).
Now comes the tricky bit. Set the gain to around 32% in rate mode (which is around 34 in the gyro menu) and attempt a quick hover. The heli will most likely try to spin, note where you are holding the stick to keep it straight and land. While on the ground, hold the stick to the same position and take note where the pitch slider is sitting. Now centre the servo (use 48 on the gain settings and no stick input) and you need to keep adjusting the control rod length until the pitch slider is about where you noted above. Do this a few times until a reasonably stable tail is acheived with little or no stick input (you wont get it perfect, just close).
Then you should be able to switch to heading hold mode at around 32% (66 on the gyro menu) and it should be reasonably stable in the air (the servo will act strangely on the bench, moving all the way with small stick inputs and not moving back to centre on its own - this is normal). Now keep increasing the gain until the tail starts wagging back and forth on its own during a hover, this means you have gone to far and you then drop back a little til the tail is steady, this is the perfect setting for hovering, a lower setting (say 5 points or so) in heading hold will not hold as tight and will be good for forward flight, as it will allow the tail to follow a little easier on its own.
Unfortunatley with the stock gyro tho, the peizo internals are not too acurate and will allow a little bit of drift depending on temperature change and battery voltage etc.. You will also need to have it sitting in the air temp you intend to fly in for a good 15 minutes before flying for the most stable response (ie, straight out of hot or airconditioned car). You most likely will find you need one or two clicks of trim to keep it still and it may slowly change during a flight a trim click or two. This is one of the reasons I have replaced mine.
However, if that top line in the Gyro menu is changed to SW-F.MODE, then you still have the two figures for the gain at 0 and 1 on the left hand side, but now on the right hand side of the screen you have the Norm and Stunt settings, with the editable option of 0 and 1 beside them.
What this means is if you have Norm = 0 and Stunt = 1, then in Norm flight mode the gyro will have the gain that you set on the left of the screen for setting 0, and in Stunt mode the gyro will have the gain set on the left for setting 1.
Why you can edit the 0 and 1 is a bit strange, since you could just as easily change the gain settings anyway. Hope that makes sense. The idea is in this setup you can have the gyro gain automatically change to suit the flight mode if you wish, rather than have a seperate gyro switch to throw as well (mind you the gyro switch will now do nothing).
As for the actual settings on the left under Rate for 0 and 1, these are the gains applied to the gyro. They are as follows: (this is the easiest way to explain it)
0=100% gain in rate mode
0.5=99% " " "
1=98% " " " "
5=90% " " " "
10=80% " " " "
20=60% " " "
25=50%
40=20% " " " "
45=10%
50=no gain
51=2% gain in Heading Hold
55=10% " " " " "
60=20% " " " " "
75=50%" " " "
90=80% " " " "
100=100%" " " " "
(and all the numbers inbetween)
Now, how to actually setup the gyro. First, set the gyro for very low gain in rate mode (ie, settings of around 48 or so) then the servo will centre properly (and not travel very far with stick movement) then place the servo arm as close to 90 degrees to the pushrod as possible with no trim or subtrim on the radio. Then, adjust the control rod to make the tail pitch slider as close to center of travel as possible. This will give around 5 to 8 degrees of pitch to the tail blades. You may have the move the linkage one hole closer to the centre of the servo to avoid the servo pushing the pitch slider too far at higher gain settings (bump the gain in rate mode higher to test, such as around 10 on the settings), as this gyro has no endpoint/travel adjustments (the servo endpoint only adjust how fast the heli will pirouette, it will not limit the servo travel).
Now comes the tricky bit. Set the gain to around 32% in rate mode (which is around 34 in the gyro menu) and attempt a quick hover. The heli will most likely try to spin, note where you are holding the stick to keep it straight and land. While on the ground, hold the stick to the same position and take note where the pitch slider is sitting. Now centre the servo (use 48 on the gain settings and no stick input) and you need to keep adjusting the control rod length until the pitch slider is about where you noted above. Do this a few times until a reasonably stable tail is acheived with little or no stick input (you wont get it perfect, just close).
Then you should be able to switch to heading hold mode at around 32% (66 on the gyro menu) and it should be reasonably stable in the air (the servo will act strangely on the bench, moving all the way with small stick inputs and not moving back to centre on its own - this is normal). Now keep increasing the gain until the tail starts wagging back and forth on its own during a hover, this means you have gone to far and you then drop back a little til the tail is steady, this is the perfect setting for hovering, a lower setting (say 5 points or so) in heading hold will not hold as tight and will be good for forward flight, as it will allow the tail to follow a little easier on its own.
Unfortunatley with the stock gyro tho, the peizo internals are not too acurate and will allow a little bit of drift depending on temperature change and battery voltage etc.. You will also need to have it sitting in the air temp you intend to fly in for a good 15 minutes before flying for the most stable response (ie, straight out of hot or airconditioned car). You most likely will find you need one or two clicks of trim to keep it still and it may slowly change during a flight a trim click or two. This is one of the reasons I have replaced mine.
05-01-2008 | 12:44 PM
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From: london, UNITED KINGDOM
RE: Gyro's
Cheers every1 but i will have to stop playing with gyro now i have just noticed the tail shaft is bent (dont know from when or how as i have not had a tail strike (yet ) .
I did notice was when i switched the gyro switch from norm to rev it didn't make any difference to rudder input is that right ?????
I did notice was when i switched the gyro switch from norm to rev it didn't make any difference to rudder input is that right ?????
05-01-2008 | 04:50 PM
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From: Sunshine Coast,Sunny Queensland, AUSTRALIA
RE: Gyro's
Hi Krash, you are correct, changing the nor-rev switch on the gyro will not make any change to the rudder input, that is controlled by the reverse switch in the TX as evdreamer said.
The nor-rev switch on the gyro controls how the gyro drives the servo when the heli turns. If you set the gyro to a high gain in rate mode and turn the heli by hand, the gyro will think its being blown around and will push the servo to correct. If the switch is wrong, it will push it harder in the direction it moved.
To check the direction, the trailing edge of the tail blades point in the direction the heli is trying to turn (as in, trailing edge pointing left, nose will try to spin left) So if you spin the heli clockwise (nose to the right) then the tail blade trailing edge should kick to the left.
Cheers, Dave.
The nor-rev switch on the gyro controls how the gyro drives the servo when the heli turns. If you set the gyro to a high gain in rate mode and turn the heli by hand, the gyro will think its being blown around and will push the servo to correct. If the switch is wrong, it will push it harder in the direction it moved.
To check the direction, the trailing edge of the tail blades point in the direction the heli is trying to turn (as in, trailing edge pointing left, nose will try to spin left) So if you spin the heli clockwise (nose to the right) then the tail blade trailing edge should kick to the left.
Cheers, Dave.
