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8UHP and GY401

duczz

Senior Heliman

Kerikeri, New Zealand

Hi all, I have an old Futaba 8uhp which I am trying to work out how to set the sensitivity up for my GY401 gyro, as my trans is not the super model it dosent have any kind of gyro sensing or any gyro control in the advanced menu, and the gyro sensitivity is all set in the basic menu under channel 5 ATV-GY What I am hoping someone can tell me is how do the transmitter values relate to actual gyro sensitivity? I have channel 5 switch (F) setup so I can switch between HH and normal, although I only ever fly in HH so thats not so important. Using ATV's to set sensitivity what would be a good starting off point, and how would changing the values effect sensitivity, when I move switch (F) back and forth the two values flash correspondingly..... does a high transmitter % value in HH represent high gain? the adjustment has a range from 30% to 140% ... any help would be greatly appreciated.

11-14-2004 Over year old.
Elmote

Senior Heliman

Los Angeles

Have you read the instructions? It's right there....
Two sample setups are given, side/side. One for 8uSuper and others with gyro func. One for Tx without Gyro using ATV. I prefer the ATV route and use it even tho I have the Super. I think my ATVs are 30 and 80. There is a deadband about the 50% ATV value, from 45 to 55 I think. So for HH any ATV from 56 to 100 and for rate any value from 44 to 0 will work. IOW, you extrapolate to find the gain setting you want.
55=0, 100 =100, so ?=50% gain in HH? (hint: 77). On the rate side, 0=100, 45 =0, so my value of 30 equals ?% of gain in rate mode? 33%? Very good, class? Who ever got 33% can stay after shhool and clean the erasers. (appolgies to Tom Leher)

Elmo Te

11-17-2004 Over year old.
Elmote

Senior Heliman

Los Angeles

Have you read the instructions? It's right there....
Two sample setups are given, side/side. One for 8uSuper and others with gyro func. One for Tx without Gyro using ATV. I prefer the ATV route and use it even tho I have the Super. I think my ATVs are 30 and 80. There is a deadband about the 50% ATV value, from 45 to 55 I think. So for HH any ATV from 56 to 100 and for rate any value from 44 to 0 will work. IOW, you extrapolate to find the gain setting you want.
55=0, 100 =100, so ?=50% gain in HH? (hint: 77). On the rate side, 0=100, 45 =0, so my value of 30 equals ?% of gain in rate mode? 33%? Very good, class? Who ever got 33% can stay after school and clean the erasers. (appolgies to Tom Leher)

Elmo Te

11-17-2004 Over year old.
duczz

Senior Heliman

Kerikeri, New Zealand

Thanks for your reply, it does show an example for ATV but its still different, my 8U dosent allow you to set a ATV lower than 30% and on the other side it goes up to 140% so therefore 30% - 140% is the settable range.....

11-17-2004 Over year old.
mikeflyz

Senior Heliman

Westlake Village, CA

Since there is a seperate page for GY and ATV on the 8U, you should only use one or the other. A mistake I see sometimes is folks setting the ATVs for channel 5 and setting gyro gains on the GY page at the same time. This will not work!!

If you use the ATV method, make sure that the gyro page is inhibited, or default values are entered. Most helicopters don't need less than 30% gain in either mode to prevent tail wag. I would start off w/50% ATV with both switch F directions (that would put the channel's setting at 75% and 25% / which equals 50% gain in heading hold and non-heading hold respectively).

If you use the GY page method, both ATV values for channel 5 must be at 100%/default values. The 8U then is set with:

Increasing gain in heading hold = 51 - 100%
Increasing gain in non-heading hold = 49 - 0%

Hope this helps

Mike

Mike
MA Fury Extreme, JetCopter SX

11-18-2004 Over year old.
steve69

Senior Heliman

Berkshire, UK.

Hi, just came accross this post, I too have the same set up as you, an old (none super version) U8 and a gy401 with a 9254 servo

I have quite a high mechanical gain, i.e. my ball link is on the outer most hole on the servo horn.
I also run a high head speed at around 1800rpm

I use the ATV on ch5 as we dont have the GY function on our radio as far as I am aware.
in HH mode (led on gyro constant/switch F towards back) the ATV is set at 41% and in normal/rate mode I have it set at 48%.

I wont lie and say I know how this all works as I had a friend help set it all up for me however these settings do work for me very well.

(I was under the asumption myself that the ATV for normal mode needed to be above 50% to tell the gyro that it is in rate mode however with my setting when I flip the switch forward the gyro LED goes off thus indicating it is in rate "or so I am led it believe" )

Like you I only fly around in HH mode anyhow so the rate mode is only there for show at the moment (I dont like flicking switches at the moment as I am still a little nervous )

Hope this helps


Steve.

11-18-2004 Over year old.
mikeflyz

Senior Heliman

Westlake Village, CA

Steve,

On the 8U, the ATVs represented on the display is percentage of travel from "mid stick". Depending on the reverse setting of channel 5, the F switch may have heading hold on with the switch forward or backward.

So, if you want to change the HH on position of the switch, simply reverse channel 5.

Mike
MA Fury Extreme, JetCopter SX

11-18-2004 Over year old.
steve69

Senior Heliman

Berkshire, UK.

Hi mike,

Thanks for your explanation,

my main question was I have been led to belive from reading in various places (including here) that one setting needed to be below 50% for HH and above 50% for rate (or as you say, opposite if the chanel is reversed) however on my setup both are below 50% and yet the gyro definatly switches in and out of HH as indicated by the LED.

I dont know why or how, however it doesnt worry me as it seems to work fine.

I was just curious incase I have it setup wrong.

Thanks


Steve.

11-18-2004 Over year old.
duczz

Senior Heliman

Kerikeri, New Zealand

Hi guys yeah I too have played around with the different values on the ATV-GY menu of the 8U, and no matter what value is entered be it large or small the gyro still succesfully switchs between heading hold and normal. The values seem to have no affect on HH/Normal selection and this is simply controlled via the channel 5 switch, reversing channel 5 does change the switches affect, making heading hold in the forward or backward position whichever is desired.. As I understand our radios being the non super version do not have an Gyro screen, and the only contorl is via the ATV-GY menu, last night I set my heading hold value with the switch forward at 74% and the normal mode to 54% i hovered in both modes and the helicopter was rock solid in heading hold with no tail shake at all, infact its the most stable ive had it to date, in normal mode it was easily controllable but did drift a little......

11-18-2004 Over year old.
steve69

Senior Heliman

Berkshire, UK.

Hi Duczz

mikeflyz sent me this mail as he was having trouble posting here, gives a real good explanation.

Hello Steve, I'm having a small problem posting on RR at the moment, but I wanted to help
clarify this issue.

Your radio is operating correctly when it comes to switch F toggling between HH and rate modes.
Think of it as a retract switch (which was its original function) where one switch position will
be above 50% and the opposite position will be below 50%, so it is impossible to have HH on in
BOTH switch positions (or HH off in both switch positions).

Since the ATV determines the "distance" from 50% on the radio, with both ATVs for channel 5 set
at 50% will result in that proportional channel setting to be at the 25 and 75% position
(halfway between mid and full "stick"). The 401 interprets ths as 50% gain in HH in one switch
position and 50% gain in Rate mode in the opposite switch position.

Hope that helps


Thanks mike.


Steve.

11-19-2004 Over year old.
duczz

Senior Heliman

Kerikeri, New Zealand

Thanks alot guys, much appreciated

11-19-2004 Over year old.
mikeflyz

Senior Heliman

Westlake Village, CA

Got my problems logging on fixed now. Happy to help

Mike
MA Fury Extreme, JetCopter SX

11-20-2004 Over year old.
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