GY401 flashing

[lextek]

I've just started hovering my Trex 450. I went through the videos on gyro set up. It hovers fine. When I land after flying the LED is flashing. When I first plug the battery in it initializes fine. I'm not sure now if it is flashing twice or just flashing.
I'm using a 9650 servo and JR 6102 TX.

[steffgiguere]

If the light is flashing it is because you are not in HH. You should fix this using you radio settings.

[lextek]

If the light is flashing it is because you are not in HH. You should fix this using you radio settings.

It starts out in HH. Why would it change if nothing changed/switched?

[steffgiguere]

If you idle up maybe your setting here is not HH. What radio do you use?

[lextek]

I'm using a JR 6102. After flying again it seems OK. I am just hovering in normal mode. No thoughts of idle up yet.

[steffgiguere]

I don't know the JR radios, I use Futaba, sorry.

[ZipZap]

Are you trimming the rudder? I have had the 401 flash on me if my trims weren't zeroed out.

[TheBum]

Are you trimming the rudder? I have had the 401 flash on me if my trims weren't zeroed out.

That's my thought too. If the LED is flashing rapidly, it means that there is some rudder input being fed to it; if it's flashing more slowly, it means the gyro either never initialized or there's an error.

[lextek]

Are you trimming the rudder? I have had the 401 flash on me if my trims weren't zeroed out.
So if I use trim in normal mode. I need to mechanically trim the rudder and reset the trim to zero?

[jlr]

So if I use trim in normal mode. I need to mechanically trim the rudder and reset the trim to zero?

By "normal" mode, I assume you mean the flight mode on the tx, e.g. normal, idle-up, etc. If that is correct, then it's not so much to do with that, but rather there should not be any need to trim the rudder if you always leave the gyro in heading-hold. If you want to be able to use rate-mode on the gyro, then you'll need to trim the rudder to remove any pirouette rate in that mode. Then (with this new trim setting) you'll need to reset the 401 in heading hold.

Did that help or just make things more confusing? :confused:

[lextek]

Well, yes now I am confused. By "normal" I meant "rate" mode on the gyro. OK start up in HH switch to rate mode. Nose of heli turns to left. Should I trim with the TX or land and mechanically adjust it?

[MarkD]

I would mechanically set up the rudder if there is any yaw in Normal/Rate mode. Any trim on the TX after initialisation and the gyro will see this as a command to turn in HH

[lextek]

I would mechanically set up the rudder if there is any yaw in Normal/Rate mode. Any trim on the TX after initialisation and the gyro will see this as a command to turn in HH

That makes sense. I think I'm making it more complicated than it actually is. Thanks guys.

Just wondering why does a gyro have the HH and rate modes? Would you want to fly one over the other?

[Skarn]

That makes sense. I think I'm making it more complicated than it actually is. Thanks guys.

Just wondering why does a gyro have the HH and rate modes? Would you want to fly one over the other?

Most of us fly in HH mode only. Apparently, there are some people that actually prefer rate mode.....they like flying the tail! Not I!

Skarn

[ZipZap]

I fly in HH because I don't want to play around with mixing.

The bottom line is that you get the tail rotor set up mechanically as close to center as possible when the trim is at 0. Then fly in HH and don't worry about it.

[jlr]

Well, yes now I am confused. By "normal" I meant "rate" mode on the gyro. OK start up in HH switch to rate mode. Nose of heli turns to left. Should I trim with the TX or land and mechanically adjust it?

My answer (that not every Freak would agree with) is that it doesn't matter trim on TX or mechanically, but the important thing is that after making the trim adjustment HH mode won't work until the gyro is re-initiallized. After the change you should double check the limits to make sure you're not binding.

[jlr]

Just wondering why does a gyro have the HH and rate modes? Would you want to fly one over the other?

Scenario: You're hovering and a gust of wind comes along and causes you to weather vane.

HH: The gyro corrects until your heading is back to where it was, i.e. you're pointing in the same direction as before the gust.

Rate: The gyro corrects until your pirouette rate comes back to 0, i.e. you're not rotating but you're pointed a little into the gust now.

As Skarn said, most people (myself included) leave the gyro in HH mode all the time (in which case you really don't need to worry about trim), but some people like to use Rate mode for FF because the heli will weather vane a little bit. 3-D is virtually always in HH AFAIK.

[Stevie W]

Hi,

I'm pretty sure that when the LED on the 401 is flashing (after being initialised in HH) it simply means that there has been some rudder input - not that it has come out of HH mode. Try moving the rudder left to right quickly (3 time in one second) then let it centre - If I remember correctly, this will tell the gyro to centre the pitch of the tail rotors and (I think) the LED stops flashing.

Catch ya later...

[BarracudaHockey]

Light on solid - gyro in heading hold mode and properly initialized
Light off - gyro in rate mode and initialized properly in heading hold mode.
Double flash, pause, double flash - gyro getting a rudder or trim input. This happens too with some transmitters that store trim position by flight mode, make sure to zero the trim in all flight modes and leave it there, if you must try rate mode, trim by the linkage not by the transmitter.
Single slow flash - error. The gyro wasnt initialized properly in heading hold mode, could be a radio programming issue, could be the wire isn't hooked up right but it didnt get the signal it needed to boot properly.

What helicopter we talking here?

[Jafa]

Double flash, pause, double flash - gyro getting a rudder or trim input. This happens too with some transmitters that store trim position by flight mode, make sure to zero the trim in all flight modes and leave it there, if you must try rate mode, trim by the linkage not by the transmitter.

Another cause is having the wrong expo on the rudder
On a Futaba you need - Expo
On a JR you need + Expo

If you have the wrong expo (like -30% on a JR)
it makes the sticks really sensitive to wind
and also shows if the TX sticks are not centering accurately
This results in off center signals being sent to the gyro - hence the light flashes