401 setup with DX7

[funeebski]

Just built my new TRex VE2 with Futaba 401 Gyro and 9650 Servo. The Gyro doesn't seem to be initializing, the light stays flashing. On the dx7 is it best to set the gyro in auto to switch with the flight mode or what? I have 2 percentage settings which are both at the default (50%), are these about right? The rest of the Gyro is all set up ok, lead into gear channell etc. Any suggestions? Still new so will just be hovering around, no 3d yet so is it best to stay in heading hold mode?

[simon_h]

The GY-401 MUST be initialised in Heading Hold mode to work properly. Sounds like you are switching it on in normal rate mode. This does not work properly. Anyway - 99.99% of the time HH is nicer to fly than rate mode.

Normal sequence of events. Turn on heli/plug in battery. Red light flashes for a couple of secs and then should (if in HH mode) go solid red. Don't move heli while gyro is initialising.

SH

[funeebski]

how do i switch to HH mode then? Do I change percentage's to above 50?

[simon_h]

Can't find the manual at the moment but...
One side of the center point is rate mode and the other is heading hold. The amount out from the center is the gain rate. If using the gear channel then the amount of gain is controlled by the T Adj(?) values for the gear channel.
On my old JR tx the + values seem to match HH and the -ve ones Rate mode so try that.

SH

[simon_h]

Just been looking at the DX7 manual and you have the choice of having of the Gyro being run off Gear (5) or Aux 2 (7) channels. make sure you have the gain channel plugged into the correct socket on the RX or have the correct selection made on the TX. Note if you use Aux 2 as the Gyro rate channel you can set the gain per flight mode on another screen.

SH

[jamiesawyer28041978]

Im running on a futaba t6exhp tranny and have it set at switch up ( away from you avcs mode set at 80+ and hh mode is -60(switch towards you) when I switch tranny on it is always in avcs mode switch away from me and light flashes three or four times and then goes on all the time that is the gyro set . Switch towards you then your in hh and light goes off. To check opperation sit helli on table and have it in avcs mode , move rudder stick and servo will centre it's self every time . Move the tail left and right the servo will counteract this movement. Flick sw to hh and the light goes off.If you move rudder stick the servo will not centre it self and if you move the tail of the heli the servo will keep moving in that direction un till it comes to its most farthest point off travel and if you move it in the other direction the servo will then move right over to the opposite side of its travel but it will not centre its self in hh mode unless you move the heli back to its origional position thus proving its in hh ,, Hope all this is correct and helps you , ,, had the same prob and ade sorted me out on here

Regards Jamie

[rombonie]

Hi,

I'll assume you have centred your sevro and the tail is setup i.e centred etc.

The 401 needs to start up in HH as simon has said and there is a few ways to set this all up but I would suggest you set it HH and leave it there.

So if your going to setup in HH and leave then I would set your TX up as follows:

[INPUT SELECT] both Aux2 and Gear set to INH
[GYRO SENS] set to AUTO , RATE 0: 72% and RATE 1: 72%
or
[GYRO SENS] set to AUTO, RATE 0: 28% and RATE 1: 72% then F.MODE all to 1(if you haven't set the travel limits yet then you will need to have one of the flight modes set to 0 to allow you to select it when the 401 has initialised thus allowing you to set the limits up using the pot on the gyro)

If you didn't know you should have No amount of trim or subtrim on the rudder and the tx limits on the rudder set to 100%

Hope that helps

Cheers Dor

[funeebski]

Thanks guys, the gyro initializes ok now and seems to fly ok. What I did though is reduced the travel on gyro and then had to reduce end points on the tx. I have a sub trim of 9 for rudder. So do I need to go back and reset it so that there is no sub trim and end points are 100?

[simon_h]

In heading hold mode the end points control the piro rate only.
Use the limit pot on the gyro to prevent binding of the control. I tend to try and set the physical linkage up so that I am using about 100% on the limit pot if possible. (It's all a balance between speed and actual movement) Then set the end points on the rudder to give you your preferred piro rate.
There are plenty of good articles around about setting the 401 up properly.
See this article on trextuning for example or this thread on rcgroups.

SH

[robgt]

So do I need to go back and reset it so that there is no sub trim and end points are 100?

Yes.
Set it up with no sub trim (ever) and 100 end points to begin with.
Cheers,
Rob

[rombonie]

This is worth a watch
http://video.helifreak.com/?subpath=...name=dx7v3.wmv

[funeebski]

Ok, have servo dead centre and arm is bang on 90 degrees. Adjusted the gyro travel and all is good. Now though, I have like a dead zone on the rudder control, I move the stick 3/4 of the way across and the last quarter nothing happens because the servo is at the end point set by the gyro. Do I bring the end points down on the TX so that when the servo is at full right the stick is at full right?

[rombonie]

You can if you wish, will make the tail less sensitive.

[funeebski]

cool, i'll do that then as I don't want it to sensitive as I'm just starting out. Just CCPM interaction and tracking and should all be set up perfectly then! Hopefully not too windy this weekend.

[applematt]

Or just move the servo linkage in one more hole... i tried expo settings on the tx and found the servo linkage was a better route for me!