DX7 & GY401 Setup Issues

DX7 & GY401 Setup Issues
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DX7 & GY401 Setup Issues - 5/11/2008 6:28:01 AM

Shadow99

Posts: 363
Joined: 8/23/2007
From: Southwick, MA, USA
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Alright Guys,
I'm having some issues setting-up my GY401 with the DX7 on my T-rex 500. I've tried setting the neutral position on the rudder servo (an S9257), I thought I was in RATE MODE (rudder D/R set to 1). But when I start-up in AVCS mode & switch to NORMAL MODE the LED on the gyro won't go out & I still do not get equal travel on the pitch slider (full LEFT & small amount of RIGHT).

The TX is set-up [GYRO SENS], RUDD D/R, RATE 0: 75% 1: 45% REV MIX: all zeros (unused), sub-trim 0 on RUDD, Travel Adjusts all 100%.

Did I miss something in the FUTABA 401 manual or is it the DX7 settings? Although I've been through the instruction page about 50 times today, my GY240 wasn't this difficult to set-up.

Thanks,
Shadow

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RE: DX7 & GY401 Setup Issues - 5/11/2008 7:59:29 AM

HeliSmith

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Joined: 1/25/2007
From: Canyon Country, CA, USA
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I don't use the gyro sense menu I use gear endpoints but I can close the deal for you very quickly if you want to follow my way. I am assuming you have your gain in your gear channel not AUX2.

1. Get into model select. (Hold Scroll down + Select when turning on radio.)
2. Scroll down to INPUT SELECT and set GEAR = GEAR not GEAR = GYRO. (Bye bye gyro sense menu)
3. Push Scroll down + Select to exit model select menu. Push Scroll Up + Select to get to Function List. Find Travel Adj. Scroll Down + Select will put you in it.
4. Push select until you get to GEAR. Set that top value to 50. Usually you will be around 45 - 60 let's start with 50.
5. Pull the gear switch down to be able to set the L value. Set this lower value to 0. (I don't use rate mode except to setup my gyro so I want no gain.)

So it will be GEAR H: 50 L: 0 or whatever it looks like in the radio.

Now to adjust HH mode gain your switch must be up. Always start the heli with the gear switch up then move it to rate mode to setup the tail otherwise it won't initialize properly. If you ever want to reset your gyro click the gear switch 3 times quickly (within 1 second of each click) ending with it in the up or HH mode position. Again never ever start your heli with that gear switch in rate mode.

Hope that helps.

< Message edited by HeliSmith -- 5/11/2008 8:02:47 AM >

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RE: DX7 & GY401 Setup Issues - 5/12/2008 1:28:16 PM

Skarn

Posts: 516
Joined: 1/1/2007
From: Pasadena, MD, USA
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I use the gyro sense menu and love it. You appear to have it setup properyly, but is your gyro signal wire plugged into the gear channel? That's the only thing I can think of why it's not working for you.

Skarn

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Post #: 3

RE: DX7 & GY401 Setup Issues - 5/12/2008 8:33:17 PM

BryFlyGuy67

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Joined: 8/27/2007
From: Grand Rapids, MI, USA
Status: offline

I do it like Helismith. Simple and quick. Works fine!

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RE: DX7 & GY401 Setup Issues - 5/13/2008 1:48:23 AM

BoysToys

Posts: 513
Joined: 3/17/2006
From: Bakersfield, CA, USA
Status: offline

quote:

ORIGINAL: Shadow99

I've tried setting the neutral position on the rudder servo (an S9257), I thought I was in RATE MODE (rudder D/R set to 1).

The rudder dual rate switch does not control the gyro sensativity. Your idle up switch will flip you from heading hold to rate mode.

quote:

ORIGINAL: Shadow99

The TX is set-up [GYRO SENS], RUDD D/R, RATE 0: 75% 1: 45% REV MIX: all zeros (unused), sub-trim 0 on RUDD, Travel Adjusts all 100%

From you setup it looks like you have normal mode setup for Heading Hold and idle up set for Rate. Power you heli on with the switch in normal or 0 position and wait for the light to turn solid red. Then switch to idle up, position 1, and your light should go out.

I hope this helps.

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RE: DX7 & GY401 Setup Issues - 5/13/2008 1:58:48 AM

Shadow99

Posts: 363
Joined: 8/23/2007
From: Southwick, MA, USA
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Thank you Helismith! Your simple procedure worked great, now I can see the change from rate to HH on the gyro.

The NEW issue is a terrible vibration in the rotorhead during spin-up. I've checked and re-checked the flybar balance and lengths from the flybar control arm to the paddle it's within .003" (each side), I balanced my (ready-to-go) 425mm blades and found the CG off about 1/8" and adjusted it. But the heli still tends to "dance-around" at 30% throttle so bad that I PANIC & hit throttle-hold, then palm the head button to stop the rotor! Blades are snug in the grips, but move easily if shaken.

I took the swashplate & rotorhead assembly off to check the runout of the main shaft, it's less than .0005" (I think that's pretty good for plastic bearing-retainer blocks). I also removed the flybar again, to check straightness on a surface plate, and it's fine.

Even though I measure the distance from the control arm to the flybar paddle, could the balance still be off? Is there a simple method to balance the flybar paddles on the rotorhead? Or could the vibration be caused be something else I'm missing?

Thanks Guys!

Rick

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RE: DX7 & GY401 Setup Issues - 5/13/2008 3:21:22 AM

BoysToys

Posts: 513
Joined: 3/17/2006
From: Bakersfield, CA, USA
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I doubt it is your flybar. I just measure my flybar and make sure the paddles are equidistant from the flybar cage.

Are you main blades perfectly straight before you start to spin up? My 500 sometimes vibrates pretty bad when spooling up for the first flight of the day. It then goes away once the main blades get themselves straightened out. If your blades are snug in the grips it can take some decent headspead to get them in the right position. This sounds like what is happening to you.

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RE: DX7 & GY401 Setup Issues - 5/13/2008 3:30:23 PM

ctg1129

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From: brunswick, GA, USA
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check out finless videos they are great ...dont use gyro sensing use end point adj like stated before

< Message edited by BarracudaHockey -- 5/14/2008 9:36:53 PM >

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RE: DX7 & GY401 Setup Issues - 5/14/2008 1:23:42 PM

Skarn

Posts: 516
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From: Pasadena, MD, USA
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quote:

ORIGINAL: ctg1129

check out finless video they are great ...dont use gyro sensing use end point adj like stated before

Why do you say this? I use gyro sense (just like Finless does in his vids) and it works great!

The Gyro Sense menu is very easy to setup and is designed for.....gyro's!

Either way is fine, but to tell people not to use it is just wrong

Skarn

< Message edited by BarracudaHockey -- 5/14/2008 9:36:28 PM >

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Post #: 9

RE: DX7 & GY401 Setup Issues - 5/14/2008 9:35:23 PM

BarracudaHockey

Posts: 10088
Joined: 7/13/2003
From: Orange Park, FL, USA
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quote:

ORIGINAL: ctg1129

check out finless video on helifreak they are great ...dont use gyro sensing use end point adj like stated before

Why do you say that?

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RE: DX7 & GY401 Setup Issues - 5/14/2008 9:39:33 PM

HeliSmith

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From: Canyon Country, CA, USA
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There's a huge debate on not using gyro sense for smaller aircraft. That it was originally intended for larger aircraft and especially for governor mode.

Since I have flown both and can see no difference I say setup for whatever is easiest for you. True I only gave gyro sense a month try before switching over to gear endpoints off the gear switch so I can't offer any support with gyro sense.
Vibrations are hard to track. Low head speed can cause it, something is bent, something is out of balance, something got loctite in it and is sticking, ball links too tight. Check everything...

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RE: DX7 & GY401 Setup Issues - 5/14/2008 10:04:53 PM

BarracudaHockey

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Gyro sense wasnt designed for small aircraft?

Hmmm...

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RE: DX7 & GY401 Setup Issues - 5/14/2008 11:09:00 PM

gnd2

Posts: 401
Joined: 5/23/2007
From: San Diego, CA, USA
Status: offline

quote:

ORIGINAL: BarracudaHockey

Gyro sense wasnt designed for small aircraft?

Hmmm...

Ya, that sounds odd, never heard that before.

But to me, using end points just seems much more straight forward than the gyro sense menu which only seems to convolute things. The only advantage of gyro sense that I can see is that you can assign gyro gain to the flight mode switch (so that flight mode and gyro gain change together with the flip of one switch), but if you don't want to do that I don't see the point.

I like using the aux switch to change gyro modes independent of the flight mode and with end point adjustments the percentages make more sense instead having to figure 0%-50% = 100% - 0% rate and 50% - 100% = 0% - 100% HH

But that's just me, my preferences are subject to change at any time without notice

< Message edited by gnd2 -- 5/14/2008 11:14:07 PM >

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Post #: 13

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