Need help adding a GY401 gyro to the Blade 400

[BKF]

I'm still learning my B400, but in the first few flights I see the tail moves around a bit. I'll mess with the gyro gain in the TX, but I'm considering just replacing it altogether with the GY401. It seems to be "the" Trex gyro, and I can't argue with all the glowing reviews it seems to get. Besides, when I move up to the Trex 500, I can move the gyro over (or get another one! hehe).

So, now I need some help. Can someone who's done a gyro swap explain what I'll need to do?

Obviously the gyro is double-sided taped to the frame. I need to unplug the tail servo from the gyro, and unplug the gyro from the rear connector where all the servos are connected.

Then I'd basically set that gyro aside as a spare, and double-sided tape the new GY401 in the same place, correct? Then I'd plug in the tail servo into the gyro, and then what? Looking at the wiring diagram of the 401, it looks like it has a 3-pin connector and a single pin connector. The stock G110 gyro used a 4 pin connector. So how does this work with the stock connector where the G110 was plugged in?

Also, the GY401 mentions it has remote gain (just like the G110) as well as a channel for turning AVCS on/off from remote. How would I go about connecting that?

Lastly, the GY401 comes alone or with a tail servo as a bundle. The tail servo it comes with uses the typical double-hole on either side of the servo, instead of the single hole on the B400 servos. I'm assuming this double hole servo won't fit in the stock mounting location on the tail servo mount? I have noticed some people have bought tail boom mounts for the servo and mounted one of these servos. I put on a Spektrum DSP75 digital servo to handle the 270Hz signal from the G110 gyro. Is that good enough, or am I really better off getting the matching servo that comes bundled with the GY401? I'm guessing if they bundle it, it must really make the gyro work well.

I'm kinda looking ahead, and don't mind spending a little extra now, especially if this expense will later move to a Trex 500. My LHS has the bundle for $210 with the gyro and servo and $140 with just the gyro. Very likely he sells the tail boom mounts as well, I hope.

I'd just like to get a few answers from the experienced folks here before I run over to the LHS today.

[carlo_the_wonder_frog]

A couple of things, DO NOT get the servo that comes bundled with the GY401, its a full size servo and will not in any way fit the blade 400. The GY401 main 3 wire servo lead plugs into the Rudder channel (channel 4). the single servo lead ( Its the remote gain single wire one) will normally plug into your Gear ( Ch5) channel. To make the gyro switch into and out of rate/HH mode you adjust the travel adjust on the gear channel to remotely set the gain, once its set you should have a Gear switch that will switch it between HH(AVCS) mode and Rate mode. Just remember that the GY401 MUST ALWAYS initialise in HH mode, if you plug the heli in and your transmitter has the gear switch set to rate mode the gyro will not work correctly. Must always power up in HH mode. the 401 gyro is very easy to setup compared to most other gyros, but it is daunting if you don't understand what its doing or how the programming affects it. Lots of help on the 401 in the t-rex section, I suggest a search, just about every conceivable question on that gyro has been asked and answered several times.

[BKF]

For a newbie pilot, is there any reason NOT to have both gyro settings (0 and 1) in the transmitter set for HH mode?

It would help immensely if the tail would hold steady while I'm learning. I just went through 3 batteries at the park a couple hours ago and no gain setting on the G110 (in the TX) I tried seem to help the tail stop wagging. It would wag a little and sometimes a lot up high (20-30 feet or so in the air), and have a non-stop wag down low. It was a little windy, as well, which I assumed was my main problem.

Each time I'd land, change the settings in the transmitter for postion 0 and 1 and try again. However, I did not pull power to the heli between each change. Am I supposed to, or can the gyro handle real-time gain changes through the TX and flipping between 0 and 1?

I tried between 55% and 75% and didn't notice much difference in the wagging.

I assumed this was going to happen after my first outing, which is what led me to believe I'd be better off with the GY401, since many people say it holds rock steady in the wind.


A couple of things, DO NOT get the servo that comes bundled with the GY401, its a full size servo and will not in any way fit the blade 400. The GY401 main 3 wire servo lead plugs into the Rudder channel (channel 4). the single servo lead ( Its the remote gain single wire one) will normally plug into your Gear ( Ch5) channel. To make the gyro switch into and out of rate/HH mode you adjust the travel adjust on the gear channel to remotely set the gain, once its set you should have a Gear switch that will switch it between HH(AVCS) mode and Rate mode. Just remember that the GY401 MUST ALWAYS initialise in HH mode, if you plug the heli in and your transmitter has the gear switch set to rate mode the gyro will not work correctly. Must always power up in HH mode. the 401 gyro is very easy to setup compared to most other gyros, but it is daunting if you don't understand what its doing or how the programming affects it. Lots of help on the 401 in the t-rex section, I suggest a search, just about every conceivable question on that gyro has been asked and answered several times.

[LockMD]

I tried between 55% and 75% and didn't notice much difference in the wagging.



I'm having the same wag as you describe and did the same with lowering/rasing the gain with little luck.

I tried to recreate the problem on the ground with throtle hold on and noticed the tail servo did not twitch, but it doesn't always return to center either. So, I'm thinking the servo needs replaced.

Question is, which one? I want something that will last but also will fit with no or little mods. Anyone have suggestions?

[thirdkid]

Dont replace the servo. The Gyro is expecting the heli to move and when its on the bench and the heli is not moving the servo wont center. Been thru it already. I put a JR ds285 on mine and it seems to work fine but Im a newb as well so I cant say its the best.

[LockMD]

Dont replace the servo. The Gyro is expecting the heli to move and when its on the bench and the heli is not moving the servo wont center. Been thru it already. I put a JR ds285 on mine and it seems to work fine but Im a newb as well so I cant say its the best.


You say not to replace the servo, but you did? how does the JR ds285 fit and it was it easy enough to replace?

or you did, learn from your mistakes? so what do I do? mess with the settings more?

[BKF]

He's probably in the same boat I am. I swapped out the servo in mine, too. Did it help? I don't really have enough experience to say yes or no... All I'm doing is hovering and some forward and reverse flight.

I found the gyro cable plugged into the receiver was rubbing with quite a bit of force (that ribbon cable is stiff!). I think that's what was causing my gyro to "hunt", since it was being slowed down by the force of the cable.

I noticed it when I hooked a battery up and tried yawing it in place while holding the skids. The servo arm was moving back and forth rather slow. That's when I noticed the ribbon cable touching it, and had to push and redirect it out of the way. Now the servo arm twitches back and forth pretty rapidly as I yaw left and right. I can't wait to go test it again and see that was the problem.

Darn work! Only 4 more hours to go so I can test it...

You say not to replace the servo, but you did? how does the JR ds285 fit and it was it easy enough to replace?

or you did, learn from your mistakes? so what do I do? mess with the settings more?

[fogger]

Just replacing the gyro and not replacing the crappy servo will get you nowhere. The real achilles heel is the servo. We put a 9650 on my buddies 400 and it is a lot better even with the stock gyro. Get a good digital servo that is reasonably fast and has good torque first.

http://helifreak.com/showthread.php?t=56113

-Fog

[BKF]

Hovered a bit after work to check things, since removing the gyro wire obstructing the tail servo's movement. At 66.5% gain the tail wagged back and forth very slightly, never yawing much to either side. At 64% gain, it wouldn't hold the tail. It yawed pretty good to the right on an increase of throttle and stayed pointing about 45 degrees off course. I had to apply opposite rudder to bring it back in line.

When people claim the GY401 holds the tail "rock solid", does it really mean it stays totally still? I'd figure there has to be some drift in order for the gyro (http://www.rcuniverse.com/buynow/keywordclick.cfm?bid_id=5302) to see it and compensate, right? Or is a better gyro so fast that the observer doesn't see it?

[carlo_the_wonder_frog]

When we say it holds rock solid we mean the wind could be blowing 30 MPH from the side and the helis tail does not drift or move one bit until you command it to. it stays in one exact place never deviating. You need a good Gyro and fast digital servo to do this. You are right, it fixes any drifting so quickly that you cannot see it.

[captonzoom]

I recently bought the E-flite Blade 400. I bought the Futaba GY401 gyro because that is what i had on my Raptor 30 and I loved it. I set up the 401 on the blade 400 and for some reason, i loose complete rudder response when i get about 1/4 stick. the gyro blinks as if it is receiving the command, but no response.

Can someone guide me in the right direction please??

-Randy