RE: Airplane rudder gyro

RE: Airplane rudder gyro
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RE: Airplane rudder gyro - 8/18/2008 3:22:36 AM

Posts: 111
Joined: 5/30/2005
From: Castaic, CA, USA
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Why when i switch between off and Normal/Avcs, the rudder is not centered? Normal and Avcs is the same, but off is slightly off. They should be the same, right?

Thanks
Lucky

(in reply to Big_Bird)

RE: Airplane rudder gyro - 8/18/2008 3:33:03 AM

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From: Castaic, CA, USA
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By the way im using a 401 gyro.

(in reply to Big_Bird)

RE: Airplane rudder gyro - 8/18/2008 3:44:24 AM

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From: Arlington, TX, USA
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Lucky, I think we need a lot more details. Radio? 3 position switch? Control channel limits? Limit on 401? Delay on 401? etc.

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Ken
WACO Brotherhood #70

(in reply to lucky9910)

RE: Airplane rudder gyro - 8/18/2008 4:04:15 AM

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From: Castaic, CA, USA
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sorry, jr 9303 using 3 position switch. no delay, not sure on limit.. need to check

(in reply to Big_Bird)

RE: Airplane rudder gyro - 11/5/2008 8:22:42 PM

Posts: 38
Joined: 5/10/2007
From: sturgis, SD, USA
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Okay, first off:

You guys are killing me. I've been in Baghdad for the last six months. I'm now in Pattaya, Thailand and I'm supposed to be deflowering local girls and instead I've been glued to this damn screen for two hours devouring every word from the confines of this hotel room. I should be in an alcohol induced catatonic state right now. This is by far the best thread I've ever read in a forum.

My sanity and credit card thanks all of you cause I have some squirrelly airplanes in my hangar back home and I think this may be the fix I've been looking for. It gets quite breezy in S. Dakota and the place I often maiden planes can be a bit of handful due to the curbs and crown of the road.

Now for questions:

I have a couple heli's (CF Trexx 600 electric) and my gyros are the Logi Tech 6100's. I realize this isn't what you folks are using but in principle they all pretty much do the same thing right?

It's been said not to touch the rudder trims on the radio with the gyro activated. Why? My heli's don't go into cardiac arrest when I do this, why would the rudder? I just can't get my head around that.

Would I want to increase the gain instead?

Where I'm going with this is on very high powered planes (USRA Giant Scale Racers for instance) if the plane starts to yaw would I crank up the gain or use trims? These planes are quite a handful on takeoff due to the torque, P factor, and lack of control surface on the vertical stab.

Next, if using a digital servo (hi techs in my case) should I still program the servo's center and end points?

There's three planes I plan on using this for. My little 50" Sundowner with a Jett60, my 80" sundowner with a Moki210 and a 115" composite Kelly F-1 USRA legal pylon racer set up with a Zenoah 80cc running gas. The last one makes my butt crunch walnuts as its a $7,000 one of a kind airplane.

The Kelly has yet to fly under my guidance as I have not picked it up yet. (Bought it from a guy in Utah and have to go get it once I get home next week) but from what I've read all the USRA legal planes tend to go where they want to on take off. I can't help but think this is a great aid during landings as well. Especially in cross winds.

I just bought a JR12X and plan to use the JR1221 receiver to take advantage of the peripheral receivers due to the composite construction of the plane. The gyro shouldn't care about this right? (I plan to stuff the Futaba Gyro in it but may fiddle with the Logitech too since I have it already.)

Last, I can't thank you all again for this thread. I've asked this question a dozen times and it always resulted in the same answer, "learn to fly kid." (hate that!)

Thanks again.

C

< Message edited by nesikachad -- 11/5/2008 8:24:03 PM >

(in reply to lucky9910)

RE: Airplane rudder gyro - 11/5/2008 9:21:21 PM

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From: Arlington, TX, USA
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Hi C (isn't that a fruit drink)

Glad you made it out of Iraq OK and I'm sure you will be glad to get home. Thanks for your service to the country.

I can only speak from my experience with a Futaba GY-401 gyro in a 1/3 scale Bucker Jungmeister. It has 2 modes plus off. The first is AVCS or heading hold mode. I use it for takeoff when the wind is not down the runway. I initialize in heading hold and throttle up without touching the rudder. If the wind is a strong cross wind then I usually have to apply some aileron into the wind to keep the plane level. Once the plane has some altitude, say 10' or better I switch to the other mode which is Normal or rate mode. All of the rest of the flight is done in the rate mode.

As far as not touching the rudder trim I think that only applies to the AVCS mode. I make it a practice to never touch trim or rudder during takeoff. It is amazing how straight the takeoff can be with a 10 mph cross wind. If the wind is straight down the runway then I just leave the gyro in the rate mode. I can think of no reason why you shouldn't use the rudder trim in the rate mode. In the rate mode if the tail should get a gust of cross wind the gyro gives it a proportional bump in the opposite direction but does not return the plane to it's original path. Rate simply smooths the flying out.

Hope this helped.

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Ken
WACO Brotherhood #70

(in reply to nesikachad)

RE: Airplane rudder gyro - 11/6/2008 12:09:09 AM

BarracudaHockey

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From: Orange Park, FL, USA
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Simple. The gyro memorizes neutral rudder (0 yaw) at boot up. If you move the rudder the gyro takes that as a command to turn. The gyro doesn't know the difference between moving the stick a little or moving the trim a few clicks, either way it sets up a turn, usually a slow one that people think is gyro drift.

Move the trim and reboot the gyro and it memorizes that as 0 yaw and goes about its business, but there should be no reason to do that.

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(in reply to Big_Bird)

RE: Airplane rudder gyro - 11/6/2008 2:39:04 AM

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From: Livermore, CA, USA
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What Andy and Ken said is correct. I will only add that if you move the rudder in AVCS mode it effectively changes the zero or neutral point. So, after initialization, moving the rudder stick a little to the right and then allowing it to immediately return to neutral will not neutralize the rudder, like it normally does on an airplane. Instead, the rudder will now be deflected a little to the right and the gyro will now hold this heading. The problem with doing this during takeoff is that it will induce a yaw into the airplane and it will be difficult to see from the ground what is going on. Holding rudder will cause the rudder to move to its limit. Then releasing the stick will not cause the rudder to return to neutral. It will stay at the limit. The bottom line is to not touch the rudder while in AVCS mode after initialization. I strongly recommend experimenting with this on the ground until you are completely comfortable with the behavior. It is different than what we are used to.

Gyros are excellent (and fun) tools for airplanes, but there is a learning curve.

Good luck!

-Ed B.

(in reply to BarracudaHockey)

RE: Airplane rudder gyro - 11/20/2008 5:38:48 PM

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The Futaba GY401 is now on sale at Tower Hobbies for $129.99

http://www.towerhobbies.com/products/futaba/gyros_e.html

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Ken
WACO Brotherhood #70

(in reply to Flyfast1)

RE: Airplane rudder gyro - 11/22/2008 10:21:37 PM

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From: Zephyrhills, FL, USA
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Maybe someone already has asked this, but is the GY401 compatible with JR/Spektrum radios?

(in reply to Big_Bird)

RE: Airplane rudder gyro - 11/22/2008 10:37:25 PM

BarracudaHockey

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quote:

ORIGINAL: Eplane65

Maybe someone already has asked this, but is the GY401 compatible with JR/Spektrum radios?

Yes. It just takes a signal and acts on it, it has no idea what type of radio sent it.

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RE: Airplane rudder gyro - 11/22/2008 10:39:57 PM

BarracudaHockey

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126 with free shipping at http://www.ronlund.com (put it in the basket, the listing on the radio page is MAP pricing)

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(in reply to BarracudaHockey)

RE: Airplane rudder gyro - 11/22/2008 10:54:51 PM

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From: Arlington, TX, USA
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Andy, that's even a better buy. My GY401 sure has been reliable.

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Ken
WACO Brotherhood #70

(in reply to BarracudaHockey)

RE: Airplane rudder gyro - 11/23/2008 1:51:59 AM

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Joined: 3/2/2007
From: Rio de Janeiro, BRAZIL
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Guys,

The best buy is this one:

http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=7647

It works perfectly well and for a fraction of the Futaba cost.

Flavio

< Message edited by flaviosi -- 11/23/2008 1:52:24 AM >

(in reply to Big_Bird)

RE: Airplane rudder gyro - 11/23/2008 3:40:51 AM

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Joined: 11/11/2008
From: Los Angeles, CA, USA
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hey,guys
Anyone ever used MT-40A-SBEC ESC. I just bought some from Maytech. Them SERVICE sounds great. Any info about their products?

I may get their ESCs in 2 days....expecting....Wooow..

(in reply to jjmretired)

RE: Airplane rudder gyro - 11/23/2008 3:45:16 AM

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Joined: 11/11/2008
From: Los Angeles, CA, USA
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Guy GGJJFLY,

I used their Maytech ESCs, and using them now.
Terrific products....with higher performance, more reasonabe cost

As far i know, Maytech is always OEM ESCs and motors for other brands...
you pls share your test info with our guys here.
They won't fail you,anyway!!!!

(in reply to GGJJFLY)