RC Jets Discuss RC jets in this forum plus rc turbines and ducted fan power systems

Where do I put my gyro?

Reply
Old 07-11-2012, 12:58 AM
  #26
HarryC
 
Join Date: Feb 2002
Location: private, UNITED KINGDOM
Posts: 3,507
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Where do I put my gyro?


Quote:
ORIGINAL: megafly

Yes Erbroens, you are right, sorry if I didn't explained correct.
But what HarryC told is true, ''fly first'', but I think I'm goind to put the gyro in the aileron, the L-39 has a short wing.
Don't worry about that, in comparison with most scale models the L-39 has a long wing. Anyway, wingspan isn't really the issue, for example my Avonds F-104 has a very very short wing and is fine without a gyro.

There are two main reasons for using a gyro in flight. The first is to stop fishtailing or Dutch rolling, and the second is to smooth out the flight when in turbulence.
Dutch rolling is yawing and rolling but the rolling is a consequence of the yawing, so if you put a gyro on the rudder it can stop both fishtailing and Dutch rolling. If the model has neither, then there is no need for a gyro on rudder. Madmodelman says his L-39 does, but it may vary from brand to brand. You can't predict it in advance so you just have to fly it and see what happens. Any model has the potential to fishtail, but Dutch rolling requires a yaw to roll coupling that is usually only present with lots of dihedral or wing sweep, which the L-39 doesn't have.
Turbulence can upset a model in yaw as much as bank but the bank seems much more noticeable to us, especially when close to the ground on take off and landing. A gyro on aileron feels more useful to us when dealing with turbulence. Even on fairly calm days it does give the model a more steady feel.
HarryC is offline  
Reply With Quote
Old 07-11-2012, 03:34 AM
  #27
snir2001
 
snir2001's Avatar
 
Join Date: May 2004
Location: Eilat, , ISRAEL
Posts: 185
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Where do I put my gyro?

I just checked it last sunday ot T-45.
No differences in the front nor the CG...
snir2001 is offline  
Reply With Quote
Old 07-11-2012, 04:56 AM
  #28
mjunior
 
Join Date: Nov 2004
Location: Sao Jose dos CamposSP, BRAZIL
Posts: 265
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Where do I put my gyro?


Quote:
ORIGINAL: megafly

Yes Erbroens, you are right, sorry if I didn't explained correct.
But what HarryC told is true, ''fly first'', but I think I'm goind to put the gyro in the aileron, the L-39 has a short wing.
Megafly,
Usually in full scale aircraft the first 'surface control' subjected to gain control is the rudder/yaw. The second would be the elevators e maybe roll would be the last.
Do it right, fly it first and observe.

Mucio
mjunior is offline  
Reply With Quote
Old 07-11-2012, 05:48 AM
  #29
flyinfool1
 
flyinfool1's Avatar
 
Join Date: Jan 2002
Location: Cudahy, WI
Posts: 752
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Where do I put my gyro?

Even on a heli it really does not matter the location of the gyro. To prove this point I once relocated my gyro to the very tail of the heli and the ONLY thing that was changed was adding long servo leads to make it reach. Without changing any gyro or TX setting the heli flew exactly as before.

Having the gyro close to the center of mass (Center of Gravity) does reduce the amplitude of other forces like vibration or G forces. This does NOT affect the operation of the gyro, but it will help the electronics survive longer by the reduction of G forces contained within the vibration and the center of mass is usually a more protected location in a crash to help prevent physical crash damage.
flyinfool1 is offline  
Reply With Quote
Old 07-11-2012, 06:12 AM
  #30
megafly
Thread Starter
 
Join Date: Jun 2007
Location: Sao PauloSao Paulo, BRAZIL
Posts: 309
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Where do I put my gyro?

Thanks for the great help guys, I think I'm going to fly it first an then decide if I'm going to install the gyro or not.

megafly is offline  
Reply With Quote
Old 07-11-2012, 06:16 AM
  #31
HarryC
 
Join Date: Feb 2002
Location: private, UNITED KINGDOM
Posts: 3,507
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Where do I put my gyro?

megafly, a few weeks ago I put a document on my website describing ways to set up a gyro, might give you some hints if this is your first time. Ignore the first two documents as they are specifically for the Weatronic brand, go for the third document.
www.modelpilot.weebly.com
HarryC is offline  
Reply With Quote
Old 07-11-2012, 06:26 AM
  #32
megafly
Thread Starter
 
Join Date: Jun 2007
Location: Sao PauloSao Paulo, BRAZIL
Posts: 309
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Where do I put my gyro?

Thanks HarryC, I will have a look!
megafly is offline  
Reply With Quote
Old 07-11-2012, 01:36 PM
  #33
bigstick60
 
Join Date: Jul 2003
Location: narvon, PA
Posts: 53
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Where do I put my gyro?

just answer the mans initial post, no need for who's wrong or who's right tantrum
bigstick60 is offline  
Reply With Quote
Old 07-11-2012, 04:24 PM
  #34
rcand
 
Join Date: Jul 2002
Location: coral springs, FL
Posts: 434
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Where do I put my gyro?


Quote:
ORIGINAL: HarryC

Quote:
ORIGINAL: FenderBean

you always want the gyro as close to the center axis of rotation. Down the middle and around CG. Just like in a heli you want it as close to the mast as possible.
Not true. It is totally irrelevant where you put it in the model. You can put the gyro out at a wing tip if you want. All parts of the model rotate at the same angular rate. If they don't, the model is coming apart!

No, that is not true and having installed and flown and troubled shot many gyro installations, it IS BEST to place it on the axis for that function
rcand is offline  
Reply With Quote
Old 07-11-2012, 04:28 PM
  #35
rcand
 
Join Date: Jul 2002
Location: coral springs, FL
Posts: 434
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Where do I put my gyro?


Quote:
ORIGINAL: megafly

Do you think is better in the roll axis or the yaw axis?


Thanks.
depends on the plane and what you are trying to correct. I had a super hornet and have an airworld cougar and those planes were/are very stable when placed on the ailerons. I have it programmed on the gear switch so I have more sensitivity when the gear is down and less sensitivity when flying, plus I can adjust inflight if needed or turn it off.
rcand is offline  
Reply With Quote
Old 07-11-2012, 07:25 PM
  #36
JackD
 
JackD's Avatar
 
Join Date: Feb 2002
Location: Berkeley, CA
Posts: 699
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Where do I put my gyro?


Quote:
ORIGINAL: rcand


Quote:
ORIGINAL: HarryC

Quote:
ORIGINAL: FenderBean

you always want the gyro as close to the center axis of rotation. Down the middle and around CG. Just like in a heli you want it as close to the mast as possible.
Not true. It is totally irrelevant where you put it in the model. You can put the gyro out at a wing tip if you want. All parts of the model rotate at the same angular rate. If they don't, the model is coming apart!

No, that is not true and having installed and flown and troubled shot many gyro installations, it IS BEST to place it on the axis for that function
rcand,

can you explain why the sensitivity will change with the distance from the axis? several of us have explained why it doesnt, on this and other threads, so it would be interesting to hear a scientific rebuttal.

later
Jack
JackD is offline  
Reply With Quote
Old 07-12-2012, 04:51 AM
  #37
rctech2k7
 
rctech2k7's Avatar
 
Join Date: May 2009
Location: Miami, FL
Posts: 377
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Where do I put my gyro?

I’m not sure if I can help to explain a little bit more. Consider the horizontal line where we used to calculate for CG and aerodynamic center of our aircraft. We can use any point along the line as a reference for pitch rotation to calculate and come up the same moment even if the point is outside the aircraft...
rctech2k7 is offline  
Reply With Quote
Old 07-12-2012, 05:08 AM
  #38
Craig B.
 
Join Date: Dec 2002
Location: PERTH, AUSTRALIA
Posts: 1,240
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Where do I put my gyro?

Harry, David and Jack are 100% correct with their comments. Simple physics/geometry at work.

Craig B. is online now  
Reply With Quote
Old 07-12-2012, 05:13 AM
  #39
BarracudaHockey
Community Moderators
 
BarracudaHockey's Avatar
 
Join Date: Jul 2003
Location: Jacksonville, FL
Posts: 21,471
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Where do I put my gyro?


Quote:
ORIGINAL: rcand


Quote:
ORIGINAL: HarryC

Quote:
ORIGINAL: FenderBean

you always want the gyro as close to the center axis of rotation. Down the middle and around CG. Just like in a heli you want it as close to the mast as possible.
Not true. It is totally irrelevant where you put it in the model. You can put the gyro out at a wing tip if you want. All parts of the model rotate at the same angular rate. If they don't, the model is coming apart!
No, that is not true and having installed and flown and troubled shot many gyro installations, it IS BEST to place it on the axis for that function
As I told FB on another forum, what you have to wrap your head around is the fact that the gyro is the center of its rotation.


BarracudaHockey is offline  
Reply With Quote
Old 07-12-2012, 05:20 AM
  #40
HarryC
 
Join Date: Feb 2002
Location: private, UNITED KINGDOM
Posts: 3,507
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Where do I put my gyro?

I'm just dying to hear from FB what carbon fibre does to a gyro and why putting a piece of metal between the gyro and c/f solves the problem!!!
HarryC is offline  
Reply With Quote
Old 07-12-2012, 05:58 AM
  #41
BarracudaHockey
Community Moderators
 
BarracudaHockey's Avatar
 
Join Date: Jul 2003
Location: Jacksonville, FL
Posts: 21,471
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Where do I put my gyro?

Yea, we debunked that little myth over on the heli forum for him
BarracudaHockey is offline  
Reply With Quote
Old 07-12-2012, 01:37 PM
  #42
FenderBean
 
FenderBean's Avatar
 
Join Date: Feb 2006
Location: Clarksville , TN
Posts: 5,725
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Where do I put my gyro?

I posted on the helicopter forum, as per the instructions the metal plate is for interference that mechanics can cause.
Quote:
ORIGINAL: HarryC

I'm just dying to hear from FB what carbon fibre does to a gyro and why putting a piece of metal between the gyro and c/f solves the problem!!!
FenderBean is online now  
Reply With Quote
Old 07-12-2012, 01:52 PM
  #43
rctech2k7
 
rctech2k7's Avatar
 
Join Date: May 2009
Location: Miami, FL
Posts: 377
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Where do I put my gyro?

"the gyro is the center of its rotation" shortest very well explanation...

With regards to carbon fiber and metal plate, FenderBean has a point due to electrical properties of the materials... In order for a conductive plate to work as a shield from electrical interference it must be grounded. Due to the size of the plate compare to the size of micro electronics it becomes the target of interference. But since it's not properly grounded it may work in two ways, either to dissipate that energy or becomes a device use to catch that energy and bounce it to nearby device which maybe harmful to very sensitive signal on the ckt. Shielding is very helpful if installed properly to protect a certain device but in most cases we don't need it. If the equipment is noise sensitive then the manufacturer will provide its own shielding for their equipment. There's nothing wrong if we provide one for our gyro a long as it's common grounded with gyro and may not interfere radio signal path.
rctech2k7 is offline  
Reply With Quote
Old 07-12-2012, 02:05 PM
  #44
BarracudaHockey
Community Moderators
 
BarracudaHockey's Avatar
 
Join Date: Jul 2003
Location: Jacksonville, FL
Posts: 21,471
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Where do I put my gyro?


Quote:
ORIGINAL: rctech2k7

''the gyro is the center of its rotation'' shortest very well explanation...
hehe thanks! I worked on a few bits and baubles in the Navy that used these gyro thingys
BarracudaHockey is offline  
Reply With Quote
Old 07-12-2012, 02:21 PM
  #45
rctech2k7
 
rctech2k7's Avatar
 
Join Date: May 2009
Location: Miami, FL
Posts: 377
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Where do I put my gyro?

Another good reason for installing a gyro on a particular axis is to make it unstable, for example: pitch. Move CG aft slightly so that the aircraft can become more maneuverable, lesser stab load, shorter takeoff, etc. then install gyro to regain stability.
rctech2k7 is offline  
Reply With Quote
Old 07-12-2012, 02:31 PM
  #46
rctech2k7
 
rctech2k7's Avatar
 
Join Date: May 2009
Location: Miami, FL
Posts: 377
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Where do I put my gyro?


Quote:
ORIGINAL: BarracudaHockey


Quote:
ORIGINAL: rctech2k7

''the gyro is the center of its rotation'' shortest very well explanation...
hehe thanks! I worked on a few bits and baubles in the Navy that used these gyro thingys
It's helpful cause I'm trying to figure out the simplest way to explain it, hopefully it's clear now. That's good advantage for our jets...
rctech2k7 is offline  
Reply With Quote
Old 07-12-2012, 03:16 PM
  #47
rctech2k7
 
rctech2k7's Avatar
 
Join Date: May 2009
Location: Miami, FL
Posts: 377
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Where do I put my gyro?

I forgot, when moving CG back: Because of its nature, high wing loading and the ability of the gyro to compensate, airspeed must not fall below its safe limit. For that reason I believe the recovery from stall would be harder also...
rctech2k7 is offline  
Reply With Quote
Old 07-13-2012, 01:12 AM
  #48
HarryC
 
Join Date: Feb 2002
Location: private, UNITED KINGDOM
Posts: 3,507
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Where do I put my gyro?

Quote:
ORIGINAL: FenderBean

I posted on the helicopter forum, as per the instructions the metal plate is for interference that mechanics can cause.

Quote:
ORIGINAL: rctech2k7
With regards to carbon fiber and metal plate, FenderBean has a point due to electrical properties of the materials...
By googling, I found the heli forum referred to and FB's admission, in effect, that he simply imagined the c/f problem, quote from that forum -
"we highly recommend using two 2mm Mounting Pads and the steel Damping/Shield Plate to help prevent electromagnetic interference from reaching the gyro"
this was taken direct from a futaba manual on my gyro, its talking about the metal plate sent with your gyros. This is why I said it should be kept off the carbon.

http://rc.runryder.com/helicopter/t702871p1/

Others on that forum debunk FB's invention about c/f. So rctech2k7 is trying to invent an explanation to give credibility to FB's self-invented and already debunked myth!

Please stop inventing myths. The OP and others have their first gyros and need proper information about how to use them. The last thing they need is to be misled with myths. Gyros have no problem being near c/f plate. Gyros work perfectly well and exactly the same even if you put them on a very long pole a mile outside the model.
HarryC is offline  
Reply With Quote
Old 07-13-2012, 04:56 PM
  #49
rctech2k7
 
rctech2k7's Avatar
 
Join Date: May 2009
Location: Miami, FL
Posts: 377
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Where do I put my gyro?

I just gave that point to FB as my opinion about his understanding due to the way I see his application of the plate. I also gave balance information with regards to the reality of the plate except for their differences and it's not my invention, I learned that decades ago from electromagnetics...
rctech2k7 is offline  
Reply With Quote
Old 07-13-2012, 07:10 PM
  #50
rctech2k7
 
rctech2k7's Avatar
 
Join Date: May 2009
Location: Miami, FL
Posts: 377
Gallery
My Gallery
Models
My Models
Ratings
My Feedback
Default RE: Where do I put my gyro?

My mistake, I didn't read that he wants to keep gyro away from carbon fiber unless to use a metal bracket under it. As I was understood from the latest comment it pertains to use conductive plate similar to metallic plate or carbon fiber. Now I have to explain, anyway I posted a fair statement about the conductive plate that it can protect, not help or cause interference depending on the situation. For example if we have existing conductive part of our airframe, this means that it has nothing to do with radio signal. If the area is big then there's nothing wrong if we install gyro or any new electronics close to the area, except with antenna or radio Rx unless tested of free radio interference. Size and distance of the plate determines the resonance frequency that the interfernce may cause. Larger the area metal plate, including carbon fiber most likely to dissipate signal and interference energy. On metallic materials may dissipate or bounch when energy are absorb caused by charges, dicharges or induce voltage... My apologize HarryC and thanks for comment!
rctech2k7 is offline  
Reply With Quote
Reply


Thread Tools
Search this Thread
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -8. The time now is 11:06 PM.