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Csm 540 Gyro problems? HH off/on get diff results.

never2busy4heli

Heliman

Fenton, Missouri-U.S.A.

First time flying after a rebuild, and I had some issues with my rudder. When I have the gyro HH turned off, and I set the trim to keep the nose straight, the nose goes the opposite way of what the trim fixed once I turn the HH on. I did have to trim it like crazy using the digital trim with HH off, so I realize I will have to set the pitch of the tail blades, but could that be the cause of the problem above? Thanks 2NB4H.

FYI: Raptor 50v2, Jr XP8103Dt, CSM 540.

You can pick your nose, and you can pick your friends, but you can't wipe your friends on the couch.

07-09-2004 Over year old.
staraero1

Key Veteran

Atlantic City, New Jersey

Take all the trim, sub trims, servo centering, and any revo mixing out of the rudder channel in the transmitter first. Be certain all trims, sub trims, revo mixing or servo centering are 0 by number in the transmitter, in every flight mode of the rudder channel. Check to see you have an 18 to 19 MM servo arm length on the rudder.

Now run the 540's auto setup routine again. As you do this during the first two steps, when the servo parks at gyro center between the steps, be certain with tail pushrod length you have about hover pitch in the tail blades. This ends up being 6 to 8 degrees in most cases.

After the auto setup is done including the last two steps which are the end point adjustments, do all four steps of the auto setup again just for good measure. First step is gyro sense, second step is super servo on or off and the last two steps are the rudder moving slow to set the rudder tail end points in the gyro.

Now go out and hover in rate mode with the gains set to about 75 to start, straight line gain radio system, and trim the tail with hover tests using the ball link on the rudder servo. No trims are ever used. Once you have it holding very good in rate mode, after triming the rudder with the ball link during hover tests, switch to heading hold mode and it should be locked dead on. If not, flip the gain switch back and fourth while hovering. Do this 5 times each way without touching the rudder stick while hovering, and the gyro will find center on it's own.

Did you happen to change the mounting tape at the time of rebuild? If you have it mounted correctly it should work fine now with this setup, if you follow it as I have described here. As long as the gyro was not damaged in the last crash. This can happen but is unlikely. The CSM gyros they are packaged well. They are hard to break in a crash usually.

Let us know how you make out. I assume you are familer with the CSM auto setup routine for their gyro systems.

Staraero1

07-10-2004 Over year old.
B.Hofferth

Senior Heliman

walkerton in.

560 csm

center all trims for rudder. do not use trim settings to hold tail. get engine stable in non heading lock and use mechanical adj. to stop drifting. then when all is well, set gyro gain settings for heading hold and conventional to the same value, then hover helicopter as steady as possible(preferably in calm conditions), then toggle gyro switch 5 times holding for one second in each position(total of ten movements), this will allow the gyro to fine tune the trim. repeat as necessary if the mechanical system is fairly symmetrical this method should help performance.

07-10-2004 Over year old.
B.Hofferth

Senior Heliman

walkerton in.

560 csm

what stataero1 said, he was typing faster than me!

07-10-2004 Over year old.
never2busy4heli

Heliman

Fenton, Missouri-U.S.A.

Still kind of new to this high tech gyro stuff. I started flying in 1990, but haven't flown for the past 7 or 8 years, so Heading Hold is a whole new ball game to me. Hell, I never even had a peizo.

I guess my big misstake was overlooking the fact that the helicopter was rebuilt, thus assuming the gyro settings would be okay. After all, that's how it used to be with the old gyros(plug it in and go). Thanks for the information guys. N2B4H

You can pick your nose, and you can pick your friends, but you can't wipe your friends on the couch.

07-10-2004 Over year old.
staraero1

Key Veteran

Atlantic City, New Jersey

Run the 540's auto setup routine again. Set the radio system in the rudder channel up from the start, as I described. Then run the auto setup and trim the tail for a no drift condition in a hover, using rate mode only for the triming procedure. You can tell rate mode from heading hold mode very easy, if you are not familer with heading hold gyro systems.

In rate mode the tail goes back to center when you release the rudder stick, every time. In heading hold mode the tail tends to stay to one side when the rudder stick is released. This is normal heading hold gyro behavior, when checking a heading hold gyro system out on the bench.

The CSM auto setup routine is a very important step to setting up any CSM gyro system. Many people who tried CSM gyro systems had trouble with them. This happened mostly because they did not clearly understand the auto setup routine. After you set all the rudder trims and subtrims to 0, in the rudder channel in every flight mode, run the auto setup. Then when you trim the rudder with the correct rudder triming procedure in a hover, you should get great tail rotor performance out of the CSM 540. It is a very good heading hold gyro system when setup correctly.

Again let us know how it goes.


Staraero1

07-10-2004 Over year old.
never2busy4heli

Heliman

Fenton, Missouri-U.S.A.

Actually I have already flown with the csm 540 this year, but crashed the first day out. It was set up like the manual and worked beautifully. I totally forgot about not touching the sub trim though. What about the digital trim buttons in normal mode though. Never mind, I will just read the directions again. Now I'm being lazy, but hey I have an excuse...I broke my ankle on May 18th, and I am still getting around on crutches. The worst part is that my townhouse has two flights of stairs, and the computer and work shop are on two different floors. Boo hoo right? JK ...Thanks again.

You can pick your nose, and you can pick your friends, but you can't wipe your friends on the couch.

07-10-2004 Over year old.
Galifrey

rrProfessor

Bristol

the thing to remember with CSM gyros (and some others) is a rudder trim is the same as a stick movement, the gyro interprets that as a command to yaw...

I actually disable the trim on my 9z for the rudder channel now, so as not to accidentally knock on some trim

Don't Email me as I wont reply - PM Only (spam countermeasures)

07-10-2004 Over year old.
never2busy4heli

Heliman

Fenton, Missouri-U.S.A.

Can the trim be disabled on the 8103? Sub trim or the button?

You can pick your nose, and you can pick your friends, but you can't wipe your friends on the couch.

07-10-2004 Over year old.
staraero1

Key Veteran

Atlantic City, New Jersey

No I don't think so. I have heard some people who fly helicopters only have disconected the wires from transmitters rudder trim button, once they have it all set to 0 in each flight mode. They are doing this on transmitters which use a digital rudder trim.

However, I don't advise you do this. I have no idea what effect this would have on the digital rudder trim system, in this particular transmitter.

Just be certain you have them all set to 0 by number in the trim, sub trim, revo mixing. Or 0 or IHB. any rudder offsets that system may have, before running the auto setup of the 540. The rudder channel ATV's or end points, should be at 100 and 100 each way before running the auto setup.

Then when you go to start your hover tests in rate mode to adjust the ball link for least amount of drift, set the rudder end points to 70 and 70. This will slow the rudder stick response down and make it smooth for the hover ball link adjustments.

Staraero1

07-10-2004 Over year old.
Galifrey

rrProfessor

Bristol

yeah, make sure they are zero'd in all flight modes as bob says...

can be mighty frustrating when u have drift in only one mode..

Don't Email me as I wont reply - PM Only (spam countermeasures)

07-10-2004 Over year old.
never2busy4heli

Heliman

Fenton, Missouri-U.S.A.

Ok, I think have it all setup properly. Thanks guys.
Actually one more question though: When I mechanically adjust the tail linkage length in normal mode, won't I be messing up the gyros internal travel limits that I just setup in auto setup mode? I would think that it would bind in one direction. Does flipping the switch 5 times in HH mode fix that?

You can pick your nose, and you can pick your friends, but you can't wipe your friends on the couch.

07-11-2004 Over year old.
I3DM

rrProfessor

Israel

i'd say you need to run the auto setup again after you find the mechanical center, but so far i found a rather good mechanical center almost all the time, its not very hard to estimate it on the ground.

hey staraero1, i got a 540 on my Evo which i just started flying, does it also have the "5 flicks" memory function like the 560 ? i got it without the manual, and i wasnt sure. it does work pretty damn good though !
thanks.

www.liorzahavi.com

07-11-2004 Over year old.
HOMEPAGE  
never2busy4heli

Heliman

Fenton, Missouri-U.S.A.

Here is the link to download the manual. http://www.rcmodels.org/csm/ I don't have my manual in hand, but I really don't remember anything about the 5 flicks. News to me if it is the case, but according to their posts, a couple guys seem to think so.

You can pick your nose, and you can pick your friends, but you can't wipe your friends on the couch.

07-11-2004 Over year old.
I3DM

rrProfessor

Israel

I just asked because i thought they might be confusing the 540 with the 560...

www.liorzahavi.com

07-11-2004 Over year old.
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Csm 540 Gyro problems? HH off/on get diff results.

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