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jackp1
04-02-2008, 10:01 AM
iv rebuilt my 500 after my first crash, & after putting it back together replacing blades boom & main shaft & servo, iv finally got to setting my spartan760 back up, well after doing the set up iv checked the software set up, and here is a pic of my gyro settings. now there a bit different to the last settings i had before the crash,& id like someone's opinion wether the new settings are ok :thumbup:

merlin703
04-02-2008, 10:21 AM
Hey man, this is great, I will save this for when I'm ready to move on to the Spartan gyro, thanks! :)

jackp1
04-02-2008, 10:47 AM
no problem there mate help yourself:thumbup:

MarkWebber
04-02-2008, 07:09 PM
Your endpoints are quite unequal. You might want to recenter your servo horn and rerun the setup. Without being obcessive, having the endpoint values closer is better.

JeromeF
04-02-2008, 07:15 PM
Your endpoints are quite unequal. You might want to recenter your servo horn and rerun the setup. Without being obcessive, having the endpoint values closer is better.

Is this not what you would expect if the servo is set up centre with no drift in rate mode? Asuming he has set it up to have no drift in rate mode?

Finless
04-02-2008, 07:29 PM
On this gyro you DO NOT set up rate mode. You don;t have to and it is not required per instructions.
All you need to do is set up for about 8 degrees of pitch when the servo is 90. But in doing so you will wind up with a difference between the end points left and right so I am a little confused about Mark's comment?

Bob

MarkWebber
04-02-2008, 07:29 PM
If your servo's centered and the tail blades are at about 8 degrees(normally what you get with the slider centered) you would see endpoints figures closer to each other based on servo ball position.

From the ds760 user guide:
[quote][
Ultimately, the most important factor is the servo travel which
ideally should be around 45 on either side of the mid-point (+/-15%).
For most servos this will result to gyro endpoints in the range 85-115%.
This combination gives a good balance between tail pitch correction
speed and available torque. If the servo travel or endpoints are
significantly different than this recommendation you may wish to change
the ball-link position to restore this balance.
/QUOTE]

Finless
04-02-2008, 07:31 PM
Mark, that depends on the heli and slider geometry... On a Trex you do wind up with quite a difference when you have about 8 degrees when the servo horn is 90.

Bob

jackp1
04-02-2008, 08:13 PM
i think its obvious that there is unequal end points, co's i set up using bob's videos,& like he sais above, with about 8 degree of pitch, the slider is always going to be off set or it should be unless its set up wrong thats my take on it:noteworthy

psindrup
04-03-2008, 02:45 AM
On the T-rex 500 at least, it seems as if there are two (conflicting) theories of setting up the tail - both found in Spartans manual.

1) The setup that Mark quotes, where you have the servo horn at 90 and the tail pitch slider centered - which does not seem possible on the 500 due to tail geometry

2) The setup, also found in the manual, that Bob quotes, where you setup the tail with 8 degrees of pitch with the servo at 90 degrees, but resulting in the tail slider not being centered, and giving quite different end points.

I am a little confused as to which of the two different setting recommendations "wins" the battle.

Best regards

Peter

wbplomp
04-03-2008, 03:32 AM
I have talked to Bert Kammerer about this by e-mail. He uses a Spartan ds760 on all his helis. At the Align Cup 2008 in Las Vegas, Nevada he placed 2nd in the 500 Masters class, so he should know.

He states that he does not center his tail slider. He uses a servo horn/arm that is in a perfectly 90 degree angle. He then sets his tail blades in a certain tail pitch. He flies in rate mode and adjusts his tail rod linkage mechanically until he has a heli that hovers in rate mode when the rudder is in neutral position and the servo horn in the 90 degree angle. He then goes back to his gyro configuration and re-modifies his gyro endpoints for the maximum tail pitch availabele. Switches back to Heading Hold and flies the baby.

But he also mentioned. The Spartan gyro is fast enough to do both methods, centering or not centering. But he says it all boils down to servo load. He things you have a better setup with the tail pitch mechanically adjusted so you have less servo load.

Hope this wil help.

Boudewijn

JeromeF
04-03-2008, 04:00 AM
On this gyro you DO NOT set up rate mode. You don;t have to and it is not required per instructions.
All you need to do is set up for about 8 degrees of pitch when the servo is 90. But in doing so you will wind up with a difference between the end points left and right so I am a little confused about Mark's comment?

Bob

I set up EVERY gyro I use in rate mode to have no drift. It's good to be able to use both modes, and not have to input loads of rudder when changing.

wbplomp
04-03-2008, 04:51 AM
I set up EVERY gyro I use in rate mode to have no drift. It's good to be able to use both modes, and not have to input loads of rudder when changing.

Well, that may be the case. But not every gyro is easy to use. For example, a GY401 has only one LIMIT, so you cannot set different gyro endpoints for each direction. The disadvantage of that tis that you cannot setup full throw on one side. Also with a GY401 when you do so (even when you program the rudder neutral positon) you will notice the piroette rate is very very different, because the GY401 does not support constant piroette rate. The Spartan ds760 does support different gyro endpoints though.

JeromeF
04-03-2008, 05:10 AM
Well, that may be the case. But not every gyro is easy to use. For example, a GY401 has only one LIMIT, so you cannot set different gyro endpoints for each direction. The disadvantage of that tis that you cannot setup full throw on one side. Also with a GY401 when you do so (even when you program the rudder neutral positon) you will notice the piroette rate is very very different, because the GY401 does not support constant piroette rate. The Spartan ds760 does support different gyro endpoints though.

Indeed... this amoungst a few other reason is why i'm selling all my other gyros and replacing them with the DS760.

Two 6100t, one GY401, one 2100t and one GY611 are going and being replaced with DS760s hehe :D

psindrup
04-03-2008, 05:17 AM
Indeed... this amoungst a few other reason is why i'm selling all my other gyros and replacing them with the DS760.

Two 6100t, one GY401, one 2100t and one GY611 are going and being replaced with DS760s hehe :D

Just as a teaser: The little (relative inexpensive) 2100T is able to set different end points, contrary to its bigger brother, the 401. :YeaBaby:

Peter

JeromeF
04-03-2008, 05:41 AM
Just as a teaser: The little (relative inexpensive) 2100T is able to set different end points, contrary to its bigger brother, the 401. :YeaBaby:

Peter

Hehe this is true, but again... amoungst other reasons it's going.

psindrup
04-03-2008, 06:02 AM
Hehe this is true, but again... amoungst other reasons it's going.

You will be spending as much on gyros as I have on heli's :)

Peter

jackp1
04-03-2008, 08:26 AM
well iv had plenty of help so cheers to you all thanks to wbplomp the explination you gave was how i set my gyro up.. what iv done is lower the endpoints to 100/100 on the radio so now my piro rate should be a bit slower, but i think the spartan is the most awesome gyro iv ever owned. i might even put on a futaba BLS351 servo and have a test, i think that combo would be great if i use 3000mah 6s lipo it should balance the tail anyway thanks:noteworthy

raylepper
04-03-2008, 09:00 PM
Mark, that depends on the heli and slider geometry... On a Trex you do wind up with quite a difference when you have about 8 degrees when the servo horn is 90.

Bob

Uh, now would be a good time for Angelos to chime in. We're in a T500 thread and the T500 tail geometry means that a centered pitch slider results in close to 0 pitch. I'd be grateful for the gyro's designer to weigh in with some 'in range' end point settings to go with a recommended set up. Yeah?

Chris7378
04-04-2008, 04:45 AM
He did already.
http://www.helifreak.com/showthread.php?t=47240&page=32

Chris

MarkWebber
04-04-2008, 05:40 AM
I ment to get back to this sooner but got distracted. I've been fortunate enough to get so schooling from The Man, himself.

The user guide does suggest setting up the linkage in rate mode. For the same reason that Bert does, as posted above. To optimize the tail performance. You don't necessarily need to fly it to see that it holds perfectly. Angelos has added a bit of creative programming to ensure that it does. I've never flown one without it working good off the bench.

Regarding endpoints readings, a reading of 100 indicates 45 degrees of servo travel in that direction. This is considered ideal. You're looking for close to a total of 200% travel. By having the endpoints with a lot of dissymetry, you are overdriving the servo on one side and underdriving it on the other. You are likely to see this result in stop characteristic differences(one direction vs the other).
In the case posted here(135/52), he is close to the 200% total but just needs to ensure the servo horn is centered and adjust the length of the tail pitch rod/servo position on the tail boom.

Happily, most of us will not likely see too much difference when actually flying the heli. Spartan has done such a good job with this gyro that it does very well at covering up setup mistakes. This is why I said one shouldn't obcess over the endpoints. I would just get them a little bit closer for best results.:thumbup:

wbplomp
04-04-2008, 07:01 AM
I fully agree. Ofcourse this all depends on the length of your servo arm/wheel/horn. I have had e-mail contacnt with Bert Kammerer about this. But I have not setup it up myself (yet). I have it perfectly centered at the moment, to get almost the same travel on each side and max 45 degree angle of the servo arm/wheen/horn on full rudder input.

On Bert his website you can download his configuration file from the Spartan ds760, specially for the T-Rex 500. When you have a close look at it he has gyro endpoints 129/91. So he has his tail pitch not centred. Mine, wich is currently centered has 120/115. I am not sure if he uses a longer servo arm/wheel/horn.

Some heli's like the HDX have a tail slider that give abou 8 degree of pitch when the slider is centered, unfortuannly the T-Rex 500 hasn't. I think it does improve performance a bit bceause of less servo load. The Spartan is fast enough to keep up either way.

Boudewijn

Bjorn
04-04-2008, 08:26 AM
If you offset the servohorn when the tailblades has 8 degrees pitch, then the endpoints are much more equal.
This is how the csm720 setup is done, and it works like a charm;)
This is what the istructions to the 720 say :

Appendix C Linkage fine-tuning
Servo arm offsetting
Some helicopter tail linkage geometries give somewhat asymmetric response to tail pushrod movement with much more rapid changes in pitch occurring
one way than the other. In these cases the servo throw to cover the full pitch range may be greater one way than the other. The SL720 has independent
travel adjustments for the two directions to accommodate these differences. In some machines more symmetrical handling characteristics may be obtained if
the servo arm is rotated around one or even two splines on the servo shaft so that it is no longer at right angles to the pushrod when the servo is centred. A
change in the pushrod length will be needed to restore the 8 degrees of pitch with the servo centred. With the servo arm offset in the correct direction the
servo throws will be more equal. Remember that the travel limits will need re-adjusting after this process to ensure the full tail pitch range is available.

Bjorn

wbplomp
04-04-2008, 08:37 AM
Sounds logical. Just for my understanding, bceause I am Dutch, what is the exact description offset?

leeph
04-04-2008, 08:38 AM
On Bert his website you can download his configuration file from the Spartan ds760, specially for the T-Rex 500. When you have a close look at it he has gyro endpoints 129/91. So he has his tail pitch not centred.

I downloaded this configuration file - the settings he uses are the stock settings that
the gyro has out of the box - no 'specially' about it !! You can't use his endpoints anyway, you should always arrive at your own endpoints based on your own adjustments of the tail linkages / servo horn etc.

Some heli's like the HDX have a tail slider that give abou 8 degree of pitch when the slider is centered, unfortuannly the T-Rex 500 hasn't. I think it does improve performance a bit bceause of less servo load. The Spartan is fast enough to keep up either way.

Are you sure there is 'less servo load'? Why would this be? Is it because the servo has to do less work to keep the spindle in a certain position while it is close to its center point?