Can anyone confirm if the Avionic D590 high speed 24g Servo sold at RcBazaar is Digital or Analog
http://www.rcbazaar.com/products/802-avionic-av590-hi-speed-24g-servo.aspx

Regards

it a analog one... (however the manufacturer states its digital but i have tested this myself and its a hi speed analog servo... almost burnt this servo when i had placed the gyro on digital mode)

Absolutely, I had my doubts too which is why I asked.
But it's a nice servo.

Thanks for sharing.

Hi Sujju
I managed a second crash on my 450 ccpm. Nothing major. Just damaged blades that need replacement. But I noticed that my gyro AV401 is not responding to the heli's left right movements. The gyro has a light buzz (which has always been there) and the rudder controls work fine but the gyro has stopped doing it job. I am using a Futaba TX and my gyro setting is at +75. Any suggestions?

thanks pradeep,
i guess you are a better flyer then what i was when i started (I used to crash on every flight if not even during spool ups )...
regarding the gyro a not sure what the issueis...
- is the gyro working (meaning is the gyro holding the servo or not?)
- can you program the gyro on rate mode and see if the tail is responding to forced movements on the tail
- frankly a gyro should not have any buzz... if there has been then there is a issue with this piece (if you can get this gyro to hold the heli pls send this gyro back and we will replace it with a new one)... you can call the store anytime and they will do the needful
- HH at +75 is good enough but cant state this is "THE" right number... my way i trim my helis are...hover with a high HH value and reduce it till point by point till the wag goes out..

also my personal way of setting a gyro like avionic or gy401 etc is... you should get to fly the heli on rate mode first.. this will mean that you have to change the tail pitch slider setting manually (usually the tail pitch slider now will not be exactly at the centre of the tail shaft, it will be slightly towards the hub which means you will have a +ve pitch on the tail {around 5-7deg} but  the tail servo link will be 90deg to the push rod.. hope i have not confused you)... you need to change this setting manually till you get to hover the heli on rate mode and once it hovers on rate mode change your tx settings to HH mode and do the limit setting again (however this time you will not get the pitch slider "almost" touching the hub and the tail rotor as the pitch slider is not at the centre of the tail shaft and this gyro like the futaba gy401 does not have the capability of having different limits setting like the spartan etc but this is fine and not an issues for our kind of flying.. i feel this way of setting the gyro will give a crisper tail... if i have confused you pls let me know and i will do a vid of this and upload it soon

but first pls check if the gyro is good if not pls send it back and we will replace the same..

sujju

i forgot to mention that satish from bangalore (i will try to search for this post here) had an issue where he had something loose in the gyro and opened the unit and got it rectified...  not sure if this will help you but worth a shot...

sujju

Sorry about that, hope you didn't bend any of the shafts (main, spindle, tail)- always take time ti check them cos even a little bend can amplify and cause your gyro to malfuntion. Thats first thing to check.

It's hard to imagine a buzzing noise from a piezoelectric gyro cos it's only heard with mechanical gyros, but anyway
did you check by directly connecting your servos to rudder ch? is the rudder servo centering and working with direct rudder commands from the Tx - just to be sure the servo is ok in the first place.
Also check the connectors - the entire Rx-Gy-Servo system

You didn't mention about any damages to the gyro in the crash, yet still you may have to check it by removing its back-plate and ensuring everything inside is intact - all the soldering etc. May also be a good time to add some reinforcement to the gyro inside the casing.

Check to ensure the gyros delay and limit pots have not changed, try different settings.
Also check the gain ch connection to the Rx - verify changes to gyro gain on the Tx results in gyro/rud-servo/slider reaction

Let us know

Thanks Sujju and Satish for the prompt replies. My response pointwise below:
Sujju:
1. Gyro is holding the servo. But it is not adjusting the tail rotor pitch when I move the tail left and right. When I go into a rate mode with a reading of say -25, then the tail rotor reverts back when I centre the Tx rudder toggle.
2. Gyro had a buzz from the beginning but was working fine till my crash.
3. I had been flying the heli with a HH at + 75 till the crash. Heli was behaving fine. No wag on this one.
4. The problem right now is that the gyro has no effect on the rudder when the heli moves left or right.

Satish:
1. All shafts checked and fine. Have set up the heli and there is no ccpm interaction effect on the flybar at any point (Finless test).
2. Gyro has been buzzing from the first day that I used it but it used to work ok.
3. Servo is fine as it still responds perfectly to rudder commands from the Tx through the gyro and the gyro holds the rudder.
4. So all connections are good. Double checked anyway.
5. Gyro looks untouched by the crash. But difficult to tell if the jerk caused any damage inside.
6. Delay and Limit pots look fine. Will re-set the whole gyro function once again and see if it makes a difference.
7. I did see your post on the AV 401 and how you opened it up and worked on it. Frankly I did not have the guts. Thought I should check with you guys first or maybe send it back to Sujju if he agrees to take a look (he has very graciously agreed to replace it, which might not be necessary).

can you pls check the wire connections especially the gain wire if anything has come out loose?... but am still concerned about the gyro buzz which should not happen..
also i dint get what you mean by "gyro holding the servo".. if this holding then its means the servo is getting moved by the gyro... can you pls clarify this...

sujju

on a lighter note :  How can one question ones own response? ....may be I am missing something

now coming back to the issue:-

I think that you need to test the Gyro on the ground and see if it moves the rudder servo when you manually move the tail of the heli,

Also check for the small reverse switch on the gyro as you need to move it if you changed your rudder servo after the crash or made any changes in the Tx for rudder channel.

The buzzing normally comes from the servo if the limits (end points) on the gyro are not properly set.

hope this helps

Hellyflyer

1.All tests are on the ground
2. Gyro holds the servo in position when I throw the rudder stick left or right. That is, the servo does not centre automatically when I release the rudder stick. So part of the gyro is working.
3. What does not work is that there is no corrective response from the rudder when I turn the heli left or right physically by hand.
4. No I did not need to change anything on the heli after the crash except the blades. So the servo is the same.
5. You could be right about the buzzing coming from the servo. I assumed it is from the gyro because (i) nothing buzzes when I connect the servo directly to the Rx and (ii) belonging to the age of mech gyros, I assumed it to be normal. The buzzing only happens when the gyro is connected. The tail slider is centered and does not touch the ends even with full rudder movements. However, as I had mentioned earlier, I will go through the gyro setup again and see what happens. But the buzzing is secondary. Right now I have half gyro function only!

Thanks again!

1. Did you try flippling the small switch on the gyro to see NOW, if there any corrective response when you move the heli by hand?
2. Do you see any corrective response when the gyro is in rate mode? (little jerks from the servo when you move the tail quickly by hand)

3. Ensure that the gyro is properly mounted with double sided tape, some times loose gyro's would also cause this behavior.

Well in that case the buzz you're hearing is most likely from the servo, and i'm assuming it's a Analog hi-speed servo - if so, I have seen this happen with AV401 Gyro. Just try increasing the Delay on the gyro. This buzz is simply because the servo is constantly searching for its center (you have mentioned you have about +75 gy gain which is a bit high), which increases if you increase the gy-gain. You may test this by reducing the Gy gain completely to somewhere between Rate-mode and HH-mode (49-50) on your Tx and the buzzing will reduce and as you increase the gain the buzz/jitter also increases. On the other hand if yours is a Digital tail servo then it's normal to hear a very high frequency buzz from the servo.

For analog hi-speed servo make sure the DS switch on AV401 is off. Increase the Delay to say 50% and Gy gain on the Tx to say 40% and see if the buzz reduces. Its very imp to eliminate any chatter from the servo and it should at all times find it's center without searching for it, else this will result in a drift in flight in hh-mode. I have seen this happen with AV401 servo myself. If the chatter doesn't go completely, you may even try adding some sub-trim to the rud-ch on your Tx. But thats the last resort and not recommended.

From your report it looks like your saying the gyro isn't countering the tail movement - if so check if you're in Rate mode or HH Mode or in teh middle. Only at mid-point bet Rate and HH the gyro does not counter tail movements, else in Rate mode it counters the tail movement and re-centers back, and in HH it counters and continues to do so until the heli returns to it's heading position.

Also you're saying the gyro doesnt re-center automatically - this is ok in HH mode. But in Rate mode, it should re-center after you center the rudder stick.

Hellyflyer:
1. Flipped the DIR switch. Still no corrective response from the gyro when heli is moved by hand.
2. No jerks in rate mode either. In the Futaba, rate mode is from 0 to -100 (theoretically). The gyro light goes off actually at -4.
3. Gyro is properly mounted with double sided tape and quite firm.
Satish:
1. The servo is analog - D590. Metal gear, 24g.
2. You are right. Buzz goes away when I reduce gain on Tx to about +10. My "in-between" on Futaba is 0. Buzz comes back at about +11.
3. DS switch is off.
4. Chatter goes at +10. So do you recommend Txgain setting at +10?
5. The gyro is not countering any tail movement either in Rate Mode or in HH.
6. Yes I am aware that in HH, the servo will not re-centre automatically.
7. I have gone through the whole process of setting up the gyro, servo and tail once again. Still no reponse.
Sujju:
1. If Sujju agrees, I will send the Gyro back to RCB for a check-up.

w.r.t point 4, the reason you hear the chatter is simply because the gyro is sensitive and constantly keeps sending
signals to the servo the reset it's position and the servo isn't fast enough to - therefore you can try increasing the Delay on the Gyro so that the servo can catchup with the gyro. Therefore you may play with both the Tx gain as mentioned in point 2, and with delay pot on gyro. Only in rarest cases we resort to rudder sub-trims on the tx to eliminate the rudder hunting behavior.

That's theory. But in your case, it's difficult to say as yet if it's gyro malfunction or Tx setting. I don't have a futaba Tx...may be sajju or someone here can help you, or you could simply try another gyro. G105 is more stable and I highly recommend.

Thanks guys for all the help. I have ordered the G105 anyway. Will write what happens when I replace the AV 401.

hi pradeep.. as stated pl send the gyro back and we will do the needful..
thanks
sujju

Thanks a ton Sujju!

excellent.

pradeep, when you receive your g105, set the delay pot to midpoint or more (50+) and keep reducing until you hear that servo buzz again - that's your sweet-spot.

Thanks Satish!

Sujju:
1. Thanks for letting me know that the D590 is a digital servo. I switched the gyro DS switch to on but still no joy.
2. Changred the gyro from AV 401 to the new G 105 and ... WOW!!!!...eveything works fine again...
3. So the AV 401 obviously has a problem.

Thanks for all the help and support all you guys. I should be ready to crash again by this weekend...What fun...

Really nice work Sujju,
I suppose there's no more need for RC powers anymore...

Good Job!

thanks controlflyer...
i just happend to see that you are in Kuwait.. pls pm me your number... i happen to travel to kuwait quite often from bahrain

sujju

Quote from: satishkbg on September 07, 2011, 11:07:33 AM
Can anyone confirm if the Avionic D590 high speed 24g Servo sold at RcBazaar is Digital or Analog
http://www.rcbazaar.com/products/802-avionic-av590-hi-speed-24g-servo.aspx

Regards

hi satish,
i thought i was referring the the avd90mg - 9gms servo here... i stand corrected the AV590 24 gms servo is a digital servo and i have been using this on my heli on DS mode and works great. (thanks pradeep for point this out to me)

sujju