Hello thestructured,
usually, the Scorpion Tribunus has a very good Governor, but I already have seen,
that the tail starts to wobble when coming down with negativ pitch and trying to
hold the height with positiv pitch.
Thx for this hint
egb.
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| poor 3-blade tail performance https://www.spirit-system.com/phpBB3/viewtopic.php?f=20&t=3528 |
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| Author: | f3a-iceman [ Mon 19. Aug 2019 12:21:00 ] |
| Post subject: | poor 3-blade tail performance |
Hello Spirit (Pro) Community, with my first spirit (pro), I'm on the verge of despair. Hope you can give me a few tips / setup examples for my 3-blade Havok, whose tail performance I'm not at all happy with: If I'm hovering in front of me and quickly make a 360° pirouette turning to the right and stop immediately after the 360°, the tail always swings too far by about 5cm and then regulates back to the stop point. Beforehand: The mechanics, the thrust bearing are installed correctly and the tail control is really very smooth. The tail servo is a BK servo DS-7007HV. My general setup problem: With the exception of the Rudder gain sensitivity, I can change any spirit parameter what I want (as well via transmitter), it has no effect at all. The Tuning Guide (http://manual.spirit-system.com/index.p ... ning_Guide) is also somewhat contrary to the manual, especially in terms of pirouette consistency. It has no effect whatsoever if I hover in front of me and quickly make 1 pirouette, it does not matter if a value of 160 or 200 is set via the transmitter - no noticeable change. At the beginning I had selected a Goblin 700/770 as a preset - that was my first mistake, since it started with a "Rudder Common Gain" factor of 1.40x and this sensitivity had to be reduced to 1.10x by try-on-error. Only then the tail does not started to oscillate (whimper) in a speed-flight at 1550 rpm with a sensitivity (Rudder Gain) adjusted via the transmitter down to 25%. (With the Rudder Common Gain I won't be smart about that. If a factor of 1.4 with 20% gain should be 28% in total, then a factor of 1.0 with 28% must be 28% gain – but it isn't ☹) Maybe my problem is caused by the missing 3-blade setting under Cyclic Phase? "This feature is recommended for models with multi-blade rotor heads. For most other models, we recommend a zero value." In this example I'm missing, that this is maybe related to a 4 blade helicopter. For my 3 blade Havok: "Do I have to setup a value of 120 because the three blades are 120 degrees far away from each other in compare to a 4 blade with 90°? I worry to change here anything, not to crash my heli. One of my basic problems are, that previously I've used a guide, related to PID controls which are, maybe because of any "user friendly grafic interface thoughts" completely gone here with the Spirit Settings. I want to setup: - Tail not oscillating while hovering – which parameter? - Tail not oscillating (wimmering) during a fast forward speed flight – which parameter? - Tail stopping at once after a 360° degree pirouette – which parameter? These parameters I've changed: ° Rudder gain – yes, but either stop oscillating during hovering or during speed flight, but not both ° Rudder delay – no noticeable change between 0 and 5 ° Rudder Dynamic – no noticeable change between 4 and 10 ° Pirouette Consistency – no noticeable change between 160 and 203 Thx in advance Any feedbacks are appreciated Br Egbert |
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| Author: | morrchew [ Mon 19. Aug 2019 14:24:07 ] |
| Post subject: | Re: poor 3-blade tail performance |
I personally have had no luck using BK tail servos . Tomas personally Sent me a email a while back when I could not get the tail to hold , and it was stated that Spirit does not like BK tail servos . Try another servo . I do have the same Heli and it’s rock solid . No issues with tail at all I’m using a Align 825 tail servo . |
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| Author: | f3a-iceman [ Mon 19. Aug 2019 14:37:45 ] |
| Post subject: | Re: poor 3-blade tail performance |
Hi Morrchew, thx for your reply, but pls have a look to the servolist (http://manual.spirit-system.com/index.p ... Servo_list). You will see a lot of support BK servos and the DS7007 is the newest one of them and if there would be any known issues, it should be mentioned. I already exchanged my FBL from a Brain to Spirt, where I have had problems with a slow pirouette during a fast forward flight, but I could manage it and finally it was working, but I wanted to get it better... I appreciate your opinion, but it may not be the answer, I'm looking for. 3 BK Servo Manufacturer Model Usage Pulse Frequency Delay BK Servo BLS-8001HV Cyclic 1520µs 333Hz BK Servo BLS-8002HV Cyclic 1520µs 333Hz BK Servo BLS-8005HV Rudder 760µs 333Hz 0 - 2 BK Servo DS-3001HV Cyclic 1520µs 333Hz BK Servo DS-3005HV Rudder 760µs 333Hz 2 - 5 BK Servo DS-5001HV Cyclic 1520µs 333Hz *BK Servo DS-5005HV Rudder 760µs 333Hz 0 - 3 BK Servo DS-7001HV Cyclic 1520µs 333Hz BK Servo DS-7002HV Cyclic 1520µs 333Hz BK Servo DS-7005HV Rudder 760µs 333Hz 0 - 3 BK Servo DS-7006HV Rudder 760µs 333Hz 0 - 3 thx egb. |
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| Author: | morrchew [ Mon 19. Aug 2019 19:55:54 ] |
| Post subject: | Re: poor 3-blade tail performance |
Yes I know it’s listed but I had several issues with BK servos I tried them on a Goblin 700, 770, Havok and a Drake . I could not get the BKs to work tail would always wag and chatter in fast forward flight . I even thought it was the servo and bought another one ands it still did not work well . That’s when Tomas sent me a email that Spirit dose not like some of the BK tail servos . I changed out the servos and had no trouble since . Cyclic servos are fine no problem with them. |
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| Author: | ZeXx86 [ Tue 20. Aug 2019 7:25:38 ] |
| Post subject: | Re: poor 3-blade tail performance |
Hello, generally if you can't see any difference when changing values then the issue is usually in the mechanics. The servo can't overcome the forces required to hold the tail fast enough. Then there is possibility the servo is not performing properly. For your model you should set Pirouette Consistency to 175 - 185, Rudder Delay to 0. Then the only thing is to adjust Gyro Gain and it must work. If not, then there is nothing you can set in the unit to fix it instead looking to a mechanics and/or servo will help. I can't confirm Spirit does not like BK servos but we can confirm there are many issues and pilot can't usually fix them in any way. BK have Spirit units for testing for several years, but we have never heard any word from them... Usually lowering BEC voltage under 6.6V helps otherwise the servo is picking up a random noise from other parts of the model (ESC) and is jittering randomly. BK-700X are the most prone for this issue. This is happening also with their Cyclic servos but it is just not visible that much. |
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| Author: | f3a-iceman [ Tue 20. Aug 2019 8:31:54 ] |
| Post subject: | Re: poor 3-blade tail performance |
Hello ZeXx86, I'm really thankfull for your technical feedback. 1.) >>The servo can't overcome the forces required to hold the tail fast enough<< --> to support the required servo force, I've put PMGs (Propeller Moment Gewichte), which are small (0,4g) discs left and right beside the blade holders and I've controlled the tail blades manually and they are going really very smoothly. I will take them out again, but previously (with the Brain) I have had problems doing a pirouette during a fast forward flight and the tail stopped for a few seconds with 90° against the flight direction. In addition, I also changed the tail gear wheel with 1 tooth less to achieve more tail force. 2.) >>Lowering the BEC voltage<< --> I think it doesn't would make sense, because I'm using a "R2BUFFER 3x25F". This hughe capacitor should eliminate all noise - hope you agree. What I'm really happy with the Spirit is the straight flight improvement during a forward fligth and performing a slow pirouette. The Spirit remains on the same heigth, compareable with the VStabi. The Brain raised up for up to 10m! I'm also happy with the Spirit performance, flying either a backwards loop or coming perpendicular down with the tail first. Question: Which Tail Servo would you recommend? Thx Egbert. |
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| Author: | ZeXx86 [ Tue 20. Aug 2019 8:44:22 ] |
| Post subject: | Re: poor 3-blade tail performance |
Some BK servos are picking up a random noise in terms of EMI because threshold between signal and noise is very low. So it is not related with BEC voltage. Personally I have seen that even touching BK 7001 servo with bare finger can change servo position. Moving the servos to helicopter with a plastic frame resolved all the issues. Lowering BEC voltage will allow servo to pickup rather only signal than noise. For this reason I recommend to try this. These problems were reported with multiple FBL systems and can be seen on youtube for example. But for the most pilots they are working well. I recommend MKS servos, but the most other todays servos will work pretty well. For example Align or Savox are fine. |
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| Author: | f3a-iceman [ Tue 20. Aug 2019 9:12:23 ] |
| Post subject: | Re: poor 3-blade tail performance |
Hello ZeXx86, I'll try your recommendation to reduce the BEC voltage first. After that will try a MKS servo. Thank you very much for your very detailed feedback Thx egb. |
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| Author: | thestructured [ Wed 21. Aug 2019 3:04:08 ] |
| Post subject: | Re: poor 3-blade tail performance |
On all of my larger models, the tail gain 'rudder multiplier' is set to 1.25x or 1.35x and in my transmitter tail gains on all of my models are between 60-70%, so the actual gain is around 85-90. You should first set this base gain value, which on a 700 should be way higher than your 25% (or 28 with the multiplier.). Only after that adjust the other gains (piro consistency, rudder dynamic). My recommendations: The base gain above, 2-4 for rudder delay, 7 for rudder dynamic, and 165 on piro consistency for a starting point. Piro consistency will not show any difference in a hover- what this value helps with most is a consistent rudder rotation rate when applying rudder during other maneuvers. If it is too low you may see your rudder rate drastically slow down while doing other hard moves at the same time, but you are unlikely to see any difference in a piro during a hover. I've had the issue with the tail bounce back too and it is gone now, I don't remember what I did, but make sure you are on the newest firmware. Your rudder end points should look similar on the goblin, if one side is a way different number than the other side you should redo your tail mechanics. Also if you are using a governor make sure the gains are set properly as this can cause the tail jitter you mentioned as well (though it's probably mostly gains or that BK servo). |
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| Author: | f3a-iceman [ Wed 21. Aug 2019 8:53:19 ] |
| Post subject: | Re: poor 3-blade tail performance |
Hello thestructured, usually, the Scorpion Tribunus has a very good Governor, but I already have seen, that the tail starts to wobble when coming down with negativ pitch and trying to hold the height with positiv pitch. Thx for this hint egb. |
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