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PostPosted: Mon 10. Sep 2018 14:30:10 
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Hi,

I've done the maiden flight of my TRex 500 ESP (flybar version) yesterday.
The electronic combo is a Spirit Pro (v2.5.1) and a HW Platinum 80A V4 (I think the version is PL-04.0.04 or PL-04.0.05).

Questions concerning the Spirit settings:
1- The Rescue is very intense. Can I safely reduce the "rescue collective pitch" from 60% to 50%? Or is it a bad idea?
2- I observed a weird behavior with the rescue: my TRex is not climbing straight. It does go back in horizontal position, but it is drifting (going away). Is it because it is a flybar heli? I don't have this behavior with my OXY3 (red Spirit unit). FYI, if I enable the coax stabilization mode, my TRex is perfectly stable and not moving. So, it doesn't look like an offset somewhere in the gyros calibration.
3- I got a small kick when starting the engine. The "spoolup rampup" is set to 50µs. Can I reduce this value? Does, reducing this value, will somehow affect the governor response/performance during the in-flight phase?

Telemetry question:
Without the blades, the HW current sensor display 0A (which is definitely not right). With the blades, the current seems OK.
However after looking at the log, there is a major difference between the displayed power consumption (mAh) and the real power consumption. There is about a 200% ratio. If the telemetry said 5A, in real is more likely 10A. I saw that the shunt ratio can be adjust in the Spirit settings. However, shall I worry about this x2 ratio?
There is something wrong with my brand new HW 80A v4? Or a 200% shunt ratio is "normal" with a HW ESC?
The real power consumption of my TRex 500 is between 15 and 28A.
Any advice will be very welcome.

BR,
Seb


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PostPosted: Tue 11. Sep 2018 14:23:07 
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Sorry for replying to my own topic. :?
I'm just surprise that Tomas didn't answer my questions. :roll:

BR,
Seb


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PostPosted: Tue 11. Sep 2018 14:38:57 
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Hi,

thank you for your patience. We have many other work so with longer questions it is much harder to reply.

1. Yes, you can reduce Rescue Collective PItch and/or Cyclic Ring range. If the model will fly well and will climb fast enough then there is no problem.

2. This depends on if model was flying previously. It should continue in its way, but ascend. With Flybar it is not that easy since mechanics can really cause some additional imprecision. Is the behavior always same? Same direction?

3. Yes, this parameter is for such purpose.

It is normal that without blades you are not getting any current. ESC sensors are not that sensitive. Unfortunately some models are less precise than others. If factor 200% will help, then it is fine. The worst case is when capacity measurement require different factor each flight as some sensors are not linear. It is hard to tell the manufacturer did some error as this feature is not guaranteed or advertised anywhere by them. But very often replacing the ESC for same, but different unit helps.

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PostPosted: Tue 11. Sep 2018 15:03:26 
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Hi Tomas,

No problem. I saw that there are many questions specially on the new Geolink product.
You have been so fast to answer my previous questions that I thought you missed my post. :D
I promise, I won't do anymore an "up", unless I don't have an answer after 1 week.

Thanks for your answers.

1. I tried with 50%. It does climb, but not very fast. So, maybe, it is not enough specially if the heli is flying very quickly to the ground? Or does the collective response during the rescue is proportional to the integrated acceleration?

2. You're correct. The "drifting" depend of when the rescue is initiate. It can continue ascendancy in its way or just climb. So, I guess, this is the expected behavior for a flybar heli. As long the heli doesn't hit the ground, I'm happy. :)

3. Perfect. I was just worrying than this could impact the response time of the in-flight governor mode.

4. You're right. The current sensor is not an advertised feature for HW ESC. I will adjust the shunt percentage and see how accurate it is. The goal is to use the consumption as a landing alert. To me, current consumption is much more accurate than voltage monitoring. I'm just a bit disappointed. Maybe I should have bought a 60A version with an external FrSky sensor. :cry:

Seb


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PostPosted: Wed 12. Sep 2018 11:59:03 
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Hi Tomas,

I had another session during lunch time.

1. I think 50% of collective for the rescue is probably to low. I went back to 60%.

2. I confirm the drifting effect during a rescue really depend where and how much is tilted the heli. Probably a side effect of the flybar mechanism.

3. With the "spoolup rampup" set to 40µs, no more "kick" when starting the engine.

4. The current sensor of the HW ESC doesn't seem reliable enough. I will probably put back my UniSens-E from my previous setup. I specially bought the 80A version instead the 60A one for its current capability. Looks like it was a bad move.
It would be very nice if you could add a note about this potential inaccuracy/unreliability of HobbyWing current sensor in your Wiki.

Seb


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PostPosted: Fri 14. Sep 2018 9:28:34 
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Hi,

thank you for your message.

2. It is possible that with a lighter flybar paddles it could work better - lighter paddles will not affect the flight to this extent, but normally the model is less stable. With Spirit this should not be a problem.

4. Usually precision is good, but we will add the note about this.

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PostPosted: Fri 14. Sep 2018 10:48:08 
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Hi Tomas,

2. Thanks for the tip. :) I think that someday I will change the head for a FBL version.

4. Look like I've been unlucky. :( I need to do more flights, maybe changing the shunt percentage from 100% to 200% will do the job. I will post my results in few weeks.

Seb


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PostPosted: Fri 14. Sep 2018 11:04:57 
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In some cases it is needed to set even 250%, but very rarely. This imprecision is occurring mainly with HW V4 160A model.

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PostPosted: Fri 14. Sep 2018 12:57:18 
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Thanks for this information.
I agreed that changing the shunt ratio (even if it is a bit surprising) is not an issue as long the current consumption is accurate. I will post my results after several flights.

Thanks Tomas for your support. :)

Seb


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