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pirouetting flat both directions

geschrieben von Marianovbar 
pirouetting flat both directions
16.09.2024 06:34:26
Hi, i noticed that in my heli i make a pirouette to the side of the torque and is flat but when i go against the torque is not flat and mix some aileron and elevator.
I feel like is an issue of compensation but idk where to start..
Regards
RV
Re: pirouetting flat both directions
16.09.2024 07:23:49
First - ist the COG "Spot on" center of the main shaft?
Second - was the trim flight done in calm condition unless the pirouettes were ok?
You can also edit the trim flight values manually for a try if you were thinking one or both axes being a tad off.

Another thing who could be possible (but no one mentioned over the years) - is phasing. Having a VBar EVO we can try to get some degrees offset here in the flight parameters decreasing the usual 90deg phasing to a lower number - depends on physics and aerodynamics.

regards (EN) / Gruss (DE)

Rainer Vetter

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Re: pirouetting flat both directions
17.09.2024 16:31:28
Hi
CoG is okay, i did autotrim manually because doing it automatic was worst, it was in a calm day
I will try the control phasing, is like touch the values of swashplate in model setup or different?
Regards
RV
Re: pirouetting flat both directions
17.09.2024 17:19:55
Are you having a VBar EVO or NEO?

On a NEO the roataion can only be done in general - on a EVO per bank.

So - let me know to guide you how to check ;-)

regards (EN) / Gruss (DE)

Rainer Vetter

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
Posting and answering - please use a PC and a standard keyboard. Answer all questions fully, take the needed time, don't forget probably requested attachments.

Für Posts und Antworten bitte einen PC und eine richtige Taststaur benutzen sowie alle Fragen vollständig abarbeiten. Nehmt Euch Zeit, beantwortet Rückfragen in Ruhe und vollständig.
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
Für Einzelkommunikation bitte ausschließlich Email verwenden! - PN, Messenger, Chat usw. werden nicht bearbeitet.
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Re: pirouetting flat both directions
17.09.2024 21:44:35
Oh okay.
vbar EVO in a logo 700
RV
Re: pirouetting flat both directions
18.09.2024 06:20:00
Okay ...

Introduction:

On a rotating system we have almost 90deg of phase shift from input to its outcome. E.g. if you move stick for "Nose down" - a blade over tail boom will not move - but (CW system) one aligned in a 90deg angle on the right side will get positive. So it is 90deg ahead and will give "Nose down" in flight. Watching the swash is for noobs - the airflow doesn't care anout swashplates in flight ;-)

This 90deg value is on a 2-blade trainer helicopter already fixed by the linkage design on the main head.

Rotor System:

As the rotor system has some parts moving in flight, e.g. the dampening and mainly the blades moving in the grips (always backwards to rottation direction) - the amount depends a bit on the exact conditions like blades, dampening, headspeed etc. - the 90deg above are a basic point but not the truth ;-)

Conclusion:

We need sometimes a tad less than 90deg having the "static look" above. For example some manned helicopters are around 72deg (BO 105). So we should try a bit less here too.

Howto:

First - put one blade over tail boom and check for "No move" on elevator.
Then dial in -30 at the current bank for phasing
Check if it now moves positive a bit when stick move for "Nose down" is applied
If this is so, the negative presign is ours. If this is going vice versa - we use positive values.

In Flight:

just try in steps of 2-5deg. starting form 0 in the estimated direction above. I think we will end somewhere around 5 deg. at least. To get it perfect - a trim flight should be done too.

regards (EN) / Gruss (DE)

Rainer Vetter

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
Posting and answering - please use a PC and a standard keyboard. Answer all questions fully, take the needed time, don't forget probably requested attachments.

Für Posts und Antworten bitte einen PC und eine richtige Taststaur benutzen sowie alle Fragen vollständig abarbeiten. Nehmt Euch Zeit, beantwortet Rückfragen in Ruhe und vollständig.
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
Für Einzelkommunikation bitte ausschließlich Email verwenden! - PN, Messenger, Chat usw. werden nicht bearbeitet.
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Re: pirouetting flat both directions
18.09.2024 19:12:20
Okay, i will try this test, also i remember now that sometimes i give elevator input and i see some aileron mix, just a little maybe can fix this too.
Is possible that in one bank does this and in other doesn't because rpm?
Regards
RV
Re: pirouetting flat both directions
18.09.2024 21:37:31
Yes - it is possible.

regards (EN) / Gruss (DE)

Rainer Vetter

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
Posting and answering - please use a PC and a standard keyboard. Answer all questions fully, take the needed time, don't forget probably requested attachments.

Für Posts und Antworten bitte einen PC und eine richtige Taststaur benutzen sowie alle Fragen vollständig abarbeiten. Nehmt Euch Zeit, beantwortet Rückfragen in Ruhe und vollständig.
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
Für Einzelkommunikation bitte ausschließlich Email verwenden! - PN, Messenger, Chat usw. werden nicht bearbeitet.
For single user communication please send a email only! PM, Messenger, Chat etc. won't be read.
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