250 Oxy 3 Build

murankar

Staff member
Now this is for my Tattu packs

Width 34.75mm
Length 73.4mm
Thickness 27mm

These are my measurements not What is advertised.


My guess is that i may have just added another minute of flight time with my changes. I won't know till the parts get here and I fixer up. I may go to 13 or 14 degrees of pitch. I am at 12.5 right now.
 
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xokia

Active Member
Now this is for my Tattu packs

Width 34.75mm
Length 73.4mm
Thickness 27mm

These are my measurements not What is advertised.


My guess is that in may have just added another minute of flight time with my changes. I won't know till the parts get here and I fixer up. I may go to 13 or 14 degrees of pitch. I am at 12.5 right now.
Thanks. I'm running 14 degrees I like the higher head speed. I need larger batteries I only get 3:30min of flight time.
 

murankar

Staff member
Got in 4 flights that were based on tuning. I just humbled myself today. Yeah I thought I knew how to tune but I guess not.

At first in had a really bad nose left tap kick, 90° bad. So for what ever reason i thought speeding up the tail response was the ticket. Nope needed to go into advanced tail tuning. There I maxed out TC Coll setting. If this is what I think it is Then its a pre comp on collective. I got most of it out . Next I messed with the head gains, governor gains and tail gains. I thought at first I had to dial everything down since its a 250 and not a 450. I didn't quite get through it but I still have a ways to go.

Punch outs are.drifting left, I think my tail stop gains are to high, head gain not high enough and I am not sure how to or when to dial in the governor. Right now I have it set low in VBar. I don't want it beating up the tail as I tune the tail. I have the gov down around 40 and it seems to be holding fine from what I can tell.

I did good off on my last pack. Just getting comfortable with the oxy. I am getting somewhat better as the tune walks in.

Tomorrow If its nice out i will video a flight.
 
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xokia

Active Member
Had similar issues with the tail. I am using a spirit FBL . Gyro gain I have around 53. I did need to adjust the servo arm so the mechanical end points was around 150. Moved the ball further towards the servo.

I like hard stops so mine is set kinda high. I did have to set some precomp but not much. Mine is pretty good now but still needs some fine tuning. What tail servo are you using? I’m using a KST 215
 

murankar

Staff member
I am running BK 3000 series servos all around. The tail is the 3005. Its comparable to yours.

I may need to move the ball link like you did. I will also look and see what measurement I need to be at for That. I have the default location of second whole out from the center.
 

xokia

Active Member
I use breakable servo arms so had to drill a hole. I think it was 2nd hole out from center. But doesn’t mean much your arms could be different. I’ll measure it when I get home.
 

murankar

Staff member
Tonight will tell if I made a good choice.

I changed the tail blades back to the 50mm. Fingers crossed.
 

xokia

Active Member
215325E3-06DB-4C70-8353-33DFB8EE878C.jpeg
Running the stock arms that came with the kit.
Sorry forgot to measure. I'll try and remember tonight. I do recall reading in the tuning section for my FBL controller that you had to ensure you had enough mechanical gain. If not then the tail was not precise enough.

Tonight will tell if I made a good choice.

I changed the tail blades back to the 50mm. Fingers crossed.
I am using the 50mm blades
 
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murankar

Staff member
So I did switch the blades out for the 50mm and ran six flights today. It was tough considering the wind was really bad near the end.

Mikado Vbar Neo 6.0 with Pro Features Enabled
here is where I am at on my setup (These numbers are not final ):

Headspeed: 3500 3700 4000

Head setup:
Expo: 20 | 20| | 20
Style: 90 | 90 | 90
Agility: 100 | 100 | 100
Gain 90 | 70 | | 70

Tail Setup:
Expo 60 50 50
Rate 100 100 100
Tail Gain: 60 45 45


Tail Optimizer
TC Coll 50 Side A 10
TC Cycl 6 Side B 91
Zero Col 0 Optimizer On

Tail Expert
Accel 43 Stop Gain 25
P Gain 65 Stop Gain 25
I Gain 60 D Gain 0
I limit Off I DIscharge off


Tomorrow I will be testing out the new servo arm setup. Manual want to have the bal to center on the tail at 7.5mm. I was getting to much tail kick and having to add way to much in to the parameters. So I moved the ball out to 10.22 mm on the BK servo arms that cam with the 3005 tail servo. Cross fingers and hope the bast happens. My Guess is that TC Coll will drop and over all gain will drop. My next hurdle will be with the P and I gains.

xokia:

Thanks for the input. I will be testing out theory tomorrow. Hoping the mechanical gain helps on this setup.
 
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murankar

Staff member
Just found a few things to try on Vstabi.info:

In the Vbar Neo Gov settings under Expert
set collective add to zero (for my referance it was at 30)
set cyclic add to zero. (for my referance it started at 10)
 

murankar

Staff member
Just so I am tracking everything I have done so far:

To night I rest the the initial setup to make sure I am at a good mechanical setup. Swash re-leveled, blade grips re zeroed. Wiped out the auto trim numbers. Now its time to go in and reset the gains back close to what is stock.

Over view:
Reset the ball link on the tail servo to 10.22 mm
Zeroed out the Governor Pre comp on the tail and on cuyclic
Set set the mechanical setup
Reset the gains.

Went through and reset everything back to stock or close to it.
 

murankar

Staff member
This morning I got the auto trim done. I might have to tweak the numbers a bit but its trained out.

I got the tail kick almost eliminated but I still need to get the tail gain dialed in. If I hold it in a hover its fine, but as soon as I do a climb out it starts to wag/shake. If I drop the gain the tail feels all mushy and does a slow wag. I am thinking the P gain may need dropped a bit.

I would say that by the basic tune document by Mikado works. Now to solve the tail wag.
 

murankar

Staff member
I got some great news after today's tuning flights. Before we get into the tuning I will say that the last days has been the challenge to fly. When your heli has to tilt 45 degrees into the wind to hover its to windy. Yes I flew in winds that I should have said no to. Left with one heli and came back with one heli. That goes to show the quality in electronics. If its the same tomorrow I will get a video of it. I will at some point post my settings so far later on.


This process applies to Pro features and not the basic Neo

Step 1 - Basic Gov settings:
  • Gov Gain to 0
  • Gov I to 0
  • Spool up at zero collective
  • dial in basic throttle unless HS matches
  • go to a hover, dial in collective add unless HS will be kept under hover too
  • do a medium climb, check hs, possibly add some collective add again
  • set cyclic add to 1/3 of collective add
  • turn back gov gain and Integral

So I had a bunch of numbers to adjust. First I had went into the Neo governor and adjusted the gov gain to zero. I was not sure where to find the I gain so I left it alone. After doing this step my gov gain ended up at around 25.

Governor Setting after this step:

Gov Gain: 28 28 28

Gov Expert
Collective Add 10
Cyclic Add 3
Collective dynamic 0
Basic Throttle 50
P lim - 20
Integral 20
P Lim + 20

Step 2 - Basic Tail together with Gov:
lower tail gain (e.g. to 40)
hover and do medium climbs
on a CW heli - if nose turns to left in the climbs - increase collective torque precomp in tail
if it stays approx. - the optimum has been found.
if it still turns although the precomp is e.g. at 60 - decrease (!) the collective add of the governor (tail is overloaded by too hard gov'ing)
set cyclic precomp to 1/3 of collective precomp​

Tail Setting after this step:
Expo: 50 50 50
Rate 100 100 100
Tail Gain 46 46 46

Tail Optimizer
TC Coll 40
TC Cyc 13
Zero Col 0
Side A 11
Side B 90
Optimizer On
Expert
Accel 50 (piro speed)
P Gain 70 (stock 80)
I Gain 60
I Limit Off
Stop Gain A 25
Stop Gain B 25
D Gain 0
I Discharge Off​

Step 3 - Tail gain:
just increase ad needed to hold the tail. The VBars have a internal gain calculation depending on the flight situation to avoid oscillations - e.g. in fast flight.
If the tail holds well - not more gain needed​

Step 4 - Elevator Precomp:
lower main rotor gain to 30-40 (approx 1/2 of the usual recommended gain)
from a hover - start a climbout
watch the tail boom. If it hangs down first - increase the precomp​

Rotor Head setup
Expo 20
style 90
Agility 100
Gain 70
Rotor Head Expert
Elev PreC 10
Paddle Sim 20
Heli Size 32
Integral 60
Pitch Pump 10
Cyclic Ring 85
Optimizer 46
Optimizer On
Now its time to go and fly. I still need to find out what some of these Neo specific things do; i.e Paddle Sim and Pitch Pump. Heli Size is also a Mikado thing, it defaulted to 32 but that is for a 450 class heli. I am going to read up on that also. I think I might make a Quick reference guide for this. I have to keep googling the stuff when I am at the field.

All of this info should apply to all Mikado units and any clones out there. So if your flying a Kbar, FuBar or any other derivatives of this unit then you will be able to use this info also. One thing note: I do not believe the clones have Pro features available. Its been 4 or so years since I flew my Kbar so I don't remember. Any feed back on this post it and I will add it to this.


xokia: Again thank you for your input. Its been useful
 

murankar

Staff member
Wow what a day so far. So I have 4 flights in 2 of which are on the oxy 3. At this point it appears that my numbers are working for a starting point. Tuning must be done from there biased on the flying style.

I have been lazy flying at 3500 rpm and 3700 rpm. From what I have seen so far at 3700 rpm I loose about 20 to 30 seconds of flight time. 5 minutes at 3500 leaves about 28% left and that same 5 minutes on 3700 leaves about 19%. So keep that in mind while setting up your banks. I think I may keep a 3700 bank and 2 3500 banks. More to come as the day progresses.
 
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