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Flybarless Rotor Head Systems > Logo 500, Vstabi issue with rolls
 
 
doug101
Heliman
Location: Upstate NY, USA

Got a few more flights to day with my l500 with it's new vstabi. Got it flying really well, felt great, tracked great even at high speeds in a good stiff breeze. But, we could not get it to roll well at all. I say we as I had another very experienced flyer try it also so as to eliminate myself from the equation. These are rolls in moderately fast forward flight. The roll pops out with the nose high. Really nursing it can get it a bit better, but not right. Doing more that 2-3 in a row is nearly impossible.
Anyone else had this issue? To me it seems as a rudder issue. One of the other guys thought is was elevator interaction. We checked the phasing and it seems to be right at 0.
Suggestions welcome.
Doug
10-22-2007 02:11 AM
 
 
ozace
Key Veteran
Location: melbourne, australia

I have no doubt that the software can fix it. Now we need a software genius to tell us how.

Please keep us informed with your progress.

we can never have too many, can we ?
10-22-2007 02:31 AM
 
 
berthoud
Heliman
Location: Toledo, OH

I was doing the same today with my L500 V-Stabi...I thought it was my poor piloting but the heli did seem more difficult to roll than I would expect....

I wonder if this is a Collective or Cyclic Rudder Mix issue...(too much or too little)??? I think I will take these values to 0 this week and see how it flys...

Scott
10-22-2007 02:42 AM
 
 
doug101
Heliman
Location: Upstate NY, USA

I believe it well might have to do with the Col/Cyc rudder mix. Stationary ail flips seemed ok, it was the moving ones that were really bad.
I just went in to look, kind of hoping I'd find the mix backwards or something like that. No such luck.
I noticed a thread on the vstabi forum about this exact thing. They thought it was a rudder issue. Unfortunately, the guy has not got it fixed yet.
I'm sure it is something the vstabi is doing, just need to identify what.
Doug
10-22-2007 03:08 AM
 
 
ulrich
Heliman
Location: Hanau, Hessen - Deutschland

Can you please post the complete Setup, including the headspeed and the Blades used. Also try to find out if it is the same on both rolling directions, and how much it is dependant on the speed. So we can sort out what the reason is.

What Setup are you using? The Factory as basis, or one of the Setups form the VBar Forum http://www.vstabi.de/forum1/list.php?6 or the CD ?

My 500 does perfect rolls, i can fly a complete medium speed fly by without touching ail or rudder at all. But i am using 100s cfk blades on tail
10-22-2007 09:20 AM
HOMEPAGE  
 
 
doug101
Heliman
Location: Upstate NY, USA

Setup:
Logo 5003d, vBar Head, vStabi unit
Neu 1910 1.5y, 212/19
12s A123
Jazz 55-10-32
Fut 9252 cyclic
Fut 9256 rudder
Rotortech 550 blades (approx 118gr)
80mm generic carbon tail blades

HS 2050 with gov

It is very dependent on speed. The faster forward the worse it is. Stationary are the best. I did not try both directions, just to the right. We were in a moderate crosswind (15-18mph) and one interesting fact was that rolling (always to the right) with the wind on the left produce a better roll that rolling with the wind on the right.

Normal fast forward/fast backwards is solid. Long tail slides produced only a small amount of movement in the rudder axis.

I already notice that my t/r blades are pretty short. That's what I had on it prior to the flybarless conversion and they were fine.

I started off by doing factory reset, then set up servos, etc. I then went through and compared with ulis_logo500_1.xml config from the vbar forum. I used that to model my parameters. So you will see that my config is similar, but not exactly as that one.

Here is my config file. You can view it or right click to save it.
10-22-2007 08:29 PM
 
 
JKos
Elite Veteran
Location: City of California in the state of Maryland

Is your sensor mounted properly? May seem obvious, but any misalignment of the sensor will cause "funny" stuff during flight.

- John

Protos -- Logo 10
10-23-2007 03:03 PM
 
 
doug101
Heliman
Location: Upstate NY, USA

John, I took a look at the sensor. It sure looks like it is square. But as you know being inside the bottom frame you cannot get a look from above. Any tips on insuring a square mounting?
Doug
10-23-2007 04:17 PM
 
 
ulrich
Heliman
Location: Hanau, Hessen - Deutschland

I have written an atricle regarding the effect in the vbar wiki in the FAQ section. Please commet this in the vbar forum http://www.vstabi.de/forum1/list.php?9 if you like.

http://vstabi.de/wiki/index.php?tit...ng_Rolls_in_FFF

The setups looks good so far, AoF seems to set up ok. Headspeed is sufficient for sure, but i am unsure about the blades which i do not know at all.
10-23-2007 04:21 PM
HOMEPAGE  
 
 
JKos
Elite Veteran
Location: City of California in the state of Maryland

First, I make sure the mounting area is perpendicular to the main shaft. For example, as many of you know, the shelves at the back of the battery compartments of the Logo 10 and 14 aren't perpendicular at all and require a wedge to fix it. Then, I use a piece of square brass stock between the side of the frame and the sensor as I place it down on the tape to insure it is aligned in the yaw axis. Substitute whatever you like for the square brass stock as long as it is of constant thickness.

- John

Protos -- Logo 10
10-23-2007 04:26 PM
 
 
doug101
Heliman
Location: Upstate NY, USA

Thanks John, I'll re mount mine using that method.
Doug
10-23-2007 04:33 PM
 
 
doug101
Heliman
Location: Upstate NY, USA

Thanks Ulrich, I went over the wiki article, very good info.

I have changed a couple of things:
remounted sensor to insure it is accurately mounted
reset the phase at the head to insure it is 0

Raining all day today and probably tomorrow. I'll try to get some tests in later in the week. I'll post results here and if I'm still having problems, I'll post on the vstabi forum.

Some info for you about the blades.
Rotortech 550 CF Taper tip - 550 x 51 x 7.2
Symemtrical 14% airfoil
Weight 113gr
Lengthwise CG 300mm from bore = 300/550 = 54%
Lead/Lag approximately 1mm of lead at tip

These are considered a good brand and are pretty stiff. The CG is pretty far out (54%), the Lead is minimal.

Doug
10-23-2007 07:05 PM
 
 
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Flybarless Rotor Head Systems > Logo 500, Vstabi issue with rolls
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