Inverted flight blade tracking

[ptarp]

I did my first grass-cutting height inverted hovers with my TRex recently, I noticed that my blades were way out of track(~1"). The blades track well upright. I did some tests and it happens every time I go inverted, and corrects itself when upright.

I am running 325 pro woodies @ around 2600rpm. I have tried two sets of blades and they both do this. I'm a bit stumped how to correct this w/o screwing up upright tracking.

Any ideas?

[zflarez]

What I relized is that tracking the blades using the long link right of the swash results in tracked blades at only one pitch. Try retracking them using the link right before the blade grip. I could very easily be wrong but when I adjusted using the long lengths my pitch was of by 5 degrees at the bottom end. I think it has something to do with the head linkage distorting the adjustments un linear like.

[zagidave]

you say you tried another set of blades were they also woodies?

imho i would say that the blades are probably the culprip i have flown my rex on the 325 woodies and the tracking is way off put the carbons back on and the tracking is spot on.

if there is a miss match in the blades that you cure by adjusting the tracking (maybe a slight twist) then it follows that this will be reversed when inverted.
hope this helps

[king kong]

It's because of slop somewhere in the head.

[Finless]

Most of my issues with this same thing are because the bushings in the seesaw (where the seesaw box pivots on the head) get worn out and the slop causes tracking issues like this.

Bob

[ptarp]

Thanks guys...my head is pretty "tight" except the swashplate bearing has noticeable slop...always has. I would replace it if I thought the replacement would be any better.

I'll check the seesaw closely to see if I could have any issues there.

[Finless]

Grab your baldes and twist them like you were putting in pitch. See if one blade has more slop than the other. Also i have seen a slightly loose ball in the head cause this too.... If all looks OK have you tried a different set of blades? I have seen some pro woods do this as well but it usually is subtile tracking changes.

bob

[ptarp]

Originally Posted by Finless

Grab your baldes and twist them like you were putting in pitch. See if one blade has more slop than the other.

They both have slop using this method, I have traced it back to the swash bearing. The amount of slop appears to be the same on each blade. It sounds like other people do not have troubles with a sloppy swash bearing...I guess I'll get a replacement and see if its better.

Thanks Finless.

[Finless]

Philip, I doubt it is the swash really I do as any slop there usually is equal up to the links.... But let me know if that solves it but i kind of doubt it.

Bob

[blahblah9]

Originally Posted by Finless

Most of my issues with this same thing are because the bushings in the seesaw (where the seesaw box pivots on the head) get worn out and the slop causes tracking issues like this.

Bob

What about on a brand new heli? is it most likely my wood blades causing it?

[mapas]

Also measure the pitch:
In both blades you should have the same range (e.g. -11,0,11)
If you have -11,0,11 in one blade and -10,0,12 in the other, then there is sth wrong with the links. E.g. the mixer arms are not both horizontal when using 0 pitch.

[blahblah9]

Originally Posted by mapas

Also measure the pitch:
In both blades you should have the same range (e.g. -11,0,11)
If you have -11,0,11 in one blade and -10,0,12 in the other, then there is sth wrong with the links. E.g. the mixer arms are not both horizontal when using 0 pitch.

just rechecked all pitch since spending most of the day adjusting links to get blades tracking. But to my suprise measuring both blades all around heli left/right front/back the pitch my vary by 1/2 degree or so. i also read somewhere that if you adjust the little links that attach to the blade grips it will throw off your tracking inverted? any truth to this, cuz mine are different lengths by 1mm.

[Lottomunch]

Well I can't say I'm glad to see others are having this problem but its nice to not be alone.

I started practicing my inverted orientations more and more and totally noticed this as well. It was only on one of my Trex's though. Never could figure out why. I am kinda lazy and ended up tracking the blades when both inverted and right side up. Pretty pathetic but it ended up having the blades pretty stinkin close in both orientations.

I'm looking forward to an answer. I'll go back and check out any differences between my "good" and "bad" head and see if I can't find something.

Daniel

[blahblah9]

okay, i got a chance to put my carbon blades on today, and i guess it was the wood blades, tracked perfect upright and inverted