cheap 500 DFC head phasing :(

[moyesboy]

Fitted this Chinese dfc copy head to my 500 but it deffo doesn't tumble as straight as it did with my std flybar head modified to flybarless.
Looking at it I see quite a significant angle on the two DFC swash balls - not 90 degrees to the grips.

500dfc phase angle.jpg

I wonder if anyone could send me a pic of a genuine align head for comparison?
I am wondering which parts are the wrong size to cause this...either the grips are not far enough apart or the arms are too long or something....
Unless the align head has this angle too...

The BeastX was trying to correct this, a slow tumble was ok but a fast one was not.
I wonder if there is an adjustment on the beast X itself that I could use to correct this electronically...

[George J]

Seriously, why on earth would you bother buying a cheap Chinese copy of a Trex 500 DFC head? They cost peanuts as it is!!!

[GIXERMAN]

I'm with you G!

[coolice]

Fitted this Chinese dfc copy head to my 500 but it deffo doesn't tumble as straight as it did with my std flybar head modified to flybarless.
Looking at it I see quite a significant angle on the two DFC swash balls - not 90 degrees to the grips.

[ATTACH=CONFIG]85856[/ATTACH]

I wonder if anyone could send me a pic of a genuine align head for comparison?
I am wondering which parts are the wrong size to cause this...either the grips are not far enough apart or the arms are too long or something....
Unless the align head has this angle too...

The BeastX was trying to correct this, a slow tumble was ok but a fast one was not.
I wonder if there is an adjustment on the beast X itself that I could use to correct this electronically...

Hey Buddy.

Oh yeah, that's well offline.

As an exercise you could try flipping the DFC pitch links connecting swash to blade grip arm 180 degrees, so the arm itself is closest to the grip. Looking at your photo once you do this on both sides, the phasing should be much better.
.

[trillian]

Yeah the phasing is offset. Sometimes there is an intentional offset to compensate for blade lag but that would be in the opposite direction. So maybe if the DFC arms can be flipped as Coolice suggests you might be right in the sweet spot. Alternatively it looks like some material would need grinding off somewhere to bring the links back to the 90 degree point.

I think there might be a phase adjust in the BeastX so if the links cannot be flipped that's prob the next thing to look into.

--- On second thought, it's the missing spacers as RichardV points out in the post below!-----

[moyesboy]

Flipping the pitch arms will make it about the same angle out the other way.
I see from my 450 dfc head that the balls should be exactly in line with the main shaft (zero lead angle, exactly 90).

Thanks for that pic Richard.
The spacers are there, but squashed right into the rather soft dampers.
Which makes me suspect there is something out on the grips, or the length of the spindle...

Is the DFC spindle the same as the std original flybarred 500 spindle?

Richard, could you put a vernier across that one and tell me the two dims marked?

align head.jpg

...expense is a matter of opinion, but this upgrade cost in align parts I thought was quite expensive because I have the old blade grips as well so quite a few parts to buy (about half the cost of the new Gaui 450 kit I was thinking of buying in fact). So I took a punt...

I suspect this one might be sorted by replacing part of it with some align parts, now I have it I'm interested to know which part is wrong...of course it could be a little bit of everything!

[George J]

I totally get your point about cost and taking a punt but so often in these situations, bit like you have now, there is something just not quite right and then after a load of wasted time you end up buying the genuine item anyway!

[moyesboy]

This head has soft dampers like the old flybar ones. I've fitted the KBDD orange ones off my old head. They had doubled up on the spacer rings inside the grip to sqwuash the soft dampers more so the spacers had vanished inside the head. Now my head looks like normal and most of the misalignment is gone.
Has some wine, so I wont stick the night blades on to try it just now...
Maybe my £23 wasn't wasted...

[trillian]

Flipping the pitch arms will make it about the same angle out the other way.
I see from my 450 dfc head that the balls should be exactly in line with the main shaft (zero lead angle, exactly 90).

You may find though that having it offset the other way works. This is because it would be compensating for blade lag which is what some rotorheads do intentionally.

[Granpappy]

This head has soft dampers like the old flybar ones. I've fitted the KBDD orange ones off my old head. They had doubled up on the spacer rings inside the grip to sqwuash the soft dampers more so the spacers had vanished inside the head. Now my head looks like normal and most of the misalignment is gone.
Has some wine, so I wont stick the night blades on to try it just now...
Maybe my £23 wasn't wasted...

I would have thought that it's the bolt and washer at each end of the feathering shaft that determines the position of the blade grips and alignment, not how squishy or hard the dampers are. Did you not tighten the feathering shaft bolts all the way to get it to line up, or am I missing something.

[GIXERMAN]

I would have thought that it's the bolt and washer at each end of the feathering shaft that determines the position of the blade grips and alignment, not how squishy or hard the dampers are. Did you not tighten the feathering shaft bolts all the way to get it to line up, or am I missing something.

they stop the blade grips from flying off!

[Granpappy]

they stop the blade grips from flying off!

Yes, I know that.

[moyesboy]

I would have thought that it's the bolt and washer at each end of the feathering shaft that determines the position of the blade grips and alignment, not how squishy or hard the dampers are. Did you not tighten the feathering shaft bolts all the way to get it to line up, or am I missing something.

They had fitted extra spacer rings between the thrust bearing and the radial bearing inside each grip - thus pushing the grips further together with the same length spindle, and squashing those soft dampers to death...
Everything else seems to be about the right size. Maybe it will work well.

[Granpappy]

They had fitted extra spacer rings between the thrust bearing and the radial bearing inside each grip - thus pushing the grips further together with the same length spindle, and squashing those soft dampers to death...
Everything else seems to be about the right size. Maybe it will work well.

Got it. That makes sense. Hope it works out.