600 Pro head or newer DFC head?

[jhamel]

I just had a crash. Since I am going to take the helicopter apart, I am wondering if I should change to the newer DFC head (with KDE holder arms), or just stay with the original style 600 Pro head? Other than additional cost, what are the pros and cons of the DFC head compared to the original head? Thanks.

[Commodore8888]

DFC head sits lower and brings the blade disc closer to the CG of the heli. This gets you quicker cyclic rates in theory.

Drawback is you can't really run slower headspeeds(less centripetal force to counter blade flex) and smack 3d at the same time. Being careful of your dampers is something else too. Boomstrikes with a head lowered as much as the DFC is a serious concern with anything short of damps in good condition especially if you're running 102mm+ tail blades.

Make sure whatever DFC you get has the stronger bolts in it. The fully rigid design is vulnerable to shock loads and weaker bolts will eventually shear due to fatigue.

Other options to the stocker align head are the RjX, rotorworks, KDE, and the Compass/TracX.

If you want to go driverless, the Compass and the DFC are the choices.
Personally I like the compass as you can set it up to be either the same height as the stock head or drop it low like the DFC.
That...and it's not a copy (sorry...bad blood. Admitting partial bias here)

[jhamel]

If I go with the Compass/TracX head, do I need to worry about the resolution issue as with the Align heads?

[Commodore8888]

I haven't found any geometry issues with the TracX stuff to date. The control arms appear to be pretty long out of the box (what the KDE arms do for Align) comparitively. I know of at least one other person who converted after me. Never mentioned any problems in the pm's we shared.

I haven't tried vbar yet but it's pretty easy to hit the blue light with beastX starting at 5.6* using small swash balls and slightly longer outer swash balls.
13.5 collec 12.5 cyclic with no biniding. Think I might be able to get more from it though.

If you do go the tracX route, the pro uses the standard length down tubes since it has a lower mast vs the old 600. The tubes that come with the kit can be cut down in a few seconds to whatever length you want. Replacements would be standard 6hv delrin tubes.

[taoY]

John,
Sorry about your crash. Hope it is not too bad.

I was intrigue by the Compass design. It is a very good design and looks very nice too. The major thing threw me off was it needs different feathering shaft. Unless you convert your 550 to Compass head, you need to stock two different feathering shafts. Parts availability is another thing to consider. Not many retailers carries Compass parts. If you have one close by, this will not be a factor.

The major concern about Align DFC head is the links between the swash and grips being too rigid. It has been discussed many times. I don't want to start another discussion here. But would like to state that we haven't heard any report of it causing any issue.

With SK720 the geometry is not really an issue with DFC head. My setup on 600 pro and 550 was 60/60/45 on the swash and 100% travel on cyclic before the putting on KDE arm and shorter swash balls. After the KDE arm and shorter swash balls, I have to increase the cyclic travel to 110% to get to the setup I like. However, I do enjoy the extra resolution KDE arm and shorter swash balls provide.

My 0.02 is either one works fine. Being a KDE fan boy, my personal choice is Align DFC with KDE arms. I am biased too.

Good luck

Cheater

[smsodhi]

I upgraded to the DFC head after a hard crash and use radix 600 mm blades with 105's.
I have installed KBDD hard dampers and it flys as sweet as. Very happy with it and it is a noticable improvement. I use VBar and have not had any issues with geometry.
Cyclic inputs much more snappy.
I still have the old tail which works fine, but am thinking of upgrading this too!!

[jhamel]

Originally Posted by Commodore8888

I haven't found any geometry issues with the TracX stuff to date. 13.5 collec 12.5 cyclic with no biniding. Think I might be able to get more from it though.

Are you using the inner servo arm holes?

[Commodore8888]

+1 the DFC interpretation isn't a bad one, I think they just sent the first batch out with bolts that weren't up to par.

As for me, I'm using the outer hole currently. Between experience/nankin and a few others now I haven't had a hard time getting replacement parts. Compass has been pretty good so far about staying on top of rush demand spikes. Granted, no one right now can touch align for parts besides eflite.

[Jonnyrl1]

Originally Posted by Commodore8888

+1 the DFC interpretation isn't a bad one, I think they just sent the first batch out with bolts that weren't up to par.

As for me, I'm using the outer hole currently. Between experience/nankin and a few others now I haven't had a hard time getting replacement parts. Compass has been pretty good so far about staying on top of rush demand spikes. Granted, no one right now can touch align for parts besides eflite.

Just to add to that, hobbyhut.com is carrying compass parts now for anyone on the east coast. For me its perfect, Im in Jersey and they are in Penn. So I usually get parts from them in a day.

[NRPY]

I recommend the DFC head. It's simpler, looks better, and flies fantastic. Since you're rebuilding anyway, I think it's a worthwhile upgrade.

[jhamel]

Originally Posted by NRPY

I recommend the DFC head. It's simpler, looks better, and flies fantastic. Since you're rebuilding anyway, I think it's a worthwhile upgrade.

OK. I should get the KDE arm holders to go with it to get it right from the get go. What else would I need? Different ball links on the swash? If so which ones?

How about the servo to swash links? Are they the same length as with the original head?

Are the servo ball links the same too?

Should I still use the inner servo arm holes, or would I need to switch to the outer arm holes?

[NRPY]

I'm using an SK-720, and my DFC head is all stock. At 60/60/43 I get 11 degrees of cyclic and 13 degrees of collective.

[jhamel]

Originally Posted by NRPY

I'm using an SK-720, and my DFC head is all stock. At 60/60/43 I get 11 degrees of cyclic and 13 degrees of collective.

Inner or outer servo arm holes?

[NRPY]

Inner holes on the stock Align arms.

[jhamel]

Originally Posted by NRPY

Inner holes on the stock Align arms.

That's impressive. Using the inner servo holes with the regular 600Pro head I could only get 9 degrees of cyclic and would get binding at the upper cyclic stick corners past -11.4 degrees collective. It seems that the DFC head would allow me to increase the cyclic without risk of binding. Cool. Thanks.

[jhamel]

Does the 600 DFC head use the same spindle shaft and thrust bearings as the older 600Pro head?

[ncarbon]

Yes same spindle and thrust bearings. I am running mine with a Vbar, the pro software has an electronic cyclic ring. Using shorter balls on the swash and longer balls on the outer swash I have gotten good numbers in the Vbar software. I an extremely pleased with the way my 600 flies...


Ned

[jhamel]

Originally Posted by ncarbon

Using shorter balls on the swash and longer balls on the outer swash I have gotten good numbers in the Vbar software.


Ned

For the 600Pro head on the 600 Pro, the swash outer ring uses Linkage ball B(M3x3) 4.75x9.77mm for all 3 ball links. The elevator servo uses the shorter Linkage ball A(M2x3.5) 4.75x8.18mm, and the other 2 servos use the longer Linkage ball A(M2x3) 4.75x13.5mm.

What sizes are you using instead?

BTW, I assume that the inner swash Linkage ball(M3x4) 5x12mm remains the same for the DFC head. Is this correct?

It's tough when there are no manuals available for this.

Thanks.

[ncarbon]

rotaryguy posted this in another thread.


Here are the parts I used, H60224 and HN7065.
From the 600 Pro Flybar version use the long balls in this pack for the outer swash -
http://www.align.com.tw/shop/product...oducts_id=3892
Not sure why they went with shorter ones in the FBL kit.
These - Φ4.75x11.76mm: stock are Φ4.75x9.77mm
For the inner swash blade grip links use the short 5mm balls from this kit -
http://www.align.com.tw/shop/product...oducts_id=2416
These - Φ5x8.5mm: stock are Φ5x12mm


Ned

[jhamel]

Ned. Thank you very much. I just added them to the cart.