new align dfc swashes

[350Z_Al]

Originally Posted by djamgils

Its about the feathering shaft teetering in the head. Watch the video again and try to understand.
Or look for all the other threads about it.

I saw this problem the first time I saw pictures of the new DFC swash, I just haven't commented on it until now.

There IS a design flaw, whether or not we will see a failure because has yet to be seen.

In my opinion, it may cause premature wear of the ball links leading to the potential for one to come off during flight. Again, whether or not the premature wear is rapid enough that this will become a problem, we will have to wait and see.

Align is probably anticipating a bit of lateral flex in the plastic rod end to compensate for the flex in the head dampers. The problem, in my opinion, is that this force is now in the direction of popping the ball link off.

Truth be told there are many mechanical devices out on the market with design flaws that work fine every day and nobody is the wiser. This DFC swash may just be one of those devices.

I guess it's just the picky engineer in myself and others who have the opinion "Just because it works, doesn't mean it's right".

[CeeveeSiN]

Originally Posted by jones007

It doesn't take an engineering degree to see that there is a problem with the DFC-type head design. While the design may fly well, it's clear that the stresses normally handled by the dampers have now been transferred to parts that were not intended to handle that sort of stress. The stiffer the dampers, the less of a problem it will be.

and thats why the new DFC dampeners are basically hard plastic. ridged head like the SAB version with those in there.
and btw.. they fly great.

[ddj74]

Originally Posted by djamgils

Compass uses delrin rods vs align using aluminium. Big difference there. But I would still prefer a regular swash driver and head above the compass design. Just to bad that there isnt a single 700 out there that meets my expectations. Probably my mechanical engineering degree is to blame for that, cant stand all the design flaws in a lot of helis.
edit, just saw that the SAB Goblin will also be available with a regular head, interesting. Apparantly they dont like it either? But it does make it a lot more appealing to me.


Its not about swash driver forces and offcourse the head rotates because of the clamping of the hub and not the swash duh...
Its about the feathering shaft teetering in the head. Watch the video again and try to understand.
Or look for all the other threads about it.

Can't "Teeter" with good dampeners plus being compress with the brass bushing and grips. If they wear prematurely who cares?! Can you not afford $5 dampeners every so often. Parts wears no matter what...vibration, poor setup, design flaws but this is nothing but talk and no one with problems. This is what we call pre-flight check. If a part is worn or sloppy then replace the problem. Truth be told if i have to buy a set of dampeners and 2 ball links once every 6 months to get the best flight performance ever from a Trex costing at the very most $15 what are you complaining about? Before you fly grab a hold of the grips and make sure there's no movement and go fly. If there's movement put in some $5 dampeners which takes 10 minutes to put on and go fly. Problems your trying to say is predictions of something that isn't a common problem or causing crashes. If the feathering shaft was solid in place look forward to replacing grips, feathering shaft, thrust bearings and main shaft on every blade strike because with no flexing area your looking at more problems. Plus a little flex gives better tracking if your off a little. Movement is minuscule to none and the ball grips can handle slight movement. Vibration alone is worse then flex.

[CeeveeSiN]

Originally Posted by djamgils

Compass uses delrin rods vs align using aluminium. Big difference there. But I would still prefer a regular swash driver and head above the compass design. Just to bad that there isnt a single 700 out there that meets my expectations. Probably my mechanical engineering degree is to blame for that, cant stand all the design flaws in a lot of helis.
edit, just saw that the SAB Goblin will also be available with a regular head, interesting. Apparantly they dont like it either? But it does make it a lot more appealing to me.


Its not about swash driver forces and offcourse the head rotates because of the clamping of the hub and not the swash duh...
Its about the feathering shaft teetering in the head. Watch the video again and try to understand.
Or look for all the other threads about it.

SAB likes the DFC head just fine.. but there are some people like some in this thread that refuse to own a DFC head becasue they think they are smarter than the engineers they are going to offer a head choice.

Bert says it will be a choice not unlike the choice between FB and FBL.
to increase the market.

[350Z_Al]

For the record, although I think there is flaws, I own 3 DFC heads. Like I said in my post above, many products on the market are flawed but serve their entire lifespan without the flaw causing any serious issue.

[djamgils]

Originally Posted by ddj74

Can't "Teeter" with good dampeners plus being compress with the brass bushing and grips.

If the feathering shaft was solid in place look forward to replacing grips, feathering shaft, thrust bearings and main shaft on every blade strike because with no flexing area your looking at more problems. Plus a little flex gives better tracking if your off a little. Movement is minuscule to none and the ball grips can handle slight movement. Vibration alone is worse then flex.

first you say cant teeter then you say it is necessary although the movement is "miniscule to none"

Then I have 2 things I am wondering about
1) why do we even have dampers on a fbl heli?
2) at the moment we have dampers and thus the feathering shaft moves (even though miniscule), then the stiffness of the linkage dictates how much force is put on the ball links. Given the fact that there are reports on m3 bolts bending I would think those forces are pretty large.
this can be "solved" with extremely hard dampers, for example the Delrin bushes they are now selling. (back to 1) But what other problems will that cause? Faster wear of all the bearings in the head and mainshaft due to more direct vibrations and forces?
Mikado even went through the trouble of using dampers in the tailhub, why would they do that if it isnt needed.

[ddj74]

Your looking at this waaaay too deep. Posting about something your not even using makes it even more useless. Like complaining about the president and not voting. Say if everything was stiff as a board and no play anywhere...pitching you heli up and down hard will flex something and stress something else. It's a chain reaction. What can't move will move somewhere else. No matter what there will be something getting punished. I'm not arguing the fact of what you are saying but i can take my hand on the DFC head and try and move it and it just doesn't happen. Something need to displace some of this energy durign hard flying. It's rock solid fully assembled. Bolts being bent could be too soft a dampener for their type of flying. There's many of causes for damages or wear but mostly due to not setting up their heli to the type of flying they do. Fly hard / 3d use hard dampeners. Fly scale or sport use softer dampeners. Use the wrong setup mechanically then accept the consequences. We could talk about this topic to no end but the fact being is if there is a big failure rate where's the video's and proof other then the one showing a head missing parts that prove nothing. Also people are using wrong size swash balls with the DFC heads all across the board. People think there's problem but they are just not educated on proper setup.

[rcflyerheli]

I want to throw in an idea that I haven't seen addressed.

With the normal rotation of the main shaft, head and blades, the forces driving the swash are essentially into the balls. I haven't done any analysis or measurement to see just what the forces actually are, but whatever the amount, on the DFC swash they are into the swash balls. They can't be in the other direction or they wouldn't drive the swash.

Even with the exaggerated tipping of the feathering shaft without the dampers in place, the net sum of forces still has to be in the direction of rotation of the blades, otherwise the swash wouldn't rotate along with the blades.

Just MHO.

[djamgils]

I dont think that matters, see image below all have the same swash driver torque but the last one is pushing the link off

[rcflyerheli]

This is where I don't agree. The only forces acting on the balls comes from angular displacement of the spindle. Blade forces should only in line with the balls and vertical or trying to displace the feathering shaft through the dampers. I don't (or rather can't) imagine that rotation (flexing movement) of the feathering shaft would induce the assymetric loads that you show. This is all in the assumption that the feathering shaft is strong enough to resist bending.

[djamgils]

I combined 2 load cases in that picture.
left figure is only swash driver forces, middle and right are with added forces from featheringshaft teetering.
So the forces in this picture below are from teetering (only direction is opposite but you can hold the previous image upside down probably), combined with forces from left figure in previous post gives the middle and/or right forces.

[tracerbob]

Just got my DFC swash today. Need some ideas on which holes in the upper swash to use. I'm still building my 600 so I haven't clue which ones to use. Inner holes on the swash outer holes on the servo arm?

[xseeker]

Had a ball link from the blade grip to the swash pop off mid flight and found the cause below...

YouTube

YouTube

[BlackTitanium]

Oh crap... I threw away the DFC dampers and installed the KBDD dampers, on my Trex 500.

Haven't had the link pop off yet, but I'll have to stop by the local hobby shop for some DFC POM dampers.

[KYM]

So when does the new 600 pro v2 kit come out? with all these upgrage it has to be soon.

[BlackTitanium]

Originally Posted by tracerbob

Just got my DFC swash today. Need some ideas on which holes in the upper swash to use. I'm still building my 600 so I haven't clue which ones to use. Inner holes on the swash outer holes on the servo arm?

Use the outer holes on the DFC Swash.
If you need extra resolution, then try using the inner holes on the DFC Swash.

I use the BeastX, and get blue light at 6*, inner holes on all servos, outer hole on DFC Swash.

[xseeker]

Though I use 3gx, I got all outer holes still heh. Didn't want to deal with binding.

Those dampers in my vid were extra hard but were well over due for a change.

What POM dampers you talking about?

[matchbox]

I brought one of these a while ago but haven't used it yet. The main dislike i have for it is how difficult it is to remove the DFC ball couplings from the centre without damaging or destroying them. Has anyone came up with a way to remove the coupling without leaving a dent in them from the corners or the inner swash or taking the paint of the swash.

[BlackTitanium]

Originally Posted by xseeker

Though I use 3gx, I got all outer holes still heh. Didn't want to deal with binding.

Those dampers in my vid were extra hard but were well over due for a change.

What POM dampers you talking about?

The POM dampers are rigid, like a hard plastic.
They do not have any flex like the KBDD or Trueblood dampers.

600DFC Head Damper H60244


500DFC Head Damper H50188

[xseeker]

Ya I'll be getting those for sure. At first I thought those were the ones that came with the head.