Broke down, wimped out and made the DFC mod, hope you lke it.

[ualdrivr]

All right fellas, I wimped out. A lot of "naysayers" here and in other forums, especially the 700E one, about the new DFC Align Head.

From my previous thread you all know that I installed it on my 700N and it looked great. https://www.helifreak.com/showthread.php?t=373261 Read all about it.

Last weekend one of the guys on RR posted that he had a boom strike with his 700E, during an inverted descend and a quick reversal into full negative pitch. His Heli exploded. Here is the thread with link to RR: https://www.helifreak.com/showthread.php?t=374518

So, without even flying my Heli, I started thinking about a mod. I wanted to use the 700 EFL main shaft http://www.align.com.tw/shop/product...oducts_id=3278
with the DFC Head.

The problem here is an additional 20mm of length, the turnbuckles included with the DFC Head are only 20mm long, so they are not long enough to accommodate the EFL main shaft's length.

I looked around for turnbuckles that are 3mm wide and threaded. I came across these.http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXY743
they are made out of Titanium and they are threaded for 3mm. I bought the 1 3/8 and the 1 5/8 lengths. The 1 5/8 was the one I used, because the length allowed for enough threads to go into the DFC arms and the ball links.



I also bought the Lunsford turnbuckle tool to make things easier. The ball links that come with the DFC head are short, same length like the elevator A frame ball link. I needed more threads from the turnbuckles to go into the ball link so I used the longer Align links from the H70066 EFL ball link kit.



The mod went smooth. The geometry of the BeastX didn't change a bit and I got full +/- 13 degrees of pitch. The distance of the blade from the boom went up 20+ mm to 147mm from around 127mm. Here is some pics.









and here is one with the canopy on, for reference and comparison with the one on my DFC conversion earlier thread.



Now, I know we're going to have some "naysayers" about this mod as well, so fire away. I think it could work, especially for the Nitro that higher headspeeds than 1950 are not advantageous, due to motor rpm limitations.

[terrabit]

Hey, that's pretty sweet. You should post this over on RR as well. I'm sure it would be appreciated.

BTW, if you don't mind, how long are the stock DFC turnbuckles? I'm thinking these Lunsford turnbuckles would be an improvement even with the stock DFC configuration. Can you think of any reason why it wouldn't?

Thanks!

[Blink 182]

Pictures dont work....

[Roger Palacio]

Don't see the pictures

[Mystic3D]

I see no reason this would not work, the 3mm turnbuckles look to be very strong.

[backburner1955]

Need pics...

These turnbuckles are nice too.

http://www.espritmodel.com/pushrod-t...raft-m3-2.aspx

[MarkFlysHelis]

I'd be extremely careful with this.

I've already heard that the original DFC head design comes slightly out of phase in flight. A mod like this can and will exaggerate that.

just my .02$

[Mystic3D]

Originally Posted by MarkFlysHelis

I'd be extremely careful with this.

I've already heard that the original DFC head design comes slightly out of phase in flight. A mod like this can and will exaggerate that.

just my .02$

What flight characteristics would show up?
I know piros not level, but that is not under load.

After thinking the entire benefit of the DFC head is lower main shaft height as far as flight characteristics.

[ualdrivr]

Uploaded the pics again, can you guys see them now?

[terrabit]

Originally Posted by MarkFlysHelis

I'd be extremely careful with this.

I've already heard that the original DFC head design comes slightly out of phase in flight. A mod like this can and will exaggerate that.

just my .02$

I don't know. You're talking about the added marginal flex. You'd be hardpresed to measure that even if you had the tools. I just can't imagin 20mm of 3mm threaded titanium rod is going to flex much.

[backburner1955]

Originally Posted by ualdrivr

Uploaded the pics again, can you guys see them now?

Oh yeah, that looks nice. You have inspired me to do this on my 700N and 700E. Waiting on flight report...

[MarkFlysHelis]

Originally Posted by Mystic3D

What flight characteristics would show up?
I know piros not level, but that is not under load.

After thinking the entire benefit of the DFC head is lower main shaft height as far as flight characteristics.

For most, I imagine the piros would be the easiest way to notice it.

My guess is they designed the head, calculated the amount of torque the arm would take before dramatically coming out of phase, then made the main shaft to accommodate.

[ualdrivr]

Originally Posted by terrabit

Hey, that's pretty sweet. You should post this over on RR as well. I'm sure it would be appreciated.

BTW, if you don't mind, how long are the stock DFC turnbuckles? I'm thinking these Lunsford turnbuckles would be an improvement even with the stock DFC configuration. Can you think of any reason why it wouldn't?

Thanks!

Terrabit, the stock ones are only 20mm long, I figured I needed at least twice that to make it work with the EFL shaft, that's why the 1 5/8 which is 42mm long worked better than the 1 3/8 = 35mm.

As far as RR goes, feel free to post it, I don't get along well with Mark R...

Originally Posted by backburner1955

Oh yeah, that looks nice. You have inspired me to do this on my 700N and 700E. Waiting on flight report...

Thanks Bryan, we'll do when the weather gets better in the NE....

[Mystic3D]

Originally Posted by terrabit

I don't know. You're talking about the added marginal flex. You'd be hardpresed to measure that even if you had the tools. I just can't imagin 20mm of 3mm threaded titanium rod is going to flex much.

I don't know also, I do know that basic physics says a longer lever has more torque.
The bolts that hold the swash arms into the grips will have a lot of stress on side loads.

Great Idea, echo be careful when testing.

[ualdrivr]

Originally Posted by MarkFlysHelis

For most, I imagine the piros would be the easiest way to notice it.

My guess is they designed the head, calculated the amount of torque the arm would take before dramatically coming out of phase, then made the main shaft to accommodate.

Originally Posted by Mystic3D

I don't know also, I do know that basic physics says a longer lever has more torque.
The bolts that hold the swash arms into the grips will have a lot of stress on side loads.

Great Idea, echo be careful when testing.

The titanium turnbuckles are very stiff, the threaded part that you see has reached all the way to the end of the aluminum part on top of it. But since we are talking about side loads, as Mark mentioned, I just got another idea. I would be willing to beef it up even more, by introducing a swash driver from the original FBL head, which I still have.

As you can see from the pics there is plenty of room above the swash to install it and phase it correctly, maybe two mm bellow the bottom of the head, or whatever keeps the arms parallel to the swash at mid stick.

Why do that you ask?...So you have the benefits of the turnbuckles and the blade clearance from the boom. Best of both worlds???

[martin_]

This will not be worst than compass delrin rod for phasing issue.

Since those arm took all the flex, I would put a lock nut on the arm side to prevent the turnbuckle to expand the threaded hole in the arm and coming loose over time.

[Mystic3D]

Originally Posted by ualdrivr

I just got another idea. I would be willing to beef it up even more, by introducing a swash driver from the original FBL head, which I still have.

As you can see from the pics there is plenty of room above the swash to install it and phase it correctly, maybe two mm bellow the bottom of the head, or whatever keeps the arms parallel to the swash at mid stick.

Awesome Plan, let us know how it works

[ualdrivr]

Originally Posted by martin_

This will not be worst than compass delrin rod for phasing issue.

Since those arm took all the flex, I would put a lock nut on the arm side to prevent the turnbuckle to expand the threaded hole in the arm and coming loose over time.

You mean like a regular nut threaded up against the aluminum and secured, so it's locked up? That could work as well, but I'm telling you the titanium turnbuckles are better quality and threaded much better than the flimsy Align ones, the rod is tight and solid the way it looks right now.

However your idea would not hurt a bit, since aluminum is much softer than titanium, absolutely.

[OnTheSnap]

Nice work! I'm also wondering if it's rigid enough to hold the phasing under load with the long turnbuckles. Is there much advantage to this setup vs the stock v2 head with the swash driver? I guess it's is still a bit lower.

Edit - my info was stale. Was looking at a 30m old thread. (-:

[perfectregulators]

i dont see why there is any issue with the "side load" on the turnbuckles because the load isnt generated to them. any side load on the head is at the jesus bolt and 2 bolts that thread into the mainshaft through the headblock. any side force on the turnbuckles will be very very minimal to none at all. pull force is whats important on the turnbuckles though and the more threads that are together, the better.

the stock align turnbuckles only catch a few threads and if you dont loc-tite them into the aluminum arm, they are a very loose fit.

great job panos, looks great!!!