CNC feathering shaft, can it use Align one instead?

[merlin703]

When I bought the CNC head, I thougth it was exactly the same as the TREX 450 v2 head. That is not the case, now I need to replace the feathering shaft so I bought Align stuff and they are TOO short and it's tight :arggg: Can I still use the Align one or no way?

I measured my existing feathering shaft and it's 42.6 MM. This size might be because of the crash since I can't find anything that size. What can I get to replace the blue CNC head?
Also, what is that I will need to preplace to make it closer to a TREX450v2... or that is just not possible?

[tom dubya]

Which blue cnc head did you buy? There's a couple of them by different company's.

[merlin703]

This is what I bought:
http://www.cnchelicopter.com/servlet/the-84/3dx450-%28A-fdsh-C-fdsh-F%29-T-dsh-REX-450X-fdsh-XL-fdsh-SE/Detail
Arter I placed the order, I had to order the swash plate B version since I want to convert mine to be closer to a TREX. Ideally, I would like to MAKE my current head to match with TREX450v2 parts but I don't know how that would work.

[another_finn]

Ideally, I would like to MAKE my current head to match with TREX450v2 parts
Why? That's a perfectly good head - the only problem I have noticed is that the washout mixing arms bind on extreme cyclic. Making it 100% SE V2 compatible essentially means a complete replacement... and the only big difference would be 4 mm feathering shafts instead of 3 mm. The feathering shaft will bend when you crash, there's no way around that. The 3 mm shafts just absorb a little more of the impact energy, possibly saving your main shaft.

If you want to upgrade that head, the only changes I would suggest are T-Rex mixing arms and a 220 mm flybar. I've been flying with V2 compatible lower arms borrowed from my CopterX head, but I just received a full set of V2 arms that are going on the head later tonight. I'll let you know if I run into any problems with the upper arms.

[merlin703]

Yes they do bind. I thought it was just my set up that was wrong. It works OK. I'm not 3d or expert of any kind but I thought if it was a TREX450v2 and something needs to be replaced, I could go to my LHS and get the part. Now I find myself having to go to a site and figure out the specific part I need without being sure if I will get the right one or not.
Here is what I think I need. There are some people advertising someone on ebay but I will never know if they would work on this type of hear.
http://www.cnchelicopter.com/servlet/the-248/trex-3dx-450-shogun/Detail

So the mixing arm has to be longer to be closer to a 450v2, uh? According to your post, that will also prevent it from binding. Let me know how it works for you.

[another_finn]

Here is what I think I need. There are some people advertising someone on ebay but I will never know if they would work on this type of hear.
http://www.cnchelicopter.com/servlet/the-248/trex-3dx-450-shogun/Detail
That's the one - and they also have a 3-pack (http://www.cnchelicopter.com/servlet/the-912/Trex-3DX-HDX-450/Detail) without the spacers for $5.90. I just stock up on the correct shafts and it's not a problem.

So the mixing arm has to be longer to be closer to a 450v2, uh? According to your post, that will also prevent it from binding. Let me know how it works for you.
Not longer but thinner. The angle I drew from the center of the ball link is the same on both arms, so you can easily see where the problem lies... Swashplate dimensions are also different to accommodate the beefier arms, but you still have to tone down your swash mix too far to prevent the arm from striking the swashplate ball mounts.

Looks like the Sonix V2 arms (http://www.cnchelicopter.com/servlet/the-1225/Head005%29-TREX-3dx-450/Detail) would be a good and inexpensive replacement. I just got the Align parts to see how they work. Now my cyclic is only limited by the links on the flybar cage making contact with the blade grips :D

[merlin703]

Actually, they are longer than the 450's. I have feathering shaft for 450v1 and put them next to the one I had and they are not the same. It goes in OK but it's short and when I tighted them up, there is too much resistance. The problem I have with my current head is that when I'm at full negative, the servo arms touch the main gear. Of course, I don't go that far at this time during flight but still, I don't think it should be that way.

[another_finn]

Wait, wait... You seem to be talking of several different things here. The mixing arms don't seem to be any longer, but yes, the feathering shafts are. You can not use T-Rex feathering shafts on the Sonix head, it requires its own type.

Exactly what frame are you using, if the servo arms can touch the main gear? Plastic Belt CP with a DTS modification? Do you still get enough cyclic and collective if you limit your servo throws to a safe range?

[merlin703]

Well, I'm using that head with the EXI frame, which I understand is the same as the TREX, right? Longer main shaft? That would explain why it touches the main gear when I go all the way to negative and side to side from there. Darn, I placed my order with CNC yesterday already. So this means that I can only use special main shafts with the CNC head? :arggg:
The heli flies fine. The only two issues I have with it is the feathering shaft that uses a longer one and the servo arms touching the main gear when in full negative from side to side. Since I'm not doing inverted, it doesn't bother me but I do want to fix that at some point.

[another_finn]

Well, I'm using that head with the EXI frame, which I understand is the same as the TREX, right? Longer main shaft? That would explain why it touches the main gear when I go all the way to negative and side to side from there. Darn, I placed my order with CNC yesterday already. So this means that I can only use special main shafts with the CNC head? :arggg:
No, any T-Rex compatible main shafts are fine. Align, Sonix, whatever. Servo end points have nothing to do with your head, it's just what the radio tells the servos to do. If you're not using the full length of the servo arm, cut the rest of it off. If you have a computer radio, limit your swash mix so the arms don't strike the main gear.

[merlin703]

I had already cut the unuse parts of the servo arms but they still touch the main gear when at full negative. I have set limit a bit at the end points for my servos but I don't want to limit it much because I like to have a high pitch. I will try to compare it with an actual TREX to see the differences. Thanks for your help on getting me the feathering shaft. I was just buying extra TREX parts thinking that they would fit on my EXI body and CNC head :roll: Thanks again Mika!