I've recently upgraded the outter and inner shafts to longer Vortex ones, i have my servo linkage on the second hole for sum outdoor flying.....i recently had a slight blade strike and i wasn't flying fast or hard or made any sudden stick movements for that matter.

I've read where sum people trim the lower blades down to 5.5" and this, coupled with the upgraded shafts, virtually eliminates blade strike....my question is y trim the lower and not the upper blades? Is there sum advantage to doin this and wat is the disadvantage of trimming the upper blades instead?

I heard that only trimming the lower blades prevents any performance loss, but I haven't tried it so...

You may also want to consider a shortened flybar for better response and even less possibility of a blade strike. It lowers the overall rotational intertia of the upper blades. One that works well is for the Dynam Vortex, but can easily be adapted to the CX. It's sold by bphobbies.com and others. Or you can modify your flybar. There are threads on this board that disucss that.

I can not attest to this, but my gut feeling as an engineer is that if you are going to shorten the blades, then shorten BOTH upper and lower sets. My reasoning is that if you significantly alter the aerodynamic behavior of one set of blades relative to the other, you distrupt the evenly balanced counter-rotating stabilization. That is, the tail is more likely to swing in one direction or the other, depending on which blade set you shorten. Just thinking out loud. You can always try to shorten one set, then do the other if necessary. You'd better work really hard, too, to balance the blades because you wouldn't need to shave much extra off of one blade to lighten it significanly compared to the other. As I mentioned above, if you shorten the flybar in conjunction with the longer inner/outer shafts, you'll likely not experience a blade strike. I haven't. However, I'm also very careful not to go from full forward flight to full backward. My motors are more powerful than stock, yet still no blade strikes with that setup. I haven't needed to cut/shorten blades. Neall

you are right, however a quick adjustment on the POT would compensate for that. You would just have to turn the shorter blades at a faster speed to sompensate for the weight of the uppers and keep it straight.

Right, an adjustment of the gain pot on the 4-in-1 will compensate, as well as adjusting left/right trim on the left stick of the tx... to a point. Not sure if it'd be enough to prevent the yaw of the tail, if one set of blades is cut considerably. I'd like to hear from someone who's tried it. However, as I stated above, when using the extended inner/outer shafts WITH a shorter flybar, I suspect that cutting blades would be totally unnecessary. Any blade strike that may happen to occur in spite of those mods, would be the result of trying to "over-control' the movement of the heli. You could get away with that on a CX/2, but if you move on to a CP or Trex, you'll want to get out of the habit of over-controlling anyway.

I am working my way towards that.. I have a shorter flybar on order.

The cool thing about the upgraded flybar is that you can move the weights in/out on the flybar shaft. I use a digital caliper to ensure they're exactly the same distance out on either end. I can move the weights about half way in, and I actually like the response I get now. Forward flight is a lot more responsive, too. With the stock flybar, after a bit of forward flight, the heli wants to stabilize and hover again. Using the new flybar with moveable weights gives you some ability to compensate for that natural desire to stabilize and hover. You can actually fly the thing. Hopefully it'll be good training for a future upgrade to a CP or Trex. It's a lot "touchier" with the reduced (weights moved inwards) flybar, and it also helps to teach one to avoid "over-controlling." No blade strikes yet.

PS: The ball/link arm that comes with the Dynam adjustable flybar won't attach correctly to the "ball" on the upper blade of the CX/2. Different diameters. You'll have to unscrew the lower link from the stock flybar, and screw it onto the new flybar upper link and it'll work great. Of course, you'll have to play with adjusting that link so that the upper blades track properly. Not a big deal, and worth the effort. If you buy the flybar from bladecxpro.com, he's already unscrewed and removed the lower link portion from the flybar. He knows it won't fit on the CX. Use your stock lower link half in any event. Also, my brand new upgraded flybar came slightly bent. Roll it on the table (with weights attached) and make sure the bar is straight (and make small adjustments if necessary) before installing on your heli. Don't assume the bar is straight, just because it's brand new. This flybar is probably the best "upgrade" you can give your heli, as far as handling and response.

So yOU got the shorter and ajdustable flybar from where again? bladecxpro has it, but i had read on here that some if not all of what those guys sell is just other parts "repackaged and more expensive" What about this claim. I was seriously considering an upgrade in the motors, and ndoren, You are completely right. I have been frustrated in how the CX moves foward a bit, then hovers, and then you almost need to move it in a different direction to get it wanting to go foward again. I was going to move the servo linkage out in the field today, but without a table, and something to make the hole bigger, uhg. oh well.
So Yeah! Where can i get this flybar? and if we dont have a digital whos-a-whats-it like you do, what would you recommend? Sight it?

A guy at my LHS said he got so tired of buying new blades for his cx that he started cutting them untill they were too small to fly. I can attest firsthand to the fact that they will fly even with almost half of a few blades off! incredible. But the reason I came up with for only cutting the lower for more performance would be because the top rotor only deals with lift and stabilization, right?? You still want to be able to climb as fast as before.

I got the adjustable flybar from bphobbies.com, though it's available from other places. It's simply the "Dynam Vortex" flybar. If you don't have a caliper, you can just use a ruler to see if the weights are equally spaced from the center. Also, although it would be new, you'll still have to check it to make sure it's straight. I think there is very little that will prevent your heli from stopping during forward flight. It's the nature of the coaxial heli and the behavior of the flybar and upper blades. Moving the servo linkage will make your heli more sensitive to control inputs, but it won't make it fly foward any more effectively.

Soloboss is a pro on flybars... maybe he'll pitch in here, or at the very least, search for his comments on flybar performance in this forum.

The top blades control the stabilization, and it's that built-in tendency to stop and hover that would make me want to cut the TOP blades, and not the bottom, if you want to improve forward flight. Just my gut instinct. No proof of that. Neall

So you are saying that there is NO WAY to improve foward and backward flight... at all?? The videos they have up on youtube for bladecxpro show a damned good foward flight, quite impressive, really. how do i get that?
-Gene