Blade CX2 Yaw's to the right HELP

[Paul_G]

hi, firstly, I'm completely new to helis so please be gentle.

I have just been given a CX2 as an early christmas present, as I'm sure most people do, I crashed it a few times and broke a couple of blades (lower), now, with brand new blades it will constantly yaw to the right either while it is on the ground, in a hover or even when flying. It seems to fly perfectly execpt for this "slight" issue.

I have played with the trim, and it does seem to do something, however with the trim all the way to the left, it still does it, just slower, I tried playing with the main motor proportional mix trimmer pot on the 3in1, and this again does have an effect, however not enough. Not sure if it is significant, but my motors are connected differently to that in the manual, as the manual states the right (from behind) motor to be connected in the lower pins on the 3in1 and the left motor to the upper pins, however mine are the other way around, it seems correct as pushing the rudder to the left causes the heli to yaw to the left so I am assuming this is a mistake in the manual.

When the heli is airbourne it seem pretty responsive to what i tell it to do, ie. if i push the rudder left it will move left instantly and feels good, yet it needs constant correction.

Hope i've given enough info for someone to help me.

[Sieze2]

The following is posted from the following website:

http://www.dacaur.com/bladecxhelp.html#foldingblades

Personally I used to reset my gyro after 60 seconds or so. Then I drilled cooling holes in the 4in1 which made the gyro alot more stable with less drift. You have the newer version with the 3-in-one but I bet it is the same gyro!

One other thing to mention is to check the inner main shaft is not bent, as if that bends the extra drag on the one motor might exceed the gyro's abilities.

-------------------------------------------------------------

Tail drift, why wont my heli stop spinning even with full left/right trim?

Some Blade CX's seem to have a problem where no matter how you adjust the pot on the gyro, you have to constantly adjust the trim on the transmitter, and by about halfway through the flight you have run out of trim and have to hold the rudder over to keep from spinning.

FixesReset the gyro. See below
Ventilate the 4-in-1. See below


Fix #1. If you dont want to do any actual modifications to your BCX, the best way to deal with the tail drift issue is to "reset" the gyro once it starts to drift. To do that all you have to do is unplug the battery and plug it back in.
Fix #2. If you are willing to modify/cut your heli, then this is a better solution. What you need to do is cut holes in the canopy and the case of the 4-in-1.
One key to effective cooling is the proportion of the OUT versus the IN. The OUT airflow should be 2-3 times that of the IN airflow. This is what creates good flow properties. IF you do not get the proportions right the air gets captured doesn't do as good a job evacuating the heat. It will still help, just not as much as if you get the proportions right. First thing to do is cut the canopy. One easy way to do this and make it look nice is with a dremal tool and sanding bit, cut an inital hole with a razor, then use the dremel to get the size/shape you like

[Paul_G]

thanks for the quick response. I did actually find that page shortly after posting. It seems a little strange that you have to go and cut up your heli one day after getting it, I'm sure my other half wouldn't be too please I was drilling holes in my new present!

I have taken everything off the shafts, and spun it up a little, and it didn't appear to be bent (i lined it up against a striaght line) and couldn't see any movement at all.

Any other ideas? I am sure it wasn't like this before i crashed it

[Sieze2]

The best way to test them is to roll the shaft on a flat surface. I had a motor not driving a main gear properly due to a retaining sleeve moving? That caused yaw problems. Also a damaged inner or outer main bearing because of a crash could have caused a problem? Anything that causes one engine to run slower than the other (beyond the ability of the gyro pot to compensate).

If the worst comes to the worst send it back to the shop and they will sort it under warrenty. Also don't expect too much from the cx2 gyro, the gyro on my T-rex costs as much as your whole heli setup ! That said you should be able to adjust it !

[pompeyjohn]

best yaw fixes for a cx2....

the stersman boom which you can get on ebay (this is the best upgrade you can buy for the heli)
heat sink[s] on the motors - I use two
cover off 4in1 / 3in1

[Paul_G]

Thanks for all your replies. I've just spoken with my local model shop and they have offered to take a look as the guy has a CX2. I have read lots of things about people saying the gyro isn't brilliant, but I wouldn't expect it to be for £120 all in, however I wouldn't expect to have to remove the case of the 3in1 to get it to just work, espically since it did work fine before the crash. I'm inclined to think that it is either a bent shaft or just lack of my ability to know what I'm doing! Hopefully the heli shop guy will be able to fix/trim it correctly.

[pompeyjohn]

your right, you shouldnt have to remove the case. that is what I'd call an advanced hack

[Bubblefish777]

Make sure the inner shaft collar (on the bottom) is tight...it's a couple of grub screws and if it comes loose then one blade loses torque causing yaw.

[Paul_G]

Make sure the inner shaft collar (on the bottom) is tight...it's a couple of grub screws and if it comes loose then one blade loses torque causing yaw.

Thanks very much for your advice, it is all very appreicated..


Are you referring to underneath the actual heli where the big cog is that connects to the two motors? I have noticed a collar type thing, but never checked it as I don't really know what I'm doing, and obviously didn't want to make a poor situation worse!

[Bubblefish777]

Underneath there are TWO main cogs....each driven by a single motor. So there's an inner and outer driveshaft...one shaft per rotor set.
On the very bottom of the shaft and main cogs is a little collar. With 1 or 2 grub screws. If these are not tight then when the shft spins it may slip....so one rotor has way more torque than the other one. This in turn causes the heli to pivot far more than the gyro can cope with.

[Paul_G]

Cool, yeah thats what I thought you were talking about. I'll investigate when I get home from work, which when you have a heli to play with seems to drag for more than normal!!

cheers for all your help on this

[Paul_G]

Well I went to the model shop, and the guy flew it and declared it was fine and i just needed practice. I also flew his CX2 with exactly the same behaviour, so i reckon I'm just not good enough.....

I thought my outter shaft was bent as there was a little wobble, but he reckons its sorta normal.

ps. anyone had any trouble getting the bearing collar off the outter shaft? I tried last night, and due to what looks like a number engraved on the shaft it won't slide off, anyone else got this issue?

[Bubblefish777]

Nope...

[Paul_G]

oh well, i guess when it comes to getting a new shaft, i don't care too much about cutting it or something.....just hope the bearing fits on the new one!


Okay, this is interesting now - I got home from the model shop all down and depressed that I had to come to terms with been a crappy pilot, thought sod this, I'm gonna fly this bird, so off i go in the lounge, and try and land it on the coffee table, make a complete hash of it due to the nose keep turning right etc, and smack it full power into the table, and shatter a lower blade. I pop a new one on, and hey presto, yaw has all but disappeared, and i can get an almost perfect hands off hover. Now, either it was a dodgy blade, although i did swap them both out, or more unlikely i've fixed whatever damage i did in my first crash. Either way I'm well chuffed!

Just want to say that I do not recommend you crashing your heli to fix the yaw!!!!

[marktigere1]

I normally use a lump hammer