BCX2 battery charge and tail drift questions - RC Groups
Thread Tools
Dec 02, 2006, 02:41 PM
Registered User

BCX2 battery charge and tail drift questions

I am new to heli's (and LIPO's) and just picked up a CX2 a couple of days ago. The battery that came with it took about 1.5 hrs to charge the first time, but takes over 2 hours to charge after running it down. The charger that comes with it says it has a .65A output so would expect a full charge in about an hour and twenty minutes. I am not over discharging as I am stopping as soon as the heli slows down a bit. Anyone else using the stock charger please let me know what you are getting for charge times.

Tail drift? Out of the box the rudder trim had to be set all the way to the left to hold the tail. I adjusted the pot to center the trim perfectly. Then after replacing the body and flying a few minutes it slowly drifts Rt so I have to trim more left. After a couple of packs, the trim had to be all the way left again, so I re-adjusted it with the trim halfway to the right. I flew one pack and it ended up slightly left of center. Is this the tail drift problem that the CX had/has? It seems to hold ok with the front body off, but drifts when it is put back on which makes me suspect it is heat related.

Any help or info would be greatly appreciated.

Thanks, Don
Sign up now
to remove ads between posts
Dec 02, 2006, 04:50 PM
Registered User
The new charger included with the CX2 works for the Blade CX/2 and CP Pro. The old CX charger was rated at .5 amps. I'm guessing that the new charger might charge the 2 cell battery and a lower rate than the 3 cell CP battery? The rating is also probably more of a maximum charge rate. If you have a li-po charger with an adjustable rate you can charge them at a higher rate and also to a full charge. The E-flight chargers have always been on the conservative side. Having an extra battery or two is worth it.

As far as the tail drift issue what you are noticing is probably close to normal. On the CX you would have to fight the tail through out the flight making it hard for people to learn how to fly. On my CX2 I have noticed a little drift here and there but nothing like the original CX. It has improved, however I have already removed my 4 in 1 case to see if it can be completely eliminated.
Dec 02, 2006, 07:11 PM
Registered User
With the case removed off the 4 in 1 unit and my canopy vented to cool it there is no noticable difference. It still wonders a little here and there. There does not seem to be any heat issues with the stock CX2.
Dec 02, 2006, 07:12 PM
Registered User
I am seeing the same thing. A bit of drift here and there.

I wonder if improving lubrication on the bearings could help? Is the drift an electronic thing or a motor performance thing?

Mounted your boom on mine, seems to balance fine. I am using o-rings to hold it down vs. the tape.

Seems to me these things become less of an issue as one's ability to fly improves. I went though a CX and a large pile of parts getting started. Was going to give up and try something else, then decided to give the CX2 a try.

At this point I can fly several times per day without a single crash. Haven't crashed the CX2 yet though I did bounce it off the ceiling once. And I keep wondering if an FP or even CP machine might actually be easier to fly in that response would be more predictable. Time will tell.
Dec 02, 2006, 08:01 PM
Lean is Mean
xtreme's Avatar
hello all
You need to take a little time to dial in the gyro gain. It can be a little frustrating. Personally I like the drift. I want to control the bird, not have it fly itself.

Good Luck

Dec 02, 2006, 10:16 PM
Forever TMWT Pilot #11
LcJ's Avatar
Set it as close as I could. It will drift a little one way for a while, then it will go the otherway for a while. Very easy to manage in my living room. Can take off and land on the corner of the coffee table. That was what I was looking for and I love it.

Has anyboyd tried XUS's 900 mah batteries for the CX? $20.0. Not bad.

Latest blog entry: RC Logger's Eye One Xtreme Quad
Dec 03, 2006, 09:52 AM
Registered User
CCbusa05's Avatar
Originally Posted by stersman
With the case removed off the 4 in 1 unit and my canopy vented to cool it there is no noticable difference. It still wonders a little here and there. There does not seem to be any heat issues with the stock CX2.
Thanks for the info Stersman, I was contemplating doing the same ventilation mods that you have done, but now I will hold off doing it. I did this on my CXs and it helps out a bunch in eliminating the drift, but like you said, with the CX2 I also notice slight drift during flight but nothing that a small amount of Tx trim doesn't control.
Dec 03, 2006, 12:46 PM
Needs a vacation
thermlin''s Avatar
try the commonsenserc.com budget pack-7.4V 800mah. i bought one of these and i got it for 17.50 shipped! the power from this thing is crazy versus the eflite packs. however, you need to strap it to the landing gear with rubber bands, which isnt an issue at all.
Dec 04, 2006, 11:35 AM
Registered User

Thanks to all who replied......

I will try to adjust the gyro gain later today.

Regarding the 2 hour + slow charger, I guess I should get a real Lipo charger. Just curious, how long did it take to charge using the original CX charger?

Thanks again, Don
Dec 04, 2006, 01:24 PM
Registered User
You know, I ordered my BCX2 and it is coming.

Well, it is good to know what to expect, so I appreciate any commento, specially regarding tail drift issues.

As I said many times before, BCX was a bit dissapointing for me because of the strong tail drift issue.

Now, I know that my BCX2 will still have some tail drift.

I guess it is unfair to compare coaxial tail drift issue with the normal counter rotating effect in single rotor CP or FP helicopters. Is a totally different situation.

I mean, BCX/BCX2 tail drift is a problem that only gets worst during flight and it is because some bad design. Tail drift in a FP or CP is not a problem, it is just a normal reaction, it is a feature of single rotor helicopters.

BCX/BCX2 tail drift gets progressively worst, so it probably implies some kind of bad design.

It would be different a tail drift due (only) to motor differences, as no motor is perfectly equal to other motor. But in this case, the problem would stay always the same without getting progresively worst. This kind of details could be satisfactorily dealt with by using tx trim/trim/gain etc, etc.

However, in the case of BCX I need to be constantly moving tx trim and/or 4in1 trim and at the end it is frustrating.

I hope BCX2 would not show this problem. I would accept tail drift, since no product is perfect. But it would be very bad tail drift wil get worst while in flight.
Dec 04, 2006, 02:17 PM
**I'm Battman**
I'm still at it with my CX2 in the basement. (Christmas present)
Having a great time! This whole tail drift issue is way over rated in my book.
I really don't want it to fly itself. I now have about six packs through it. Amazing machine!


ps. Got to go get another flight in before my wife gets home! Wish me luck on not getting caught!
Dec 04, 2006, 03:04 PM
Registered User
Vipula AD's Avatar
Just got myself a CX2 this Friday.
Yes, it takes two hours+ to charge a pack from the included charger. I want to find an adaptor for the taps so that I can plug it in to the Hyperion, without having to cut and solder a different charging tap.
I found mine to do the exact same yaw to the right even with full left trim. However this is not a big deal, I figure, at the end it is going to give me more left thumb training (which I do need). I have not adjusted the motor gain on mine yet but will do that soon.

I have a question to all you original CX owners; How long do the motors last?

Also, so you donít think the proximity of the to ESCs to the gyro in the 4-in-1 does not have any heat related affects with regards to the drifting issue?

Dec 04, 2006, 03:46 PM
**I'm Battman**

Don't fight the tail...

Time to adjust the main motor mix...

Dec 04, 2006, 03:59 PM
Registered User
as far as battery goes you shouldn't charge it more than 1/10 of the mah. so 700mah .70 amps.
Dec 04, 2006, 04:51 PM
Registered User
CCbusa05's Avatar
Regarding the time to charge with the new CX2 battery charger, it all depends on how far down you drain it. I always try to land/recharge after about 10 minutes.
Puzzling observations:
1. takes almost exactly 1hr 30 minutes to recharge using the new charger.
2. only takes 1hr 15 minutes with my older CX charger(s).

Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Idea BCX2 tail drift eliminated Rob Hair Coaxial Helicopters 11 Jan 14, 2008 05:54 AM
Help! BCX2 Tail Drift & True RC battery Tilly Coaxial Helicopters 14 Mar 03, 2007 04:58 PM
Discussion BCX: After ventilation mod, tail drift and battery problem remains.. bambino Coaxial Helicopters 12 Apr 19, 2006 10:07 PM
battery and charge questions? yodafm1e Vendor Talk 2 Apr 19, 2005 07:21 PM
Battery Charge rcdreamer Beginner Training Area (Aircraft-Electric) 2 Jun 24, 2001 10:56 PM