Crabbing BCX2

[cambs flyer]

Hi Guys

I'm still having the forward flight crabbing issue where the nose is at 1 O'Clock and the tail is at 7 OClock while the cyclic stick is pointing forward at the 12 O'Clock position.

If however I point the cyclic stick right at the 1 O'Clock position while going forwards you can see the heli straighten up and fly dead straight

Also when using the rudder stick when turning right she turns at a fantastic rate, yet when turning left she almost seems as if she's struggling to do so.

Does this sound like a motor is packing up, or hasn't the power it once has, as I can't think of anything else, and my supplier who has been brilliant trying to solve it is stumped as well.

Plus this also causes trouble controlling her like if you stop she doesn't and almost bounces back a few feet, all I know is the fine control I once had has gone to pot right now.

I've explained as best I can but also on the lower rota head (alloy one) if you take off the lower blades your see a collar that the blades slide into, this actually moves, and if I have a slight blade strike the plastic arms that connect to the swash/rota head seem to go off at a slight angle, then if I hold the blades and gently rotate the swash it brings them back in line.

I've got someone coming over at the weekend to give a few pointers if he can, but it's so bloody annoying, she went from a beautiful flyer to this almost over night, and for weeks I've had her boxed as quite frankly I'd end up damaging things around the house, she hovers fine, OK moves around a bit but what BCX2 doesn't, it's when you imput forward or backward flight does things become interesting.

Also the pattern lines you see under the the rotas when above you don't seem to make the same cross line as before.

I'm thinking eventually sod it and just buy a new one, don't want to and can't really afford it right now what with other stuff going on, but she's such a simple little heli, how can she cause this much hassle

I'm also thinking of binding her with the DX6 on the chance I can sub trim out the problem, but the only thing I can think of is one of the motors haven't the power they once had.

My supplier has adjusted the pots to max advantage BTW, but from bitter sweet experence this doesn't help the crabbing at all.

Please advise....... Thank you.

[scallybert]

Also when using the rudder stick when turning right she turns at a fantastic rate, yet when turning left she almost seems as if she's struggling to do so.

Does this sound like a motor is packing up[...][?]

Yes.

The motor that drives the lower blades.

BTW, have you upgraded the swashplate ?

[cambs flyer]

Yes bud' I've all the alloy parts on her.

So you say it's the lower rota motor, cheers for that mate. If so I'll buy a new pair for good measure, start off fresh as it were.

So just on the off chance, this couldn't also be a result of a dogy servo at all?

If I had to choose and with the evidence, the motors would be my first choice.

Thanks.

[jboweruk]

I had the same issue almost with the ally swash, have you knocked it at all since fitting it? I found there's a little piece that twists under power and that seems to be what causes that, it twists the control so that it became forward and left in my case and rear and right. Urgh! I took it off and put the plastic swash back on, and yes I'm afraid it sounds very much as though your lower motor is about to die on you I'm convinced it was the ally bits that did it, they tell you they are available, but other than the heatsink there's no instructions on whether you should grease the swash or anything to remove friction, which I'm convinced is what kills the motor, remember the lower blades are the outer shaft, which is exactly what would rub against the swash if it's binding. Hmmm, Now I'm 100% convinced. I know it sounds silly and it's up to you, but I decided to buy a pair of motors, as that way both were brand new as it were, no hours on the clock. And my little lady flies like a dream now. But I would say lose the ally swash anyway if you kept the old plastic one in good nick.

[scallybert]

[...]I'm afraid it sounds very much as though your lower motor is about to die on you

Yes - wanting to spin right.

I'm convinced it was the ally bits that did it, they tell you they are available, but other than the heatsink there's no instructions on whether you should grease the swash or anything to remove friction, which I'm convinced is what kills the motor, remember the lower blades are the outer shaft, which is exactly what would rub against the swash if it's binding. Hmmm, Now I'm 100% convinced. I know it sounds silly and it's up to you, but I decided to buy a pair of motors, as that way both were brand new as it were, no hours on the clock. And my little lady flies like a dream now. But I would say lose the ally swash anyway if you kept the old plastic one in good nick.

As you say, the swash is on the lower blades, so extra friction in the swash loads the lower motor - which seems likely to shorten its life.

There does seem to be a vague relation between alloy swashes and dead BCX2 motors.

Personally, I'd move the servo linkages from hole 1 to 2 or 3 (mine are on 3 - others may have gone further) rather than 'upgrading' the swash. There's not that much play in it to start with, and less play is really likely to lead to more friction and associated problems.

[cambs flyer]

Thanks chaps.

That would explain why the "hub" on the lower rota assembly keeps turning, due to the motor struggling to keep up with things.

On a plus note an hour ago I ordered two new motors, theres no point keep guessing whats happened, obviously as you guys said somethings wearing out and the motor seems to be the guilty party.

I was thinking about the hours she's been in the air and loading the hours in a straight line, she must have done a couple of miles at least since having her.

I've kept all the plastic parts, so replacing the alloy Swash back to the plastic one might be a good idea then?

[t4ttyt3ddy]

Where did you order your motors from??

[cambs flyer]

Elite Models in Kent, Rod's a good bloke, and as I purchased my heli from them I buy all the spares from there too.

[cambs flyer]

OK I've done four test flights and on freshly charged batts, the lift off performance is terrible, whereas before I always had to be careful on a new batt as it went up like a rocket.

Also while hovering close to me there's a small sound that's not a healthy one, also once landed the bottom rotas stop almost instantly unlike the top ones that slow down to a stop slowely.

Again 1 O'Clock stick position dead straight, 7 O'Clock position for straight backward flying, so I guess what's happening here is the servos are making up for the unbalanced motors with what in normal flight conditions would turn the heli left instead of correcting the forward motor problem and again why when rudder turning left she's struggling.

Plus after each flight the swash/rota assembly plastic arms are on the tilt, so the hub which the lower blades are attached to is this acting like a crude clutch?

So ball point Q's when the motors arrive do I put the plastic lower rota assembly and swash plate back on, as where the hub has moved on the rot' ass' will this be a problem now it's happened quite a few times?

And the plastic Swash Plate will over time put less load on the motors so even though it doesn't look as fancy as the alloy one, long term would be better around.

Another thing (while I'm at it) with the blue body, the servo arms rub against it when moving, like a creaking sound as they rub together, plus the body is quite tight against the servo arms, is this a prob' and should I cut away a little of the rear body where this is happening so to lessen any stress caused?

Thanks for your time helping me answer these questions.

[jboweruk]

It's that shift I think that causes the weird movement. For my 2p worth I'd go back to plastic. As I say that's what I did and I'm as happy as Larry with my little girl now. In fact, confident enough now that I've moved the control rods out a notch on the servo arms (take the arms off for this, trust me, I killed a servo for not doing it,) and I've upped the DX6i to 125% movement, so more throw, she's a lively little lass now.

[cambs flyer]

Cheers mate, thats what I was thinking.

[cambs flyer]

Success!

This morning my new motors arrived, so i stripped the CX2 down to the bones installed the motors, put the shafts back on with the plastic Swash and lower Rota Assembly, aligned up the linkage arms as there a little higher with the plastic Swash, fixed the rotas started her up and all the blades went in the same direction, then I realised I hadn't reversed polarity the lower blades, then sorted.

It took more time with the pots then physically taking apart and putting back together the tweaking took a bit as the setting were all over the place with the older motors.

I modded the rear canopy and cut away the area which the Servo arms were hitting, done a nice neat job and for all accounts you'd never know I'd trimmed it back, plus doing so made the rear body more flexible and easier to fit.

After I got her half decent trimmed (oh yea I also mover the servo arm linkages down a hole, now the forward and reverse flight is much more responsive and faster) I fitted the twin LED (headlights) to the two grill areas where the "E-Flite" name is on the front canopy, I just heated up an old inner shaft and melted the holes until they were a tight fit then taped them down on the inside.

Also with the light set there's a rear red flashing LED, using two long plastic ties (like you'd use on training gear) I taped two together and taped the LED housing to the top of the forward Tie, melted a hole in the very rear, pushed the LED and wires up through the rear canopy and once in place tapped the Ties inside the rear canopy the tidied up the remaining wires and attached the from canopy.

As with the extra wiring making taking off the front canopy a bit of a pain I melted two small holes in line with the two Pots, so any further pot adjustments can be made without the canopy off, which I can't do now due to the wired LED's.

All in All an enjoyable experience, the noise of the new motors made me realize how bad the old ones were.

I'm still adjusting the pots as the motors are wearing in and I'm trying to find the perfect balance torque wise.

Oh yea and my new fancy Trex Blades arrived today as well.

Have to say it's been a good day.

Many thanks for the help and advise.

[marktigere1]

Glad your all sorted

[gazza]

Well done that man...It's amazing sometimes how such minor & yet frustratingly unfathomable problems dishearten us to the point of almost chucking the lot in the nearest bin!!
Happy flying pal

[brin]

hi cambs flyer i would like to know which motors you used and did any of the wiring upset the balance , and well done for sorting it all out
as with mine it was silly things like flybar slightly bent inner shaft slightly bent blades not ballanced etc etc but it is now hovering and flying well

brian