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Aug 23, 2006, 09:37 PM
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Blade CX sat for two months and then.....


Now I'm having problems.

I had left the batteries fully charged when I left and topped them off when I got back.

Now I go to fly and the red light comes on the 4 in 1 with any major throttle input.

After about a minute, it won't hover at all. Like the batteries are dead or something.

I know you aren't supposed to leave the lipos fully charged for long periods of time, but I don't think two months would kill them, so I'm thinking its something else. I have put new motors on maybe 20 flights ago.

I have to check the battery voltage and see if they are holding a charge, but like I said, I really don't think that's it.

Ideas?

Thanks,

Tom
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Aug 23, 2006, 11:38 PM
Sippin' on Kool Aid
i'd try and cycle them, maybe get them back up to their full potential. try that and see what happens
Aug 24, 2006, 05:59 AM
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Thanks Heligrom,

Like I said, I don't think its the batteries as I checked voltage, and they are taking a full charge.

Now I'm wondering about the motors (which I replaced not long ago, got over a hundred flights on the first pair and they were still working), or the 4 in 1.

I was thinking maybe excessive binding, or bad bearings might be causing this, but everything appears to be smooth.

Would excessive power draw be a symptom of something going bad in an otherwise functioning 4 in 1?
Aug 24, 2006, 03:40 PM
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Quote:
Originally Posted by TommyB
Thanks Heligrom,

Like I said, I don't think its the batteries as I checked voltage, and they are taking a full charge.

Now I'm wondering about the motors (which I replaced not long ago, got over a hundred flights on the first pair and they were still working), or the 4 in 1.

I was thinking maybe excessive binding, or bad bearings might be causing this, but everything appears to be smooth.

Would excessive power draw be a symptom of something going bad in an otherwise functioning 4 in 1?
YES! I have several hundred flights on my original motors. At one point I put it away for 3 months and I had the same problem. I had to relube everything and it flew MUCH better. I also had to readjust the 4in1 to compensate for the new differenece. Try this with the canopy off to eliminate any cooling issue as well.

My bearings are so loose they rattle, but with the lube it still flys fine,
Aug 24, 2006, 04:18 PM
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RE lube?

I never lubed it in the first place

Thanks for the info, I'll try it, but it just doesn't seem to make sense. I did find that the gear on the outer shaft has a bit of a flat spot, but I think that's been going on awhile now.

I seem to recall the 4 in 1 not wanting to initialize at times before I put it away, but it initializes fine now.

Gonna strip 'er down and pop some new bearings and a new outer shaft in just for kicks.

I'm kind of reserving this one for two of my boys (6 and 8) who have been learning on it more than I've been flying it.
Aug 25, 2006, 12:05 AM
Us "Repairmen" just love you guys to whom the idea of lubricating any moving parts is as foreign as why apples don't fall up ! We've gotten you pretty well weaned off the idea of "preventative maintenance" so you just charge blindly on, thinking your new toys will last forever, and you will never have to worry about taking care of it . In the small engine repair business, we see so many engines that were stashed away in the basement, without benefit of "winterizing". A few minutes on our workbench, and a bunch of your dollars later, and the whole hassle could have been avoided by some very simple actions on your part, when you put it away.

So keep up the good work, guys, - mama needs a new pair of shoes for her Ferrarri.

Aloha,
Steve
Aug 25, 2006, 06:20 AM
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Quote:
Originally Posted by Steve Shepard
Us "Repairmen" just love you guys to whom the idea of lubricating any moving parts is as foreign as why apples don't fall up ! We've gotten you pretty well weaned off the idea of "preventative maintenance" so you just charge blindly on, thinking your new toys will last forever, and you will never have to worry about taking care of it . In the small engine repair business, we see so many engines that were stashed away in the basement, without benefit of "winterizing". A few minutes on our workbench, and a bunch of your dollars later, and the whole hassle could have been avoided by some very simple actions on your part, when you put it away.

So keep up the good work, guys, - mama needs a new pair of shoes for her Ferrarri.

Aloha,
Steve
That's a stretch, comparing maintenance habits of a CX with internal combustion equipment. I have on occasion put some graphite on my CX, but come on, its all plastic on plastic other than the bearings.

I just swapped out all the bearings and the old ones are fine. Basically at this point its al new except the motors and esc.

I guess I'll try some new motors.
Aug 25, 2006, 05:47 PM
Preventative maintenance is the same, whether we are talking about micro-helis, or lawnmowers, or Rolls-Royces. Any place where there is motion between two objects, there is friction. friction is a real enemy in the little birds, as most of them are operating at the limits of the design. Never mind what the manufacturers say, (no maintenance needed, as our plastic is just naturally slippery). What is behind that statement is the fact they want you to wear things out, so you'll have to come back to them, with a big shopping list of what has worn out.

Anything you can do to reduce friction (= wear and tear), will go a long way toward extending the life of your machine, and preserving the domestic tranquility.

As an example, I bought 7 Bladerunners when they first came out. First off, before ever trying to fly them, I gave the whole machine a grease job, and a fine tuning. As a result, I had well over 20 hours on each of the machines before the motors finally wore out. The expected lifespan of the BR motors was only ~3-5 hrs. The only problems I ever had with them was damage caused by my cats, and my recklessness. (crashes).

All a good lube job consists of is applying the right kind of product at all places where there is relative motion between two parts. There are a lot of lube points, when you get down and seriously study the mechanicals.

"Grease The Machine", and enjoy your plane for a lot longer.

Aloha,
Steve
Sep 28, 2006, 08:39 PM
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Thread OP
Well finally got around to trying to fix this, and have tried a number of things.

Replaced both inner and out shaft including main bearings, top bearing and retainer.

Got new batteries

Put two new motors on

Even tried lube

Everything else seems fine.

Red light still comes on now after maybe 2 minutes of flight. Seems like the batteries are at the end of the discharge. But I charge them on my triton and I'm only putting back maybe 2-300 mah, ending voltage at 7.8-8.0v.

The only thing left that's suspect is the otherwise perfectly functioning 4 in 1.

Is this normal? Or an expensive lesson in paranoia since I have not flown it for awhile?

The only other thing that seems odd is the starboard motor that drives the lower blades still seems notchy. Like maybe the gear mesh is to loose. I'm thinking maybe the frame has gotten sloppy although I don't see any signs of that. I flew my brothers cx and was blown away at how smooth it is.

So which is more likely, that the 4 in1 is overheating or something, or the frame is bad?

I'm really baffled because I manage to keep a whole hanger full of 3dpros and trex's flying but I can't fix this
Sep 29, 2006, 01:32 AM
Registered User
Hmmm. something's working hard.. One thought.. Servo system mechanics. If something in there is causing a servo to keep active, it may be that the v regulator in the 4in1 is getting very hot and dropping the voltage to the cpu etc. Maybe an already 'lubed' servo has not liked it's hibernation. I would check servo's, links, and swash. Just pull out the motors, etc and check servo cases for any heat as you kick the cylic around.
Just a morning thought.
Sep 29, 2006, 05:46 AM
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Thread OP
Thanks roffey, I'll try that.

I had considered the servos and they are looking very smooth, but I have not checked them for heat.

Do you know if there is anything in the 4 in 1 that could be bad?

I really think it has to do with the loose mesh on the lower rotor drive. That one tends to strip too. Its possible the machining was off and it was like this from the start as it was always a little rough. I suppose I could try to improve the mesh by working the mounting holes a little.

On second thought, I powered up the motors without the shafts in place before and after replacing them and the motor in question doesn't have as long a spooldown. It seems to grind to a halt in about half the time of the other motor. And that was with the new motors and the old motors. Is there something in the electronics of the 4 in 1 that could cause this?
Sep 29, 2006, 10:20 AM
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elan's Avatar
It seems to grind to a halt in about half the time of the other motor.
-It sounds mechanical not electrical...
Sep 29, 2006, 01:57 PM
Registered User
It's possible a spike protection scottky diode is playing up, but I would doubt it. (the diodes that shunt the motor coils). Swap motor connections over and see if the same motor comes to a halt first, it may be the swash mechanics introducing more friction forces and halting the lower motor earlier.
Thinking again about your last sentence and relating it to your original description.... the only thing you don't mention is how warm the battery is getting...
2 minutes into flight the red light comes on.. indicating a flat out drive to the motors. (new motors, good batteries, mechanics ok). That indicates low voltage available. Something in the path from battery, battery connection, supply wiring, mosfet drives, motors is either taking a lot of current and pulling the voltage low, or there is a resistance building up dropping the voltage for the same current drive.
The increased current could well be due to mechanics.
If I couldn't find a mechanical reason immediately, I would want to know what current is actually being drawn and either power the heli from a dc supply with monitors, or fix an ammeter in line with the battery. (10A standard meter would do). Then I'd power up with no motors connected, and expect to see very little current draw, and some extra with servo movement, settling back down again with no servo movement. Taking the throttle up, again I would expect no more current to be taken. (4in1 check). I would then connect one motor and check again. Obviously as throttling up, current draw will rise to amps. (with blades on and heli restrained). Probably around 2A at hover setting. Then I would check the other motor on it's own, and expect the same. If not, then I would swap motor outlets and see if that made a difference. That would sus the 4in1.
Then, if one was taking a lot of current, what reduces it? Work back through the mechanical chain to the motor on it's own. Who knows, dead spiders in swashes have a lot to answer for!
It's probably gonna be a slap forehead solution.. 'I knew it all along' answer, but might as well learn something along the way. I learn something new everyday, (you should see my forehead!)
Sep 30, 2006, 08:57 AM
I'm just a 2.5D Pilot
rickgode's Avatar
I seem to be having the exact same problem... Put mine up for months, but I used my lipos in a little shocky I built. The lipos run the little CD-Rom motor just fine. Hmmmmm.
Oct 02, 2006, 07:00 AM
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Thread OP
Thanks for that info Roffey, have not had time to do a thorough diagnostic such as you described but I did try running the motors separately and switching them the 4 in 1. Seems like both motors run rough on the same side of the 4 in 1.

I gotta pick up an ammeter to do the rest. Would a watts up watt meter be able to do this? I've been meaning to pick up one of those or and eagle tree for diagnosing all my birds.

Thanks again,

Tom


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