AP2000i glitching like an SOB!

[AZ ChopperCam]

the new AP2000i I just bought has been recording an enourmous amount of glitching (up to 35/flight). And the heli is jumping all over the place and it scares the hell out of me.

I took it off the heli and no glitching.

I've tried every usual glitching fix... the RX is about 12" from the motor, the AP is about 2" from the RX, I've lubed the tail belt with graphite powder, switched ESC's, tried 3 different BEC's, swapped gyro's and tail servos. nothing fixes it except removing the AP.

Is there something else I ought to try???

[WillJames]

What kind of Heli?

[AZ ChopperCam]

sorry... forgot to mention it is an E-Raptor

[catfight]

n74dv,

What happens if you disconnect the IR sensor and disable in AP2000i? Same issue? How about loose connections or bad cables/connectors (either extensions or sensor cable)? Worth a try :arggg:

[MLaBoyteaux]

DJ,

Have you been able to see if it's just one servo or all of them? I know you've determined it doesn't glitch without the AP installed, just curious.

I've got a 9202 on order for the Vario that's glitching intermittently. I'm pretty sure it's not the AP, but I haven't removed the AP to make sure......

[dreslism]

Did you swap out the ap2000i for another one?

I thought you had a couple of them. Swap the ap2000i's around and see if it goes away and follows to the new install.

[AZ ChopperCam]

i havent swapped yet because I have still photo shoots on a regular basis and haven't had the chance to swap and test. Hopefully in the next week I'll have some down time.

[Load Factor]

DJ,

Is the glitch just in the collective? I have this problem with my Maxi. I have installed a new IR sensor, but my ESC puffed when I spooled up to test the AP.

Let us know what you find out.

Tanner

[MLaBoyteaux]

The new AP-2000 on my E-Raptor started glitching this week. I put it on the bench and spooled it up without blades and all 3 servos on the swash start jumping.

I can watch the aileron and elevator inputs and they don't change. I can watch the servo output on the AP-2000 and they stay rock solid, but all 3 servos begin jumping when I spool it up.

It doesn't seem to be mechanical, I can tap on the case and nothing happens.

I removed the AP-2000 and it's rock solid.

Definately the AP-2000. Since this is my primary bird, I'm going to have to rob the one of my Condor to keep it flying.

Guess I'm about to find out how long it takes to get one repaired or replaced. :(

[MLaBoyteaux]

Aha! I swapped it with one of my other AP-2000's and it does the same thing!

I installed a new QuickUK metal tail rotor assembly just before this started happening. While testing the second AP-2000, I was holding the frame of the heli on my workbench and had it spooled up. I was holding my finger against the TR belt and I suddenly was popped with a static discharge from the rudder servo mount (which is metal) on the boom to my right hand. It was at least an inch away!

Boooyah! I don't recall what the breakdown voltage for air is, but I know for a one inch arc, it's got to be on the order of 10's of thousands of volts.

Hmmm, so now I'm suspecting it's static buildup that's dissipating through the servo's on the swashplate and into the AP-2000. The tail boom is a carbon fiber boom.

So how do I prevent the static buildup in the first place?

[AZ ChopperCam]

hmmm... I have a metal tail rotor assembly also. my boom is aluminum though. I may try it again with a stock tail gear box and see what happens.

I heard that lubing the belt with graphite powder helps. I did it and there was no change.

[Tonystott]

Other suggestions.. use silicone R/C car shock oil on the belt and/or run an earth wire from the tail gearbox back to the neg side of your battery.

Good luck!

[lakespinner2]

Man, a glitching camera ship sounds scarey !

One thing I've been meaning to test, but haven't, is to use a carpet/computer room trick. I've repaired a few computers from winter time static shock when someone would touch a keyboard and a spark would jump, usually in carpeted offices.

A company I used to work for would buy a really expensive liquid solution to mist on carpet and it could be used to wipe down monitors, keyboards, desks, chairs, etc. It worked great and eliminated the static shocks. I read that a mixture of water and fabric softener would work as well. I tried it and it worked great around the carpeted offices. We've used the same bottle so long I'm not sure of the recipe but I think it's about 3/4 water and 1/4 liquid fabric softener.

It may not help a bit on a heli but it might be worth a shot. If it can prevent the static buildup it might prevent the arcing and fireworks. If nothing else the heli will smell springtime fresh. :mrgreen:

On the gasser, I've noticed the boom and one of the two boom supports will hold a charge after spinning down, much like a capacitor.

On humid days I can't detect the static charge at all. Here's the cheap little gadget the I used to sniff out the static charge. I think I got it at the Lowes Home/Hardware store.

http://www.specialized.net/ecommerce/shop/layout.asp?product%5Fid=297X886

Running the ground wires is probably a great idea too. Good luck with it guys.

[WMann]

Hi Guys,

Since you both have metal tail boxes I will assume that the tail rotor pulley is metal also. Before the swap to the metal tail box was the tail rotor pulley plastic? If the tail rotor pulley is metal you also need a metal pulley up front to keep from building a charge. Since we are talking about a raptor I will naturally assume that it has the stock red plastic tail rotor drive pulley below the main gear. I would suggest using a grounding strap to ground the tail boom to the main frames to keep a charge from building up or trying a plastic tail rotor pulley if possible.

I hope this helps


Wayne Mann

[GGoodrum]

I agree with Wayne. I'd try a plastic pully in the back. I haven't seen this problem too much recently but I would definitely look at running a ground wire to one of the motoro screws, and thento the negative side of the battery pack harness. Carbon cunducts so I'd do this even if you have a CF boom. The graphite spray will help keep the static charge from building up in the first place, but it has been my experience that once you have it, only grounding everything metal/carbon that doesn't rotate will cure the problem.

-- Gary

[MLaBoyteaux]

Yes, it's a new metal tail rotor gear and the red plastic one up front. It's definately being generated by the tail. I pulled the drive belt off and spooled it up, solid as a rock. I then unplugged the rudder servo to see if the boom is discharging into the servo and feeding back into the system. Didn't make a difference.

It doesn't manifest itself when I remove the AP-2000, but I know it's still there and needs to be resolved.

I tried the silicone on the belt, but it didn't make any difference.

I'm going to try and ground the boom and main shaft assembly to the negative side of the power supply from the Duralite regulator to put them all at the same potential and see if this cures it. I think part of the problem is the Raptor frames are plastic and non-conductive.

If this doesn't work, I'll put the plastic gear back on the tail and try that.

[MarkWebber]

Boy am I glad I've got TT drive for my T/R! :D

I've also seen 'static wipers' made up for problems like this in other types of equipment. Basically just a copper brush that would ride the belt and have to be grounded to motor, battery and what ever other conductive materials you can find.

[MLaBoyteaux]

I've learned the stock Raptor swashplate frame is made from a non-conductive frame. I found if I connect a grounding lead from the carbon fiber tail boom and put it in contact with the main shaft, it prevents the build up of a static charge.

I spooled the heli up in the dark and I could see the charge arcing across the swashplate when it built up enough to jump the gap.

I rubbed the drive belt and main drive pulley down with a "Bounce" dryer sheet (anti-static). The static build-up stopped, although I don't know how long it will last.

I think the permanent solution is to use an all metal swashplate so I can attach a bonding lead and ground it to the tail boom.

Or just keep a Bounce sheet in the flight box and rub the belt down if it starts glitching again!

I was trying to use my Fluke volt meter to see if I could measure the potential between the boom and the main shaft. I had the meter connected to the boom and had the heli spooled up. When I put the other lead against the spinning main shaft, the meter would flash and reset.

The humidity is much lower now than it has been this fall, I suspect I've had this problem all along but it's more noticeable now because of the lower humidity.

I think it has to do with the belt from sdp-si.com for the stretched tail boom. The belt is made from neoprene rubber with a fiberglass reinforcement. The rubber on the plastic drive gear makes a perfect Van De Graff generator.

The stock raptor belts are made from some sort of translucent material, I suspect it's some form of polyurethane and may be why they don't have this problem?

[GGoodrum]

Hmm... I'm confused. Where exactly does it arc? I have a metal swash on mine but the swash is not physically touching anything but the main shaft. Anyway, I'm having a hard time visualizing where the "jump" is coming from/going to. What is the "circuit" that the static charge makes, do you think? If it arcs across the plastic in the stock swash, I assume one "end" is the main shaft, but where does the other end of the "arc" go to? This is really good stuff. :)

-- Gary

[AZ ChopperCam]

I concur that the humidity change is likely to be what is causing mine to happen as well. We're out of the monsoons now and humidity is very low now.

I'm going to do some more testing with mine soon and see if I get the arcing as well.

[MLaBoyteaux]

The inner portion of the swash that rotates is arcing to the screw for the aft servo link ball. I have the TPPacks ccpm conversion, the outer ring that the swash plate attaches to is aluminum, but the swash frame that attaches to this ring is some sort of plastic. When the four balls on the inner piece of the swash plate rotate past the screw that holds the aft servo link ball, it must be the shortest gap, because this is where it arcs.

The path then seems to be through the outer ccpm ring, through the anti-rotation pin and into the aluminum frame that supports the two front servos. I suspect it then arcs into these servos and into the system.

I put a metal swashplate on it and grounded the swashplate to the power supply for the receiver and AP-2000. It seems to have solved the arcing from the main shaft, but I'm still getting a very intermittent glitch in the rudder now.

Tomorrow I'm going to ground the tail rotor housing and see if it gets rid of the rudder glitch.

[cainebean]

LaBoyteaux I'd love to see a picture of how you did this when you finish.

Webber where did you get that TT tail? I having a HARD time getting my tail belt tight. Well I can get it tight but gets loose fast. But is has been anywhere from 30 to 73 the last few weeks here. Odd though because this is the first time I've had problems with a belt driven tail.

[MarkWebber]

Caine

The TT is on my Bergen. I don't use my Raptor for AP. And I hate the belts...what a pain. Mine was loosening often as well. I really cranked down on the tail boom bolts and it seem to hold now. It was eating the l/h idler. I found I had to add quite a bit of up preload to the tail boom to keep the belt centered in the idler. I'd switch to TT in a second if I knew where to get one for the R50.

[WillJames]

You might be able to sue the new TT drive for the T-REX 600 with some mods???

[MLaBoyteaux]

Bonding the main shaft and tail boom assembly has eliminated my glitching.

On the tail boom, I had to lightly sand a spot under the tail rotor housing and sand the anodized finish off of the inside of the housing to get them to bond. I also did this to the aluminum rudder servo bracket. The CF boom shows about 100 ohms resistance between the TR housing and the rudder bracket.

I ran a wire from the rudder servo bracket to a common point, the screw which holds the left tail boom brace. I then ran a lead from the swashplate to this point. Testing with this arrangement solved the glitching on the AP-2000, but lead to intermittent lock-outs on the PCM receiver. I then ran a wire from the battery "-" lead to this point and this solved all of the glitching.

I also learned I could put an AM radio tuned off station next to the heli while spooling it up and use it to detect arcing. If I disconnet the leads at the common point and spool the heli up, I can generate some nice arcs between the main shaft lead and the boom lead.

I've always had a very intermittent glitch in this heli since I converted it to electric, but never could figure out what it was because it was so infrequent. I'm pretty sure it was the tail belt all along. While researching this phenomenon, it looks like this is not an uncommon problem with belt driven tail rotors. I didn't try it, but a lot of pilots seem to have had good luck with graphite sprays and other anti-static materials applied to the belt.

Now I've discovered the CastlLink software won't recognize the HV-85 ESC, just like the first one I had. I got a feeling the static discharges may be the culprit.

I'm trying out a new set of 695mm semi-sym blades with 3 degrees of washout. While practicing auto's yesterday, I discovered my boom is a few mm short. While doing a bunny-hop landing, I nicked one of the TR blades with one of the mains. :oops: