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HomeAircraftHelicopterCentury Radikal G20-30 N640 Hawk Predator › PG2000V2 failure - one side doesn't work!
07-21-2002 05:30 AM  16 years agoPost 1
ncostes

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Va, US

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I was flying for the first time with a 5 cell pack. Highest voltage was 6.8V, the PG2000V2 is supposed to be ok to with that.

Well towards the end of the day I wanted to raise the gain so I did so remotely on the radio. Even at 100% it wasn't wagging, so I remember reading in the instructions that you're supposed to adjust the "gain res. pot" on the gyro until you can get wagging at 100% remote gain.

I cranked the gain res. pot up on the gyro, lowered my radio gain, and started flying. Now the tail seemed way too sensitive, just a touch and it would spin.

I flew like this for a little while but it was unnerving so I landed and checked the gyro - it was not working! It didn't do anything when I rotated the heli. I'd been flying w/out the gyro and didn't know it (and boy did it suck).

I experimented and found that if I have the gain res. pot all the way at minimum, the gyro would work, but it would only compensate for movement in one direction! No wonder I'd been having trouble earlier w/ the tail turning too easy in one dir. I had thought the new 5 cell rx pack was making the tail servo too fast and had dialed in some expo to compensate.

Anyone else seen this mode of failure on their gyro? Is this common? I'll call Century monday and see if I can get warranty service - not sure how long the warranty is, it's less than 2 months old.

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07-22-2002 07:24 PM  16 years agoPost 2
oldfart

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Vancouver, Canada

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PG-2000
Nick,

I am sure they will replace it.

I found years ago, that using an UNREGULATED 5-cell pack was not a good idea on most radio equipment - even if rated for higher. then the standard 4.8V. I higher voltage power supply is also open to drawing higher amperage also, for a far higher then regular amount of power flowing (watts) through it. I even fount that the 6.0 volt requlatorts were too high and now only use those with regiulation at 5.3 or 5.1, which is about the highest voltage one will get from a freshly charged 4 cell pack.

Also, your gyro may be rated to work at that voltage but its associated the servo may not. This may well cause problems with the complete circuit.

Phil

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07-22-2002 07:35 PM  16 years agoPost 3
Twobeers

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Toronto, Canada

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I don't know what the voltage rating is of this gyro, but i can tell you this the Futaba gyro's are rated to work up to 6volts. Now having said this, it states on the phamplet -----6 volts. A 5 cell pack is rated 6volts. When you reach somewhere in the neighborhood of 5.7volts you would recharge it. What is the voltage of the 5 cell pack fresh off of the charger, its well over the gyro's rated maximum of 6 volts. I would not be suprised if you did some internal damage to the electronics in your gyro.

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07-23-2002 07:10 AM  16 years agoPost 4
ncostes

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Va, US

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Thanks guys. The gyro is rated to 7.2V (century pg2000V2).

AMC said the same thing on another thread - that futaba stuff is rated to 6v only. I'm running hitec and it is also rated to 6v, but 6.8 should not be that big of a deal (6.8V is what the 5 cell pack measures open circuit (no load) when fresh off the charger - will be lower under load, don't recall how much - and that's only at the beginning of the day). The problem developed towards the end of the day when the voltage was down to about 6.2V, though I certainly could have started to damage it earlier.

The same gyro and radio equip. was in a crash 2 weeks ago, and though none of it seemed damaged at the time and flew fine the following week, perhaps the gyro was damaged in some way and then just crapped out this past weekend - would be my fault.

That being said, I'm going to get a 78S40 and do a step down for 6.something to 5.something so everything will work over the Vin range 5.5 - 6.8 (discharge - full charge for my cell pack). I know someone sells a switching regulator plug in but it's like $20 or $40 I think (if you have a source for cheaper ones let me know please), the 78S40 part itself is $2 and you just need an inductor, some caps and some resistors.

Oldfart I wouldn't argue with your years of experience : ) it is possible if the tail rotor servo was binding it could draw more current through the gyro since it is plugged directly into the gyro, didn't consider that. But mine is set up mechanically not to bind even when the servo is at full +/- throw (adjusted t/r ctrl rod length and ball distance from center of servo), and I was just hovering all day in various orientations, with little or no wind. And with all the load from 5 servos, rx, and gyro...

Ceratinly you are right that given a constant internal resistance the circuit could sink more current from the higher voltage source, and if the resistance remains constant it is dissipating more power. But this can happen with a regulator as well, since it is regulating voltage, not current (though you have an Ipeak), and P=I^2R= I(I*R) = I*V. So even if you regulate V, given a higher Vin you can source more I and produce more power.

Anyway I'll try it out and see what happens, I just got a replacement scope off ebay for $76, and this one actually WORKS Now I can finally explain to my wife why I needed a scope

When I call century I'll tell them what I did (crash, 5 cell). If they still will replace/fix it great, if not, it's my fault - the question then is do I buy another gyro, or do I get their $219 deal where you get the Hawk IV + the gyro, in essence buying another kit for $219-$85 = $134

After all my spare parts kit is now becoming the mutant Hawk IV OS50, where will I get spare parts from???

As usual thanks for the info!
Nick

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07-26-2002 07:08 PM  16 years agoPost 5
ncostes

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Va, US

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Not covered under warranty if crashed...
I called Century today and spoke to Dennis. Apparently their electronics are not covered if you have had a crash (even if it worked properly for 2 weekends after the crash). I can understand this policy, even with only a 2 month warranty I guess people could crash stuff left and right and try to get warranty service.

Like I posted before, the crash was from about 10feet up, and all the electronics survived, only damage was to blades, feathering shaft, flybar, and plastic landing gear struts. The canopy absorbed most of the energy in the nose - my electronics didn't even come out of the rubber bands, and the gyro was still firmly attached to the double sided tape.

But it's not unreasonable not to cover something after a crash I supposed.

Though I am suprised there's no option to pay to have it repaired, only order a new one.

I'm not planning to order another century gyro by itself - they're great when they come with a kit for free but for $85 - I may grab one of the lower end futaba HH gyros - for not much more.

Anyone know if other mfgrs (CSM, Futaba, JR, etc.) will cover stuff if it's been through a crash but was working and then it failed later?

And do they normally offer the option to have items that are out of warranty repaired or not?

Thanks!
Nick

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07-30-2002 05:41 AM  16 years agoPost 6
ncostes

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Va, US

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Follow up
Just a follow up. Richard from Heli-World called and offered to help w/the gyro - he offered to do an exchange for $50 - which was very nice. I may take him up on it, or I may look at the low end futaba HH gyro, as I have one pg2000v2 in my other heli and another one on the way from guam in a used Hawk III (right Ray?)

Thanks
Nick

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