Servo Lockup in snaps

[VIPER69]

Once in a while I experience a weird situation with my H9 Extra 300s 33%er.
In 45 degree uplines moving pretty rapidly at the time...I snap roll and when the plane is about 3/4 the way around it will just hang in that position for a split second, then come on around.

Scares the bejesus out of me when it happens too!!!
What is weird is once I flew without recharging my batts and noticed it would do that several times in a row. Now it happens once every 10 flights or so... always at the same position in my sequence.

My assumption has been that the amp draw is greatest at that point and my servos can't get the go-juice they need and go neutral for a half second.

Another thought is that this is something aerodynamic in nature and it just can't quite get around as fast as I would like... but the fact that it happened once repeatedly when the batts were low seems to rule this out.

My set-up is...
8 Futaba 3305 metal gear servos (2 rudder, 4 aileron, 2 elevator)
2400 Fromeco lion batt
MPI regulator

Any thoughts are appreciated?

[green@3D]

one battery, one reg?

Does sound like a lack of juice.

not just batt induced, could be a voltage drop somewhere else, a connector, switch, too small a wire somewhere. But honestly, isn't one 2400 a little, well, you know, ahh small?

[notorious_benny]

I agree, get a second 2400 and reg.

[40%plane]

I had a buddy that had this exact problem with his 42%. We were running the sportsman sequence from last year and when we pulled to a 45 upline and did 2 of a 4 pint roll it woul go into pcm lock up for a short second and then come right back. It would only do it in that situation or another situation were there was a lot of use from the servos. For him it turned out to be old battery packs not putting out ample power for his system, a new set of 4000 fromeco fixed the problem and we now have about 30-40 flight with no problem. I am guessing that you are having the same problem too.

Mike

[Reza]

Ok that reminds me of my crash. My plane did it only once in a level flight snap and the receiver went to failsafe for about a second and it came out. Second time after 10 flights or so, did it again and the receiver never got back from failsafe. Eventhough my receiver battery was fully charged I noticed there was some issues with the battery that would drop the voltage a lot. Change to 4800 Fromeco before same thing happend to me happens to you. I tell you electronics are not predictable, there is always a chance if you are using pcm that your pcm receiver locks up!! Take this really serious. Good Luck

[TheTank]

That is interesting? If you didnt have enough juice, you would notive more of a fade or a washed-out snap. Do yourself a favor and check your crystal and your RX. It may be that a positive snap is causing the crystal to move causingthe reciever to lock out for a second. Its just a thought, but I would be giving it a good once over. Turn on your TX and RX, and handle the reciever, put some pressure on the crystal, and gently squeeze your RX with surfaces deflected and see if it goes into lockout. Definetly sounds like a problem that needs to be tracked down.

[VIPER69]

Just bought a Fromeco reg and 4800 pack just in case, and will try the receiver tonight. Very odd that only the snap is causing me the problem, and only once every 10 flights or so. I do all kinds of freaky stuff with blenders and such, with this never going on as far as I can tell.

I was thinkg that there must be some serious windspeed forcing the ailerons to push back, as well as rudder and elevator causing the amperage to really spike during a mid-speed snap.

Thanks for the replies guys. Any and all thoughts are appreciated.
--james vanwinkle

[YaKs are BeSt]

if its only 1 2400 doing all the servos on a 33% er than you deffinately need more amps before its something elses fault.

[VIPER69]

I just bought a Fromeco 4800 with a reg... I assume that will supply enough amps???

I won't fly that bird for a few weeks until the goods arrive, but it is killing me to keep her on the ground. Better safe than sorry though.

[green@3D]

yup, that should be enough juice now. let us know if this works

[Cajun]

	Quote: Originally Posted by VIPER69
	I won't fly that bird for a few weeks until the goods arrive, but it is killing me to keep her on the ground. Better safe than sorry though.

A few weeks!?

My good came from then in about 3 days... and I'm sure your a good bit closer.

[Rolling Thunder]

Change regulators. MPI regs can not take much amp draw.
One 2400 battery is not enough

Are you running PCM? If so, How is the failsafe set?
Futaba or JR TX?