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blorph · 07-14-2015, 06:25 PM

Hi all. So far this year has been a year of almost no flying. Been 2,000 miles away training for work so flying opportunities have been lacking lately.

Anyway, last flight with 450 heli #2 (as described below) it suddenly plunged vertically straight down (at the time it was upright in straight and level flight) as if it had been given FULL negative pitch. I fly inverted quite a bit and know the diff between positive and negative pitch and know I didn't do it. Worse, this is the second time this heli has done so in the last year or so. The radio is a Spectrum DX7 that I also use for the other 2 450's with no issues so am pretty sure it's not the radio. I'm using an AR6200 receiver with satellite and suspect I'm having receiver issues. Originally I bound the receiver with blades at zero pitch and idle power probably 5 years ago. Perhaps I need to bind again and/or get a new receiver.....Any thoughts?

Flightpunch 34 · 07-15-2015, 05:15 AM

Maybe the ESC needs reprogramming,if you run the packs too low or anywhere near LVC then it will drop out of the air like a rock.

Normally they come as default on high voltage cut off to protect the battery,i think this is not good because most of us run the packs as low as 10- 11 percent region, i think once you hit around 3.7v or slightly under it the ESC shuts down to prevent battery over discharge.

So what you may need to do it reprogramme the ESC with your TX throttle stick and set it and change the cut off to *LOW* cut off.....

So you then should be able to run your packs a little lower without it dropping down,if you suspect it's not the battery and you have sufficent charge in flight maybe you need to test the packs,maybe one of your packs is gone bad and not holding a decent charge!

Dan

blorph · 07-15-2015, 10:04 AM

Thanks for the reply. I don't think it's the LVC. The battery is a good strong battery and this incident happened within the first 30 seconds of flight on it. And, the heli didn't fall out of the sky, it pulled itself hard toward the ground as if full negative pitch had been input.

Flightpunch 34 · 07-15-2015, 02:22 PM

How is your set up? what pitch have you? how do you set it up,so you use a pitch gauge?

If you have too much negative pitch it could be extremly sensitive to any negative stick input and may even do what you describe very easily,450's turn a nice head speed.

macdad · 07-15-2015, 02:42 PM

Also wonder if it just went into failsafe mode for some reason. Maybe it lost signal or had a voltage drop.

Perhaps take the blades off and test the failsafe? That may point you in the right direction. If so, you may need to rebind.

blorph · 07-15-2015, 04:20 PM

Running +12/-12 on it.

Right now I'm suspecting I need to do a rebind on it and then a re-test.

blorph · 07-16-2015, 04:18 PM

Well....did a rebind on it yesterday with throttle at midstick (zero pitch) and throttle hold on. Afterward, took bind plug out and rebooted. Then moved the throttle all the way low and turned off the radio. It didn't move a muscle. I thought since the throttle was all the way low but I had just binded it with the throttle at midstick that when I turned the radio off the heli would go to midrange (zero) pitch. But, again, it didn't move a bit. Doesn't seem right..

Anyway, put 8 batteries through it today and all was well

blorph · 08-25-2015, 06:58 AM

Well, it's up to it's old tricks again.

I ended up putting an new receiver in it recently, a Spektrum AR610. Did a range test and it tested perfectly out to 49 paces!

Here's what it's doing now. It'll take off just fine in Normal mode (low rpm). Shortly after I switch to Idle 1 it will start twitching in pitch and roll and I know it's about to do something drastic on it's own. Usually, then switching back to lower rpm's (Normal mode) will 'cure' it and I'll regain control. But yesterday after switching back to Normal I totally lost control of it: it gently pitched forward and down into the ground totally against my commands.

Just before this happened I had lubed the belt very well, thinking maybe it was a static issue. No help.

Could it be the servos? This is my bottom of the barrel beater heli that I use for practicing new stuff. For years I have been using el cheeeeeepo HXT900 servos (yeah, the under $4 ones) and they have worked great on this heli.

I am totally out of ideas. Any thoughts?

sdunne · 08-25-2015, 07:23 AM

Failsafe on the AR610 will drive the throttle signal down only, it will not change pitch.

sconel · 08-25-2015, 07:31 AM

Have a look at that. Could be that it takes some vibration to short it out, like a running motor, maybe begin looking at the Pitch servo wires first.

blorph · 08-25-2015, 09:04 AM

Ok, thanks for the ideas. Please keep em coming.

Will be off for a while. About to drive our youngest to college.

CrashNburn420 · 08-25-2015, 04:29 PM

Those hxt900 servos are pretty weak. I have used them in cheap foamies but would not trust them in a Heli. Invest in some decent servos

Crashtestheli · 08-26-2015, 06:20 PM

I had this happen as well. for me it was a broken solder joint on one of the motor bullets.
check all joints / resolder

blorph · 09-28-2015, 08:53 PM

Well (ding ding ding) it appears we have a winner. CrashnBurn 420. It's been a month but I finally got the chance to really delve into this heli. Here's what solved it. I ended up spooling it up with no blades and, yup, at higher rpm's and only at higher rpm's the Elevator servo just sat there chattering and shimmering like crazy. All uncommanded. Replaced the Elevator servo and all is well. So far, at least. But I don't expect any further issues.

Again, this is my most beat up of my beaters and I'll still use the HXT900's but only on it and until they're gone.

So thanks again Crash. And everybody.

07-14-2015, 06:25 PM	#1 (permalink)
blorph Registered Users Join Date: Oct 2007	Trex 450 V2 decided to plunge straight down Hi all. So far this year has been a year of almost no flying. Been 2,000 miles away training for work so flying opportunities have been lacking lately. Anyway, last flight with 450 heli #2 (as described below) it suddenly plunged vertically straight down (at the time it was upright in straight and level flight) as if it had been given FULL negative pitch. I fly inverted quite a bit and know the diff between positive and negative pitch and know I didn't do it. Worse, this is the second time this heli has done so in the last year or so. The radio is a Spectrum DX7 that I also use for the other 2 450's with no issues so am pretty sure it's not the radio. I'm using an AR6200 receiver with satellite and suspect I'm having receiver issues. Originally I bound the receiver with blades at zero pitch and idle power probably 5 years ago. Perhaps I need to bind again and/or get a new receiver.....Any thoughts?

07-15-2015, 02:42 PM	#5 (permalink)
macdad Registered Users Join Date: Jan 2014	Also wonder if it just went into failsafe mode for some reason. Maybe it lost signal or had a voltage drop. Perhaps take the blades off and test the failsafe? That may point you in the right direction. If so, you may need to rebind. __________________ Oxy 2, Gaui X3 #1, Protos 380, Gaui X5, Synergy 766, Specter 700 Oxy 2/X3/Protos 380/X5/766/Specter 700 Consecutive Successful Flights (Current) = 32/16/12/145/7/50 Consecutive Successful Flights (Max) = 145

08-25-2015, 07:31 AM	#10 (permalink)
sconel Registered Users Join Date: Mar 2011	chafed/shorting wire? Have a look at that. Could be that it takes some vibration to short it out, like a running motor, maybe begin looking at the Pitch servo wires first.

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07-15-2015, 05:15 AM	#2 (permalink)
Flightpunch 34 Registered Users Join Date: Feb 2015	Maybe the ESC needs reprogramming,if you run the packs too low or anywhere near LVC then it will drop out of the air like a rock. Normally they come as default on high voltage cut off to protect the battery,i think this is not good because most of us run the packs as low as 10- 11 percent region, i think once you hit around 3.7v or slightly under it the ESC shuts down to prevent battery over discharge. So what you may need to do it reprogramme the ESC with your TX throttle stick and set it and change the cut off to LOW cut off..... So you then should be able to run your packs a little lower without it dropping down,if you suspect it's not the battery and you have sufficent charge in flight maybe you need to test the packs,maybe one of your packs is gone bad and not holding a decent charge! Dan

07-15-2015, 10:04 AM	#3 (permalink)
blorph Registered Users Thread Starter Join Date: Oct 2007	Thanks for the reply. I don't think it's the LVC. The battery is a good strong battery and this incident happened within the first 30 seconds of flight on it. And, the heli didn't fall out of the sky, it pulled itself hard toward the ground as if full negative pitch had been input.

07-15-2015, 02:22 PM	#4 (permalink)
Flightpunch 34 Registered Users Join Date: Feb 2015	How is your set up? what pitch have you? how do you set it up,so you use a pitch gauge? If you have too much negative pitch it could be extremly sensitive to any negative stick input and may even do what you describe very easily,450's turn a nice head speed.

07-15-2015, 04:20 PM	#6 (permalink)
blorph Registered Users Thread Starter Join Date: Oct 2007	Running +12/-12 on it. Right now I'm suspecting I need to do a rebind on it and then a re-test.

07-16-2015, 04:18 PM	#7 (permalink)
blorph Registered Users Thread Starter Join Date: Oct 2007	Well....did a rebind on it yesterday with throttle at midstick (zero pitch) and throttle hold on. Afterward, took bind plug out and rebooted. Then moved the throttle all the way low and turned off the radio. It didn't move a muscle. I thought since the throttle was all the way low but I had just binded it with the throttle at midstick that when I turned the radio off the heli would go to midrange (zero) pitch. But, again, it didn't move a bit. Doesn't seem right.. Anyway, put 8 batteries through it today and all was well

08-25-2015, 06:58 AM	#8 (permalink)
blorph Registered Users Thread Starter Join Date: Oct 2007	Well, it's up to it's old tricks again. I ended up putting an new receiver in it recently, a Spektrum AR610. Did a range test and it tested perfectly out to 49 paces! Here's what it's doing now. It'll take off just fine in Normal mode (low rpm). Shortly after I switch to Idle 1 it will start twitching in pitch and roll and I know it's about to do something drastic on it's own. Usually, then switching back to lower rpm's (Normal mode) will 'cure' it and I'll regain control. But yesterday after switching back to Normal I totally lost control of it: it gently pitched forward and down into the ground totally against my commands. Just before this happened I had lubed the belt very well, thinking maybe it was a static issue. No help. Could it be the servos? This is my bottom of the barrel beater heli that I use for practicing new stuff. For years I have been using el cheeeeeepo HXT900 servos (yeah, the under $4 ones) and they have worked great on this heli. I am totally out of ideas. Any thoughts?

08-25-2015, 07:23 AM	#9 (permalink)
sdunne Registered Users Join Date: Feb 2011	Failsafe on the AR610 will drive the throttle signal down only, it will not change pitch.

08-25-2015, 09:04 AM	#11 (permalink)
blorph Registered Users Thread Starter Join Date: Oct 2007	Ok, thanks for the ideas. Please keep em coming. Will be off for a while. About to drive our youngest to college.

08-25-2015, 04:29 PM	#12 (permalink)
CrashNburn420 Registered Users Join Date: May 2012	Those hxt900 servos are pretty weak. I have used them in cheap foamies but would not trust them in a Heli. Invest in some decent servos

08-26-2015, 06:20 PM	#13 (permalink)
Crashtestheli Registered Users Join Date: Jan 2012	I had this happen as well. for me it was a broken solder joint on one of the motor bullets. check all joints / resolder

09-28-2015, 08:53 PM	#14 (permalink)
blorph Registered Users Thread Starter Join Date: Oct 2007	Well (ding ding ding) it appears we have a winner. CrashnBurn 420. It's been a month but I finally got the chance to really delve into this heli. Here's what solved it. I ended up spooling it up with no blades and, yup, at higher rpm's and only at higher rpm's the Elevator servo just sat there chattering and shimmering like crazy. All uncommanded. Replaced the Elevator servo and all is well. So far, at least. But I don't expect any further issues. Again, this is my most beat up of my beaters and I'll still use the HXT900's but only on it and until they're gone. So thanks again Crash. And everybody.

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