Predator Going into Failsafe!?!?!

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Home › ✈️Aircraft › 🚁Helicopter › Century Radikal G20-30 N640 Hawk Predator › Predator Going into Failsafe!?!?!

05-27-2007 01:31 AM 13 years ago

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0Post 1

Furious Predator

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Kitchener, Ontario, Canada

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Predator Going into Failsafe!?!?!

i'm at a total loss here, i dont know why its doing it.

it would happen a while ago, until i re-routed the antenna, then the glitching went away, good enough for me...

but then it returned earlier this week. a fellow pilot told me it sounds like its going into fail safe (the throttle would pulse very rapidly).

so i took my Voltmagic volt meter/glitch/failsafe counter/monitor.

i set it up to count how many times, if any, the heli goes into failsafe....

well, today i went out and burned almost a gallon of fuel, and i lost count how many times the heli went into fail safe.

sometimes the monitor would detect a failsafe so rapid that i didnt even know it happened. other times i would pulse the throttle enough to be noticable. on average it would happen 1-2 times per flight.

it didn't seem to matter what the heli was doing, hovering or 3D'ing, it would go into failsafe for a fraction of a second at random.

i currently have the antenna running from the radio tray, to the front skid, then to the rear skid, then it runs up to the tail boom held away from the boom supports using 1" long pieces of fuel tubing. i did my best to keep the wire away from any metal and carbon.

i went over the entire heli looking for look parts that could be causing RF noise. i did find one loose screw (loose canopy mount), but tighening that had no effect.

all blades are balanced. engine/clutch/fan is balanced and dialed in. the flybar assembly is BALANCED, BUT the paddles are not the same distance apart. one paddle is about 3mm further out, BUT, the assembly is balanced.

there is a tiny vibration, noticable only when the heli is in idle up, and it can only be seen from the tail fin (very slight) and the rubber tip on the MP2 shaking around a little.

SETUP
Radio is a 10X, with a PCM 10ch RX. everything is set to go into hold except the throttle (goes to idle). using a 2S2P lipo with VS-5S regulator.

Futaba 601 with 9251
9253 on throttle
9451's on swash.
YS91 with Viper Head and MP2
TJ RevMax

I plan on getting a DX9 when it comes out, or shortly after, but i would like to solve the problem as it stands right now.Shawn
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05-27-2007 02:10 AM 13 years ago

0Post 2

oldfart

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Vancouver, Canada

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Such type of fail safes are usually caused by power supply issues. Whenever the voltage drops below a specific voltage (for whatever reason) your PCM receiver is programmed to do so. Ditto for an intermitant switch.

As you are using all Digital servos sometimes the current draws may momentarily cause the voltage to dip drastically, specially on lipos of a low "c" rating (you did not give the specs on the battery pack other then it was a 2S2P pack).

A quick and easy check would be to byapass your current power supply system (battery, switch and regulator), and replace it with a good well charged "C" size NiCd of 2400mah 4 cell pack for a flight and see if you read the same glitching/lockouts.

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05-27-2007 02:49 AM 13 years ago

0Post 3

Furious Predator

rrProfessor

Kitchener, Ontario, Canada

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it is a DUALSKY lipo, 4500mah, 12C continuous, 16C burst.

but i doubt that is the problem, because my heli would go into fail safe even in a hover.Shawn
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05-27-2007 03:11 AM 13 years ago

0Post 4

Jafa

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Sydney, Australia

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I don't know anything about JR
but the Futaba PCM gear does not go into and come out of failsafe
in a fraction of a second - it's much longer

The throttle pulsing is most often the TJ Pro
having a bun fight with an engine that is slightly lean

Make sure your antenna is not tied directly to the carbon boom brace

I seem to remember another guy having glitches
and the tail push rod was hitting something
under the tail box
(my predator also hits but no glitches)

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05-27-2007 03:57 AM 13 years ago

0Post 5

Furious Predator

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Kitchener, Ontario, Canada

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hmm...i dont even have a pack i could use to try it out with. i have one, but its burried inside my Bell 222. taking it out would require a fair bit of work, and its not even that good of a battery, i dont trust it to a 90 with all digitals.

but if its the power supply, could i not simulate it on the bench? if i were to load up all the servos and get thigns warmed up, maybe at some point it would go into failsafe assuming its the power supply.

my antenna though at the moment is completely isolated from metal and carbon....atleast now it is. it wasn't quit before. i'll giver a go tomorrow if its not raining.

one thing though i didn't mention....it never seems to happen right away. it seems to act up at about 4-5 minutes into a flight. maybe the power supply is over heating...i'll check its temperature after a flight. with everythign so tight and close together on the heli, the heat sink must not get a lot of air moving around it.

at the moment, the YS91 seems to be tuned perfect. earlier in the week it was REALLY rich. to the point were it would sometimes flameout on spoolup. but now i have it tuned so it runs very smooth. i set it up so its about 2-3 clicks away from being lean. its putting out a lot of power right now.Shawn
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05-27-2007 04:02 AM 13 years ago

0Post 6

Spitfire_mk5

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Canada

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could be a notchy bearing, also could be a servo with a stripped gear overamping, or otherwise just bad. Also could be a lose connector in the power system is causing momentary contact or a bad solder joint has let go.

Also another thing to check would be that the antennea wire is firmly connected to the Rx, if that has a bad connection, well, bad things happen.

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05-27-2007 04:14 AM 13 years ago

0Post 7

Furious Predator

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Kitchener, Ontario, Canada

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hmmm....thats what i fear most, that kind of stuff is hard to detect

Shawn
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05-27-2007 04:50 AM 13 years ago

0Post 8

Furious Predator

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Kitchener, Ontario, Canada

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i forgot to mention too.

the monitor i'm using displays current voltage, AND the peak lowest voltage during the flight. according to the monitor, the voltage during the 6 flights i had today, never changed even by 0.1V, it was a rock solid 5.6V the entire time.Shawn
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05-27-2007 04:52 AM 13 years ago

0Post 9

BC Don

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Calgary, AB Canada

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When you go into failsafe with PCM, what are the settings for your other servoes? Also, if you are having a drop in power and go into failsafe, your gyro will reset as well so I'm not sure you are actually going into failsafe (although I'm not sure what else it could be). One way of testing would be to get an FM Rx (PPM) and try it. The PPM will show you pretty quick if you are glitching.

I've had problems with gyros causing interferance, bad anntenna connections, bad servoes, its real tough to trouble shoot. One way of testing whether it is failsafe or not, deliberately make it go in and out of failsafe and see if you can make it happen as rapidly. Go out to the field, get the heli in "N"ormal mode and get the throttle up to about 1/4. Keep the antenna down and walk away the 100 paces or so till failsafe kicks in (you'll hear the engine suddenly drop). Now walk forward quickly a couple of paces and it should reaquired the signal. When I tried this with my Futaba radio the transition wasn't nearly as rapid as you described.Got Money? Send it to me, I'm a Heli Addict.

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05-27-2007 04:57 AM 13 years ago

0Post 10

Furious Predator

rrProfessor

Kitchener, Ontario, Canada

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i have it set so all servoes go into hold except for the throttle, it goes to idle.

the monitor i have which will detect a fail safe works by setting its travel to max on the ATV, and set that to be its fail safe position(signal). then the ATV gets braught back down. when a fail safe occures, the ATV for the montore gets set to 150%, when the monitor detects the max travel like that, it detects it as a fail safe.

the monitor also shows a rock steady 5.6 Volts the entire flight.Shawn
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05-27-2007 04:59 AM 13 years ago

0Post 11

Spitfire_mk5

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Canada

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do you know for certain that the monitor is logging the whole flight (i've never used one)? Some kind of internal timer? if not and you are loosing Rx power it will show no lockouts because it could get reset and you are only getting data for the last good couple seconds.

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05-27-2007 05:03 AM 13 years ago

0Post 12

Furious Predator

rrProfessor

Kitchener, Ontario, Canada

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its hooked directly to the RX, if the RX has power, so does the monitor. its logging the entire time. i think if the RX lost power, it would reset the gyro, and the throttle would also not go to idle.

CLICK HEREShawn
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05-27-2007 05:06 AM 13 years ago

0Post 13

Furious Predator

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i have tested the failsafe function on it by turning the TX on and off real fast. everytime i turn the TX off, the heli goes into failsafe, and its recorded on the monitor.Shawn
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05-27-2007 10:41 AM 13 years ago

0Post 14

Jafa

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05-27-2007 06:16 PM 13 years ago

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FenderBean

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Huntsville Alabama

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its funny to see this, last weekend I had my bird go into fail safe twice, one high up and the other in a hover nose in coming toward me! Scared the crap out of me, got it back about 5 feet away. It had been fine up till last weekend with no problems! The week prior I did cycle my batteries a few time since they started to not hold well. I have a 2500 MAH pack and run 3 futaba 3310s, 502 gyro, Gov-1 with hitec digital servo on throttle and a futaba digital on the tail. The batteries are good. Held a charge just fine and was still showing a top charge after the 1st flight when this happend. I did however find a lose part, my gyro is mounted to a carbon fiber plate that is mounted to the front of the servo tray. It was lose and I tightend it up and got a slight glitch once after that. I think this maybe my problem, plus I want to change my stock switch with a heavy duty. Any ideas on this problem? The above mention about fail safe taking a few secs to kick off is true I would lose control and good 4 secs!!!!!

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05-27-2007 06:41 PM 13 years ago

0Post 16

Furious Predator

rrProfessor

Kitchener, Ontario, Canada

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hmm....i made some changes to my heli. mostly to the antenna, plus i found a couple loose items. i'll try it out with the setup as is and see if i still get the glitch. if it still happens, i do have an identicle RX i could swap with.Shawn
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05-28-2007 03:22 AM 13 years ago

0Post 17

Wyn

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Oregon, USA

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As you already said Furious, it's not a voltage problem since VoltMagic isn't warning you about peak low voltage, and the RX is definitely going into failsafe because that's what VoltMagic is actually detecting (even when it's so quick that you can't hear the throttle respond). There's typically a fraction of a second delay going into failsafe, but none coming out, so the failsafe itself can be very short.

I had a bearing that was spinning it's outer race (just loose, not bad) do similar to what you describe. Drove me nuts for a while. Swapping the RX sounds like a good idea, but I suspect most of the time it's the loose stuff and bearings that your already looking at.

Have you tried a range check with engine idling? Since your servos (except throttle) go to hold, maybe run the engine up a little on the ground for a while (antenna collapsed at a distance) and see if you get the failsafe detected on VoltMagic before flying? This is what I did until the bearing mentioned above was finally found. Of course that was after almost crashing a couple times

.Wyn
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05-28-2007 03:40 AM 13 years ago

0Post 18

Furious Predator

rrProfessor

Kitchener, Ontario, Canada

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i'll try the range check tomorrow when i go out. i did a close inspection and found a couple loose items, but none that i would consider a cause to a glitch.

How do you find a bad bearing? i know bearing in the engine can make rattle sounds, but there are so many more bearings then that. i cant imagine how i could check each one.Shawn
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05-28-2007 04:08 AM 13 years ago

0Post 19

Wyn

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Oregon, USA

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How do you find a bad bearing? i know bearing in the engine can make rattle sounds, but there are so many more bearings then that. i cant imagine how i could check each one.

Short version: Tried different RX and crystal, put new bearings in the engine (needed those anyway) and checked the bearings for the clutch, etc that were now easier to get at. Same problem. On the tail drive (this is a Fury) there was some aluminum powder where the outer race was turning in an aluminum boss, which I should have noticed earlier. Problem solved. So in retrospect, I'd say really look close with a flashlight for the glimmer of aluminum dust first. May not be it, but it's easier than tearing it apart first.Wyn
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05-28-2007 04:10 AM 13 years ago

0Post 20

Furious Predator

rrProfessor

Kitchener, Ontario, Canada

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ok, thanks. i'll get in there with a flashlight