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what the? Axe CP jumping in the air!

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what the? Axe CP jumping in the air!

Old 08-20-2007, 09:51 AM
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Default what the? Axe CP jumping in the air!

I just did a rebuild on my CP, it flies fine, but as it's hovering, it seems to suddenly pick up head speed and jump straight up! It's probably only a 3 ft or so jump, but this could be bad... I have no idea what is happening, I replaced the motor yesterday and it's doing the same thing, does anyone have any idea?

Old 08-20-2007, 12:27 PM
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Default RE: what the? Axe CP jumping in the air!

Strat,
Just an Idea, but might you have the motor pinion too tight. Happened to me short while back after a hard touch down.

Good luck,
Splat
Old 08-20-2007, 12:50 PM
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Default RE: what the? Axe CP jumping in the air!

hmmmmmm [:'(]

[>:] or maybe too loose? do you think?

(I'd go loose over tight, my mesh is very nice)
Old 08-20-2007, 04:27 PM
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Default RE: what the? Axe CP jumping in the air!

Mine's doing the same exact thing. This is actually the second time it's done this - the first was after my first crash. After some deliberation in these forums, someone suggested that it was a bad servo. I did notice that a servo was glitching and after replacing it everything was fine...

...until recently. I would throttle up to just over hovering, it would hover a foot off the ground and then it would zoom up a foot or too. And the symptoms were the same as the first time - sounded like the engine throttling up and a jump. I'm fortunate to be more experienced in my hovers now than I was then so I've been able to recover and land. What's different this time is I haven't crashed in a month or so. I'm not sure what the problem is yet, so I'll need to look it over.

So, in short, it may be a servo? I'm certainly going to look at all of mine.
Old 08-20-2007, 07:08 PM
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Default RE: what the? Axe CP jumping in the air!

Im only a couple of days into flying my axe and that same surge you guys are explaining happend to me today.. I havent crashed yet but have had a few solid touch downs on the training gear. Would be nice to get the surge problem figured out before it bites me...
Old 08-20-2007, 10:06 PM
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Default RE: what the? Axe CP jumping in the air!

Strat,

So, did you go with the stock TX, or did you get the Futaba 7 to work?
Old 08-21-2007, 07:42 AM
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Default RE: what the? Axe CP jumping in the air!

Pilotlight, I finally got the futaba to work with it friday night. Everything is good with the exception of that launch thing (and gravity kicking in yesterday evening).

I'm thinking I'll look at the servos and replace bad ones...
Old 08-21-2007, 01:22 PM
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Default RE: what the? Axe CP jumping in the air!

How did you get the Futaba to work with it? What was wrong?
Old 08-21-2007, 02:30 PM
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Default RE: what the? Axe CP jumping in the air!

ORIGINAL: PilotLight

How did you get the Futaba to work with it? What was wrong?

hell if I know...

I went home friday evening, took the entire CP apart, replaced bearings, main shaft, etc... I got everything going right mechanically and then put the electronics in and compared it to before, it worked totally perfect! I must've had a wire crossed, but I know for sure I checked them at least 3 times! aaarrrrggghhhh!! [>:]
Old 08-21-2007, 03:56 PM
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Default RE: what the? Axe CP jumping in the air!

well, I would offer to help but seeing as how mine is in the shop for repairs (Hobbico) for the same symptoms as you describe (only mine went down instead of up) I can't tell you anything. Starting my second week now [], No Axe - no fly. I will post what I find out about mine but I know that is of no help to you for now.
In the meantime, I am shopping for another heli. Looking to go to a 500 size.
Old 08-21-2007, 04:01 PM
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Default RE: what the? Axe CP jumping in the air!

Could be a bad servo, sticky swashplate, the main shaft might not be held securely in place by the wheel collar, radio glitch, vibration, or dirty potentiometer in the Transmitter.
Old 08-21-2007, 04:15 PM
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Default RE: what the? Axe CP jumping in the air!


ORIGINAL: PilotLight

Could be a bad servo, sticky swashplate, the main shaft might not be held securely in place by the wheel collar, radio glitch, vibration, or dirty potentiometer in the Transmitter.
that's what I'm going after now.. I changed the motor, but that didn't do it.... so we're back to the drawing board...


after the crash I had last night with it, she'll be under repairs for a few days (I may just wait till the brushless motor comes in)..

K94max - check out the MX400.. they are very cool once it's set up and flying.. much nicer to fly than the CP (sorry guys, but it is)
oh yeah, and I went through the same deal on my CP, I went and bought a new one, flew it a bit, the other came back (which had the gyro on it) I used the second one I picked up as a parts heli...
Old 08-21-2007, 09:53 PM
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Default RE: what the? Axe CP jumping in the air!


ORIGINAL: thestratcat


ORIGINAL: PilotLight

Could be a bad servo, sticky swashplate, the main shaft might not be held securely in place by the wheel collar, radio glitch, vibration, or dirty potentiometer in the Transmitter.
that's what I'm going after now.. I changed the motor, but that didn't do it.... so we're back to the drawing board...


after the crash I had last night with it, she'll be under repairs for a few days (I may just wait till the brushless motor comes in)..

K94max - check out the MX400.. they are very cool once it's set up and flying.. much nicer to fly than the CP (sorry guys, but it is)
oh yeah, and I went through the same deal on my CP, I went and bought a new one, flew it a bit, the other came back (which had the gyro on it) I used the second one I picked up as a parts heli...
Instead of going into an MX400 why no get a CopterX, Diablo, or Phoenix 450 (they are all T-Rex clones). The pricing on some of these are insanely low!
Old 08-22-2007, 04:38 PM
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Default RE: what the? Axe CP jumping in the air!

Thx for advice on heli's. I am currently really looking hard at the Hurricane 550. I want something I can use for scale and the Hurricane has got some good talk about it. Since this is the Helimax thread I don't want to say too much about it.
I checked my Axe's status and it was shipped for return to me today. I hope Hobbico doesn't mind me doing this but based on the repair invoice they are sending me a new helicopter. Ain't bad customer service if that be the case. Of course, they probably took pity on me considering how banged up my bird was when I sent it to them. Still yet, got repairs free of charge minus my cost to ship and looks like it will be a new bird.
Old 08-25-2007, 12:02 PM
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Default RE: what the? Axe CP jumping in the air!

So did we ever figure out what was causing our birds to pop up a foot or more during a hover?
How do you determine if you have a bad servo?
Could any of this be linked to the -Z- connecting rods binding or comming loose?
My heli has popped up on me twice. Not too bad since I'm only 6 to 10 inches off the ground when it happens.
Let me know if anyone has narrowed this common problems down.
Also, has anyone contacted Heli-Max??

Ted
Old 08-25-2007, 01:10 PM
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Default RE: what the? Axe CP jumping in the air!

I'm not sure if there are other symptoms, but my bad servo would just stop responding and for it to get going again I would have to nudge the arm with my fingers. It would rotate fine for a bit after that but get stuck again. I'm not sure if twitching is an indicator as all mine glitch when the radio is near. Ever since I've switched to HS-55's they've always twitched like this, but the heli's only started popping up on me recently. I was able to hover mine through two batteries the other day without it popping up on me...and I didn't change a thing. *shrug*
Old 08-26-2007, 09:39 PM
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Default RE: what the? Axe CP jumping in the air!

Well, I got mine back from repairs and it was a new one in the box. I do not know what the problem is on the hopping though. I am ordering a DX7 tomorrow and also a AR6100 reciever to see if that helps down the road. Making simple mods right now to heat sink etc. I flew my "new" one for a short flight today and I know it's been 2 weeks since I last flew (hovering only stage) but I swear it seems like it had some jitters. I am going to see how the new radio and reciever work before I fly this anymore. Also ordered a flight sim to practice on. I will post back later if I see any improvement over the new radio etc. I may fly it tomorrow some and if I do I will let you know if it is jumpy.
I know that we all have tried just about every suggestion to get it to stop hopping (flying mostly stock stuff) so it doesn't seem to be one specific thing UNLESS it is the reciever or esc? I dunno.
Old 08-27-2007, 08:54 AM
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Default RE: what the? Axe CP jumping in the air!


ORIGINAL: strat1960s

So did we ever figure out what was causing our birds to pop up a foot or more during a hover?
How do you determine if you have a bad servo?
Could any of this be linked to the -Z- connecting rods binding or comming loose?
My heli has popped up on me twice. Not too bad since I'm only 6 to 10 inches off the ground when it happens.
Let me know if anyone has narrowed this common problems down.
Also, has anyone contacted Heli-Max??

Ted

check this out...

that collar on your main shaft just below the swash plate... make sure that it's tight and don't allow a lot of up and down play for the gear... it shouldn't bind, but shouldn't have slop...

(that's what was going on with my MX400 this weekend, I moved it and it flies fine)
Old 08-27-2007, 09:12 PM
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Default RE: what the? Axe CP jumping in the air!

Last week I emailed the folks at heli-max. I'm still waiting to hear back from them.

Ted
Old 09-04-2007, 10:57 PM
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Default RE: what the? Axe CP jumping in the air!

Same problem here popping for no reason hovering fine then pop seems to go up for me , i recently replaced 3 in 1 adjusted some pots she was flying fine 3 batts then after charging went up again then notice pop up , WHOA *** , just when u think you r getin her, BAM the mysterious popping up down mystery[:'(].Man i was doing best yet[8D] , good hover , tail not movin , little trim here -there , was great, feelin good about this venture (better than watchin it spin in circles on floor to timmid to move that tricky left lever). When mine does it i also hear the surge.The SURGE thats got to be root cause sudden jump in power to something seems to do it more when im movin right stick to try to hover or at least keep it in my 3 foot circle not to mention propwash recovery down low she likes to slide her own way had to get that one down in a hurry lol. When i center the right stick after correction it seems to do it more or for me thats when i notice it happening [:@] left stick is about mid or little better for hover , once there left stick keepin tail trackin straight so to me i thinks its in surge after, small correction input then when i return or kinda let stick stay center (let go,let her fly see where she wants to go so im ready to correct) Pop and that noise (surge cant spell it "whreeeee" like its throttling up and im not moving left stick except for tail correction. My guess its in that stupid 3 in 1 r u guys with gyros havin this problem?
Old 09-05-2007, 05:46 AM
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Default RE: what the? Axe CP jumping in the air!

I did not really notice any popping before I installed my gyro. But then again, I wasn't really hovering much before the gyro either. I wander if it has something to do with the gyro, maybe an inconsistent voltage draw. If the voltage draw drops as the battery is wearing down, maybe the power surges to the main motor.
I got a reply from the heli-max folks. They suggested inspecting and adjusting the linkages. I looked my heli over and nothing seems out of place and I don't really want to mess with the factory settings just yet.
I flew yesterday after work and it popped up a few times as the battery was wearing down. Thats why I was thinking about battery/power surges.
I'll keep a closer eye on it today and post any findings.

Ted
Old 09-05-2007, 10:26 AM
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Default RE: what the? Axe CP jumping in the air!

I went into work a few hours early to get some flying time and here is what I found.

1. after hovering on a fresh battery (charged up last night) for a few minutes it popped up a couple of times.
2. i noticed that it would pop up just after i moved the the tail/gyro moved the tail.

So it could be some sort of power surge and here's my reasoning.
When manually or gyro moving the tail additional electricity is needed to to meet the need. The heli may make adjustments to maintain the same altitude. Once that additional need for electricity ends there may be a surge to the main motor.

I could be totally off the mark with this because I read a few posts where the folks have upgraded their servos and the popping up/down has gone away.

Let me know if I could be right or if I'm totally pissin in the wind.

Ted
Old 09-05-2007, 10:56 AM
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Default RE: what the? Axe CP jumping in the air!

Does this only occur with aftermarket gyros? (not the rate gyro in the 3n1)
Old 09-05-2007, 06:50 PM
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Default RE: what the? Axe CP jumping in the air!

Like I said I did not notice prior to installing the gyro, but I wasn't really hovering before the gyro either.

Ted
Old 09-05-2007, 06:58 PM
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Default RE: what the? Axe CP jumping in the air!

I still think its vibration causing extra friction on the swashplate and the main shaft. As you keep adding more collective, the servos finally overcome the friction and the swash jumps downward and the heli jumps up.

Reduce friction/vibration and the jumping goes away.

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