Cyclic inputs cause "bobble"

[mmtecg]

Hi, I just finished my Gaui 200 build and was test flying it and everything was going pretty good. I did a little tuning and was just starting to enjoy it when all of the sudden the heli got behind me and hit the ground.:arggg::arggg::arggg:

The crash was pretty hard and the main blades were the first thing to hit but anyway I picked it up, checked for damage and tryed to fly it again... here's where the problems started. First thinng I noticed was that the tail wag wagging a bit, no prob, just back down on the gain... I ended up going all the way down to 30% gain from what it was before, 50%.

The next thing I noticed was that when I add a cyclic input and then released the stick, the heli would "bobble" or "wag" up and down the or in the direction that I had made the input. I know it was not doing this before and it really upsets me because from what I could tell on the first couple of flight before the crash, it was a really fun little heli.

I would really be thankful if you guys would help me fix the heli to what it was before the crash.
Michael

[rotorhead58d]

Hi, I just finished my Gaui 200 build and was test flying it and everything was going pretty good. I did a little tuning and was just starting to enjoy it when all of the sudden the heli got behind me and hit the ground.:arggg::arggg::arggg:

The crash was pretty hard and the main blades were the first thing to hit but anyway I picked it up, checked for damage and tryed to fly it again... here's where the problems started. First thinng I noticed was that the tail wag wagging a bit, no prob, just back down on the gain... I ended up going all the way down to 30% gain from what it was before, 50%.

The next thing I noticed was that when I add a cyclic input and then released the stick, the heli would "bobble" or "wag" up and down the or in the direction that I had made the input. I know it was not doing this before and it really upsets me because from what I could tell on the first couple of flight before the crash, it was a really fun little heli.

I would really be thankful if you guys would help me fix the heli to what it was before the crash.
Michael

check for damage....sounds like the boom might be bent/moved. check the grip screws. buy a big magnifying glass. when it flies weird like that, something is bent or not adjusted right. be prepared for this after every crash. i find something loose or broken after every crash.

[stoatnchips]

Michael, i can only suggest the obvious... First you almost certainly have bent the Blade grip bolts... take the blades off and then undo the bolts... you will see/feel almost imediately if the bolt is bent as the grip will precess! If the Heli vibrates when spooling up... before lift off... then remove the main shaft and roll it accross a mirror to check its not bent. If you only get problems when you alter the swash orientation, then it sounds like an uneven setup somewhere in the head. Check the blade grips are not twisted slightly at the hole for the mixer/seesaw arms and check the mixer/seesaw arms themselves that the Balls are parrallel to each other.. i use a digital Micrometer to measure between the outside edges of each ball.. soon shows up if there is damage... i posted about these yesterday i think... Hope this is a help to start with ;)

EDIT - Looks like Rotorhead beat me to it! but hes right... definatly damage is to blame

[mmtecg]

Thanks a lot guys. I'll check eveything that you said and start to replace whatever is damaged. One thing I did see was that the seesaw arms were slightly bent so I used a pair of plyers and bent them strait.. I think. But the point is I'm gong to recheck for damage and try everything you said. Michael

[jimgrant]

" the seesaw arms were slightly bent so I used a pair of plyers and bent them strait.. "

Haha, I laughed at that, I thought it was just me that used that expression, to bend something straight.

The damage wont be much. Its amazing how robust these helis are

[J-Heli]

One thing I did see was that the seesaw arms were slightly bent so I used a pair of plyers and bent them strait..

From my experiences, bending them back is okay, but it's better to just replace them. The reason being that when they're bent in a crash, they're stressed at the point where they were bent. This being said, bending them back just stresses them more, and causes them to become really weak. Then, when you spool her up to fly her again, you have a really weak seesaw arm that is likely to fail. This especially applies to smaller seesaw arms, hence the Gaui seesaw arms. Correct me if I'm wrong, but that's just what I've learned from my experiences. Good luck finding the culprit.

[mmtecg]

heli cuzz, your probably right but as of right know everything is going to he_ _ with my Gaui. Last night I took it apart so that I could find out what the problem was and I broke the spindle trying to get it out of the head. (How are you supposed to get the spindle out?) Now as thats not enough, I have to wait for replacement parts to arrive before I can continue testing.... HECK I don't even know what the problem is in the first place. It was flying fine before the crash but now it seems as though everything is falling apart...literaly.
I guess if I knew what to replace would make it slightly better but I don't even know that. I don't know what else to do, I mean I took the whole thing apart and could'nt find the problem. What do you guys do when this happens? Do you start to replace thing hoping that you'll get lucky? Sorry for the rant but it's awfullly vexing. He he.
Michael

[J-Heli]

We're trying too hard to find this problem. If the heli gains and then loses altitude, then you'd think that it was a pitch problem. This maybe kind of abstract, but it could be a servo problem or a programming issue and didn't show itself after the crash. If it were me, I would replace the cyclic servos and rebuild the Gaui again and see what happens. Boy I'm helpful ;).

[rotorhead58d]

it would be great to post a video if you were able to.

[mmtecg]

UPDATE: I just replaced the main gear, tail boom, belt, tail gear, spindle, spindle bolts, dampers, tail blades... and much more.:thumbdown::thumbdown::arggg::arggg: Anyway I just tested the servos (The only thing that I did'nt replace) on the ground and found that they will not return to the center without 'jittering' along the way. Is this normal with the 45-HB's?
I'll try to explain... If I move the right stick all the way to the right and then release it, the servo will bounce bach and fourth until it centers. On the other hand if I move the stick all the way to the right and then move the stick back to the center without releasing it from my hand, the servo will move smothly the whole way. To make this clear I'll post a video within about 20 minutes.:YeaBaby: Thanks for your input and I always need more of it.
Michael. :lol:

[rotorhead58d]

UPDATE: I just replaced the main gear, tail boom, belt, tail gear, spindle, spindle bolts, dampers, tail blades... and much more.:thumbdown::thumbdown::arggg::arggg: Anyway I just tested the servos (The only thing that I did'nt replace) on the ground and found that they will not return to the center without 'jittering' along the way. Is this normal with the 45-HB's?
I'll try to explain... If I move the right stick all the way to the right and then release it, the servo will bounce bach and fourth until it centers. On the other hand if I move the stick all the way to the right and then move the stick back to the center without releasing it from my hand, the servo will move smothly the whole way. To make this clear I'll post a video within about 20 minutes.:YeaBaby: Thanks for your input and I always need more of it.
Michael. :lol:

watch your sticks and move it to the right. then release it. see it go boiiiiiing? the servo is doing the same thing. it's doing exactly what your input is telling it to do. never release the sticks.

[stoatnchips]

Not sure if i'm not understanding you or just cant see what the problem is:confused: Are you saying, if you move the cyclic stick to the right and then just 'let it go' the servo horn 'bounces' around its center before stopping!!?? However, if you gently return the stick to the center it does not do this??
When you let the stick go... look carefully, does IT return to the center directly.. or does it oscillate a little before coming to rest in the center?
Is the servo not supposed to directly reflect what the stick is doing (discounting expos/mixes and other digital tweaks)?


EDIT...Doh!!! you did it again Rotorhead!!:)

[rotorhead58d]

Not sure if i'm not understanding you or just cant see what the problem is:confused: Are you saying, if you move the cyclic stick to the right and then just 'let it go' the servo horn 'bounces' around its center before stopping!!?? However, if you gently return the stick to the center it does not do this??
When you let the stick go... look carefully, does IT return to the center directly.. or does it oscillate a little before coming to rest in the center?
Is the servo not supposed to directly reflect what the stick is doing (discounting expos/mixes and other digital tweaks)?


EDIT...Doh!!! you did it again Rotorhead!!:)

= boiiiiiiiiing:rolling

weird american slang, dude. the hardest part about understanding americans, i believe.

[Gr4yb3ard]

Regarding the bobble on cyclic input, I'm not sure I'm reading all that you have to say on the problem, nor understand completely.

Is it going to one side or other when you power up hard? If so, have you checked for cyclic servo interaction? (see Finless vids, Understanding CCPM2). I.E. one servo travels farther/faster than another and puts the heli on a new course, when you just wanted to go up...

Regarding the difficulties in working on the bird, Jeez! This thing is small and squirrelly, but really, pretty well engineered for what it does.

A small "pinion puller" should press the spindle pin out for you. You will probably want one of these tools anyway when you start playing with new motors and pinions, etc..

From there, just use a sledgehammer and oaken stump to bash the old spindle out, carefully....

Hang in there, it gets better...

Gr4yb3ard

[mmtecg]

roterhead58d, I understand what your saying but it never does this on my Trex 450SA with DS285's. I can release it the same way and it never boiiiiings. Also, it did not do this before the crash.
Michael

[mmtecg]

[quote=stoatnchips;665661]Not sure if i'm not understanding you or just cant see what the problem is:confused: Are you saying, if you move the cyclic stick to the right and then just 'let it go' the servo horn 'bounces' around its center before stopping!!?? However, if you gently return the stick to the center it does not do this??quote

You've about hit the nail on the head. I guess I did'nt explain myself very clearly but what you suggested is exactly how the heli behaves. My only remaining question is as follows... With the heli on the ground, when you move the right stick to the right and then suddenly release it, does the servo return to the center smoothly, or does it slightly "bobble" "vibrate" or "boiiing" back to the center?:confused: Thanks
Michael

[northcarolinadan]

i think this video will fit in this conversation about stick/swash "boiiiing

its filmed at 1200 fps, i would say they all boiiiing to some degree


http://www.vimeo.com/897956

[rotorhead58d]

north kakalaki, that is exactly what i was describing. thanks for posting it. boiiiiiiiiiiing! lol