weird issues at higher headspeed

[kuskye25]

well i got some carbon blades so i could up my headspeed, when i set my radio to 85% TC no major vibes when spooling, really smooth once its at full head speed, then i pull into a hover and it will violently and quickly tilt to the right, then tilt forward then to the right... it does this really fast and harshly and only for just a split second then stops, then in a few seconds does it again, and just repeats...

i have tried messing with my gain values, anywhere from 60% up to 77% and all imbetween, honestly it doesnt even matter, doesnt make it worse or better....

then i set to 75%TC and gain to 77% and it flys flawlessly... obviously something is imbalanced or vibrating but i just cant seem to find it... im fine with the helo at this headspeed i just wanted more its the only reason i bought carbon blades

ive went threw and cleared up as much vibes as i can in the head/tail/motor/maingear/ect...


so heres my question
?anyone else have this issue when upping headspeed if so what did you do to fix it, or do i just need a new motor or main gear or something because the factory parts are not dead on/smooth enough to run that kind of headspeed, such as the never true main gear, and the always mildly vibration prone motor?

[Kalashluvr]

I had the same issue...and may still be having this issue. I can't get off the ground now the vibration comes in so hard.

[kuskye25]

Originally Posted by Kalashluvr

I had the same issue...and may still be having this issue. I can't get off the ground now the vibration comes in so hard.

yeah it sucks man, dont get it, when i have the thottle down its flawless flying, but when i turn it up all heck breaks loose, and everything is good on the heli, my issues just has to be bad stock main gear or motor is all i can think....

i saw in your thread you replaced the motor and main gear, and it still does it, but does it do it when you turn your head speed down...

[Kalashluvr]

I need to turn it back down and see. Too late tonight but will be first thing I do when I get home tomorrow. I've been looking it over and my belt drive is not as tight as my 450x which has never been touched and has very few flights, and runs flawlessly. I wonder if the tension should be the same on both. I think I read where you have to pull on tail boom while simultaneously tightening the 4 boom screws.....

[kuskye25]

Originally Posted by Kalashluvr

I need to turn it back down and see. Too late tonight but will be first thing I do when I get home tomorrow. I've been looking it over and my belt drive is not as tight as my 450x which has never been touched and has very few flights, and runs flawlessly. I wonder if the tension should be the same on both. I think I read where you have to pull on tail boom while simultaneously tightening the 4 boom screws.....

what i do when i tighten my belt is loosen the 4 screws that hold the boom, then loosen the screw and nut that hold the horizontal fin mount on, then i pull on my boom till my tension is proper, then hold the boom in that exact spot and tighten 4 screws that hold the boom, then tighten the screw/nut that is for the tail fin...

my belt tension is perfect so that isnt my issue...

also you can hold the main gear and try and turn the tail rotor, if the belt skips teeth easily on the tail rotor shaft your belt is to loose

[Kalashluvr]

I've been searching and found some other posts about belt tension on this 300x....you might look into tightening your belt a little just to rule out a loose belt....you should push on the belt through the window and get tension when your prodding device is halfway into the boom. Maybe turning up that head speed is causing the belt to touch itself like stated below and is making your heli vibrate.....

------Quote:
Originally Posted by B2Y3K8
Are the belts on these helis supposed to be so tight? I have run my belts fairly loose on all my other ones and the one on the 300X seems excessively tight. How are everyone else's?
I thought this too, and loosened mine when I checked the belt tension after a few flights, but got resonance/shakes, I tighted it up again and they went away, I think due to the main pulley/guides arrangement, if the belt isn't tight the slack side swings out at speed and rubs on the other belt coming the other way, causing shakes.

I'm running mine as the manual says, a gentle prod in the little window will only move the belt halfway into the boom, this means at the guides the belt is very tight and won't move at all when prodded with a screwdriver.---------

[kuskye25]

Originally Posted by Kalashluvr

I've been searching and found some other posts about belt tension on this 300x....you might look into tightening your belt a little just to rule out a loose belt....you should push on the belt through the window and get tension when your prodding device is halfway into the boom. Maybe turning up that head speed is causing the belt to touch itself like stated below and is making your heli vibrate.....

------Quote:
Originally Posted by B2Y3K8
Are the belts on these helis supposed to be so tight? I have run my belts fairly loose on all my other ones and the one on the 300X seems excessively tight. How are everyone else's?
I thought this too, and loosened mine when I checked the belt tension after a few flights, but got resonance/shakes, I tighted it up again and they went away, I think due to the main pulley/guides arrangement, if the belt isn't tight the slack side swings out at speed and rubs on the other belt coming the other way, causing shakes.

I'm running mine as the manual says, a gentle prod in the little window will only move the belt halfway into the boom, this means at the guides the belt is very tight and won't move at all when prodded with a screwdriver.---------

cool man thanks, i checked my belt and according to that mine was pretty loose, i just now set it so at the pulley of the tail its really tight, and in the window of the tail case it only lets me move it half way, prolly moved my boom a few mm to achieve this, so quite a bit...

ill test it tomorrow and report back....

[DoubleCH]

As I posted in the other thread, have you guys tried loosening tail case phillips screws a bit?

[kuskye25]

Originally Posted by DoubleCH

As I posted in the other thread, have you guys tried loosening tail case phillips screws a bit?

yup i have always ran mine loose

[kuskye25]

ok i ran my 300 with the tail belt being tighter, absolutely no change at high headspeed the swash violently tilts forward and right out of nowhere...

turn down headspeed and its perfect... i dont get it, im sure ill figure it out eventually but for now i give up and run low headspeed...

[DoubleCH]

Originally Posted by kuskye25

ok i ran my 300 with the tail belt being tighter, absolutely no change at high headspeed the swash violently tilts forward and right out of nowhere...

turn down headspeed and its perfect... i dont get it, im sure ill figure it out eventually but for now i give up and run low headspeed...

85% throttle with stock ESC, motor, and pinion is not high HS at all so it's not because HS is exceptionally high. I still think it's vibe issue. Have you tried loosen the 4 motor mount screws, back motor off from main gear, tighten mount to the frame and run up to full speed and check for motor vibration? You're aware of the common stock motor shaft issue and the loctite mod fix, right?

[eltreato]

Good thread, I'm having the exact same issue with my heli when I go into IU at 80% with my Turnigy 4200kv. Tail shakes in hovers but is okay in FFF. Other than that it flies beautifully. OP, please let us know when you get your issue sorted. Mine all started after a big crash that required a new main gear, hence I loosened the tail from the block.

Good luck.

[kuskye25]

ok i figured my issue out...

took all my blades off and ran it up to speed on the workbench, head tilts/twitches randomly...


tried a hole bunch of stuff to no avail...

put my tail blades on and still same, so took them back off and played around some more with random stuff...

so i thought to myself about belt tension, most people say run it as loose as possible without it being able to skip gears, at least from what i read on other choppers this is what ive seen people say...

so i loosened my belt, its not really loose or anything, but it isnt as tight as it should be according to blades instructions, or the ones listed here in this thread anyway...

spooled it up with no blades on and the swash stayed perfectly level no matter what i did, then i installed the tail blades, perfect no more random swash tilt, so i installed the main blades and took it out for a test at 75%TC, flys perfect as it used to...

so then i upped it to 85% TC, still perfect, so i upped it to 100% TC, all is fine... end result apparently your belt isnt supposed to be super tight... when i push on my belt at the pulley it moves some, and when i push on it threw the window of the tail case it moves a bit more then halfway...

ran 3 full batteries threw it and it flys perfectly, case closed for mine anyway

also just as a note it was tilting at 75% it just wasnt as violent of a tilt, but on the bench it was doing it with no blades on at 75%TC, at 85% on the bench with no blades it was a terribly violent tilt

so you guys are right had nothing to do with upping the headspeed really, that just made it much more noticalble

[Kalashluvr]

Time to loosen my belt!! Gonna do it and check right quick.....

[mlucia]

This is ironic as I have read all the posts as I had the same issue until tonight and now it is fixed. The strange thing is I flew 2 packs out of the box and it was perfect. Stick banging and such everything was fine. I changed packs and it started to violently shake at high head speeds. Strange since nothing had changed.

After:
-lock tight the inner bearing race on the motor shaft
-replacing the tail setup with a trex 450
-replacing main shaft
-replacing tail shaft

In the end , the belt was too tight. Just tested it successfully with 2 packs and its back to normal. How the belt got too tight after 2 flights is beyond me but that seemed to be the cause. Now to be fair I did just change the main shaft AND loosen the belt tonight so it could have been the main shaft too but doubtful as it rolls straight as an arrow on a sheet of glass. But hey, ya never know.

The only reason I bought this 300 is my buddy let me rip a pack on his and I was impressed and ordered one up. Impressive little heli when it's flying good.

Here is the question I have. There seems to be a different resolution all over the place for the shakes and roll right (obviously the roll right is due to vibration). Why right? No idea, why not left

In any case I would be curious if someone starts having this issue and they simply loosen their belt to see if it fixes the issue.

Fun stuff.

P.S
Not that it matters but I'm running edge main blades and Lynx tails at 100 throttle.

P.S.S
The trex tail flys no different then the stock. Unless you want to spend the money I'd say save your $$.

[Kalashluvr]

Well, I loosened and it didn't really help mine at the higher 95% throttle but when I backed it down to 75% its smooth again. It's like the vibration is brought on by higher was speeds (obviously). I only sport fly so its not like I need the 100% throttle but it would be nice to have it on tap if I need it. I think that having a tight belt might build up resonance a lot quicker and hold it longer than a loose belt....at any rate I need to get the materials to enable me to loosen the tail case screws to put that fix in place also. I need to balance my main blades but don't have a bolt or anything the right size to make that happen tonight.

[kuskye25]

Originally Posted by mlucia

In any case I would be curious if someone starts having this issue and they simply loosen their belt to see if it fixes the issue.

this was 100% my issue, but mine wasnt just a right roll, it was a very fast and sharp right tilt then it would go away, then id get a good hover going and it would very fast again tilt right then go normal again...

very weird, ive had the standard right roll before but it was a constant slower roll, this was a perfect hover then rip right tilt then go flat again... very different from any right roll i had before was more like a twitch like a bad servo or something but it wasnt a bad servo...

end result chopper worked fine then started doing this, then loosened my belt and viola fixed, 100% throttle and it flys perfect... one of the few reasons i still have a lot of love for my flybar 450 3d, only one gyro to worry about, if its doing weird stuff with its head i know its purely mechanical

[DoubleCH]

Originally Posted by mlucia

The trex tail flys no different then the stock. Unless you want to spend the money I'd say save your $$.

That is until you look at the stock aluminum tail hub wrong and it'll bend. Mine was bent out of the box. I had to balance tail rotor out of the box and after chasing the tail for some time without crash I realized the stock aluminum tail hub was bent without crash or hard landing. I love the stock plastic tail weight and the stock fine-tuned chinese weight (for the wimpy stock tail servo) but instead of replacing the bent stock aluminum hub with another one that may bend when I look at it wrong, I decided to go with Tarot 450 tail assembly.

[Tim Wolff]

My 300x started vibrating so hard in flight Sunday that it was buzzing loudly and the landing gear was a blur. Started 2:00 min. into the flight while I was doing a couple pirouettes. Switching back to normal mode calmed it down. Landed and did a quick eyeball for anything out of place and found nothing. Took off and it started vibrating again as soon as I switched to Idle up (85% flat throttle curve). Put it away for the day.

Pulled it out last night and started checking things out. The tail belt didn't appear too loose, but would skip teeth if I held the tail rotor and rotated the main head. So, I snugged it up. also found the follower arm screws were both a bit loose. Snugged those up too.

Flew as it normally does before work this morning. So, one or both of these somewhat loose items caused enough vibration to really make me pucker. I'm surprised that it didn't roll right on me when it started. My stock motor was bad enough to cause the right roll, but the resulting vibration wasn't anywhere near as loud or visible as this last episode.

[Kalashluvr]

Tim, I'm afraid I messed up at some point and over tightened my follower arm screws. Appears the top plastic main shaft head is stripped in the screw holes. Mine aren't loose, but they are not snug either.