.30 jerking lock-up just above idle (help)(please)

[robbin wilham]

ive got a .30 raptor and just above idle (about 30% throttle,not at 40%) it sounds like a loud pop then it jerks hard enough to fold rear blades like something is locking up then it will let go for about two turns of the head then do it again, theres not a consecutive pattern it might turn three turns then maybe one turn till it does it but when it does it every moving part will stop spinning for a fraction of a second, and im not sure if the pop happens after or before everything locks up, it happens to fast to tell. and im afraid to put the main blades on and see how it acts because im afraid they might fold unless they were really tight and might do a boom strike and i have a carbonf boom that i want to keep in one piece,then when i give it about 30% throttle it does it and it doesnt do it at idle or above 40% ,i bought this heli used and got ripped bad ,ive replaced alot but still like alot. if anyone has ever heard of this or might know what it is i would greatly appreciate ideas ,thanks :confused: :mad: :arggg: :flamedevil

[ghtracey]

Something must be binding, you're going to have to eliminate sources. Even if it means a complete dismantling. I'm assuming everything freewheels fine for you? The first couple of things I would check:
Pull the tail boom and make sure the belt is installed properly.
Drop the main gear out and check the one way

[kmcclain]

Another thing to check on would be a broken clutch shoe....

[robbin wilham]

ive eliminated the clutch ,fan ,and bellcrank with all new ,and new belt and idlers new ,the only thing i havent checked is the one way ,could it cause this kind of eratic behavior,i was thinking about pulling the boom and starting it to eliminate the entire rear mechanics,would the one way lockup and then loosen up that quick then do it again, ive never had experience with oneways, and when sitting on bench everything freespins ,i will try to drop the main and start eliminating ,thanks for ideas ,another thing is there anything in the starter shaft assembly that could make it do this and what kind of grease is best to use on the oneway and where is it used and where do you not grease

[rototiller]

Its your belt. I had a Stinger 50 that after the first crash it did the same thing you were talking about. New belt and pulleys didnt help. The only solution I found was to really crank down on the belt tenstion.

DK

[OHIOBOWHUNTER]

Its your belt. I had a Stinger 50 that after the first crash it did the same thing you were talking about. New belt and pulleys didn't help. The only solution I found was to really crank down on the belt tension.

DK

Me too on my titan....I always thought it was tight enough but it wasn't:arggg:
It did the same as described above,but works fine now

[BigBoh]

Hes Right it happened to me on a Rappy 30 as well , tighten the belt..:wink:

[ghtracey]

thanks for ideas ,another thing is there anything in the starter shaft assembly that could make it do this and what kind of grease is best to use on the oneway and where is it used and where do you not grease

The starter shaft also has a one way, I'd check that one also. Use silicon dielectric grease (can be bought as spark plug contact cleaner/grease at auto stores). Grease the rollers in the bearing, and around the metal collar when you insert it (it should float in grease more or less). Make sure when you have it apart that it grabs and holds.

That's if you need any of this once you make sure your belt tension is ok. :)

[robbin wilham]

hey thanks to all for the help,i really appreciate ,this thing has really gave me a head ache but it looks like by reading all the replies that it the belt,tomorrow i will drop the oneway and grease it and the starter assembly and grease it then after i put it back together i will tighten the belt a little at a time till it stops the jerks ,i guess it just needs a little additude adjustment by tightening the belt ,before i had thought about footballing it across the front yard a couple times but my wife said no,really thanks alot for all the messages and help, i will let you know how it turns out .i decided to try out my new airbrush i got for christmas on the canopy and i kinda like the flames ripping thru the side, and if anyone is wondering why im running helimax 530 factory carbon blades its because its been in the air once and the wore out .36 motor didnt have enough power with the 550 wood to barely lift off so i put the only else i have,and after disassembling the motor i found large dent about 1/8 in deep in piston ,here are some pics of canopy i airbrushed today

[OHIOBOWHUNTER]

WOW :shock: canopy looks cool ! good job

[robbin wilham]

thanks ,its hard for the person who does the work to see how it really looks ,so i just wait to see what others say,thanks

[LiteTouch]

It may be that it is not a one-way bearing that is causing your problem, you can also check for excessive axial play between your mainshaft and gearset.

I was chasing a lock-up on my Raptor 50 for quite some time - until i came across a post on Heli Freak....

Hold the rotorhead with one hand while checking for play in the lower(white) gear. If you can rotate the rotorhead back and forth a few degrees while holding the gear without any movement, you will have found the scource of your problem.
It appears that the hole which is drilled in the mainshaft is machined prior to the shaft being ground and hardened, which causes the hole to be distorted. During spool-up this play will make your autorotation bearing to catch momentarily.

I was able to take up this play by CAREFULLY using a center-punch to dimple the bolt where it passes through the mainshaft.

I have three new mainshafts on hand, all showed the same distortion where the hole was drilled.

You COULD over-tighten the bolt that holds the gear to the shaft, however I know from experience that this will result in a crack forming in the gear.

I do have some concern that dimpling the bolt might result in failure at some future time, however even if it were to fail it should only result in an autorotation to landing.

I am doing some experiments concerning the use of a bushing at this location, I will advise if this proves to be a viable fix.

I would like to thank ALL the freaks out there for thier helpful posts!