raptor 90se vibration

[dxbman]

hi all,

My raptor vibrates allot in the beginning, it wobbles allot sometimes i am afraid it will tip over it's side. but when the head speed get up the wobble disappears.
A friend has R90 which he upgraded to 90 set, he was suffering form the same issue, the problem went away when he went back to plastic fan.
could it be that the Aluminum fan from TT is not well built.
he said when he checked it on the balancer it was wobbling but at the same time he checked the fan of fury and it didn't so the balancer is OK.
i am confused the fan should be an upgrade not a down grade..

any suggestions will be appreciated??

[wattybotts]

When you first built your rappy 90 se kit, did you balance your fan?

I doubt this would cause your problem tho. Seems to me that either your blades are off center when you are spooling up, or your dampening is too tight.

Next flight, when you are done, make sure that you do not move your blades from their center position. Then on the next flight, spool up and see if you have the same problem.

Good luck
Bob

[dxbman]

thank you fo rhte advice.
i regreased the dampners, and the spindle. although i did that before the defrent was the i greased the inhole of the dampner not from outside.
this time i greased it all and it wibbled a bit becouse of the blade off center.

now i am suffering form another problem when i tried to start the heli again the start shaft was truring very hard and it's making a skweeking noice.
i turned the main gear and there is a lot of resistance.
i will pull out the engine today and see.
any suggestions ????? :?:

[Russ McC]

dxb,

If your engine is hydro locked it will be very hard to turn and can make a squeaking noise witch could be the one way slipping.

[capebob]

It's most likely what Russ said, but it could be that your fan nut has loosened allowing your fan to unscrew and contact the underside of your clutch bell.

Bob

Edited to correct spelling :oops:

[dxbman]

I checked the engine yesterday, wow lots of aluminum ships in it.
The fan nut got lose and crack shaft back to the back plate, that caused the grinning feel in the starter shaft. luckily i didn't over do it and took the engine apart i think this saved my back plate and the engine. i was sure i locktight it last time, this time i used 262 locktight i hope this holds it.

thank you all for the help

[Russ McC]

I hate when that happens, glad you found it :!:

[dxbman]

I am glad that I didn't insist on starting the engine otherwise I would have destroyed it.
A guy in the field did it; he was saying that he will start his heli engine no matter of what the result.
he burnt his and my starter and drained the starting battery, plus he totally destroyed his engine, connecting rod gone, back plate ....... he ended up buying a new engine and swearing he will never do it again.
The price for being stubborn

[LuckyLandings]

Im missing something I guess. I dont understand how you can mess up the back plate by trying to start it.. :?

[Russ McC]

The fan came loose and was trying to push the crank out the back of the engine :shock:

[WillJames]

Exactly Russ. When the nut backs off the crank the fan which is threaded on the crank unscrews and jams itself against the underside of the clutch bell pushing the motor crank into the back plate of the motor. Not pretty, I have done it to myself 2 times with flooded C-SPEC PS Motors even with blue locktite on the crank nut. This is one of the downsides to a fan that screws onto the crank. They are also much harder to get dial indicated to .001 than a colleted fan, but they are easy especially if you don't dial indicate. ;)

[LuckyLandings]

I understand now.. Thanks guys.. I have had my fan come loose once. But it was totaly obviouse. Noway I would have kept cranking on it. But I now see how this could happen. Luckly I got away with just a few scraps on the underside of the clutch bell.. I didnt know it could cause such a sever problem. Will watch my arss!
Thanks again! James G

[Hitch-Hiker]

"My raptor vibrates allot in the beginning, it wobbles allot sometimes i am afraid it will tip over it's side. but when the head speed get up the wobble disappears.
"

Did the engine solve the wobble issue?

That sounded to me like the blades were simply to tight.