View Full Version : raptor 50 vibration ?
Hello to all the heli members !
I`m new to the forum and I think the people and info is just great .
I have a raptor 50 and 90se (still building the 90). The problem that I`m having is with the 50. Its done this since I built it . Vibrates left to right at the main rotor grips , like a dog shaking water off . It can be so bad sometimes you would think it might toss a part off or two. :shock: This only happens at or around 1700 rpm. I have not crashed it until just lately ( bad auto ). I have tried changing the feathering spindle(put grease on spindle),main shaft,checked for bad bearings ,tracking and fly bar paddle alignment . I even took the whole main shaft assy.blades( CF TT ) and everything and put it on my high point balancer just to make sure I was not missing anything.
I`m not sure what to check for next ? Any help would be great. Thanks for looking even if you cant help.
airwalk
01-21-2006, 11:01 PM
Hi Carl,
I'm also new to the site, today in fact. What a great resource.
Have you checked the blade tension? Are they equal? I saw a similar problem on a rappy 30 with unequal blade tension and also too loose. Also is the spindle centred and is it remaining that way. Are the paddles spaced at equal distance from hub.
edon.
RPM 1.5
01-22-2006, 07:50 AM
Did you glue the bearings on main blade grip just a little bit around them and check thrust bearings are in correct,also flybar both distance on each side
Ray :D
Hello Airwalk and Vigor.
I set the blade tension so that they would just move with a quick jerk with the heli on its side and they feel the same.
The flybar and paddles are centered. I`m not sure about the spindle remaining centered . It is centered when not flying . How do I check that ?.
I did not glue the bearings to the grips but the thrust bearings are in the right way.
airwalk
01-22-2006, 08:58 AM
Hello Airwalk and Vigor.
I set the blade tension so that they would just move with a quick jerk with the heli on its side and they feel the same.
The flybar and paddles are centered. I`m not sure about the spindle remaining centered . It is centered when not flying . How do I check that ?.
I did not glue the bearings to the grips but the thrust bearings are in the right way.
Hi Carl,
I was visualising by your discription quite a violent vibration is occuring if you had concerns of unwanted component departure. For a vibration like that to occur something certainly is running out of balance/ weight to one side. I guess I meant if there is any excessive movent in the thrust bearing side of things. If you hold the hub and push/pull on the blade grip do you get any excessive movement. ie the spindle can move back and forth through the hub.
Hi Airwalk
It is violent sometimes. I do not feel any kind of movement. There is a washer between the grip and the flap damper, does that put some kind of preload on the flap damper ?
airwalk
01-22-2006, 09:33 AM
Not far from owning a rappy myself so not up to speed on the exact setup. I have been flying a jr heli and they have a tapered collar between the grip and damper which centres the spindle and pre loads the system. Has this problem occured since new or rebuild. might be time to consider a cnc arrangement.
It might be shivering from the cold :D what temp is it there today. Was going to fly here today however 43 degrees celcius is just to damn hot to be outside.
since new , :arggg:
yes your right it is cold in comparison 0 degrees Celsius .
I would like to go flying today but my wife has other plans.
I have been thinking a cnc setup might fix the problem but still not comfortable with inverted flight :shock: and using the dirt brakes with fancy parts sucks . Not sure what to do.
airwalk
01-22-2006, 10:21 AM
I dont think I would be comfortable with upright flight with vibrations goin on the way you have described. I agree about the dirt brakes bending bling components, I guess you just have to weigh one concern against the other. The odd thing about your problem is the fact it comes in at a specific rpm. Are the blades equal weight, I guess your balancer would determine that. How is the cg of the blades. Maybe it is time to also consider if your pitch/engine settings are causing issues at that particular rpm range compared to the load on the blade. Difficult to say without seeing the problem occur first hand.
what i did to mask this problem , i went and bought a gv1 governor and fly at 1600 rpm.
I do not have any problems as long as I stay below 1700 but would like to get to the bottom of the problem
johndale
01-22-2006, 11:08 AM
What Brand of blades are you using??????? If you are using Mavrric they gave both of my 50s that same problem. Woodies carbons it did not matter. When I changed back to TT it went away :D
they are C F TT blades. :dontknow
maybe just unlucky and got a bad set
dean masters
01-23-2006, 07:11 AM
:?: Hi carl thoght i might be able to help a little the thrust bearings on the rotor heab have to be fitted the correct way it is very easy to make this mistake have a good look at your instrution book . also mayby your throttle is to high when flying what percentage is it at on your tranny or it could be to low hope this helps hit me back deano. :noteworthy
Thanks for everyones help. The problem was the main rotor hub did not fit tightly on the main shaft , it would pivot on the bolt that held it on. I bought the metal one with the clamp on the bottom and no more shake. yay :mrgreen:
flyinfool
02-15-2006, 12:24 PM
Over tightening the Jesus bolt will force the plastic headblocks out of round.