View Full Version : vibration / stability on cyclic
I've gotten my heli quite well balanced...The blades both peg out at 184.0g, the CG lines up, the paddles are balanced and equidistant, no visible shakes from the heli once it's up to speed, etc....
It goes through a spot of vibration on spoolup that goes away as it hits flight revs.
In a hover the video is nice and smooth. However, as soon as I touch the cyclic it starts to "chatter" - you can see vibration on the video and hear it in the sound.
I'm a bit eager to go review today's flight later on and see if it still happened. I made a tweak to the flybar mixing. Won't be able to look it over until tonight tho.
AZ ChopperCam
10-10-2006, 03:43 PM
are you running flybar weights?
how is your CG?
No flybar weights at this time...I plan to eventually. What I might even do is put weighted Tiger 50 paddles (they have a lead stick that goes into the paddle) on. These paddles also take the flybar through the entire length of the paddle which would also provide me the clearance to put the servo/pulley back on top of the mount.
CG of the rotor disc is all spot on. The heli has been "very close" - I've always balanced it out under the main shaft before liftoff.
I'm pondering one possibility now and that's the fact that I'm using a Raptor swash on a Gohbee head. The geometry is a bit different and may be amplifying any misalignment. The gohbee swash wouldn't fit the CCPM ring without a lot of...customizing.
On the gohbee swash, the pairs of balls on the inside have different lengths - the balls that connect to the mixing levers are further out from the center (greater throw) and the ones that connect to the washout are shorter. (I may have that backwards - don't have it in front of me)
I may yet be reverting back to a rappy head. There's a few things with the gohbee head that I'm not completely comfortable with.
AZ ChopperCam
10-10-2006, 04:18 PM
go with what's proven (Raptor Head) unless you want to spend the time to test and tweak.
I have the Kasama head and it works great
The gohbee seemed like a decent deal at the time - full metal head at a reasonable price. I figured the strength would be there since one of the guys in my club is a Gohbee fan/rep/guru and drag races his (spinning the 600s up to...2300-2400 before blast off).
But, all things considered, I think I will be moving back to a Rappy head of some kind. This one has taken too much tweaking to get it to this point.