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View Full Version : New setup - huge vib at 1/4 throt

futura
06-22-2005, 02:35 PM
I have new shogun setup and ready to fly but.....

In throttle up, after the low RPM spin straightens (I think) the blades (heli is stable to this point) and at about 1/4 throttle, the heli vibrates violently. Its enough to knock it over if the training gear was not attached. two throttle clicks up from there and its smooths out and ends with about 2 mm diff of blade tracking. No vibrations at 1/2 throttle when I switch over to collective.

What can cause that big a vibration and then go away with another 200 - 300 rpm increase?

setup:

11.1v 1800mah lipo
stock motor w/CC 35p ESC
stock blades (foam/plastic)

gy240
JR6102
DebianDog
06-22-2005, 04:10 PM
How "balanced" are the blades?
futura
06-22-2005, 04:16 PM
Well, I took all my blade pairs to the post office and they were identical to 100th of a gram.

I then pick the two with the closest cg end to end. These two were about a mm dif. and I made no adjustment.

If the blades were not balanced, would it smooth out so at the higher throttle settings?
futura
06-22-2005, 04:24 PM
Everything I can check is tight

One other thing though....

How much flex does the shogun have when holding the frame and moving the tip of the head. My frame is flexing with the top of the main moving about 5mm and is bending mostly where the main gear slots through the frame.

I see nothing loose but what about something I can't see? for instance the oneway bearing in the main gear....I don't feel or hear anything that would indicate it was broken....sorry, grasping here.

this is a brand new machine...spun for the first time today....never flown....no "oop's" during construction.!
futura
06-23-2005, 08:56 AM
well, the blades were not tight enough and were swinging rather freely so I tightened them so they would just about stay when the heli was tilted.....no more vibration. Don't really know if that was the problem but the vibration was happening at the LHS at the pre first flight checkover and the LHS guy was also spinning her up rather quickly. In any case, blade alignment must have been the cause and it does make sinse.

thanks debiandog

what a great heli.....first time with a hh gyro for me too. It fly's so strong!
DebianDog
06-23-2005, 01:31 PM
Sure! I guess if you think I helped... no problem ;)