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vibrations - customair - 10-03-2017

Hello, I am a new mosquito xe285 owner. I am having trouble with rotor vibrations. I have rotor tip lights  and trim tabs, I have set the tracking with the lights at hover and in forward flight and it is very close to perfect in both. In a hover it is smooth but at 70+mph there is a dog house shake that is coming from the rotor. I have added and removed weight in the front and it gets worse when I add or remove weight from the front. It seems to be fairly smooth if I am slightly decending at 80-90mph but if I am trying to fly level or ascend it starts shaking. Any ideas?

Thought I would add this detail. The more collective I add the more shake there is. Thanks for the help.

RE: vibrations - FlyGuy - 10-03-2017


I am no expert but I would think you need to find a "happy medium" in your blade tracking. Try tracking them at speed and check the difference in vibration at a hover. Sometime it is a matter of splitting the difference. Email or PM marcher07, he might have some insight.


RE: vibrations - mosquito - 10-04-2017

Because it is a two bladed semi-rigid rotor system you will always have a little bit of shake, not matter how well you tune the rotor. Its just the physics of the system. And it will vary in different phases of flight. The goal is to minimize it.
Have you used an electronic balancer to check both balance and sweep?
Have you done the hang test? I find 1.5 degree nose down to be the best.
Have you checked the control system rigidity? You should be able to move the cyclic in any direction and feel no slop. Other than overcoming about 1/16" of system flex at the tip of the cyclic, the blades should move as soon as the cyclic moves. Check all the bolts along the control system and make sure they are tight. Most important of all is the swash plate bolt. There should be no movement in the swash plate other than in the rod ends themselves.
Did you loosen all the rod ends in the control system. Most important are the ones on either end of the push rods going through the shaft. If one is tight and the others are loose it can cause unwanted blade movement. They should all be loosened as per the manual. You should be able to grab the upper rod ends on the push rods above the rotor shaft and twist them back and forth with your fingers without too much difficulty.
Final tracking of the blades in flight should go more by feel (or balancer) than by matching the tips. A smooth rotor may not have the blade tips exactly in line. Adjust the rod ends for the smoothest ride in forward flight rather than trying to match the tips. They should go together and generally do but not always due to minor variations in the blades. Since you have them together now try moving the master blade up one and down one and see if it helps.