Establishing Center of Gravity


 

Well, we are almost done with interior detail, anything else will just be small, so there will be no impact on the CG or Center-of-gravity, so now is the time to set it!  First, I removed a ceiling panel in the garage, and attached a pulley.  I milled/lathed a part that bolted to the head, where the head button would normally go.  This allowed me to suspend the heli a few inches above the workbench.
 


 

Breaking out my trusty laser level, I sat it on the drill press and cranked it up and down until the laser struck a line across the mechanism's mount.  You can see the mounting plate below, it is black, between the carbon frames of the mechanism, and the grey plywood of the heli's structure.  You can just barely make out the laser line here. I taped a plastic cup to the nose, and added 5 ounces of lead to get the balance perfect.  
 


 

Once I knew how much weight to add, I tilted the heli, dropped the weights in the nose, and used a funnel/tube assembly to add some West System 24 hour epoxy to keep the weights in place.  
 


 

The epoxy's weight adds about .75 ounces, and together with the lead, keeps the center of gravity at, or in front of the rotor shaft, with the gear in the UP or DOWN positions (it does change a fair bit as the landing gear and wheels are heavy).   All in all, a lot less counterweight was needed than I thought, 

 

 



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