# Nose heavy Lindurg 3 axis skull



## time2dive (Dec 29, 2007)

I was having balance problems with the Lindberg Skull using the Graveyard Skulls parts. It is very nose heavy. If I remove power from the servos the head immediately goes down. The servo is constantly fighting to keep it level with power on. This is what my skull looked like.









I believe that I have alleviated the problem by making the following changes. I have never been accused of being small. When I was a kid on the teeter totter they had to move the fulcrum point so I could ride it with the smaller kids.... that is what I did.
I move the "A Frame" to the front side of the plate....effectively moving the fulcrum. I drilled and tapped four new holes for the plate.









Mounting the "A Frame" in front caused a problem with mounting the servos, so I made a minor modification to the servos.... I cut off their little toes.... and I reversed the rotate and tilt servos 180 degrees.









This allowed me to mount the "A Frame" in front as well as the servos.


















It is still a little nose heavy, however I believe that can be fixed with a little lead and the nod servo is not working as hard.

Tim


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## SpookySam (Mar 27, 2007)

I have the same issue with my Lindberg kit. I'm not sure how much of a problem it actually is - I don't mind the head going down between routines as this is for my gravedigger who will be "at rest"


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## scubadog (Nov 18, 2008)

I have built one of these and it works great. However I agree the weight and the room the servos take up leaves little room to throw in the eye movement. So what I am thinking about doing is using Dubro Flex Cables and moving the servos to a tray in the body. This would eliminate almost all of the weight and make it much easier to adjust them. The cables come from Tower Hobbies. You could even run the eyes with the cables.


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## Spookineer (Aug 20, 2006)

Tim, did you try adjusting the pivot rod forward? that may help with the balance and line up the pan and tilt linkages as well.


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## Spookineer (Aug 20, 2006)

scubadog said:


> I have built one of these and it works great. However I agree the weight and the room the servos take up leaves little room to throw in the eye movement. So what I am thinking about doing is using Dubro Flex Cables and moving the servos to a tray in the body. This would eliminate almost all of the weight and make it much easier to adjust them. The cables come from Tower Hobbies. You could even run the eyes with the cables.


I agree, if the prop has a body, there is no need for the servos to be inside the head. That way the servos don't have to move their own weight as well as the head. I've done several designs using cables and have a new one on the bench right now.


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## time2dive (Dec 29, 2007)

I did adjust the pivot arm and moved it forward. It help a little more with the balance. I added two small weights at the back of the skull and now it is almost perfectly balanced.
On a side note the servos in the body sound like an interesting idea.


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## graveyardmadness (Oct 17, 2006)

Also, our you using 325 servos to control tilt? If so, upgrade to the 425. And adjust the pivot arm by moving it forward. 

graveyardskulls


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