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Rotisserie

Barneybc12d

Well Known Member
Yesterday I attached the pivot point to the front of my 14. I located it at the center of the structure so that when rotated there would be the same clearance from the floor right side up or upside down. During the night I realized it should pivot about the center of mass.

Today I will lower the pivot to the center of the 4 motor mount attach points. Have you experienced rotisserie builders found this to be a good balance point?

207qlbo.jpg
 
I don't think the balance point matters so much as the work height. Mine isn't at the centre of mass, I set it up like yours is now, to make it a good working height when the fuselage is on its side. Even though my pivot point isn't central to the mass, it is still very easy to rotate, you just have to lock it using the pivot locking pin (Drill extra holes if you need different angles..)
I think yours looks good as is!
PM me for photos if you like.
Hugh
 
I wish I had stopped and built one. It was a painful lesson.

I see you made one for the camera too. :eek:
 
The CG moves around during the build

Hi Barney,

You're going to find that the CG of the fuselage is going to move around quite a bit depending on what you have clecoed/riveted onto the fuselage. What I did was make some wooden boxes on the motor mount that allowed me to add 25 lbm bags of lead shot where I needed it to get the CG back towards the center of rotation. Depending on what I had attached to the fuselage dictated where I added/removed the shot bags. It worked out pretty nice. I can rotate the fuselage with just finger pressure. Of course you want the rotation axis to be fairly close to the CG to begin with.

I hope this helps.

Jeff
 
Just made my front pivot mount (thanks for the photos) and was wandering if I should lengthen the tubing the wheels are mounted on for better stability when rotating ?
 
Cable fairings

Barney,

Are those homemade rudder cable fairings? I'm planning on installing them as well.
 
Mine is a little below center of the firewall. Roughly centered between upper and lower engine mount bolts. Tail is at the bottom of fuse. Seems to work fine.
 
Cable fairings

J_Hartline,
If you look up San Buchanans' builder site you will find the dimensions and instructions for making cable fairings. I simply stole his hard work for my build. :)
 
J_Hartline,
If you look up San Buchanans' builder site you will find the dimensions and instructions for making cable fairings. I simply stole his hard work for my build. :)

So if you are going to "Sam's" site, it's under the fuselage, page 8 for those of you looking to save a little time searching.
 
Just made my front pivot mount (thanks for the photos) and was wandering if I should lengthen the tubing the wheels are mounted on for better stability when rotating ?

Stability isn't an issue. The only change I would make is to extent where the mount attaches to the firewall. I plan on insulating the firewall then installing the battery box, master cylinder, etc. In hindsight, I should have installed the insulation under the rotisserie mount and trimmed that area when the motor mount is attached..
 
I did extend the arms with pipe to allow for the battery box clearance. I also adjusted the pivot point much lower on the firewall closer to the center of gravity and it rotates easier. I need to play with the tail pivot point tonight to see if I can make it rotate still easier. I'm nervous rotating as I do not want things to go south, if something goes wrong what a mess I will have on the floor.
 
Finished my rotisserie today , very pleased other than it leaves the fuselage a bit high off the floor in the upright position. The roll bar clears the floor by about six inches when inverted. Perfect work height rolled on it's side so I'm OK with it. Very stable in all positions.
Thanks for the tips.
 
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