Author Topic: Colibri Hummingbird Dynamic Sculpture - WIP  (Read 16252 times)

Offline Tennessee Whiskey

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Re: Colibri Hummingbird Dynamic Sculpture - WIP
« Reply #120 on: January 30, 2018, 11:02:07 PM »
:lolb: :lolb:

Great work BTW

Cletus

Online 10KPete

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Re: Colibri Hummingbird Dynamic Sculpture - WIP
« Reply #121 on: January 31, 2018, 04:34:23 AM »
Thanks, Cletus. That brings back the memories...

Pete
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Offline b.lindsey

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Re: Colibri Hummingbird Dynamic Sculpture - WIP
« Reply #122 on: January 31, 2018, 12:33:20 PM »
That is looking wonderful Kirk!!  At 12 lbs. plus it shouldn't fly away on you either :)

Cletus, yeah...I am old enough to remember that one too. Now I am going to be thinking of that song all day  >:(

Bill

Offline Perry

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Re: Colibri Hummingbird Dynamic Sculpture - WIP
« Reply #123 on: January 31, 2018, 12:49:00 PM »
That is an art! Will you power it with electric motor?

Offline kvom

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Re: Colibri Hummingbird Dynamic Sculpture - WIP
« Reply #124 on: January 31, 2018, 04:09:36 PM »
Perry,

Derek Hugger recommends a maximum speed of ~ 7 rpm on the input shaft.   With an 8:1 gearing that means the entire cycle of the motion will be about 53 seconds.  Until I finish the assembly and figure/build the counterweight, I won't know how much torque is needed at that speed.  I expect it to be greater than the 3.5 inch-pounds max he gets on the wooden version.

I purchased an air-operated gear head motor at CF that might work.  It's speed is a function of air pressure and flow, so it would allow an easier way to display it in action at model shows.  Whether it has sufficient torque at low speed is the question.   JL's experiments with 12V gearhead motors is also interesting if the model can be operated on battery power.

Offline kvom

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Re: Colibri Hummingbird Dynamic Sculpture - WIP
« Reply #125 on: January 31, 2018, 11:44:33 PM »
I spent today's shop time finishing the spacers for the input shaft as well as shortening a few of the cross tubes  that keep it all together.  I noticed some extreme backlash in the two lower cams, and since the shaft and gears are all turning together rigidly, it seems that the grub screws in the eccentric disks aren't holding properly.  I am going to need to remove the cams anyway to orient them properly according to the plans, so I'll take it a step further and remove the hypocycloids to check the screws and their seating on the flats milled in the axles.  Since the holes for the screws are deep, I might put a second one in on top of the first, or use thread locker.

I have three more CNC pieces to make as well.

One worry I have now, based on holding the pivoting frame, is the amount of weight needed for the counterweight.  I hope it's not so much as to make the piece ugly.  Of course I could try to source the heaviest metal: tungsten.  Or possibly a spring support underneath.

Offline ShopShoe

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Re: Colibri Hummingbird Dynamic Sculpture - WIP
« Reply #126 on: February 01, 2018, 01:01:17 PM »
A Post of Diversion?

Just my brain going off on a tangent again:

"...way to display it in action at model shows."  I would vote for some kind of electric motor or actuator so that you could have some way it might be automatically activated as viewers came by. I can see it sitting on the table, then suddenly going into motion as a viewer came close. Enhanced WOW factor. Add one of the cheap digital noisemakers concealed somewhere...

No intent to butt in and a tip of the hat to a wonderful piece of mechanical art. I've been following this project and find it fascinating.

Thank You for posting,

ShopShoe

Offline kvom

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Re: Colibri Hummingbird Dynamic Sculpture - WIP
« Reply #127 on: February 02, 2018, 10:55:55 PM »
I decide to put my worries about the counterweight aside and worry about the stock market instead.  Of course that didn't help either, so I'll just keep plugging along and see how it works out.

Today was for fitting the two brass "hummer mounts" to the frame along with the wing frame.  A tight fit on everything here is required, so a good bit of fettling was necessary to get everything in position.  Then I could make the pivot tube for the assembly, mill some grub screw flats, and fit the spinners.


Offline zeeprogrammer

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Re: Colibri Hummingbird Dynamic Sculpture - WIP
« Reply #128 on: February 02, 2018, 11:37:28 PM »
I decide to put my worries about the counterweight aside and worry about the stock market instead.  Of course that didn't help either,

No point worrying about things one can't control.  ;D

Love the picture. Looking really good!  :ThumbsUp:
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Offline b.lindsey

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Re: Colibri Hummingbird Dynamic Sculpture - WIP
« Reply #129 on: February 03, 2018, 12:29:35 AM »
Seeing all the pieces together only makes it all the more impressive Kirk. Really nice work throughout. Looking forward to the maiden flight.

Bill

Offline crueby

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Re: Colibri Hummingbird Dynamic Sculpture - WIP
« Reply #130 on: February 03, 2018, 12:35:44 AM »
Seeing all the pieces together only makes it all the more impressive Kirk. Really nice work throughout. Looking forward to the maiden flight.

Bill
Agreed!


Seeing it come together shows the size too, I was thinking it was a lot smaller.


 :ThumbsUp:

Offline Art K

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Re: Colibri Hummingbird Dynamic Sculpture - WIP
« Reply #131 on: February 03, 2018, 02:52:36 AM »
Kirk,
It's looking good, I'm starting to think that building an engine would be much less complicated. :lolb:
Cletus,
I have to admit that looks all to familiar, and reminds me of my dear old departed Dad. He liked both kinds of music country & western, and the other one polka. I've mostly done pretty good avoiding them and acquiring my own taste in music.
Art

Offline kvom

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Re: Colibri Hummingbird Dynamic Sculpture - WIP
« Reply #132 on: February 04, 2018, 12:50:47 AM »
Not as much shop time today as we went to play trains at the club and have lunch.  Our new dog behaved himself with a small crowd, which was part of the exercise.

I finished the last CNC piece and did the next 2 stages of the assembly.  The "back" piece was 3/8" thick, but the brass mounts are only 5/16 apart because they have to grip the frame.  I didn't want to trim the entire length because the head attached to the top end, and it's 3/8.  So I took some off at the bottom just enough to squeeze between the mounts,

Then the next stop was to attach the right side of the bird to the mount and then to add the cam follower for the body,



For the next stage of the assembly, I need to reassemble the tail (which were the first parts I made at the start of the project), attach the left body part, and add it all.  That's a job for another day.

Offline Perry

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Re: Colibri Hummingbird Dynamic Sculpture - WIP
« Reply #133 on: February 04, 2018, 08:38:37 AM »
 :ThumbsUp: Fantastic!

Offline kvom

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Re: Colibri Hummingbird Dynamic Sculpture - WIP
« Reply #134 on: February 04, 2018, 07:34:30 PM »
This morning I reassembled the tail mechanism, this time fastening the bearing shafts with loctite after a test of the operation.


Then with the left side of the bird attached to the tail, the combined assembly was added to the sculpture, along with the cam follower.  Following that, I added the head and its cam follower.



I found a couple of issues that will require some disassembly, but nothing too serious.  The weight of the mechanism continues to concern me, as after all the transmission of power boils down to some 1/16" steel pins being pushed by nylon.  And as well, another "fuse" is the holding power of 8-32 grub screws on flats of shafts.

I also found myself short one needle bearing for the wings.  Looks as if the shop gnomes have hidden it away.  I'll give it a day or two to show up before having to order another.