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Colibri Hummingbird Dynamic Sculpture - WIP
kvom:
I decided that after cogitating on this project for 2 years, I'd better commit to an actual build in 2018. What better way to commit than to invest $170+ at McMaster in the various pieces needed to put together the parts I need to machine.
For those unfamiliar with this model look here: http://www.modelenginemaker.com/index.php/topic,5404.0.html
Rather than plywood this build will be aluminum for structural parts primarily, with some acrylic a possibility for some parts. The aluminum parts in many cases won't be as thick as the wooden prototype, but to maintain the overall width of the model spacers will be needed to align them. I plan to modify the Solidworks model I did using the original dimensions in order to verify fits.
b.lindsey:
Great, I will be looking forward to it. I have looked up the individual prices for the McMaster items (excluding the wood) but hadn't added them all up yet. Not very surprised at your total though...no worse that a casting set for an engine though :)
Bill
Vixen:
Hello Kvom,
You are going to enjoy making your Colibri come to life. As you know, I built my version entirely out of tinted acrylic sheet (perspex, plexiglass) at a reduced size of 40%.
You do not need any fancy gear cutters to produce the core mechanism. I used a 3mm end mill to profile all the gears. Derek Hugger makes generous allowances in his design to fret saw them from wood. They are a rattling good fit and everything moves freely with very little fetling required. The bird is similarly straightforward to make, there are many, many pieces. The four link mechanism to articulate the wings needs plenty of attention to reduce binding and friction so that the wings beat smoothly. A bigger and heavier bird (mine is only 40% size) will help considerably.
Enjoy your build and please keep us posted with plenty of photos
Mike
Dreeves:
Looking forward to following along.
Dave
kvom:
Considering materials, one issue I foresee is with the hypocycloidal gears are in contact with the frame across their entire surface. They have a mean diameter of 4.3". They can't be made of aluminum as galling could occur against the aluminum frame. I originally drew them as brass in SW, but stock for making 3 of these would be well over $120. I considered PTFE and Delrin, but here the material would be about $45 each. Since these parts are quite hidden by the cams I decided to have one printed in a hard nylon by Shapeways for $25. I'll see how the friction is before deciding whether to order two more.
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