14-Dec-2008
photos by jwz


I built an ornithopter.

It's a scale model of Leonardo da Vinci's flying machine.

I bought the kit at davincistore.com.

It is by far the most complicated thing I've ever built.
The kit was, basically, a 20+ page instruction manual,
and a box of twigs.

I think it turned out pretty well, though!

Many of the instructions were of the form,
"Take this roughly-hewn chunk of wood.
Sand it until it is shaped like this."

So much sanding. So much sanding.

To put curves into the various ribs required
gluing two pieces of wood together while
clipped around a form. The instructions said
to cut the forms out of plywood, but I didn't
have any, so I used cardboard. I think it
would have gone better with plywood.
Pulleys and cable guides, threaded with
beads and wrapped with string.

There was a lot of this sort of thing.

The gondola! This is where you strap down your Leonardo action figure.

The wood for these fiddly little wing bits
was so soft that I tore them both while
trying to shape them to the right size.

So I carved new ones out of a clothes pin!
It was a real MacGuyver moment for me.

Stitching the mesh to the wing ribs was
probably the single most time-consuming
part. But unlike the rest of it, that was
easy to do while sitting on the couch and
watching TV.
While doing that stitching, I caught the
outer wing ribs on my shirt and snapped
them -- both wings! Go me.

I added some extra wood to reinforce
the repair site.

The wings are pretty sweet. So are the cables and foot stirrups.

The cables don't really hang as straight as I'd like, and as slack
builds up in them, they tend to hop out of the pulleys.

I suppose that's an inevitable function of the scale of the thing
and pesky, pesky gravity, though.

The wings do flap, but only if you move them by turning the
crank-shaft directly. In an ideal world, they would move when
you pulled on the stirrups, as the pilot would.

Unfortunately, that doesn't work at all. The cables bind up before
any wing motion occurs, even though they appear to be tugging on
the right bits. Maybe the the friction on the threads is just too
high. It's hard to tell what the problem is.