Love me some Kakuta that dude just whipps out models. ive seen how to train your dragons themes ornithopters, and even one hooked up to a autopilot
heres a good place to pick up gearboxes for those filmed flexible wings..
however, those are all film on frame style wings, heres a guy that was building bigger stuff a few years ago...
been sitting on this site for a while, waiting to try this stuff out...
its in german so let google translate do its thing
been meaning to take this and convert it to work with a 25lb highvolt servo and a 3d printed housing, his development seems to focus and stall out on the gearbox to make all the movement automated and linked, would be much more efficient and easier to control those aspects individually with a modern micro-controller. he even struggles with establishing glide position in his later models, which would be simple stuff with an arduino converting RC commands to make it work.
Could be simplified greatly with arduino an acceleromiter and gyro sensor, multiple servos with hollow spars and torsions rods for twisting the wingtips. controls would get tricky, probably a reciever gets PWM/PPM command, Arduino reads this and coverts it to "bird movements", then sends it to the servos(with a voltage step up somewhere).
probably try to imitate a hawk to try it out, as they dont really bend their 'elbows' as much as other species, and their body shape would be pretty easy to recreate.