Re: [SeattleRobotics] hovering mini ornithopter
>> > > Can an underwater bot be used as a relevant parallel?Those are nice papers but don't really answer what I was asking. For
>> > Well, I can link you to papers if you want.
>> Yes please. As long as it's for bird-sized ornithopters. I don't believe
>> that fly-sized ones will be possible for decades.
instance, what's the Reynolds number of your bot? More than 1e7 or have I
worked it out wrong? Which would put it into the category of a light
aircraft rather than a bird-sized ornithopter. So can an underwater bot be
used as a relevant parallel to an indoor ornithopter?
For instance, you can adjust your fin's shape in a leisurely way. To do that
with a mini-ornithopter isn't practical.
>> Anyway, that applies to a robo-fish. I can imagine that subs _might_ workWhich implies that, if the wing is passive, they'll have huge difficuly
>> better with fins. But I was questioning the wisdom of ornithopters. In
>> video of the mini-ornithopter, it was flapping its wings so fast, I bet
>> they're using mechanics to do all the complex motions.
> I haven't seen the paper, but I'm pretty sure it relied heavily on
> whats called 'passive curvature'. Its when you intelligently select a
> wing shape and stiffness so that at a particular natural frequency it
> natural bends in just the right way to optimize thrust. This requires
> serious fluidic-structure interaction CFD calculations, so I think
> they used experiments to guess a good design.
adjusting the curvature within a single flap to change the direction of the
thrust (as your fins do).
I still don't see that a practical indoor ornithopter can do anything that a
heli can't. And it's harder to make and much less efficient.
>> For an ornithopter (or submersible), for a givenYes. So how does the low speed efficiency compare?
>> manoeuverability or speed, which would move a vehicle around for longest
>> with the same battery?
> What if your mission is for low speed maneuverability about an
> obstacle course? Say, for mine inspection about a pier system? In that
> case, high speed efficiency is useless.
> You can also argue that a finI'll believe that. I don't have any trouble believing in robot fish. (But
> is quieter than a prop (for secret spy missions or something).
I'd still like to see your efficiency figures ;-).) It's ornithopters that I
don't see a future for. I think an indoor ornithopter would be noisier than
a prop-plane - its wings would have to flap too fast. It wouldn't be
I really don't see why they're worth funding other than at a low level as