Hey what is up everybody, Jason here. Today we're going to take a look at
an honest to goodness official LEGO kinetic sculpture.
This is the relatively new Hedwig set, and it's got this cool wing flapping mechanism,
that happens when you turn the crank at the base,
and I think it's a beautiful set. I think
Wes did a fantastic job designing it, and the mechanism is pretty nice.
It's relatively simple and yet it captures a basic flapping
motion quite nicely. That being said, there are a couple of
things about it that I'm not 100 percent sold on. I'm not too keen about this hyper
extension of the elbow. Birds wings don't really bend that way. The other
thing is the way the wings fall down abruptly after the transition from being
lifted to being lowered. It's a little bit jerky.
So, we're going to see if we can do anything about that,
and of course this model is just screeching to be motorized,
so we're going to add a motor into the back so that it can be run continuously.
But, before we jump into all that, some people have been complaining that
these cranks slide off super easily, which they do on mine as well, and it's
funny because i just randomly got one of these cranks from my
collection, and it has a really strong connection
to this axle. Super strong friction and yet these new ones slide super
easily. I'm not sure what that's all about.
So, if this is an issue with yours, you can try and find
an older crank to slide on. Or, if you want to secure at least one of
them you can actually just replace the axle in the back here with an
axle with a stopper on the end. Just pick whichever crank you use the most.
You can just actually slide that axle with a stopper
all the way through to replace the regular five long axle, and now at
least that one crank will be held in place
securely by the stopper.
So, on to my modifications, which are actually pretty minimal.
First we'll take off some of the decorative pieces
so we can get to the mechanism. There is a crank at the base of each wing
which drives all the movement through a pretty simple set of linkages.
The upper lift arm is anchored at the shoulder
and the change in relative position between these two lift
arms causes this section of the wing to tilt.
As the wing moves up and down
the jerkiness of the movement is a common problem in pretty much
any centrally driven wing mechanism, and it's a combination of the weight of the
wings being pretty far away from the anchor points,
which results in a lever effect to magnify the forces acting on the mechanism,
and also the backlash inherent in any
LEGO gearing system. You can see that with the wings being
held stationary, there's actually quite a bit of play in
the crank, and the more gears you have meshed together in the system, the more
backlash there is. Similarly, if I hold the crank still,
there's quite a bit of play in the position of the wings.
So, as the wings transition from being
raised to being lowered, all of the backlash in the system is
taken up, and the wing essentially just free falls for a split second.
I actually don't mind the wings falling fast. It kind of gives the impression
that the owl is really pushing the wings down hard to gain lift.
But, we can dampen the movement by
introducing some friction into the system.
In fact, we just have to replace this regular pin at the crank with a friction
pin, and conveniently there is a friction pin
located right here we can use. So, I'm actually just going to swap these two pins.
And, we'll do the same on the other side.
The wing still falls during the transition, but it's dampened a bit and
falls a little bit more smoothly, which I like a little bit better.
There are, of course, some side effects of doing this.
The added friction does make it a little bit harder to turn the crank,
and that friction pin will wear a bit over time.
As far as the bend in the elbow goes, there is a really easy change we can
make. We can just shorten this linkage between
the upper and lower lift arms, and we just need to replace the full
bushing between these two connectors with a half bushing. Conveniently you
usually get an extra one of these half bushings in any sets that have them
so you should get one from this set and maybe you have another one floating
around in your extra parts pile.
As a result, the wings stay straight on the downward stroke,
and they actually bend a little bit more on the upstroke.
And, it's a pretty subtle change but personally I prefer it.
And, the last thing we're going to do is motorize the model. I designed
this motor assembly and it's a pretty simple
nine-to-one gear reducer that can just slot into the back.
And you might be able to figure out how it's built just by looking at it, but if not,
I have created a parts list and instructions which you can find over
on my website. So, we just need to remove the hand crank assembly.
And the axle as well. And this actually needs to be assembled in a pretty
particular order. First, we will actually get this short lift arm
from the hand crank assembly, and slot it into the top of the motor assembly.
Then we'll remove this connector,
and stick it into the base axle hole here.
Then we should just be able to slot the motor assembly
up into the back
You may have to adjust the position of the wings to make sure that the axle
from the motor aligns with that axle connector.
And, it's pretty much hidden in the back under the tail which is quite nice
It's a little bit out of the way.
And that's about it for this video.
I certainly hope LEGO will make more of this style of set in the future.
As always, thanks for watching, keep on building, and I'll see you in the next one.