Even for companies invested in additive manufacturing, it can be
hard to see all the wins.
This company needed the delay of a pandemic to have the chance
to take a second look and discover one of its best opportunities
to redesign a part for additive manufacturing.
Welcome to The Cool Parts Show.
I'm Pete.
I'm Stephanie.
We are doing special episodes of The Cool Parts Show, looking back
at companies and people we've looked at in past episodes.
Yeah, so we are in the midst of the coronavirus pandemic right now.
So it looks like we're sitting side by side.
But actually we are six feet apart.
We are social distancing and we're filming all of these updates with
this setup.
So today we are checking in with Cobra Aero.
Stephanie, do you remember them?
Yeah, so we talked about Cobra Aero in Season 2, Episode
3, and we'll put a link in the description if you haven't seen it.
But if I recall, Cobra Aero was a spin out of Cobra Moto,
which is a company that makes motocross bikes.
And they found that their expertise with small engines
actually gives them a leg up in making drone engines.
So we looked at the cylinder that they had redesigned for Additive
manufacturing.
So during this shelter-in-place period, Cobra Aero is
running with a skeleton crew.
And so CEO Sean Hilbert looking
for what they could do with this time, what the opportunities are,
leveraging one of the strengths of their additive manufacturing
capability, which is product development.
They're experimenting with new product designs.
Just as you said, we talked about the dramatic changes
to this engine cylinder.
Well, they've redesigned their exhaust system
now through additive. During this time and discovered even more
profound product improvement.
So if I recall from the cylinder episode, they were
able to reduce the weight of that part.
They improved its performance.
The redesign part cools better and they made it easier to
manufacture. And it's only it's only one part where used to be two.
So I imagine there's sort of the similar benefits they're seeing
now with the exhaust.
Yes. Even more so.
So listen to this. So the redesigned exhaust system redesigned for
additive the benefits that they won.
Yeah. Assembly consolidation.
Instead of two parts to one, they took what used to
be 13 different machined parts and combined
it into one.
Ease of manufacturing, they were able to design it
with a wrench access now that it didn't have before.
Greater efficiency because they designed the shape of the
part around some fluid analysis of how the exhaust should
flow. It's 100 grams lighter and that's
off of a part that was only 400 grams to begin with.
It's quieter because they've changed the design to point the
exhaust in a different direction.
If you don't point the exhaust down, then the drone is quieter
to the people on the ground.
Sean Hilbert can talk about all of that.
That's the cylinder, that's the old school fin
cylinder that everybody is familiar with from the video.
And then this part on the bottom here is the exhaust system and
it's got a lot of volume, you know, it's big.
As you can see from all these different pieces here,
we've got different chambers that
have different shapes inside those chambers that need to be machined.
And then this whole system is bolted together
by six bolts on the outside and everything has to be sealed.
And then furthermore, it's very difficult to get installed onto
the engine because we have some
some pretty poor bolt access here.
You know, header bolts are kind of hidden behind.
And then all the bolts for connecting to
the main the main part of the engine case are all hidden way
down deep in there. So very, very difficult to install, difficult to
make, expensive.
And in the end, you know, we've had this design for four or five
years now. We've been able to simplify the internals
of the design so that we can get the
same amount of sound output or more power.
So what that says is that if we went to the next level design, we
could we could take some volume out of it and make it a better part.
With all that in mind we redesigned this
little piece, which is quite a bit smaller and lighter.
It's got these nice features that you see on the top here for
bolt access so that  when we're installing things,
I don't know if I can line this up with of the camera very well.
But we have a nice wrench access there.
The shape of it is angled down towards the
propeller so that we get less what's called masking
of the prop. So the prop can actually produce more thrust with
the same amount of engine output.
And then internally, you can't see any of this.
But internally, we've done some very interesting things with
allowing the passageways to do.
We have got a Helmholtz Resonator this package inside there.
We've got some expanding passageways.
It's a hundred grams lighter than the than the current design.
And then this little feature on top here, you can see a bolt pattern.
We've actually created a sound deadening device
that we can basically pull out of the of the
muffler that allows cleaning inside.
And it also allows us to do various exit
types. You basically you don't want the exhaust to shoot down
toward the ground because that's that creates more noise, perceptible
noise for people on the ground.
But a lot of things that we were able to pull together in terms
of function that we couldn't do with a machined
part and then manufacturer ability
of the part itself and also assembly of the final engine,
has been improved. And then and then weight, one hundred grams out of
about 400 grams, we were able to save twenty five percent
on weight with that part. So that's that's kind of the next thing.
That's what we're doing next.
Wow. So that's a great story. Maybe even better than the one that we
had in our episode.
So was this exhaust redesign like a project that was already in
the pipeline?
Yeah. So that's a good question. The answer is no.
Like they did not intend to produce this through additive.
You know even for someone invested in additive capability, it
can be hard to see all of additives potential
wins. You know, Sean, for a small business
owner, he is a visionary when it comes to additive.
And he's got you know, they've got this this Renishaw metal
additive machine that they committed to, big investment
for their company, because because he's convinced of the promise
of additive. And in spite of that, he didn't necessarily
see that there was such a huge opportunity for additive within
this particular component.
He talked about that.
Do you believe that you were always going to do this refinement and
move the exhaust into additive?
Was this always going to come?
And it's more like a question of this is just a chance to accelerate
your way there? Or is this just a rethinking that
you maybe would not have come to?
Yeah, definitely the latter.
You know, we dove into additive with a few key components in
mind that we thought, oh, boy, you know, we might be able to do some
neat things with the cylinder.
And this was one of those things that I mentioned to you last time
where we just honestly weren't sure where the next
ROI was going to come from but we knew it was there somewhere.
And so now that we've got, you know, got the machine sitting
there, that's got us thinking in a completely different way than
otherwise. So, yeah, definitely the latter.
Oh, wow. So if this had never happened and if you'd stayed busy,
like you just wouldn't have had the chance to think through all that
and might have just stayed with a less efficient way to produce
that component.
Yes, for sure. Less efficient and heavier.
And the other thing that I didn't mention is this exhaust is actually
going to be a more powerful unit as well.
So, you know, we're breaking, one of the key constraints with with
engine design has always been the tradeoff of power
and sound. Right?. So if you, if you plug up the exhaust system
to create a quiet exhaust, you always lose power.
And so there's been a lot of effort on our part
to maybe not completely break that constraint but minimize
the tradeoff that we have between sound and power.
And and we're able to eke a little more
power out without having any sound
detriment with this design.
That's a big deal. And one of the things that we haven't done yet
with this design is you could do basically surface,
you know, you could do surface treatments.
Not a treatment necessarily, but imagine a
surface texture that was put on, say with a piece of software
like the nTopology platform.
You know, you can create sound attenuation, surfaces
built right into the part where you couldn't otherwise.
Or it would be very difficult and an expensive to machine, but
essentially no more expensive to
print. And that's one of the things that we're looking forward to next.
So that's neat. Like we talk about additive manufacturing as being
this disruptive technology, and now here's a case where additive
actually benefits from a little bit of disruption.
Yeah. Yeah. This disruption that we're all in created
the context for the disruptive technology to thrive.
That'll do it for this episode of The Cool Parts Show.
If you have not subscribed do that now, you don't want
to miss our next episode.
We're going to talk about a cool part coming out of
this period of time, the coronavirus crisis, but it
is one of the greatest scale production
wins for additive manufacturing so far.
You won't want to miss it.
If you haven't seen the original Cobra episode or you want to find
any of our other episodes you can find them on YouTube at
AdditiveManufacturing.Media or TheCoolPartsShow.com.
Thank you for watching.
