Forming a rocket nozzle!

[HP-ILnerd]

In case you missed it, here's how SpaceX forms its rocket nozzles.  Blowtorch refractory metal on a lathe and push it on to a nozzle shaped mandrel.  Obvs.

It's only 10 seconds of video, but I think I could watch an hour of that...

https://twitter.com/elonmusk/status/807354766804168706

[CatalinaWOW]

Lots of hidden trades here.  Many rocket nozzles have huge numbers of cooling passages in the bell.  Both preheats the fuel for better performance and cools the nozzle to allow more heat flux from the rocket flame.  This much simpler nozzle from SpaceX has forgone this route for something else.  Maybe arranging excess oxidizer or fuel to flow along the inside of the nozzle for cooling. Or a thicker (heavier) nozzle wall to provide strength at higher temperature.  Or something else altogether.

Time will tell if SpaceX has found a sweet spot for overall cost and performance.

[John Coloccia]

In case you missed it, here's how SpaceX forms its rocket nozzles.  Blowtorch refractory metal on a lathe and push it on to a nozzle shaped mandrel.  Obvs.

It's only 10 seconds of video, but I think I could watch an hour of that...

https://twitter.com/elonmusk/status/807354766804168706

It's a hi-tech version of spinning. For example:

[HP-ILnerd]

Lots of hidden trades here.  Many rocket nozzles have huge numbers of cooling passages in the bell.  Both preheats the fuel for better performance and cools the nozzle to allow more heat flux from the rocket flame.  This much simpler nozzle from SpaceX has forgone this route for something else.  Maybe arranging excess oxidizer or fuel to flow along the inside of the nozzle for cooling. Or a thicker (heavier) nozzle wall to provide strength at higher temperature.  Or something else altogether.

The Merlin 1D (as you can see below) is both regeneratively (top part) and a radiatively cooled super-thin nozzle extension--hence, the refractory materials (niobium alloy in this case).  When you watch a launch, you'll see that skirt glowing pretty brightly.  I had no idea how they'd go about making them, though.  I suppose they'll still have to make nozzles/skirts like this, even though the SuperDraco and Raptor engines will have the chamber parts 3d printed?

On that note, thanks for that "spinning" video John Coloccia.  Beefy tool post on that rig.   

[wasyoungonce]

We picked up a few used discarded rocket nozzles from Woomera range. They were 50/60's design, ceramic nozzles.  I'm guessing they were from that era! Who knows a lot went on there.   The ceramic ablated away so what we had was...."very used"... but still good enough for wall displays.

[langwadt]

In case you missed it, here's how SpaceX forms its rocket nozzles.  Blowtorch refractory metal on a lathe and push it on to a nozzle shaped mandrel.  Obvs.

It's only 10 seconds of video, but I think I could watch an hour of that...

https://twitter.com/elonmusk/status/807354766804168706

It's a hi-tech version of spinning. For example:

https://youtu.be/IM1nNqqMAfs?t=2m20s

[CatalinaWOW]

These videos don't make the forces involved obvious.  I have tried a little metal spinning on relatively soft materials.  There is a reason those tools are so stout.  But when you get it working it is like magic.

[Brumby]

I was aware of the forces involved....

One look at the tool rest and the working bars and it became exceptionally clear to me the leverage being utilised.  Of course, understanding that is one thing ... doing it is quite another.

[calexanian]

The Merlin engines are fuel film cooled. Its a byproduct of Pintle induction.

[Red Squirrel]

I would totally watch an episode of "How It's made dream cars: Falcon 9".

I feel that would require more than an episode.

[Rerouter]

I think that would be more than a season to get into some of the bits in it, but if they glossed over the fun stuff, then maybe 3 episodes.

[HP-ILnerd]

The Merlin engines are fuel film cooled. Its a byproduct of Pintle induction.

Well, also.  The pintle injectors get that as a "Free" byproduct.  Film cooling is generally not desirable (unburned propellant, hence worse mass ratio), but if you are going to use a pintle injector, you may as well take advantage of it and declare it a "feature."  It's like the "engine out" capability they get from large engine clusters.  Only a feature because they are forced to use a large cluster.

[calexanian]

The Merlin engines are fuel film cooled. Its a byproduct of Pintle induction.

Well, also.  The pintle injectors get that as a "Free" byproduct.  Film cooling is generally not desirable (unburned propellant, hence worse mass ratio), but if you are going to use a pintle injector, you may as well take advantage of it and declare it a "feature."  It's like the "engine out" capability they get from large engine clusters.  Only a feature because they are forced to use a large cluster.

Is this a cousin of the Real Estate agent saying its not small, it's cozy? Or its not old and falling down, it's rustic? I love that one.