Forming a rocket nozzle! - Page 1
Forum section: electronics / general

author: HP-ILnerd
author_rank: Frequent Contributor
timestamp: December 11, 2016, 11:50:02 pm
content: 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

author: CatalinaWOW
author_rank: Super Contributor
timestamp: December 12, 2016, 05:29:56 am
content: 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.

author: John Coloccia
author_rank: Super Contributor
timestamp: December 12, 2016, 09:50:56 am
content: Quote from: HP-ILnerd on December 11, 2016, 11:50:02 pmIt's a hi-tech version of spinning. For example:

author: HP-ILnerd
author_rank: Frequent Contributor
timestamp: December 12, 2016, 08:51:51 pm
content: Quote from: CatalinaWOW on December 12, 2016, 05:29:56 amThe 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.

author: wasyoungonce
author_rank: Frequent Contributor
timestamp: December 12, 2016, 10:44:10 pm
content: 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.

author: langwadt
author_rank: Super Contributor
timestamp: December 12, 2016, 10:54:09 pm
content: Quote from: John Coloccia on December 12, 2016, 09:50:56 amhttps://youtu.be/IM1nNqqMAfs?t=2m20s

author: CatalinaWOW
author_rank: Super Contributor
timestamp: December 13, 2016, 02:25:30 am
content: 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.

author: Brumby
author_rank: Unknown
timestamp: December 13, 2016, 03:13:47 am
content: 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.

author: calexanian
author_rank: Super Contributor
timestamp: December 13, 2016, 05:57:59 am
content: The Merlin engines are fuel film cooled. Its a byproduct of Pintle induction.

author: Red Squirrel
author_rank: Super Contributor
timestamp: December 13, 2016, 08:57:16 am
content: I would totally watch an episode of "How It's made dream cars: Falcon 9".I feel that would require more than an episode.

author: Rerouter
author_rank: Super Contributor
timestamp: December 13, 2016, 09:06:51 am
content: 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.

author: HP-ILnerd
author_rank: Frequent Contributor
timestamp: December 13, 2016, 05:31:56 pm
content: Quote from: calexanian on December 13, 2016, 05:57:59 amWell,also. The pintle injectors get that as a "Free" byproduct. Film cooling is generallynotdesirable (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.

author: calexanian
author_rank: Super Contributor
timestamp: December 13, 2016, 08:56:56 pm
content: Quote from: HP-ILnerd on December 13, 2016, 05:31:56 pmIs 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.