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The Rocketdyne Tripropellant rocket had great specific impulse, one of the best. But-- there are many reasons it never caught on: one of the byproducts was FOOF
by GarnetFloride 2y ago
The Rocketdyne Tripropellant rocket had great specific impulse, one of the best. But-- there are many reasons it never caught on: one of the byproducts was FOOF, along with other things like hydrofluoric acid.
- rbanffy 2y agoSounds OK in vacuum...
- Sharlin 2y agoIf you want to actually get momentum out of a rocket, the reaction products are going to touch the combustion chamber walls and the nozzle. While film cooling can help with minimizing heat transfer from the hot stuff, I doubt it’s enough to keep this stuff from eating your engine from the inside.
- shadowgovt 2y ago"These modern SpaceX kids and their fancy reusables. Back in my day, when we went to space, we used the whole engine!"
- narag 2y agoSomething like this? https://www.reddit.com/r/aviation/comments/vpu3fv/lockheed_sr71_blackbird_the_plane_that_was/ https://www.reddit.com/r/aviation/comments/vpu3fv/lockheed_s...
- rbanffy 2y agoThat’s what engine-rich exhaust is for.
- Sharlin 2y agoHmm, I wonder if anyone has tried to use ablative coatings in a rocket engine.
- shadowgovt 2y agoArguably, the solid rocket motor is in this vein. While I've never seen a design that consumes the outer shell, the inner material is designed to burn as completely as possible, and the chemistry and physical composition is even designed to cause the burn to happen in a proper combustion-chamber shape.
- Sharlin 2y agoYeah, good point!
- tekla 2y agohttps://en.wikipedia.org/wiki/Executor_(rocket_engine) https://en.wikipedia.org/wiki/Executor_(rocket_engine)
- Sharlin 2y agoThanks, interesting!
- Tuna-Fish 2y agoYes, many. It's widely used on solid rocket motors, but it's considered a bad idea on liquid fuels because regenerative cooling is usually lighter, more efficient and easier to design and build. It's hard to get a rocket nozzle to ablate in such an even and consistent way that you wouldn't have to provide much larger safety margins than you'd really want to in a rocket.
- Sharlin 2y agoThanks!
- GarnetFloride 2y agoYeah, that was one of the downsides. They actually did build a test article and ran the engine a few times, enough to gather the data but it indeed ate the engine, and the concrete and the rocks and coated it all with explosive powder. They did imagine coating the proposed launch complex with quartz but it quickly became obvious it was going to be way too expensive to actually build.
- deleted 2y ago[deleted]
- the8472 2y agoThe line between serious proposals and shitposting is thin. https://ntrs.nasa.gov/citations/19700022572 https://ntrs.nasa.gov/citations/19700022572 https://x.com/ToughSf/status/1769958999279927787 https://x.com/ToughSf/status/1769958999279927787