Aerospike Engines Explained in 60 Seconds 

Thanks mate! I love the capability of 2D animations to illustrate complicated things in a simple way.

​@@spaceiac i love your accent ❤️ you're German??(my father side is German. Meaning my faternal grandpa is German!!)

"Thanks mate! I love the capability of 2D animations to illustrate complicated things in a simple way."@@spaceiac I am curious what software do you use?

Extension: they're not as efficient as they seem on paper

I wish this was the only "problem" Nicholas...

kinda doesn't make sense

Which lowers your efficiency, yeah-

thanks mate. Much appreciated

It’s incorrect unfortunately

Jeremiah, the thrust increases with altitude, but once the nozzle reaches its design point (between 2-5 km usually) the efficiency grows lower than it could if all the expansion happened all inside the nozzle (optimal expansion) so it realises a potential less 20% payload to bring in orbit. Moreover, the operative condition you're describing below design point (namely, over-expansion) is the only regime during aerospikes increase the efficiency! That's why we design aerospikes at higher area ratio (between 15-20km) 😉

This is correct. Upvoted and bumped for visibility.

The engine gets more efficient, the nozzle doesn't

A straighter plume is still more efficient in a vacuum than a expanded one

​@@andresmartinezramos7513 True. Which is why a different nozzle is made for space. Rarely does the first stage ever reach space. So a vacuum optimized nozzle isn't necessary and it only adds issues and cost

​@@snakevenom4954 We're not talking about space... There's several miles of atmosphere before that... And a significant drop in ambient pressure with altitude... The energy dissipated from the spread out exhaust is wasted... Such energy could be used to get the rocket to it's destination faster... The aero spike config is an attempt to reduce this wastage...

Hou te samaz🎉 m

Thanks mate! And thank you for the comment. Much appreciated 🙏

Thanks mate. Much appreciated!

no worries mate. No plan to ever stop

Of course it has. Every good engine needs a turbo

@@spaceiacmy thoughts exactly

Habe ich aufgeschrieben. Werde ich bei Gelegenheit mal machen, aber davor kommen noch paar andere Sachen

All large rocket engines burning liquid fuel have turbopumps, some of them having tens of thousands of HP.

I think could actually work very well (in my opinion I’m not a rocket scientist). The heat from a nuclear reactor could heat up hydrogen and flow it though an aerospike, since aero spikes surface area is so much larger than a bell nozzle there’s more space for hydrogen to flow through the engine to heat it up before passing over the reactor making the hydrogen exist even faster and therefore with more efficiency. I find it very fun to talk concepts with GPT like the VALP a manned aerial electric plane that flies in the upper atmosphere that I have though to be made in the late 22nd century

Sure, alcohol was used as a fuel in the V-2, Mercury, and most recently - the small VTVL test bed vehicles produced by Masten and Armadillo. XCOR also build some alcohol engines. It doesn't leave a residue, readily evaporates, and basically cleans your plumbing as it runs through. Also, it's pretty benign to handle. It's a good fuel, albeit not quite as efficient as kerosene (RP-1).

Liquid alcohol is already used. They add oxidizer.

Theoretically less efferent, 1 stage would be great but as in reality the aerospike is less efferent but it's still cool

what stuff? If you are talking about the efficiency thing relating to the underexpanded nozzle: it"s correct. A vaccum optimized nozzle is more efficient than a sea level optimized nozzle because the exhaust travels in a straighter fashion. I could have worded it better in the context. And please, if you spot errors. Don"t just tell me that there are erroers. Tell me what I said wrong so that I can correct my error in the future. Just saying that something is wrond is unproductive.

@@spaceiac Ok, well let's go through the first two errors right at the beginning. "...keeping it in a straight line" This is incorrect. Only once the exhaust is at ambient pressure will it roughly travel in a straight line. With an over-expanded engine nozzle, the exhaust will actually contract. This can be seen in the Raptor Vac test videos. Your video would suggest having the largest engine nozzle possible is best, however, this ignores the issues with over-expansion, such as decreased thrust and flow separation. "Exhaust gas goes sideways, making the rocket engine less efficient" That's kinda true, but not in the way you framed it. *All* rocket engines will be more efficient in a vacuum than at sea level. It doesn't matter what the engine nozzle size. A sea level optimized nozzle will still be more efficient in the vacuum of space. A larger nozzle would be *more* efficient, but the engine itself doesn't *lose* efficiency as ambient pressure decreases.

"This guy haven't heard the vacuum variant of the simple engine." It is just a bigger bell..

Everything you said is exactly backwards, and you haven't the slightest clue what you're talking about. Aerospike engines are better than bell type nozzles because they self-correct for the transition from operating at atmospheric pressure to a vacuum, which was clearly explained in the video but you apparently still did not understand. A bell nozzle can't do that which is why you would want to use an aerospike instead. The reason that aerospikes aren't used is because, again as the video noted, they are heavy and they have heat dissipation problems that need to be fixed before they can fly.

I should have phrased it differently. A straight exhaust plume is more efficient than an expanded one under the same pressure. So what I meant to say is that it could be more efficient if the exhaust plume wouldn't expand. It's bad wording, and I am totally aware of the mistake

Well, they do but not for very long as they tend to overheat

⁠@@spaceiac would it work if I used a material that is a good thermal insulator?

@@dwalvynthat’s called a heatsink engine, works in small durations but anything will eventually overheat from the exhaust especially in an aerospike as well as driving up the cost

who cares about an accent?

@@spaceiac no i was just asking whether or not you are german

Yes, sort of. The aero spike is much harder to cool as there’s more surface in contact with hot exhaust that needs to be cooled, the aero spike in practice also seems to be a bit less efficient in reacting fuel.

Then you are probably unable to explain it simply and efficiently

Check out everyday astronaut.

The rocket is pushing against the exhaust gas that it is ejecting its back. After all, it has to push against it to eject it.

newton's third law. Throw a rock out of a boat and it will push the boat forward

Bros using 1 of his 2 braincells to type this