Are Aerospikes Better Than Bell Nozzles?

Timestamps:

00:00 - Intro
06:20 - How Nozzles Work
16:00 - How Aerospikes Work
19:55 - The Problems With Aerospikes
32:50 - Comparing Aerospike Engines To Bell Engines
41:30 - What The Experts Say
51:35 - Future Aerospike Prospects
54:00 - Summary

Today we’re going to look at the history of aerospike engines, go over how nozzles work including things like overexpansion, underexpansion and even expansion ratios, we’ll look at the pros and cons of the aerospike, the physical limitations and problems, then we’ll compare the aerospike to some other traditional rocket engines.

But that’s not all, I obtained never seen before photos and videos of some aerospikes, we’ll get opinions from some people who have actually worked with aerospike engines, look at some promising prospects and compelling concepts and by the end of the video we’ll hopefully know whether or not the holy grail of rocket engines is just waiting to be utilized or if aerospikes just simply aren’t worth it.

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Thanks to my Moon Walkers for helping produce each and every video! - Neurostream, Max Haot, Thomas May, Jason Padilla, Joe Leva, John Malkin, Larry D Lysinger, ArcTechInc, Blake Jacobs, Ole Mathias Heggem, Jared Smith, Mac Malkawi, Jethro, TTTA and NSS North Houston Space Society!

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[JaySmith]

Genuinely one of the best 1 hour 'documentaries' I've seen. Those on TV are always dumbed down, hyperbole, unbalanced, or full of filler B-roll. This video was packed full of well-researched facts, videos, interviews with leaders in the industry. Thanks for making this and sharing it for free with the world.

[rogeriopenna]

"this is a really long video"

Don´t be so modest Tim.




This is not a video. This is a high quality documentary.

[SkylersRants]

This is what journalism should always be like. My understanding is that the Everyday Astronaut is not an engineer of any sort, yet he has presented this issue more clearly than anyone else. I had been reluctant to watch this, assuming that it would be filled with mistakes and lacking in analysis, but I'm happy to see that I'm wrong. Good job, and thank you.

[nophobia]

The comparison of the arrow spike engine to the rotary engine at the end of this video was brilliant

[mayankshrivastava]

Everyday Astronaut has truly outdone himself on the aerospike video. What an amazingly researched video. Simulations from Stanford, restored footage from Aerojet Rocketdyne, great animations, reading through NASA's decades old documents & reviews from Elon Musk, Tory Bruno and Peter Beck.

[SakariRannikko]

Main argument for aerospike: they’re so cool
Main argument against aerospike: they’re too hot

[mspencer]

That entire hour was extremely watchable and quite enjoyable -- like a well produced TV show. Very well done.

[Dynoids]

I really love this video, I did a 10-page report for one of my engineering classes discussing aerospike rocket motors. I only had a chance to do so much research before the deadline so it's awesome to see this full-length video go so in-depth and go so much further with research than I could.

[kenkirtland]

Truly surpassed the title of “YouTube video” this is a documentary

[TheNighthawk]

Peter Beck summarized it perfectly: the advantages that the physics promise are lost due to engineering problems.


Magnificent video!

[MattLowne]

"Huh, it's going to be difficult to summarise the aerospikes vs nozzles in a 1 minute video. Wait a second, it's a whole hour!"

Serious props, this must have taken a huge amount of effort! The animations are really slick too, I always found it hard to explain the concept of how the "virtual bell" works with aerospikes

[kencroker]

I just watched the whole hour long video and it was ABSOLUTELY WORTH IT!!! You explained things so well that even though I'm a complete newbie when it comes to rocket science, I could still understand the vast majority of your content. This must have taken an immense amount of effort, and I can't wait to see what you do next. You've definitely earned my subscription!

[TechyBen]

Me: "I need to chill for an hour"
Everyday Astronaut: "I got you covered"

[alfredlorber]

Amazing job Tim!! I’ve got three degrees in Aerospace Engineering, including a PhD, so I know something about this stuff, and your video is terrific. I think your nozzle pressure section will be used in a lot of Aero classes.

[nilsdock]

we should award a "no-bell prize" for the first company to get one to orbit.

[CAMacKenzie]

I didn't get around to seeing this vid until Dec 2022, having been referred to it by a Scott Manley vid, so I wonder if you have an update in the works. After all, a lot can have happened in the 3 years or more since it was posted. I was really glad to see this, as I had only the vaguest idea of what an aerospike engine was, though I had heard of them for a long time, but hadn't gotten around to reading up on them.
A couple of ideas I had while watching this, with regard to ablative cooling. 1) A solid fuel aerospike engine. It wouldn't likely be reusable anyway, so ablative cooling would be the way to go. That would be for a strap-on booster or for a ballistic missile. 2) For a reusable engine, a replaceable ablative section for the areas most susceptible to heat overload.
The other thing that struck me was the similarity (superficial, at least) of an aerospike to the tail cone of a turbojet engine.

[EverydayAstronaut]

Timestamps for mobile users:
6:20 - How Nozzles Work
16:00 - How Aerospikes Work
19:55 - The Problems With Aerospikes
32:50 - Comparing Aerospike Engines To Bell Engines
41:30 - What The Experts Say
51:35 - Future Aerospike Prospects
54:00 - Summary

Also sorry about including my ignorance on mixing temperatures 😂 when I realized that a few years ago, it kind of blew my mind but I hadn’t really thought about it too much I guess. And with no formal education or even ever having taken a single physics class, I definitely lack some of those basics. But I thought it was fun to include so people can remember that it’s ok to keep learning at all times! But yes everyone, I understand it now, you can stop explaining it to me 😂

[nickbird]

This is what You Tube was built for, the amount of work that went in to this video is mind blowing. The way everything was explained was just right. Thank you for sharing your thoughts and experiences.

[fatballs]

My Brain at 3 in the morning: plz go to sleep
me: yeah yeah...but are aerospikes better than nozzles tho ?

[billstech]

With 28 engines on the Space-X Heavy and looking at the inward angle of the Firefly Aerospike, it looks like Space-X has accomplished the same end result which is basically to vector the thrust inward around the outside to compensate for the expansion as the ship goes up in altitude, basically what you said in the video, combine this with multiple stages and there you go!!!