SpaceX’s Explosive Engine Problem 

Non-vacuum optimised engines don't 'become less efficient' the higher altitude they get, they actually get more efficient, it's just that vacuum optimised engines become disproportionately more efficient.

There’s also a ring they put around the edge of the nozzle for static fire tests that is removed before flights. You can actually see it in the video you showed

My Man is finally back

The spaceshuttles nozzle also curls inward slightly to reduce the likelihood that the flow separates.

1:01 Saturn V isn't the most powerful rocket ever made, this goes to N1 It(the Saturn V) is the most powerful rocket ever successfully flown.

This man's transitions to advertisements is too clean

Saturn V isn't the most powerful rocket ever made. It is the most powerful rocket to reach orbit so far however.

Dude, I absolutely LOVE these videos! Thank you so much!!!

Thank you for making these videos. You're a big part of keeping my interest in space. So glad I found your channel at 10k subs.

Love your videos and the animation style keep up the hard work!

The only problem with Raptor imo is that it doesn’t have the “honk” on shutdown anymore

Your videos are better than any TV documentary ever made. .. LOVE your work. ... Thank you.

Great video with fantastic helpful explanatory graphics!

i'm more interested in the steam ejector system that can remove the exhaust from tons of liquid combusting every second from a fairly small pressure vessel.

Excellent explanation of the challenges involved !!!!

So what is the "SpaceX's Raptor Testing Problem" if it can be tested at sea level without any problem?

Primal Space, the Saturn V wasn't the most powerful rocket ever, that goes to the N1 currently.

Love your videos keep it up

There's a bit of a mistake at 2:22 where you say, "if the pressure is higher than the ambient temperature". I'm sure it was just a slip of the tongue

Instead of launching a car to space, they should have sent a vacuum raptor test vehicle.

I read the title and was worried, after watching the video i feel like this problem Sounds like one of those good problems, one that is pretty much solved. In fact you even mentioned they have an advantage concerning this issue.

I think I’m gunna be able to hear the starship launch from the UK.

Just because the Raptor has a higher chamber pressure doesn’t mean its exhaust pressure is higher than sea level ambient. The job of the vacuum nozzle is to reduce exhaust pressure as low as possible, regardless of how high the chamber pressure is.

Great video 👍🏽

This was so good, were is part 2 :)

Excellent video.

Yes Elon tweeted that thrust was high enough to prevent flow separation for Rvacs at SL.

I guess SpaceX couldn't (or didn't feel it was necessary) to launch a single 2nd-stage Raptor vacuum engine, mounted on a regular Falcon 9 first-stage booster? If it were possible, then you can directly test the single Raptor engine in the true vacuum of space, thus cheaply re-using a first-stage booster to get the Raptor engine into space. Hopefully the strong Raptor bell nozzle will continue to hold up during further testing.

thanks

New video!! I like that

Title sound like "SpaceX has a major problem! oh no!" The video is like "Nah it's all good homie".

Brilliant ly created video...

If they send an rvac up in a module on a falcon9 they could theoretically test it pretty well. Would be expensive though

We also see a bit of nozzle flex on every second stage engine start up on a Falcon 9

I learned from this video more than a 6 years of KSP missions!

Nice

Love primal space

The explanation at the end that Raptor has a higher chamber pressure enabling Vacuum Raptor sea level tests without over-expansion issues doesn't make much sense. If the nozzle is designed to be properly expanded in vacuum, then it is by definition over-expanded at sea level, that is completely independent of the chamber pressure. Ultimately at the nozzle exit plane in a sea level scenario for any vacuum optimized nozzle, there is exactly 1 atmosphere of difference in pressure between the nozzle's optimal design exit ambient pressure and the actual exit ambient pressure. For any given chamber pressure, a vacuum optimized nozzle should be designed to get the exhaust as close to 0 kPa at the exit plane as practical, which just means more expansion for engines with higher chamber pressures. I get that this was Elon's response to a tweet, but that response doesn't make much physical sense. My guess is that the explanation of higher chamber pressure isn't meant as a direct explanation, but instead is alluding to a more indirect effect. For example, maybe because the chamber pressure is higher, you can get still get a large pressure ratio between the throat and exit while still having a relatively higher outlet pressure. But that would still mean you are leaving performance on the table by not sufficiently expanding your vacuum optimized nozzle (essentially wasting some of the performance gains associated with designing to a higher chamber pressure). I think that is what was meant when he said the engine isn't fully vacuum optimized yet, which is the actual reason they don't have to worry, because they aren't dropping the exit pressure as low as they could be. Maybe that is made more tolerable by having a higher chamber pressure, but you are still needlessly leaving performance on the table, performance you worked hard to get by designing to such a high chamber pressure.

nice vid

Just bought a poster :)

This video is really great, it should has more views!

0:51 N1: Hi 👋

Hoo boy. Looks like your title selection was jinxed. Or maybe it jinxed spacex

If you can just increase the chamber pressure to make the exhaust match atmospheric pressure, surely you could just use that capability in flight to get better exhaust velocity and higher ISP?

Certainly seems like they could design and adjustable titanium sleeve that could slide down and expand as they got into higher altitudes.

hey guys.. hope everyone is well

By the time Starship goes into standardized production, it won't be called Raptor anymore (Elon commented to thus already). The current Raptor has went through hundreds if not thousands of tweaks over the last few years. You never know, they might even figure out a sea-level/vacuum hybrid that eliminates the need for separate models.

The shuttle engines turned out to be the most reliable in between engines ever built and every one of them has been used at least four times the true meaning of reusable

This aged well.

I love primal space.

This is the same problem the USSR’s N1 had

2:23 ambient pressure

Primal Space mastered "Art of Thumbnail"

RIP Boca Chica village and surrounding nature reserves.

Did the Saturn V have a RUD? Would be a good preview if the Starship blows up.

How mouch would cost shipping that poster to Slovak Republic?

Come on double saturn!!!!

2:20 “If the pressure is higher than the ambient temperature” huh?

Biggest problem with Raptor is starship isnt allowed to fly yet...

i guess they should have hired me if they wanted their problems solving quick

I visited the spaceX launch site

Just a short fact check. the soviet N-1 rocket was the most powerful rocket ever built. also a 1960's moon rocket but wrong side of the pacific

It went boom lol

The vacuum engine still experiences overexpansion at sea level

Didnt the N1 put off more thrust than the Saturn V?

Q: Does "...run the engine at a much-higher chamber pressure" equate to saying they "overdo it" on the ground as an analog for the actual run? I re-watched it a couple times, and bluntly, I don't think I get it!

Booster 7 just blew up

what people see in the thumbnail : Raptor what I see : Raptop

main problem.. we still use round nozzles, think we have done most we can with this old rocket engine design- yeah, u can push it- but that just makes it even easyer to demage.

SpaceX is gonna do some building for a non/air pressure lock for the engines. No way will spaceX will ignore the engine problem, so it’s possible for the testing.

Why are they worried about air getting into the exhaust funnel in space

Think about the explosion when super heavy has a launch accident.

Sigma company rule 101: don't say you are promoting yourself, say that you are sponsoring yourself

Fun fact: the Raptor Vacuum is a pretty good sustainer engine, just like the RS25 and Vulcain engine. Might be a good contender for the main engine for the Vulcan rocket…

33 points of failure and a bad design. Smart!

crei que habia visto el cohete , pero no aparece en las noticias entonces no se que vi . jaja

"loose efficiency no matter how they're shaped".... Aerospike?

0:52 ever successfully flown* , not made The N1 actually had more thrust on its first stage

Hi

So basically with Raptor there is no Explosive Engine problem :/ just like Elon said in a single tweet.

la beast music ftw

Saturn 5 is *not* the most powerful rocket ever made as described in the context to liftoff thrust. It's the most powerful US rocket so far in terms of thrust at lift-off. It's the most powerful rocket overall in terms of payload to LEO. But Saturn 5 had less trust and gross mass at liftoff than both N1 and Energia, if I remember and Wikipeia correctly.

So the point is not that the vacuum engines explode, it's just that they have not been tested in a vacuum?

But nucler rocket more powerful. Then chemical engine.

Don’t aim for success if you want it; just do what you love and believe in absolutely, and it will come naturally. 🌹Good Morning🌹 *यदि आप सफलता चाहते हैं तो केवल बिना लक्ष्य के वही कीजिए जो आपको अच्छा लगता है और जिसमें आपको पूर्ण विश्वास है, सफलता आपको खुद-बखुद मिल जायेगी ।* 🌹 सुप्रभात🌹o

That sponsor segway

Sooooooooo, what's the explosive engine problem?

That's why we need a facility on the moon . Or while we test them on the iss - pusch it to the moon . ( joke , little)

this aged well

Actually all rocket engines have better efficiency at high altitude even sea level ones

Please, tell me they are working on 1 or 2 more starships, if this fails. I’m not getting any younger.

Where's the phone ?

The brightest minds on the planet ? SpaceX just fired loads of their top guys for pure incompetence. Brightest minds INDEED !

well it exploded

So apparently the head of Raptor development was recently let go

Awesome. Just a small correction, engine thrust and ISP increases with altitude, sea level or vacuum engine but a SL engine will get more thrust at lower altitudes than a vac and a vacuum engine will ouptperform a SL engine in vacuum. But both get better in a vacuum despite a sea level engine loosing thrust to the low expansion ratio relative to a high expansion ratio engine. RVac does have a pretty low expansion ratio of around 80-100 vs. 200 on MVac. SSME got around 78 so similar to RVac. The nozzle would be huge with 200 ER. 6-7 m probably vs around 2-3 m currently. So they wouldn't fit.

VLB7:28

The real problem is in the production line and engine supply, spacex is going bankruptcy next year because of that.

No one stops to think what a blessing it is that we only have one world. And what a blessing it is that we know of no other species in the universe. It is a blessing! We should be so grateful for being alone, and having only one world. Thank God! Can you imagine the burden of having to keep track of more than one world of people? We can't even keep track of everything happening on this planet - it is just too much information for human minds. Can you imagine how much of a burden it would be if there were other species - and we had to deal with them. I thank God every night that we are utterly, completely quarantined from all other species. We don't even have to know they exist! What a blessing! I thank God that I don't have to think about other worlds full of humans or other species. Oh, the blessed peace and security and tranquility. You should get down on your knees and thank God too. Weep with gratitude! God is so merciful to keep things relatively simple for us. JUST ONE WORLD. Thank Christ! Oh, the relief! And yet, God is doubly kind, because he lets us know that there are many other worlds, and that the universe is huge. It provides a stage for our imagination to run wild. We get to imagine as big as we want, without the burden of the real thing. Oh, God is very good to us!