What’s inside a rocket nozzle?

[@BPSspace]

Thanks to Henson Shaving for sponsoring this video! You can use the code bpsspace to get 100 free blade refills at hensonshaving.com/bpsspace

[@1943vermork]

I wish your rocket an unbreathable black sky one day 😂

[@creesch]

I love the content you put out. Just one little thing that does bother me a little bit. Isn't onshape also sponsoring this video? I see it popping up in several channels, and they all have a custom referral URL linking to it. Yet none of them, including you, call it a sponsor. Which seems a bit odd and not really transparent to me. Not to mention that federal regulations require that sponsorships are disclosed.

[@TexDrinkwater]

It's a really good product. I ordered one after seeing several plugs for it on Practical Engineering, and I've been really pleased with the results.

[@rasmis]

I'd happily spend 10-50 USD on merch that supports my favourite creators, but even the Swedish and German creators have webshops that favour Americans, and place huge burdens on Europeans. Why is it easier to buy random stuff off of Wish, Aliexpress or Temu, than to support KZbin channels?

[@Bear049]

Suggestion you might be able to correct this by a step coming up from the top of the curved section of the nozzle so that the finallic overlaps slightly near the area it is burned back. I could send you a drawing if you would like . The area of the amorphous carbon

[@PracticalEngineeringChannel]

Man. There really is nothing like a good cross section.

[@yashank_singh]

thumbnail looks like some hentnai cover. looked like thighs im sorry xD

[@lessel1103]

@@yashank_singh i think you need to go outside more

[@misokocka2752]

hi i didn't expect you on this channel

[@misokocka2752]

love your videos

[@thomasrogers8239]

​@@lessel1103 the dude needs to go touch grass

[@LafayetteSystems]

Im blown away by how well Mystery Goo is performing!

[@Bandit-u3u]

Bro y'all should colab

[@liljohn118th]

You should definitely mount the cross sections up as art in your house. That way all your guests can see the threads on the forward closure! 😂😂😂

[@Skye-Was-Taken]

I don’t get it

[@prothomasgaming]

This guy is the only youtuber i never skip sponsors time of the video... Love this channel!

[@BPSspace]

🙏💙💙💙

[@ilyaholt8607]

Jay Foreman also puts a lot of effort into his sponsorship bits, and also The Yogscast, though to a lesser extent.

[@prothomasgaming]

@@ilyaholt8607 oh, i didnt know any of those 2 channels, though Jay Foreman seems interesting

[@basvn]

@@ilyaholt8607 was about saying look at Jay. you are absolutely right

[@Z0ctB0x]

It was actually interesting for once!​@@BPSspace

[@simonebonfanti3983]

That transition between real life cross section and cad model is so satisfying

[@AstroCharlie]

Let's go! Super awesome cross sections and an absolutely FIRE t-shirt!

[@constantins.2981]

My first thought was to use diesel glowplugs, for iginition,. For the following reasons: 1. Price: You can get chinese knock-off models for a few bucks and qualitiy brand ones for 20 bucks. 2. Weight: They are relativly light in comparison to your huge stainless bolt. Every gramm saved is one gram more Payload. 3. Pressure limit: A disel engine can reach compression pressures (combustion pressures are wa higher) similar to your recorded chamber pressure

[@boi829]

this is a pretty cool idea but i think the problem would be that a glowplug doesnt "go off" the way a charge does, and you usually use a sudden burst of energy to ignite a rocket motor. I dont know for sure that this wouldn't work, but i would be concerned about how slow the ignition process would be because if the motor start burning unevenly, it could lead to more problems and the worst case is the motor blows up. I have seen a high-powered rocket explode shortly after ignition because of an improperly placed igniter in the motor

[@mattkingston6157]

@@boi829you’re right and you’re wrong too. Your thinking is good though. The diesel glowplug wouldn’t ignite the motor, it would ignite the propellant mixture inside the igniter. The glowplug replaces the large bolt that is used to house the electronic igniter which ignites an ignition mixture which then ignites the main propellant. There would be no need for the massive bolt it would simplify construction and definitely be lighter. Plus it is already designed to work in this environment and glowplugs are very simple devices. Off the self components rule

[@boi829]

@@mattkingston6157 oh that makes more sense i thought they meant the glowplug should directly ignite the motor, thanks for explaining

[@mattkingston6157]

@@boi829yeah man good thinking though. I agree I don’t think a glow plug could ignite the motor on its own. I think you’d need to have an ignition mixture too

[@SuperSpy00bob]

@@mattkingston6157 You could also "speed up" the glow plug by overvolting it. It's not like you need it work work for more than a like second.

[@patchvonbraun]

When I was making (smaller) graphite nozzles on the lathe, I ended up making a custom little tool out of flat HSS with the right divergent angle in it, and then just slowly drove it into the bore of the nozzle until it was perfect. Even iso-molded graphite is pretty easy to machine this way. I ALSO learned that the very-high-priced iso-molded graphites are not that good for nozzles. They're a bit like glass, and thermo-shock and crack really easily. I ended up backing-down a grade or two and that problem went away.

[@WinstonMakes]

There is so much interesting nuance in this dissection and it adds so much context I didn't know I needed. I specifically remember years ago watching a video about Space Shuttle SRB testing, how Orbital ATK/NG would immediately purge the booster with CO2 after a test fire. I didn't understand what kind of information they were trying to preserve in doing that, but knowing now about the heat soak and continued degradation of the materials involved after firing, I can appreciate it more. Thanks, Joe!

[@aaronatstate]

If you ever have graphite chunks on the ground, you’ve had a major problem, even if your superiors think you’re delusional. I learned this from Chernobyl.

[@amyshaw893]

I mean it's not great, but it's not terrible

[@kalebbruwer]

Especially if they're glowing

[@ryaninwa5375]

I really liked the breakdown of what's happening inside, and that when you use complex jargon, you stick to it and continue to ingrain the language into what you do.

[@RavenRof]

I love the fact that you keep your mistakes in. The threads weren't great, and as a complete "normie" which never made a thread or a rocket (me), I appreciate watching the "fails" + learning moment the fail offers of a highly educated, expert, human being (you). This is what makes me a regular watcher.

[@jjchouinard2327]

I wish there was a double thumbs up for all the effort put into this channel.

[@WiSPMusic.]

What an awesome clip at the end. “Boom.”

[@chefpatat]

Chat can i eat graphite dust with my cornflakes?

[@relwalretep]

You can eat anything if you're hungry enough.

[@Gingerbread3232]

Of course

[@chefpatat]

@@Gingerbread3232 alright thx, was asking for a friend

[@shaughnreilly6928]

Lemme know how this turns out. I’m curious now

[@relwalretep]

​@@shaughnreilly6928graphite is just fancy carbon, we're carbon based life, what can possibly go wrong‽

[@mrobinson9297]

hey perfect timing. i had a thought. for spincasting. you might want to look into the vices that glass blowers use. they make them to hold glass tubes and spin both ends at an equal rate, for hand made scientific glass blowing , and the mechanics isnt super complex. im pretty sure they can be 3d printed though i haven't tried to build one yet. ive also seen rollers made from the wheels from roller blades that you can use to support one end.

[@mattkingston6157]

Yeah good idea. Another one is basically a super long ball mill. Some caster wheels on a piece of plywood with an electric motor mounted beneath with a belt going from the electric motor to the rocket case. You can make something like this for any size motor, up to hilariously large sizes

[@agsystems8220]

Seems overkill. Glass blowers need that because they often want to join two things and spin them as they do so, so the work piece cannot transmit torque between the ends, but that isn't the case here. The case will always be solid enough to transmit the rotation, so an unpowered work holder at the other end is fine.

[@benjaminnevins5211]

I love your power cross feed on the lathe.

[@C-M-E]

My wife and children are notorious for looking over my shoulder when purveying 'boring' white papers and technical jargon, but I need to keep them on their toes. Enter a BPS Space viewing this evening. I await the inevitable 'what cha watchin' Daddy?' "Macaulay Culkin turned it around and is launching rockets."

[@cf_spacetime]

OH! Two ideas just came together in my head right now. @HammerlyCeramics was demonstrating vibrating their molds during pours to reduce the bubbles in their slip casting pottery. The bubbles at 15:54 reminded me of it and using a vibration source like a hand sander to the outside during the pour may be worth a shot at reducing that.

[@loganmerryman202]

18:44 a wise man once said .. " Bigger da gob, better the job"

[@wojciechsosna9230]

Joe bepis as always comes out with an absolute banger of a video (Im barely 1 minute in)

[@jacksonsolomon8769]

My day job is testing rocket motors. To keep the pressure transducer from getting fried on every shot separate it from the combustion gasses by an inch or two of silicone grease. The pressure transfers through the grease but it helps save the diaphragm on the transducer from some of the abuse.

[@spaceluxbirocket]

Once again, thank you so much. I don't have your expertise to make some videos. Your knowledge in Cinema is making difference as french Cousteau personality made with his movie about world of sea. You let so many professionals out your level of camera tooks!

[@AlphaPhoenixChannel]

Such a cool breakdown! The soak heat thing had never even crossed my mind, but wow it did a number on the graphite interface! I have to say I also love the air can technique - the other day I needed a continuous 40 minute shot and I was using a leaf blower on my a6400. Duster cans sound SO much better 😂

[@studiomodoki]

Maybe think about putting a small radius in the machined steps of the forward section. This sharp internal corners could lead to cracks under load.

[@davidjuckem8850]

my thoughts as well. It is just good engineering practice to incorporate a radius in corners when possible.

[@centaur1a]

Thank you for this video. It is very much in-depth on how a solid motor works without the high tech mumble jumbo that most documentary’s do. It does show how the weak points of the solid motor on the Challenger happen too.

[@DodgeCrazed]

I deal with hydraulics quite a bit and you can get what is called an o-ring backup. It’s a relatively thin part made of the same material as the o-ring. It goes on the non pressure side of the o-ring and fills the void in the corners giving the o-ring support across the whole profile. This improves the durability of the o-ring by a good bit. It’s a worth look into.

[@judet2992]

How is it mass wise? He hasn’t had o ring structural problems and except the case burn through with risky Batman, and the gasses have never really done anything to the second backup o ring

[@Nishye501]

0:18 make sure you add an s so it’s secure lol (https)

[@ilyaholt8607]

Sorry to ruin it, but it's HTPB (hydroxyl-terminated polybutadiene)

[@Nishye501]

@@ilyaholt8607 I know lol

[@mattholmes00]

Each video is better and better, thanks for taking the time to make quality content

[@SpaceflightSimulator_Official]

There is something amazing about seeing the hardware from this close up, cut in half and broken down to every detail.

[@GrahamHill-oz1bu]

End closure and nozzle sections on a shelf with other trophies. Well Done!

[@Hannah-451]

This is one of my favorite and most in depth journeys I've had the pleasure of observing.

[@nicholasfraley6353]

This is a crazy undertaking for a hobbyist. you may not be the first but you're the first I've seen. I wish you luck!

[@SpaceMace31]

SMOOTH transition from cut-away to CAD! Nice one bruv!

[@andrewadams4000]

Love henson, they are game changing i have very sensitive skin so being able to change and clean everything is awesome and they really do a good job on longer hair

[@drakkon_sol]

This was a great video. Very informative. Also, yes; these are pieces of art. They tell the story of a journey.

[@TLBSBD]

Let go BPS!!! I am stoked to see you scale this up.

[@renegadethesandwing02050]

i can personally say Henson razors are great me and my dad have one and they're really nice to use

[@michaeljames1857]

Love your analysis and honesty (with your threads)

[@grumpygreg7505]

Joe, I'm so glad you post such excellent stuff. I will never be building a rocket motor but the learning I get is so enjoyable. Your bit for the sponsor was pretty good too.

[@RobertRangel-l8h]

Love, love, love the cross sectional breakdowns!

[@clbwright]

Hell yeah. Another Joey B video.

[@esjihn]

4:14 Delta P huh? When it's gotcha, it's gotcha B)

[@paulholmes672]

Joe, Exceptional cross sectioning and brilliant critical thinking throughout. Having burned a thousand plus motors, with a goodly part of them graphite solid and graphite insert nozzles (as well as the typical, commercial, full phenolic) your analysis is spot on. When showing the graphite to phenolic char, I was waiting for the 'other shoe to drop', and you nailed the analysis challenge (with my accompanying big grin), on graphite's tendency to go post burn crazy with heat transfer. During the burn, there would be little to no heat effect on the phenolic. That is the 'other' benefit of using a nozzle insert, by using the sleeve as a post burn insulator/anti heat prophylactic to the case/airframe. The first, of course is the geometrically increasing cost of high density graphite by diameter/mass. One other item was your O-ring analysis. I have some Canadian students building an O class hybrid motor, and they had a bit of an issue with their forward closure O rings with slightly incorrect assumptions. I will suggest to them this video to better illustrate my written analysis. And you are correct, your forward closure primary O-ring was more than likely ineffective due to the RTV filling the required pressure gap, but, Hey, that is why we use two rings, one for us and one as an offering to the rocket gods. KUDOS, Sir!

[@nickgoodhart2769]

Your editing skills are amazing

[@thermicdude9164]

The handmic segments have serious "Explosions and Fire" vibes😂

[@frankh3230]

This is the nerdiest autopsy video I’ve seen. Awesome work!

[@TheLonelyStreetLight]

I’m excited to see the space shot

[@marcelpost4052]

Wow, you keep on setting the bar higher and higher. You are truly inspiring!

[@Zardwark]

The best video this year by far. There is a metric[1] siht ton of data there. It's going to work, it will reach 100km, for sure. [1] Also available in imperial measurements.

[@Ezis9]

I really appreciate the low-key vibe of this video over the extra that was the last video.

[@Werdna12345]

That sponsor spot was genius. 👍 I’m not interrupting a video. I’m helping you pass the time that i definitely didn’t dilate 😉

[@DanielDyck379BA]

Love me a good cross section. Great video!

[@ast_rsk]

This was such a great breakdown of what happened in the last test. Thank you!

[@keithjurena9319]

Liner looks perfect. RTV between linen phenolic and graphite is probably less than optimal but probably generated gas which protected the downstream linen phenolic from erosion by making an opaque boundary layer.

[@NeonNijahn]

I am riveted! 🎉 great video as always.

[@Zaiyetz]

Could part of the reason the char layer is thicker under the graphite be simply because the char layer at the exit has been stripped away by the gasses exiting the nozzle?

[@Poult100]

Fantastic detail, thanks! But oh, man; those threads! 😅 Thanks for your honesty!

[@peteabc1]

When I see that (glued in) graphite nozzle..I think various 3D printed jigs would improve the process a lot. For example one positive control (a contour) when you're turning the nozzle, one for keeping it aligned when gluing it in and a spatula for spreading that rtv silicone.

[@D-Khaz]

Hope you go in depth on the electronics and telemetry architectures and design choice!

[@extremetech6836]

I like it when he dives into details Super nerdy i like it ❤

[@frafracho473]

Great video ! About the miniature that you changed, I preferred the one with the close up on the nozzle, hope it helps !

[@Allan_aka_RocKITEman]

Great video, Joe...👍

[@yahwea]

Very interesting. You have worked hard at this goal.

[@ronnilokoro7394]

Amazing content, Sir

[@neilweinstock4194]

Making my own motors is not something I have even the slightest interest in, but this was nonetheless really fascinating and informative. Just superb work all around.

[@lukaborland-lye6800]

Love what you’re doing, keep up all the epic work!!!!

[@dylanhalifaux]

Henson Razors really are amazing!

[@JosiahKeller]

They didn’t work for me. Big disappoint.

[@KionLionGuardOfficial]

Joe is back with another slammer of a video! Great work as always :)

[@carlsoll]

Woah this was a lot to learn :o Those parts get *really* hottt

[@GNARGNARHEAD]

"it's a misconception that all pressure inside a thrust chamber or rocket motor is the same, um in fact you can sometimes get a Delta P or change in pressure of several hundred psi", that, is worth a thumbs up right there alone

[@artyombeilis9075]

Good injection of sponsor note on shaving. One of the few sponsor notes I actually didn't skip 🙂

[@roboman2444]

Since the phenolic in the exit throat seems to only have a thin char layer, and a very thick layer of untouched phenolic... is it possible to make it significantly thinner? I would guess that may be a source of weight saving. Some areas look to be over an inch thick of "redundant" phenolic.

[@sethhope]

Since the spincast liner works via char layer, could you, in theory, spincast hotdog meat into a rocket motor and end up with nicely charbroiled hotdog after a successful burn? The meat would form a pretty dense char layer and could work in a similar capacity, albeit with a thicker liner.

[@janstransky442]

Payload was data. Awesome work, awesome shots.

[@testpilotmafia862]

I was really grateful you made the time to meet with us rocket fans at Open Sauce 2024.

[@TheBloodypete]

On the top end metal piece, those parts you're worried about the distance on, try adding a fillet to that outer edge. I do that on my 6000m rated subsea enclosures and it massively helps with stress build up on thaose thin sections!

[@mojaverockets]

Nice video as always Joe. For our head end igniter bulkhead bolt we simply used a hardware store (Lowes-Home Depot) 1/2" bolt drilled through for the wire and pyro charge...I think they were like 75 cents with red RTV sealing the threads if you need to save some money.

[@BPSspace]

Thanks Rick! See ya out at FAR again soon :)

[@Ionee-q4f]

1:08 leaked spaceshot motor size

[@connormartin9644]

0:36 Wait, Doesn't the Seperatron motor in KSP make around 5-6kn of thrust?

[@r.allengilbertjr.6457]

Thank you for sharing. This was a great walk through.

[@williamcaldwell9431]

Excellent informative video! Thanks for sharing.

[@mikeconnery4652]

Excellent video

[@tedapke6519]

Excellent video as always. Please keep up the great work.

[@user-nbfkxngjmyb]

Can't wait for the next video!

[@bobthecomputerguy]

I love seeing the engineering of rocket science.

[@azazahmed3708]

more videos like this please damn please a whole playlist or series sooo in dept

[@Sock_real]

Every video is a step towards SPACE

[@metalworker3]

Love it! Thanks Joe!

[@watchguy7986]

This is my favorite video. I love this!!!! More more ! It all makes so much sense how you explain it. Congrats! Would love to be at FAR when you accomplish your goal

[@peter360adventures9]

Awesome work.

[@waylontmccann]

amazing work!

[@landonkryger]

Quick question before I buy a shirt. Did you design this in metric or imperial? I want the authorial intent version.

[@supernova8986]

I love this new relaxed style of content. It feels more informative and less performative. Dont get me wrong i love all your content, some of your more chaotic videos are my favourites. But i do indeed really like this new style.

[@ChaitanyaSrikar]

This is incredibly impressive but it also put into perspective the achievements of SpaceX in landing a booster back! And its reusability given there is so much perishable material used!

[@Spaceroc]

Wow best video on youtube

[@Alex-mn4wz]

Joe we love you

[@1320crusier]

Would it be possible to....pre-bake... the cast liner and would it actually provide any sort of advantage?

[@theelectricwalrus]

For the 10th time: JOE! USE A TAP ALIGNMENT GUIDE!