As is traditional in computer networking, simplex means single way communication, duplex means dual way communication. Naturally, your Duplex V1 engine must have thrust coming out of both sides.

I for one would actually love an entire episode dedicated to the safety aspect of this! Not a "tutorial", but just some insights into the considerations you had to make.

5:15 - Joe bringing us all right to the peak of the Dunning Kreuger curve and dropping us off

I have built smaller scale I class motors out of PVC and there are so many things that can go wrong. Safety cannot be overstated. Even at the smaller scale, a motor exploding is exceptionally violent. Richard Nakka is a great resource for learning about designing motors on a much smaller scale.

Hey Joe, I would recommend placing the pressure transducers at 135° and 90° apart. This helps in preventing pressure oscillations being invisible due to symmetric sensor placement. Would be really interesting to see if there are some modes other than the L1-mode visible in the pressure data.

My day is always better when BPS posts. Keep up this amazing work! Can’t wait to see what’s next

I'm super excited to see this series Joe! It was super fun to work on this with you!

I used to work for a company that was making, let's say a very, VERY fast rocket motor for a very specific application, and one of the guys I worked with used some very expensive, very complicated software to simulate the rocket grain geometry. The company even had him fly out to the software developer to get in-depth training on how best to use it. I still remember, and I'm very jealous of that experience he had, because simulating rocket grain geometries sounds freaking fun as hell.

"Comfort gets you hurt", words to live by. Not just applicable to rocketry, but to any usage of dangerous materials or equipment.

don't forget about friction between the motor wall and the nozzle retainer! In college I grenaded a motor because I only considered the fasteners. in reality the friction was carrying an immense amount of shear. factor this into your nozzle ejection calcs and measure preload on install!

The complexity of your projects is exponential!!! Can't wait for the “I LANDED A ROCKET ON THE MOON!” video .🚀🤣🚀🤣🚀 Great video once again btw.

Honestly, you need to make a full video covering the chemistry and building of the motor. Theres hundreds online but they all lack the attention to detail that you put into your presentations as well they’re not as articulate. I think youre doing a disservice to all the kids out there by not covering it in depth . From the kids of a coal mine community 60 years ago to today. This subject is fascinating and interesting to all age groups. The more accurate and informative information out there , the safer the hobby becomes. Bombs are easy to build, and theres a lot easier and more efficient explosives out there than rocket fuel. So i dont think you should worry about that . Other than that/ I’ve enjoyed watching your videos over the years. I understand how much work goes into your channel and the time it takes- but I really wish you could post more often if that’s something that becomes available if time permits. Take care and happy launch

Don’t know if you are an aerospace engineer but if not you should be because you have all the qualities to become one. I was one for 40 years specializing in strength engineering. Your video really takes me back to the good old days of solving complex engineering problems. I wish you the best of luck. Take care.

Absolutely incredible! You're such a scientific inspiration!

joe i need episode two right now my adhd can’t handle the wait

This video is on a totally different level of quality. Your work is absolutely breath-taking and I am so excited to see more! Best of luck!

Perfect timing. My daughter is doing science fair and we are building a rocket. This will be perfect for us to watch together.

I know the footage from space shot will be incredible, and in the meantime I’ll enjoy these updates :) keep it up!

Nice. I too have built up to O class, using a couple different classes of APCP - some standard R45-HTLO, some with a pre polymer polyurethane, and some with platinum catalysed silicone. The silicone burns REALLY fast btw, it’s great for end burning geometry when combined with organoiron burn rate catalysts. Wonderful to see some rocket motor development here on YT, when I started this stuff was way less than mainstream and it’s great to see more getting into it!

I'm proud of you guys. From wanting a job, to crying, to this confidence you have. You got this.

The timing of this video is great because I just started my first very small scale rocket and just finished making my first test batch of ACPC. This video is a great resource!

I have loved watching your journey from hobby motors to full space shot. Well done Joe!

Wow -- this is at a whole other level! In my youth, my best friend an I built rocket motors inspired by Estes designs, starting with cast potassium nitrate/sugar grains and then going to ammonium perchlorate/aluminum/rubber based grains. But we our designs were mostly seat of the pants ball-parking, and a result most either didn't build up enough thrust for stable flight or exploded due to overpressure in the combustion chamber, with only a few successful flights. I really admire the level of sophisticated science, engineering and dedication you're putting into this!

Your channel has been, and will continue to be one my absolute favorites of all KZfaq.

Don't worry BPS space, thanks to the Dunning Kruger effect, I have total confidence in my ability to make a solid rocket booster solo

One of the best KZfaq channels. Period.

Hooray, a new detail video, so much joy! When “Tech Ingredients” started mixing rocket fuel I got excited but this is aiming for _space_ !! :) Thank you for sharing all this cool stuff!

Great video as always; what you've been able to accomplish on this channel is wildly impressive

Exciting stuff Joe! Very excited to see the progress towards a space shot!

I'm looking forward to hearing more about the design and build process! Even with "rocket candy" motors, the difference between a model rocket engine and an explosive device is pretty thin- granted, you can eyeball casing thickness and the nozzle diameter for an engine that's around 1-2 cm in diameter (of course as long as you're cautious) and be _relatively_ safe, but that is a completely different scale. I'm sure that the design and manufacturing of a motor that big will be a fascinating material to watch!

Great video. Always happy to see your stuff.

Awesome stuff. Great episode. This is the reason why I subbed in the first place. I look forward to more in the near future. Thank you!

"O-rings that climb on rocks..." what now? I'm stoked for this series! I've been on this platform since 2006 and have been looking for something like this content the entire time. I loved watching Codyslab's rocket motor series but he didn't take it all the way to space.

I have been (im)patiently been waiting for this video. Bravo sir. Excited watch and rewatch this series.

YES, caught a BPS vid early! I've made a few rough designs for rocket candy motors before, but nothing this complicated and deadly. That igniter is very clever, that was an issue with my motors. Very glad it fired off well, and let's hope the next one works!

SPACE IS THE PLACE BABY

This is great, there is so little video content on the design and manufacture of solid rocket motors, I've been learning as much as I can about it the last few years and have just started making my own motors, I finished a much smaller J270 a few weeks ago. Making APCP motors is surprisingly complicated for such a simple concept, the number of things that can go wrong is quite high, I've blown more casings and nozzles up than I'd like to admit lol. The biggest thing for me was getting the right surfactant to let the gas bubbles float out when casting under vacuum, Isodecyl pelargonate sure makes life easier, porosity will cause you no end of trouble, and getting the right mesh sizes for all the dry chems is imperative. I'm looking forward to the next video!

This is awesome 😎 you are a legend 💪 I have been following from the beginning and it's so inspiring, keep going, never stop!

This is awesome Joe! Years ago, I tried making some G-class motors with a rock tumbler. Your process looks a bit more methodical, and bonkers. Best of luck!

Thanks for the amazing videos love them and great hype to carry on in 2023 as well ❤❤❤

To me it's just magic how one could possible calculate that kind of stuff. But I'm happy those people exist and show us the result of their work.

That was so interesting, thanks for sharing your work with everyone

Its the coolest thing seeing you and this channel evolve!

Finally 😃. last week i destroyed the egg pan trying to make solid rocket propellent . It was fun actually😅. Appreciate your work by the way. Its good to see you on a exiting project

This is an absolutely bonkers scale project! Fantastic work.

Thanks for making such great videos, these videos becomes inspiration for us youngesters, how amazing and beautiful the world of science is, and encourages us to work more to achieve our goals!!!❤

One day this man is gonna make a makeshift spaceship and make a video from space

Super happy you did this video!!

I just poured a 77% O for our 25k competition rocket a couple days ago! Very interesting to see all the ways we are similar and different. Good luck!

"O-rings that climb on rocks" 😂 loved it Edit : actually there where many more joyful side notes which all together made my day.

This was a fantastic video - loved it. Great stuff.

So excited for this series!

Love this content and the quality sponsors too. Always excited to see your new videos! Hopefully you are able to go higher than 100km, though curious if there is an altitude limit for hobby rockets (to avoid some of those low hanging satellites)?

Great info, thanks for sharing! I hope the space shot is a success.

Good to see new adventures and to see you back. You might want to consider a "wagon wheel spoke design" for the grain as that will maximize area of propellant. I worked at a startup, long ago (in the '80s) that had a solid propellant (pretty good Isp) known as polybutadiene mixed with carbon (pressurized helium pressurizing LOx sprayed into each spoke of the wheel). As I recall, we had a 12 spoke design. (ref: "AMROC|Know Your Rocket" - which later became SpaceDev, then became the solid booster for Virgin Galactic ). Your design is very close to that design, minus the wheel hub.

Awesome video. Thanks to you, I now have the confidence to build a 100 lbs solid rocket booster for the first time alone in my garage.

Wow, blown away by the leaps and bounds you're making on your journey past the Karman line!

I've been waiting for this!!

Looks awesome. Looking forward to the future videos.

Awesome video! Excited to see more

You're absolutely brilliant - Keep up the good work.

I'm excited for this!!!!

Love your stuff. Keep up the great work!

Very detailed and in-depth. Happy engineering!

You are a reason why KZfaq is amazing !!!!!!!!

Thanks for the video. I’ve just recently finished a motor build myself and did not know about open motor. Will be a great resource, any extra information is a step towards a safer test.

Incredible intro. Cannot wait for part two.

Im am making a scientifically accurate space craft in a 3d software and these videos have helped SOOO much since i am no where near qualified to make the judgments for what numbers to use or actually get test on the field for accurate data

Nice 👍 learning lots, thanks

You guys are amazing. Keep up your great work.

Superb (series of) video! In your "discalmer", you talk about being "afraid" of your construction because it's dangerous! I would say rather that in this type of practice have a look not "fearful" but "respectful" (yes we take risks but we know them and we are aware of them and we act accordingly). Mistakes with this type of thing can be deadly. Safety rules MUST be followed almost fanatically. Another detail in this type of practice, one of the basic rules is: "When" it goes badly not "If" it goes badly

Great introduction to small-scale solid rocket motor design and development. And thank you for the information regarding cherry limeade! I have never heard of the MIT team that formulated that rocket propellant. Sounds very interesting from my preliminary search of this solid propellant formula.

This will be very useful, thanks!

10/10 tutorial, got an engine built over night, testing tomorrow. wise me luck.

your work is just insane, man! :)

What a wonderful work Keep going❤😮

Super interesting, can't wait for the future videos! I hope your lathe survived the graphite nozzle 😬

18:50 - Best line in the video. XD Jokes aside, this is a SUPER interesting look into the design process of Simplex. I'm looking forward to the next episode!

You are very right about a lot of the safety. You should be scared but not to the point where you can’t do any work. You shouldn’t be too comfy to where accidents happen. Took me a little to find that balance. It’s always be aware of what can go wrong and keep it at the back of your mind. First time I made propellant for HPR motors I was a on edge. Second batch, not as much. Then I made my first commercial motors. When I knew what and who they were for, I was shaking and didn’t sleep lol. But 3rd batch in, I was fine. But I knew the risks. Can’t wait to see your rocket fly! Good luck!

10:00 "I'm sure.. sure.... sure.........." In my 68 years I have found that when someone says "I'm sure" what he actually means is "I don't know, but I hope to God that..." :=) Very interesting video, Joe. I stumbled on it by accident, and I wouldn't say I understand all the points, but I enjoyed it.

really appreciated and really needed

Just awesome! Great job!!!!!

Absolutely great vid

Oh this is gonna be a cool project!

Thanks for the tutorial video

Very nice, keep us informed!

As a Palestinian, I find your content super exciting!

Explained really well 👏👏

Thank you so much for sharing all of this with everyone. And as always the quality is top notch. Quick question, what material do you use for O-Rings ?

NEW BPS VIDEO GO GO GO

Useful message, thanks

This is the best channel on KZfaq.

Nice video! Excited to see the rest. When are these planned to be released?

Well May I just say I am here for this. All of it.

10/10! Keep it up bother!

love it! And i also wonder what should ever go wrong when casting ;)

Thanks for the tutorial bro. I’m gonna go build a rocket motor now.

Normally i skip ads/product placement, but the onshape ad actually caught my attention. I run Linux, and can’t be arsed to dual boot. So cad stuff has been kinda out of the picture for a while.

Wow, you never cease to amaze, What a lot of knowledge you are gaining. BTW what did you think of Starship?

great video... commenting to support!