Rocket Engine Test Stand Pressure Regulation

[@CopenhagenSuborbitals]

We hope get back to the regular production/manufacturing and testing video content soon, but let us know if you would like to see more of these concept videos in the future as well!

[@ndanilo]

Oh yeah! bring us more!

[@anybody108]

That kind of videos are also really interesting and instructive, in my opinion you should continue to produce them!

[@minties01]

Definitely a fascinating video, love these ones. Wondering whether the hot nitrogen gas does bad things for your Lox boiloff though? Perhaps it's for such a short period that this doesn't matter though.

I think it is great are allies are endevering to push forward there rocket/ engine exsperimental concepts. They are the dark horse that makes the brake though from out of no ware. I think one of the countries like Sweaden, Norway , and Finland have come up with a cammeoflag blanket you put over a tank or truck and the Russians would think they are looking at a small car. I think this is achieved by bending the light with Nanoe tecnology. Nice to have them on the team.

[@ptonpc]

Definitely

[@_tyrannus]

I will come back to criticize your design, when I see another crowd-funded organisation manage to get their own engine above 200sec ISP. ^^

[@youkofoxy]

200 ISP is pretty low for today standard. Still, not bad for a fist attempt rocket engine.

[@CopenhagenSuborbitals]

200s ISP is certainly low by todays standard in rocketry. Heck, it is even low for 1960’s rocketry. CS has never aspired to develop efficient rocket engines. We develop extremely cheap rocket engines. In order to do that we accept a significant performance penalty. The only way to get much higher than the 200s ISP mark is by using (turbo) pumps and then complexity and price really starts increasing. It is important to keep in mind that we don’t need the performance that launch providers need since we are not going orbital. We are “only” going to 100 km altitude and the energy requirement for doing that is substantially below that of any LEO.

[@_tyrannus]

@@CopenhagenSuborbitals Hell, you can get to orbit on 200s ISP, at least in modded (Realism Overhaul) KSP. It just takes an absurdly large rocket to do so.

[@BartJBols]

@@CopenhagenSuborbitals You could get orbital with that, just add more boosters.

[@brians8799]

@NABIL Iben sobih Self-pressurization is quite hard to control and adds complexity. Also, N2O is very low performance and will destroy the isp even if there's a higher chamber pressure.

[@monochrome82]

Thank you for another great video. Blender's Eevee is also a great way to visualize it. Looks great.

[@DylanEdmiston]

This great, please create more videos like this. I have a question though. Are you using liquid nitrogen because you cannot get enough volume to the fluid and oxidizer tanks from the gaseous nitrogen? Or are you doing it because liquid nitrogen will take up less room when in the rocket?

[@CopenhagenSuborbitals]

Glad you enjoyed the video, Dylan! Housing enough (60,000 standard liters) of gaseous nitrogen means it needs to be stored in high-pressure bottles, which are not only expensive but also add a lot of weight to the rocket. So bringing nitrogen as a liquid saves a lot of mass (we'll only need to store 30-50 liters) and is a lot cheaper for us, as we can manufacture the heater and heat exchanger in-house, compared to ordering high-pressure bottles from a manufacturer.

[@shakaibsafvi97]

Hi Copenhagen Suborbitals Team, I'm part of a small Company with a staff of about 125 people. Mechanical Works: Mechanical Design Team, CNC Sheet Metal Works, CNC Machining Center, including a CNC Turning Center, Welding Workshop and a Powder Coating Unit Electronics: Embedded Control Systems Design, Telemetry and Telecom Systems and Electronics Power Systems Design Software: Embedded Linux, Web Applications Development & Database Architecture Let me know if there is anything that you need done.

[@TJ-up8vj]

Yes! These concept videos are fantastic, they really help build up the back stories to what you do, and it's not just slapping things together and it all works. Good job guys!

[@CopenhagenSuborbitals]

Good to know, thank you!

[@tomasberger9980]

It looks very typical for simple rocket engine actually. It is very similar to V2, A-6 etc

[@rorypenstock1763]

I was just thinking the same thing.

[@gesamtszenario]

The V2 had a ridiculously complicated turbo pump, though. Some of von Braun's engineers used to joke that that the whole machine is basically an expensive pump with a metric ton of explosives on top. I wonder if the V2 would have benefited from a similar, much simpler, pressurized fuel system. Thankfully (for the people of London) we will never know.

[@mishkamcivor409]

Is a nitrogen generator like that going to be used in the rocket or is that just for the test stand? It's a pretty cool idea

[@CopenhagenSuborbitals]

It is going on Spica as well, if we prove it works.

[@brunofporto]

@@CopenhagenSuborbitals Nice! Less complicated than pumps! And could be even lighter if compared to all Helium/N2 pressurize system or ePumps for the low pressure engine.

[@CopenhagenSuborbitals]

@@brunofporto Definitely lighter (and cheaper for us) than storing all the N2 aboard the rocket, in fact that's the reason we came up with the idea. Though questionably lighter than electric pumps, especially when you factor in the weight savings from thinner tanks and lesser fuel requirements that come with a pump fed engine.

[@brunofporto]

@@CopenhagenSuborbitals true! I forgot the tanks and tough only about the batteries! :D

[@johndododoe1411]

@@CopenhagenSuborbitals How is liquid N2 lighter than gas N2 ? Sure the LN2 tank will be smaller and lighter than big 20 bar gas tanks, but the N2 itself weighs the same at any practical pressure.

[@ebrahimchalhoub9313]

Wait, you use blender for CAD or just to visualize the work.

[@CopenhagenSuborbitals]

Just to conceptualize. For that it's faster, for the actual project design we use Solidworks.

[@olsonspeed]

Excellent explanation of the engine design, the graphic was very helpful and well done.

[@CopenhagenSuborbitals]

Thank you for the feedback!

[@tigertalar]

Doing a great job there of showing rather then telling. Flames down pointy part up.

[@jmspaceR]

You're right!

Nice job and good description. It was clear to me how you want to pressurize the propellant tanks, also the purge system, all with Nitrogen. Many thanks and keep going!

[@ges7991]

Very Cool. Great to have the components and systems explained. Well done!

[@CopenhagenSuborbitals]

Great to hear, thank you!

[@keatonroe7559]

How are you planning on chilling/filling your propellant tanks? And from what source? Will you do an initial engine chilldown?

[@keatonroe7559]

The concept videos are awesome!

[@spencerlittle6931]

Great Question! Id Be interested in hearing how they do that too

[@johndododoe1411]

In all their previous designs, the tanks are left at whatever temperature pumping in the liquid propellants leave them at. I hear that SpaceX gains less than 3% by superchilling the tanks, so almost nobody else bothers to do that. LOX, N2 and He storage tanks may have some cooling to stay liquid for days of transport, but this diagram only shows the (rearranged) rocket tanks and the bootstrap N2 bottles that will probably remain on the launch platform.

[@keatonroe7559]

Not so much interested in the over chilling. I mean that prior to filling the tanks, do they ramp down the flow rate if propellant to 'chill' their tanks down to near propellant temps to minimize boil off during the fill procedure. And if they are chilling the engine, where is the cryogen coming from ? Is it draining from the tanks or do they have a specific chill system

[@DelBast9249]

Thank you for this new video ! I imagine that there will be some delay between the moment the sensor detects a drop of pressure in the tank and the reaction of the pressurizer (burner), it would be interesting to have some informations about the PID control and the way you will adjust it.

[@SciFiFactory]

I would also like to see that :)

[@hansmarteau3110]

The ethanol and LOX will be injected in high pressure in the chamber by nitrogen if there’s no pump is it that ?

[@CopenhagenSuborbitals]

Hans Marteau yes

[@cantsolvesudokus]

I don’t know how severe, or likely, a catastrophic failure would be, but making that blast wall angled at an V shape and weakening the containers walls and roof around the blast area would direct any unexpected release of energy in a more desirable way i think.

[@howardbartlett3419]

Coming from an aerospace engineering student who has built a few small liquid fueled engines, I think that it is a wise decision for you guys to run at a lower pressure than professional engines. Not only does it reduce the need for exotic materials in the engine to deal with the pressure and heat production, it also allows you guys to use a much simpler fuel feed system that makes the vehicle much more feasible with your given budget. Props to you guys and I can't wait to see this thing launch someday.

[@eaofdeath187]

Are you planning to fire it with all container doors open or just the back doors? I'm a little worried about creating a venturi and the high speed airflow though the container reducing pressure enough that it caves in.

[@PauloDutra]

Nice! Very inovating system! I like it!

[@tanaes]

Wonderful as always! In the last video, you mentioned using the other half of a 40 ft container as a mobile workshop. Did you decide to scrap that plan? It's definitely easier maneuvering a 20 footer around. :)

[@nachocortizo3321]

Really cool to see those renders of the test stand! Super stoked to see what's next!!

[@AirCommandRockets]

Very nice update. Good to hear the methodologies behind the different systems. Will the start up nitrogen pressurisation tanks be on the rocket or will that be in the launch pad?

[@buraqaerospace9945]

What if there is is a Cato while testing Hope that never happens

[@CopenhagenSuborbitals]

We talk about safety precautions like the blast wall, the container shell as well as sound and fire suppression system in our previous video: kzbin.info/www/bejne/hHmrg4J8g5V-ick In term of crew safety, everyone would be a large distance away when pressurization starts, of course.

[@buraqaerospace9945]

@@CopenhagenSuborbitals thanks for your valuable time

[@inex4431]

@@CopenhagenSuborbitals thats so cool!

[@srenkoch6127]

Well considering that they have always run tests with huge concrete barriers between rocket hardware and any 'wetware' in the worst case scenario for the test stand is that it will be reduced to scrap and and they get no video of it. Slightly better outcome is they get some glorious high speed video like the one from the famous GoPro Hero 3 camera which sacrificed itself to document the failure of the HEAT-2X engine :-) Best case of cause is 'no boom' but lots of shock diamonds :-)

[@yokowan]

wouldn't it be possible to significantly simplify the plumbing by running the heat exchanger off of some some sort of monopropellant gas generator? you're already packing a separate fuel for it with the dilute ethanol, so using a catalytically decomposed monopropellant instead would save you a great deal of complexity, and they generally run a lot cooler, so temperature management is less of a concern. nitrous oxide seems particularly attractive because it's completely self pressurizing, so you don't need an additional system to keep it at pressure. in case you haven't already looked into this (or someone else trawling these comments is interested) there's some great research done by stanford that outlines it all pretty well web.stanford.edu/~cantwell/Recent_publications/Lohner_Scherson_JANNAF_2008.pdf

[@AirCommandRockets]

I wonder if the same could be achieved with solid propellant which could be even simpler. Though once lit, you don't get to shut it off. :)

[@jnielsen20]

Also a possibility, although two phase flow and abrasion could be potential issues.

[@johndododoe1411]

@@jnielsen20 Solid propellant with regulated LOX flow could be a solution. As only heat is desired it'll be a lot simpler than their actual hybrid rocket engines (HEAT 1X series). Basically like a fireplace without the aesthetics. To refuel, open a lid and throw in some coal or pellets. Cleaning of heat exchanger will be harder though..

[@willywgb]

Good job. Really enjoy the amount of detail in your videos. One sugestion would be to make your cursor larger (if possible) so it's easier to follow. Cheers Willy

[@CopenhagenSuborbitals]

Thank you! I'll pass that on if we do more conceptual videos like this.

[@archangeblandin676]

I guess not having to deal with 70 bars makes it a lot safer too.

[@Apollo-16]

Ever think of using an aerospike? Great video as always.

[@CopenhagenSuborbitals]

Apollo 16 only on april 1 :-)

[@pynbiangborlanglyngwarapth77]

Thank you this is a great video....

[@johnashcroft8355]

Great project, really interesting to see a pressurised liquid rocket system. An interesting pressurising system but could you give some more info on alternatives such as blow down or helium And why this is better? What is the estimated mass of the system going to be? Mass of the system? Total, fuel mass, and presurant mass. Have you thought of using a "Hot water rocket"? If you drop me and email I can share some thoughts on how this may help make a simpler system.

[@low-keyforce7204]

What if instead of the mini rocket engine, you pass the liquid nitrogen through the main engine, not only will it help with the cooling of the engine but the heat absorbed by the nitrogen while flowing through the walls of the nozzle will heat it up enough so that it turns the nitrogen into gas, you can then use that nitrogen to pressurize the tanks. This process will save you a lot of weight and will increase the efficiency.

[@CopenhagenSuborbitals]

There are definite benefits to that approach, since there is a lot of available heat around the engine. But it also complicates the engine design and production. Such a system could also only be tested by firing up the engine, whereas a system that runs on a separate burner can be tested and validated on its own. Furthermore, we will be testing an electric fuel pump from Orbital Machines on our BPM100 engine and we'd like to easily interchange between the two systems, so for these reasons we have stayed away from running LN2 through around the engine. If you're interested, more on the electric pump: kzbin.info/www/bejne/Y6a4Y6pooN6Nn6c

[@hafizuddinmohdlowhim8426]

How much power the turbo pump will generate?

[@CopenhagenSuborbitals]

The system we talk about here is not a turbo pump. It's a burner (small rocket engine) plus a heat exchanger. This burner will generate about 0.5 megawatt of power. But if you are referring to the electric pump by Orbital Machines which we will also test on our BPM100 engine (kzbin.info/www/bejne/Y6a4Y6pooN6Nn6c) then the electric motor running that pump is 150 kilowatts.

[@jagdishahire8104]

Which software do you using for design can u tell us plz?

[@yokowan]

in the last video, he mentioned that he's using blender

[@CopenhagenSuborbitals]

Yes, it's blender, but just for these conceptualizations. Actual project design is made on Solidworks.

[@olivergledhill8668]

How big will the liquid nitrogen tank be and how much gaseous nitrogen will this produce ?

[@CopenhagenSuborbitals]

We'll need around 40,000 liters of gaseous nitrogen to pressurize the tanks throughout the flight and we'll get that from 40-50 liters of LN2. Test stand tanks will be smaller as it will run for shorter burns.

[@olivergledhill8668]

@@CopenhagenSuborbitals Will there be a weight penalty going down the heat exchanger LN2 route rather than carbon fibre tanks ? Or is it a cost issue the carbon fibre tanks being very expensive ?

[@CopenhagenSuborbitals]

@@olivergledhill8668 Not at all. Going the COPV route is both very expensive and very heavy. Using this LN2 burner we save a lot in mass (2-3x, if I remember correctly) and a lot in expenses. The only penalty is bit more complexity.

[@AirCommandRockets]

@@CopenhagenSuborbitals At what temperature does the Nitrogen enter the LOX tank? How fast do you think it will cool inside the tank reducing the effective pressure?

[@olivergledhill8668]

​@@CopenhagenSuborbitals Rather than gaseous nitrogen would using oxygen to pressurise the tanks be more complex ? Or even possible ? Would gaseous oxygen pressuring a fuel tank be a seriously bad idea ?

[@juliankandlhofer7553]

What sort of education is needed to be able to apply for a job or an Internship with you guys?

[@CopenhagenSuborbitals]

Julian Kandlhofer we’re not a company, so we all volunteer in our spare time. Mostly, we need people who can weld and work in a metal workshop. So if you live in or near Copenhagen, and have some spare hours every weekend that’s a good starting point

[@jhwblender]

Man I wished I lived close enough ❤️ You guys are awesome!

[@CopenhagenSuborbitals]

@@jhwblender We appreciate it, Jesse!

[@hafizuddinmohdlowhim8426]

What CAD software do you use to make this test stand?

[@CopenhagenSuborbitals]

We use Solidworks for actual project design. This preview was made in Blender.

[@zapfanzapfan]

It seems like a lot of extra complexity compared to "just" using a 200 bar nitrogen bottle for pressurization. Are the weight savings that large? A natural gas tank from a retired flex fuel car could be an alternative to a regular gas bottle. Edit: Or do you plan to use the exhaust from the burner for roll control so that you want to keep it for that reason?

[@CopenhagenSuborbitals]

We'd need 11 of those 20 liter, 300bar nitrogen bottles for Spica. And the total mass of such a system would be around 350 kilograms, whereas the gas burner system would weigh in at around 100kg, so it is a significant difference. Roll control will likely be via thrusters fed by the same nitrogen as the propellant tanks.

[@zapfanzapfan]

Hot gas thrusters, cool! Thanks for answering.

[@NikhilVerma_TstyBns]

Are you going to have a load cell attached to measure thrust generated during testing? If so just curious how and where you attached it on the test stand. Great work btw

[@CopenhagenSuborbitals]

Yes we are. You can see that in our previous video on this test stand design. The load cell is shown at around the 2:20 mark: kzbin.info/www/bejne/hHmrg4J8g5V-ick

[@NikhilVerma_TstyBns]

Ok thanks just checked it out and looks great keep up the good work!

[@HaraldSangvik]

What would be really cool would be to run the exhaust from the heat exchanger into the motor, like a staged combustion. One can burn up the rest of the carbon in the exhaust that way. Probably a plumbing nightmare for a very small benefit though

[@tigertalar]

Fuel feed pressure prolly needs to be higher than inside engine

[@HaraldSangvik]

@@tigertalar That is always a reqirement :)

[@markhatch1267]

This is really cool. Just discovered you. I have become interested in what amature groups are doing in high end high power rockets. I just learned more about rocket engines in ten minutes than I have in the past ten years. Thank you for being so willing to share how you do everything.

[@CopenhagenSuborbitals]

That is really great to hear, glad you dropped by! If you've learned a lot in this video, wait until you dig through our archives! We are a crowdfunded project, so sharing is what actually allows us to do all this.

[@alexanderzayarny4872]

Can you run all 3 (liquid nitrogen, lox, fuel) tanks on the same pressure line? initially pressurized with helium. This way only one heat exchanger needed and 3 times less control components? May be add some check valves to ensure liquids don't mix...

[@agtovrgs5607]

What is the cycle which best fit in this set up. Gas generator? It would be consider a new cycle?

[@Rasmus0909]

It resembles a pressure fed cycle the most.

[@Ameliaross106]

Great video

[@karma-xv1fd]

whats the price of that engine ?

[@Vishnu-nz3qk]

Why not use the tapoff heat from the engine for the heatexchanger instead of using a seperate burner and ethanol tank

[@CopenhagenSuborbitals]

That is a great way to do it, certainly more efficient. It is however much more complex as the pressure of the tanks is then dependent on the heat you tap of from the engine and the only way to test that is with a running BPM100 engine. Separating the burner and the BPM100 engine we can develop, test and fine tune the hole burner and pressurization system completely separate from the engine. Thus for the very first BPM100 test that system can already be fully developed.

[@lewismassie]

Interesting point about the low pressure engine. I kinda assumed that the unusual shape was due to the flat plate for all the injectors being easier to manufacture

[@jamesperzinski1733]

i see you on a lot of videos i see and cant help but ask, have you played space agency?

[@lewismassie]

@@jamesperzinski1733 Yep

[@ndanilo]

wow! I'm loving this! I question myself.. Why not use a closed loop? is it more expensive or not worth it?

[@Rasmus0909]

If by closed loop you mean closed cycle, then yes, it can be boiled down to being more expensive.

[@PederSkyt]

Copsub intends to upgrade to an ELECTRICAL turbopump being developed by a Norwegian company - watch kzbin.info/www/bejne/Y6a4Y6pooN6Nn6c (the description has a link to the company's website). Copsub gets to test/use the pump for free. To allow the nitrogen high-pressure system to be easily replaced by a turbopump, the feed system must be an independent "component", and not be integrated into the engine design.

[@ndanilo]

Thank you guys for the reply😁 and yes I meant closed cycle😅

[@patrichausammann]

I've got some questions. What are you doing about icing at the valves? Are those valves "simple" magnetic valves? Do you control them by fast "switching" to limit the throughput. I hope these questions will be answered in the next announced video.

[@CopenhagenSuborbitals]

We actually have a very interesting valve project going on at the moment. It won't be in the next video yet, but coming shortly!

[@patrichausammann]

@@CopenhagenSuborbitals 👍

[@DragonsAndDragons777]

When do you plan to launch the rocket when it is manned?

[@CopenhagenSuborbitals]

When we are comfortable enough. Hopefully within 10 years

[@kingreece903]

This is awesome

[@angelleal3005]

What kind of software you use for such renders ?

[@CopenhagenSuborbitals]

This was made in Blender whic is free and open-source, but this is purely for conceptualization. For design work we use Solidworks.

[@steve000023]

I don't follow you since long time but I'm big fan of your project. How about liquid Co2 instead of the LN2 preburner ? You can give it the more heat you can on the co2 tank before the starting, since the heat/pressure relation stop at 73 bar(a) (30°C) and goes to supercritical phase. Supercritical co2 is widely used in refrigerant system. Maybe in this way it's possible to get rid of the LN2 preburner. But the co2 tank will cool down when the pressure will drop maybe it will need a system to reheat it. Also it's probable to heat a bit the LN2 tank before as well of co2 and keep the system like it is. Valves used for refrigerant can be useful (high pressure up to 120 bar, available and costless) and PWM and modulable valve is available (eg : Danfoss AKV / CCM)

[@diotough]

Am I correct in assuming you're going for LN2 as the pressure medium because you can actually store it in liquid form whereas LHe would be at

[@CopenhagenSuborbitals]

You are right on point! It's mass and cost reduction. Large, lightweight high pressure tanks are quite expensive and we would need nearly 70,000 standard liters of Helium onboard for the flight, so storing all that at 300bar in COPV's as we did with Nexø I and Nexø II is a substantial penalty. We actually have a blogpost with more details on this choice: copenhagensuborbitals.com/bpm100-dpr/

[@diotough]

@@CopenhagenSuborbitals Well, this makes me reevaluate my tank choice then. I'm wondering if the excess heat of the engine could be used to heat up the nitrogen to turn it into a gas, but then again gaseous nitrogen probably doesn't cool that well so you'd still need to have the LOX cooling the chamber probably. It could probably be done with an heat exchanger though. Maybe with some potassium or sodium heatpipes. P.S.: thanks for the article by the way, I've just realized I failed to account for the volume loss due to depressurization of the Helium so I'd need ~1.5x the amount of Helium and therefore 1.5x the size.

[@CopenhagenSuborbitals]

@@diotough You could definitely heat the LN2 by running it through the engine, but that complicates engine design and production. So as always, one needs to weigh all the pros and cons.

[@jungleb]

What an amazing video. Thanks for sharing, it's was super clear! Will definitely donate to the crowd funding!

[@CopenhagenSuborbitals]

Great to hear! And thank you for donating, it is our rocket fuel and what makes everything possible!

[@awelder4040]

You need to use a type of turbo pump for your main fuel and Lox pressurization, there are a few methods to manufacture a inexpensive turbo pumps... The efficiency of your engine would be so much higher... :)

[@Ray_Getard42069]

Could you guys please make a video about the legal logistics of planning a manned flight to 100km? I'm very interested as to the implications for other civilians building spacecraft and launching.

[@zyxwvutsrqponmlkh]

Make sure you have good check valves feeding the oxygen. Lots of accidents happen when pressurized oxygen finds it's way into unexpected places. Solid rockets are all 'pressure fed'. I have always wondered why there were no serious pressure fed liquid rockets, I have to believe they would have better isp than a solid and should have a better mass ratio too after a certain point as the tanks don't need to support chamber temperatures. Kinda sad your not using LNG, if you already need one cryo system why not two. An electron knockoff may be the easiest way to go these days.

[@hafizuddinmohdlowhim8426]

Hello I am one of your contributors. May I know the calculation how many Nitrogen is needed for your rocket engine thrust requirements?

[@montage1926]

[ ] Why did you guys heat the nitrogen with the heat exchanger before using it to o pressurise the propellant tanks, why didn't you use the helium to pressurise the propellant tanks like you did with the nitrogen tank. Another question; why didn't you guys just use the nitrogen to cool the burner, that way the engine gets cooled and the nitrogen gets heated and you wouldn't need a heat exchanger

[@SteveSiegelin]

You know what kind of sucks is I've been following the space race since I was a child , I followed every space channel on KZbin since most of them had started but I had never found your channel until a month ago!that saddens me but the fact that I found the channel now extremely extremely excites me. Good luck guys I want to see this thing fly! PS I built a little rocket motor before using electrolysis but electrolysis cannot sustain the combustion and my nozzle exploded. I've seen firsthand the power to these motors put off and I cannot wait to see what you guys end up creating.

I need to check it out later. But Elon would keep it simple right?? I do think that what ever gives you a unadulterated, precise, messurement and hopefully easy to operate (instillations, in and out) would be good.

[@joshuabarosin779]

Heat exchanger makes sense. You could have also done something similar to the RL-10 when the fuel runs the heat exchanger after going through the engine. Then again it also make more sense to use a turbopump.

[@mmb3006]

Hey so is this going to be used only for the test stand or is it also going to be used on the rocket because if yes why not just use autogenous pressurization with gox and I think you're using ethane so g-ethane? wouldn't that make the system lighter and more efficient plus what you're doing with nitrogen could also probably be switched to lox and ethane with a few tweaks to the design but I know that you're limited on the budget and nitrogen is probably just the cheaper way. (sorry for the long comment)

[@Muss_._]

hi, i very like your project, and i think i want make diy for my learn and knowledge,but i don't know how to do. 🥺.Teach how to make engine rocket like real rocket.Can u teach me?😢

[@גבריאלפאלקאו]

Wouldn't run the nitrogen through the casing of the rocket to heat it be more lightweight, instead of making it a regenerative cooled engine with a different system to pressurize it? Wasn't it capable of heating the nitrogen enough or did you face other problems with that? Genuine question here, since it seems to be an enhanced pressure-fed engine.

[@CopenhagenSuborbitals]

There are definite benefits to that approach, since there is a lot of available heat around the engine. But it also complicates the engine design, its production and makes it more expensive (we are a crowdfunded project with a shoestring budget). Furthermore, everything we've learned about engine cooling with ethanol on our BPM5 engine would be thrown out the window and would require essentially a new R&D phase for LN2 cooling. Such a system could also only be tested by firing up the engine, whereas a system that runs on a separate burner can be tested and validated on its own. And lastly, we will be testing an electric fuel pump from Orbital Machines on our BPM100 engine and we'd like to easily interchange between the two systems. More on the electric pump: kzbin.info/www/bejne/Y6a4Y6pooN6Nn6c

[@גבריאלפאלקאו]

@@CopenhagenSuborbitals Ah, good.

[@גבריאלפאלקאו]

@@CopenhagenSuborbitals I didn't know about the electric pump until now.

[@kalpanaverma4277]

What's about orbital machines electric turbopump

[@helenlawson8426]

Sorry for this probably dumb question but could you use an induction coil or coils instead of a small rocket engine to heat the nitrogen?

[@stekra3159]

Why are you running the fule down the engine and not the liquid oxygen which should be colder? I think ther has to be some reason for this design decision that I do not know..

[@jnielsen20]

It is not about the temperature difference alone, specific heat and vapour pressure vs temperature is important factors as well. Additionally, phase changes of the coolant will also be important to consider.

[@SciFiFactory]

Heating up the oxidizer could lead to it reacting with the metal or impurities, I think. Basically there is a risk to blow up the engine?

[@CopenhagenSuborbitals]

The LOX is already at its boiling point inside the tank. If you were to run that through the engine jacket for cooling the engine it would evaporate straight away within the first section of the cooling channel. The rest of the channel will then be cooled only by gas which is very poor at exchanging heat with the wall of the engine, at least compared to liquid.

[@Steven7920]

How hot will the gaseous Nitrogen will be exiting the heat exchanger?

[@gabrielhacecosas]

Here's a question from someone who doesn't know anything about these things. But why don't you heat up the nitrogen in the engine itself? or by diverting part of the combustion gases to the exchangers. Is it much more complex?

[@CopenhagenSuborbitals]

It's a fair question. There are definite benefits to that approach, since there is a lot of available heat around the engine. But as you mentioned, it also complicates the engine design and production. Such a system could also only be tested by firing up the engine, whereas a system that runs on a separate burner can be tested and validated on its own. Furthermore, we will be testing an electric fuel pump from Orbital Machines on our BPM100 engine and we'd like to easily interchange between the two systems. More on the electric pump: kzbin.info/www/bejne/Y6a4Y6pooN6Nn6c

[@chrisrussell9346]

Hello this is awesome and was wondering what type/brand of load sensor you are you using for your engine testing

[@samikshamahakulkar1018]

As it is the thrust stand, where is the load cell mounted? Can you highlight this part?

[@adidonlot1245]

nice design,simple and removable container ..

[@royfrancisciron1944]

Is LN2 used instead of gas because you get more nitrogen?

[@cameronbluhm2842]

Is this called autogenous pressurization when the rocket engine is supplying pressure into the propellant tanks? Is this similar to how SpaceX is approaching their Starship design with their raptor engines? Or is this process totally different being the Raptor uses turbopumps? Also what you guys do is very inspiring and I love it, keep it up!

[@HaraldSangvik]

Autogenous pressurisation means using the fuel and oxidiser itself as a pressurant. So this is just pressure fed with extra steps.

[@listerdave1240]

In Starship the tank pressurization is for a different purpose. The pressure in the combustion chamber is extremely high (almost 300 bar) and is achieved by turbopumps mounted on the engine itself. The pressure in the tanks is less than 10 bar and is just to ensure there is enough pressure at the inlet of the pumps to prevent cavitation. The other difference is that rather than using nitrogen to pressurize the tanks they use the fuel and oxygen itself and that the heat exchangers are heated by the hot gases from the preburners rather than a separate burner. The meaning of 'autogenous' in the context of Starship is that the pressurization is provided by the engine itself rather than a helium tank or some other separate system, so in that sense the Copenhagen system would not be called autogenous since there is a separate distinct system generating the pressure for the propellant tanks.

[@anupranamagar5276]

can-you-describe-through-animation?

[@duanemerrill7248]

Do you have a video on the propulsion sensors and instrumentation?

[@SergKiev87]

You have a preburner and you using it just to pressurise main tanks?

[@kabirkhan4543]

👍👍

[@milkdrinker7]

Are you at all open to the idea of one day using turbopumps or is that pretty much out of the question?

[@CopenhagenSuborbitals]

We will test an electric pump from Orbital Machines on the BPM100: kzbin.info/www/bejne/Y6a4Y6pooN6Nn6c There are some in-house turbopump projects in the skunkworks as well, just not enough time to work on them recently. Also not much to report on yet.

[@milkdrinker7]

@@CopenhagenSuborbitals thanks for getting back to me! As always, your progress is exciting to watch :)

[@CopenhagenSuborbitals]

@@milkdrinker7 You're welcome!

[@MaximumMatador]

Awesome video! Please keep making more!

[@quaidbergo]

It's like pressurisation Inception.

[@brunofporto]

Please point the burst exhaust of the propellant tanks to different directions :D Nicely done as always.

[@wespacewalk]

Since the fuel is liquid, does it matter? :)

[@brunofporto]

@@wespacewalk of course! If the fuel touches any high temperature or sparking thing it will burn as it will be mixed with the air outside. The LOX is no issue, but the fuel line need to be direct to some safe drain - even the dirt outside.

[@jnielsen20]

The burtsdisc is located in the top of the fuel tank. The tank is pressurised with nitrogen and the vapour pressure of ethanol is not problematic at temperatures less than 50 celsius. I fail to see how the fuel will be sprayed outside the tank unless there is already an ongoing fire on the teststand.

[@brunofporto]

@@jnielsen20 true... I tough about that AFTER the comment :D

[@SteveSiegelin]

So you only have 230 lb of thrust?

[@wyattb3138]

Did you go to college to learn all this?

[@albertomourao4443]

Good job and explanation! What is the ignition method of the main engine and the heat exchanger? I deduce that it would be pyrotechnics in the main engine...

[@CopenhagenSuborbitals]

Up until this point we used pyrotechnics, but we're looking into spark plug solutions at the moment.

[@highseassailor]

Fire suppression?

[@CopenhagenSuborbitals]

We talked about it in the previous design video: kzbin.info/www/bejne/hHmrg4J8g5V-ick

[@royramirez3343]

Favorite rocketeers of all time!

[@militaryaeronautix812]

What is its specific impulse , are high energy materials used here ? I AM AN AERONAUTICAL ENGINEERING STUDENT I AM CURIOUS PLS

[@CopenhagenSuborbitals]

Isp is roughly 200-220s depending on the fuel's mixture we will use. It runs on ethanol and liquid oxygen and we dilute the ethanol with water.

[@Miata822]

Clever. This should work.

[@deuce454]

i don't understand the decision to go with an alcohol fuel as its already half way oxidized.. the energy content in aæcohol is much lower that of the corresponding hydrocarbon, ie methane vs methanol.. you will be carrying a lot of extra weight, why that decision and not just LNG ??

[@petermaersk-moller3014]

Handling and burning alcohol is relatively simple and for CopSub a well known process. Alcohol an be stored and transported in plastic containers. An alcohol leak is not that big a deal. Methane on the other hand is far more difficult to handle and require pressurizing for storage and transport. We have little experinces with burning methane in an engine and a leak is a big deal. Storing LNG at room temperature requires tank capable of 320 bars not to speak of a very hot summer day. So if alcohol can do the job, why not?

[@alexandernikolaevich1839]

remind me nazist Vergeltungswaffe-2

[@abhinavsrivastava8457]

does it has a turbo pump?

[@listerdave1240]

No. It is pressure fed, that means the tanks themselves are pressurised with nitrogen and that's the only thing that drives the propellants into the engine. The heat exchanger he described is what generates that gaseous nitrogen to maintain pressure in the tanks as the propellant is expelled.

[@CopenhagenSuborbitals]

No, it is pressure fed. We are however working with Orbital Machines to design and build an electric pump for propellant delivery.

[@Vaasref]

So the nitrogen bank is not supposed to be on the Spica, right ? The fuel tank is to be pressurized before landing and then the line is disconnected once the burner is running. And the second tank pressurizing the burner fuel tank would be on the Spica since it is needed to keep the burner fuel under pressure. Why is it a separate system from the main tanks ?

[@johndododoe1411]

Pressurization gas needs a lower boiling point than the liquid it pressurizes. So He can pressurize LN2. N2 can pressurize LOX and Vodka.

[@DaveRibber]

What is your education? Did you finish some universities or only highschools? How is it in your team

[@CopenhagenSuborbitals]

We have members from university students to PhD's in many various backgrounds and occupations. In order to do what we want to do we need to operate as an organization, not just a rocket club, so our whole team is very diverse. From people in IT, public relations, media or live video production to skydivers, sailors, medics, teachers and of course physicists, mechanical and electrical engineers, material scientists or chemists and so forth.

[@Handelsbilanzdefizit]

Could you increase performance by changing fuel (Ethanol --> Methanol, Isopropanol, etc.)? Or does it need massive changes in your design?

[@theodoremanning663]

Hello, could you not boil the liquid nitrogen by running it through the bpm100 channel wall instead of the fuel or by running the ethanol through the channel wall and then running that hot ethanol around the nitrogen heat exchanger?

[@CopenhagenSuborbitals]

Yes, but the plumbing would be a nightmare

[@theodoremanning663]

Ok, thank you.

[@AmiraliTaghavi]

Hi, I really like what you're doing it is a dream comes true, but why I can't see any calculation or simulation, the error in flow rate of the combustion chamber nozzle could have been avoided by some calculation or in best case some CFD simulation with free softwares like OpenFoam !. Good job keep going.

[@jnielsen20]

What error are you referring to?

[@pedrovelazquez138]

Really,really cool video! I´m learning so much from you and I thank to the amazing work that you are performing. I hope I´ll build a rocket engine in the future here in Paraguay. You are bringing oportunity to learn in lands that are not english-speaking or technologically developed. I congrat you to simplify the analysis for us. Big thumb!!

[@yogimarkmac]

So any nitrogen condensate in the LOX tank will just float on top?

[@CopenhagenSuborbitals]

Engine will operate for 60 seconds. Very little nitrogen will condensate during this time.