Great work guys!! It makes the SpaceX stainless steel tanks' 8,5 bar totally wimpy. I must confess to grinning when you were getting anxious at the first test 😁
@@freakysteve140281 Don't forget that the real ones shoot flames. Operator safety is maintained by the rocket either burning fully inside the tube or having a boost and sustain phase where the sustain is only activated after the missile has travelled a safe distance.
If it is posible to avoid two different matirials being applied by these extreme loads, than it might help to shift the delamitantion cracks to higher pressures. I think, that even a little bit of difference in elasticity of materials can cause unwished weakening of the structure.
You guys should look into the concept of designing a second stage chamber, with effervescent tablets or tums and cola. Perhaps will eliminate the need for as much compression? I dunno food for thought. Either way I believe it'll create additional thrust
The edited videos are quite fine, and they compress the time involved into something very watchable - it'd just be educational to see what real-time progress is like in a live stream, and have the opportunity for a question/answer session.
Get a mirror which you can mount in your doorway when doing pressure testing. That way you can get eyes on without being in direct line with the pressure vessel. RE. the tape, do you need the tape to extend to the end of the vessel? Or could you have a section of tape missing where you plan to cut the tube to length? That way you avoid having the tape in the location of the join with the end caps
Not a bad idea with the mirror. I think that would work. Yes, the tape will now not extend into any part of the end cap joint and will stop a centimetre short.
So question...you're already using a CF tube from Soller Composites as the final overlay...couldn't you also use the CF tube as the first layer as well and eliminate the tape altogether? Also, I've seen some people using Sollers heat shrink tubing as a wrap-layer over the final product to achieve a glass-like surface and, they claimed, also help ensure good resin penetration. I'm curious what your thoughts are on that part of a process given all your experience and knowledge thus far on your projects?
Good questions Josh. In fact we did that first, we used a sleeve for the inner liner, but as you can see in part #14 ruclips.net/video/sG-YXnAGYdU/видео.html we ended up with a banana. Here is an explanation why: ruclips.net/video/I7i8ELEF3ro/видео.html and so to fix it we now use this process. We looked into heat shrink tape to compress the pressure chamber a bit, but this would leave a spiral ridge on the surface that you would then have to sand out which is a lot of work. You would need to put the entire pressure chamber inside the heat shrink sleeve to get a smooth finish like soller sells. I am not sure how that would go over 2m length and how it would shrink length ways as well. It may be worth investigating though. We find that the outer glass layer we put on gives us quite a smooth finish that's relatively easy to sand.
I wonder what pressure it would take for the pressure vessel to completely burst. Perhaps what is happening is similar to structural concrete for example the concrete needs to crack for the rebar to work most effectively. Similarly, the carbon fiber is provides the tensile strength and the resin provides the compressive strength. If this is this case maybe the solution is to rap the carbon fiber over a rubber sleeve to allow for cracking and to prevent leakage. Just an idea although I might be completely wrong.
We actually bought liquid rubber membrane that can be painted on on the inside, but haven't tried it yet. It does add more weight though. We would like to see if we can seal it first without it, but it is a backup plan. Realistically we think the pressure chamber can probably hold 1500psi. We've tested the narrower version for the sustainer to 1600psi without bursting but it did make a lot of fiber breaking noise.
Have you guys managed to figure how you are going to store and release the pressure for the second stage? I could imagine that could be a tricky problem to solve, with out adding too much extra weight.
hey george, i just started water rockets and was wondering if you know anything about a safe presure to make sure they dont explode, they are made out of 2L coke bottle
Most carbonated drink bottles will fail at around 180-190psi. (13 bar) But you don't want to take them above 120-130psi (9 bar) as they will deform permanently above those pressures. If you have spliced the bottles together, then you need to test them to see how well your splice holds.
@@AirCommandRockets ok thanks, i am preparing to launch my newest rocket, i want to know around how high it will go, do you have any good simulations you would recommend?
I love your videos, but I really wish you would use different background music. It contains sounds that are very close to a human voice, but not quite. It makes my skin crawl. I guess it's the uncanny valley.
A really good question. The process we are using is something we can easily do in our garage with the equipment we have and get repeatable and consistent results. One problem with wrapping is you need to be able to get the form/mold out of the pressure chamber once you wrap it and it has cured.
@@AirCommandRockets Maybe you could take your sheathing process to the next step by using a wrapped strand approach rather than a large swatch of carbon fabric. That way you could tension the wrapped strand a small amount. So for the last step put your chamber on a lathe and wrap it with a single strand criss-crossed over itself many times.
@@motoflyte You still need a proper computer controlled wrapping machine for this to evenly tension the tow and evenly spread it across the entire length of the pressure chamber. This can't be done by hand.
I don't think hot glue will work for splicing. A splice made out of 2L bottles at 20psi will want to pull apart with a force of 1,300N / 134kgf /295lbf.
@@AirCommandRockets ok thx george, also do you think if i just used the hot glue to hold the seal and used strong tape to hold the bottles together it might work? and do you know of any websites i can use to find data on my launches?
Hi George! Your videos are very educational. It is very instructive to see how you learn from your mistakes and move forward. I prefer condensed and well-explained videos over streaming. Also, it would be cool to see the older videos from your channel which apparently have been deleted. My favourite was the day when you flew the Polaron Vb rocket with Gluon boosters. The flight of that rocket was truly magnificent. Keep up the good work!
Thanks Daniel. I was thinking the same about re-uploading some of our old videos, though I will need to re-edit them because of the music sound track I used on them. (The reason I removed them) They are fairly low quality too, and would take a bit of time to dig up the original footage. They were also edited in a different video editor, so it would be quite a bit of work to bring them back. It's either spending time on that, or creating new content. :)
Ultimately that would be the preferred option, but the tape did make things easier. In the next pressure chamber the tape doesn't go all the way to the ends.
Ah ok. Vaccumm sealing your container removes heaps of air impurities when making fibre vessels. You dont know about that? Such as copv or just regular vaccum bags?
All of our water rockets are reusable. It would be possible to make the nozzle swappable, (something we did on our Dark Shadow rocket) but for this particular project, it is designed with a very specific nozzle size.
That was the idea to get a bit of interaction happening, and let people get an idea of the process we are doing, and perhaps suggest other things to try.
Also. Wondering why exactly a hydraulic ram ti force water out wont work?. I would have thought that sustained low g's would mean less wind friction and more efficient?
Not sure what you mean by hydraulic ram? In terms of low Gs, the problem is that most of the flight the rocket is coasting, so theoretically if you only achieved 1 or 2 Gs, then the rocket wouldn't go very high in the coast phase.
@@willyouwright Drag is proportional to the square of the velocity, but drag is only part of the whole picture. If you had zero speed, drag is 0, but you also aren't going anywhere. You need to balance the induced drag against the speed of the rocket to maximize altitude. That is what we are doing here by limiting the size of the nozzle to spread out the thrust phase and reduce the overall top speed.
@@willyouwright Again, I am not sure I am following what you mean here. Do you mean that there is some kind of piston in the rocket that pushes the water out? ... What pushes on the piston?
Thanks a lot for your videos! I am wondering how to calculate the nozzle orifice for a hydropneumatic rocket. I googled but couldn't find it. I am planning to make a rocket 5 or 7 cm in diameter and 1 meter long.
It really depends on a number of things. First is what kind of launcher you are using will limit the size of the nozzle you can use. Also what kind of a flight profile are you after, fast and short burn, or a long and slow burn? It's best to use a simulator and enter various sizes of the nozzle and see how that will affect the flight of your rocket. cjh.polyplex.org/rockets/simulation/
@@AirCommandRockets Solid or liquid. You guys are so capable I asked in general. I wouldn't be surprised to see you build your own liquid or hybrid rocket motors :-)
@@BlisterHiker We do fly with regular commercial solid motors, but Hybrid motors certainly would be interesting to work with. A few club members have built decent sized hybrids and they are always impressive. They're also a good engineering challenge.
@@AirCommandRockets In my humble opinion, hybrid motors are the future. I hope to experiment with them some day, but first I will have to move to an area where I will not be arrested for doing that :-) I'm looking forward to your future projects.
Good to see you back again. Do you think that this year the full two stage rocket will be launched? Also what is the name of the lathe that you are using? The parts you guys make with that mini lathe look very good. i am looking for a (small) lathe for my workshop as well.
It all depends on when the launch opportunities occur this year when we have club launches at the high power launch site and the weather also has to co-operate. The next launch opportunity is in September which is too close and the rocket won't be ready by then, and then there are covid lockdowns to consider as well. The lathe is a Sieg C3 mini lathe. There are many copies of this lathe made or re-branded by different manufacturers. It's a little on the small size, but good enough for small parts.
I love the shirt.
Same here
Where did you get it from and are you going to wear it out west in Sept?
Best to listen to your dad.... :-)
Yup, he knows his stuff. :)
man i wish this channel had more followers, this is so cool!
Thanks :)
True! They show the process, successes and failures and explain everything in detail, which so much more than most rocketry videos present.
True... they deserve it as everything is explained with full process.
Why only one layer of carbon fiber? Why not several? Considering the pressures.
Livestreams are nice but I feel that this style of content is better suited to normal edited videos. Great work, guys!
Thanks, I appreciate the feedback. :)
Live stream are great
Great work guys!! It makes the SpaceX stainless steel tanks' 8,5 bar totally wimpy.
I must confess to grinning when you were getting anxious at the first test 😁
Cheers :)
it would be so neat to have a shoulder mounted water rocket launcher.
I’d pay money to see that! Water blasting back into the face of the person firing it at 1000psi! Brave and hilarious!
@@freakysteve140281 Don't forget that the real ones shoot flames. Operator safety is maintained by the rocket either burning fully inside the tube or having a boost and sustain phase where the sustain is only activated after the missile has travelled a safe distance.
If it is posible to avoid two different matirials being applied by these extreme loads, than it might help to shift the delamitantion cracks to higher pressures. I think, that even a little bit of difference in elasticity of materials can cause unwished weakening of the structure.
You guys should look into the concept of designing a second stage chamber, with effervescent tablets or tums and cola. Perhaps will eliminate the need for as much compression? I dunno food for thought. Either way I believe it'll create additional thrust
The edited videos are quite fine, and they compress the time involved into something very watchable - it'd just be educational to see what real-time progress is like in a live stream, and have the opportunity for a question/answer session.
Get a mirror which you can mount in your doorway when doing pressure testing. That way you can get eyes on without being in direct line with the pressure vessel.
RE. the tape, do you need the tape to extend to the end of the vessel? Or could you have a section of tape missing where you plan to cut the tube to length? That way you avoid having the tape in the location of the join with the end caps
Not a bad idea with the mirror. I think that would work. Yes, the tape will now not extend into any part of the end cap joint and will stop a centimetre short.
Hi, i am wondering if i can use superglue instead of Pl premium for reinforcing and connecting bottles together as well as splicing
Great work! Love following this project. Registering my preference for edited videos. Keep it up!
Thanks, and cheers for the feedback.
I've missed seeing your videos.
So question...you're already using a CF tube from Soller Composites as the final overlay...couldn't you also use the CF tube as the first layer as well and eliminate the tape altogether? Also, I've seen some people using Sollers heat shrink tubing as a wrap-layer over the final product to achieve a glass-like surface and, they claimed, also help ensure good resin penetration. I'm curious what your thoughts are on that part of a process given all your experience and knowledge thus far on your projects?
Good questions Josh. In fact we did that first, we used a sleeve for the inner liner, but as you can see in part #14 ruclips.net/video/sG-YXnAGYdU/видео.html we ended up with a banana. Here is an explanation why: ruclips.net/video/I7i8ELEF3ro/видео.html and so to fix it we now use this process.
We looked into heat shrink tape to compress the pressure chamber a bit, but this would leave a spiral ridge on the surface that you would then have to sand out which is a lot of work. You would need to put the entire pressure chamber inside the heat shrink sleeve to get a smooth finish like soller sells. I am not sure how that would go over 2m length and how it would shrink length ways as well. It may be worth investigating though. We find that the outer glass layer we put on gives us quite a smooth finish that's relatively easy to sand.
I wonder what pressure it would take for the pressure vessel to completely burst. Perhaps what is happening is similar to structural concrete for example the concrete needs to crack for the rebar to work most effectively. Similarly, the carbon fiber is provides the tensile strength and the resin provides the compressive strength. If this is this case maybe the solution is to rap the carbon fiber over a rubber sleeve to allow for cracking and to prevent leakage. Just an idea although I might be completely wrong.
We actually bought liquid rubber membrane that can be painted on on the inside, but haven't tried it yet. It does add more weight though. We would like to see if we can seal it first without it, but it is a backup plan. Realistically we think the pressure chamber can probably hold 1500psi. We've tested the narrower version for the sustainer to 1600psi without bursting but it did make a lot of fiber breaking noise.
No excuses, you were supervised by Dad. 😂 Wish I’d found these videos when you made them. Fascinating to watch the process and the progress 👍
Have you guys managed to figure how you are going to store and release the pressure for the second stage? I could imagine that could be a tricky problem to solve, with out adding too much extra weight.
This is how the staging mechanism works: ruclips.net/video/ppbfhgk-USg/видео.html and here are the tests: ruclips.net/video/T9PLB9kaXlM/видео.html
I would say to make the tape length a couple centimeters shorter so you don't have to scrape it away.
That's exactly the plan for the next one.
hey george, i just started water rockets and was wondering if you know anything about a safe presure to make sure they dont explode, they are made out of 2L coke bottle
Most carbonated drink bottles will fail at around 180-190psi. (13 bar) But you don't want to take them above 120-130psi (9 bar) as they will deform permanently above those pressures. If you have spliced the bottles together, then you need to test them to see how well your splice holds.
@@AirCommandRockets ok thanks, i am preparing to launch my newest rocket, i want to know around how high it will go, do you have any good simulations you would recommend?
@@hoppy791 cjh.polyplex.org/rockets/simulation/ or www.aircommandrockets.com/sim/simulator.htm
@@AirCommandRockets ok thanks for the help!
Please show the pressure also in bar in the next video
The gauges are in both psi and pascals, but perhaps not as easy to see.
Great shirt!
Really cool
Very nice
Hi George, love your work. I assume you're getting your gauges periodically calibrated
Thanks John. No, we don't calibrate the gauges, but that's why we use 2 of them in these tests so that we can compare that they both read the same.
@@AirCommandRockets of course - you'reon the ball George!
I love your videos, but I really wish you would use different background music. It contains sounds that are very close to a human voice, but not quite. It makes my skin crawl. I guess it's the uncanny valley.
Interesting, I thought those were human voices or at least sampled.
@@AirCommandRockets I don't know, maybe they are.
Hello George, can i just ask, how much does it cost to build s rocket like Nova? One stage, not that big as Horizon. Thanks.
Nice to see you back again on RUclips George.. It's been a while..👍
This channel should be named "Welcome to NASA". Well done for such a well thought testing.
Is that a Go Pro Hero 9, George?
Yes. It was time for an upgrade. The last time we bought a go pro, the Hero 3 was brand new. :)
Live stream would be pretty cool! You guys are amazing!
Why are you not constructing the chamber from a single strand of woven carbon fiber wrapped around a form ?
A really good question. The process we are using is something we can easily do in our garage with the equipment we have and get repeatable and consistent results. One problem with wrapping is you need to be able to get the form/mold out of the pressure chamber once you wrap it and it has cured.
@@AirCommandRockets Maybe you could take your sheathing process to the next step by using a wrapped strand approach rather than a large swatch of carbon fabric. That way you could tension the wrapped strand a small amount. So for the last step put your chamber on a lathe and wrap it with a single strand criss-crossed over itself many times.
@@motoflyte You still need a proper computer controlled wrapping machine for this to evenly tension the tow and evenly spread it across the entire length of the pressure chamber. This can't be done by hand.
I prefer edited video. Live streams not so much.
hey george, do you think hot glue and take will work for splicing bottles if i will only presurise them no more then 20PSI?
I don't think hot glue will work for splicing. A splice made out of 2L bottles at 20psi will want to pull apart with a force of 1,300N / 134kgf /295lbf.
@@AirCommandRockets ok thx george, also do you think if i just used the hot glue to hold the seal and used strong tape to hold the bottles together it might work? and do you know of any websites i can use to find data on my launches?
Best way to know is to do an actual test. My gut feel is that the tape won't be enough, but 20psi may be manageable for smaller diameter bottles.
@@AirCommandRockets ok thx!
Hi George! Your videos are very educational. It is very instructive to see how you learn from your mistakes and move forward. I prefer condensed and well-explained videos over streaming. Also, it would be cool to see the older videos from your channel which apparently have been deleted. My favourite was the day when you flew the Polaron Vb rocket with Gluon boosters. The flight of that rocket was truly magnificent. Keep up the good work!
Thanks Daniel. I was thinking the same about re-uploading some of our old videos, though I will need to re-edit them because of the music sound track I used on them. (The reason I removed them) They are fairly low quality too, and would take a bit of time to dig up the original footage. They were also edited in a different video editor, so it would be quite a bit of work to bring them back. It's either spending time on that, or creating new content. :)
skip the tape?
Ultimately that would be the preferred option, but the tape did make things easier. In the next pressure chamber the tape doesn't go all the way to the ends.
R these vacum sealed? Isnt this just air bubbles?
Not sure what you mean by vacuum sealed. Do you mean did it use a vacuum bagging process? .. No it didn't. And no air bubbles isn't the problem here.
Ah ok. Vaccumm sealing your container removes heaps of air impurities when making fibre vessels. You dont know about that? Such as copv or just regular vaccum bags?
It dramatically reduces porosity..
Livestreams would be so cool!
Excelente George!!! , como siempre tan metódicos y analíticos. Saludos 👌👋
Gracias :)
Is it possible to make a reusable first stage water rocket by controlling the size of the hole?
All of our water rockets are reusable. It would be possible to make the nozzle swappable, (something we did on our Dark Shadow rocket) but for this particular project, it is designed with a very specific nozzle size.
Great to hear more news from you! I neither prefer edited videos nor live streams I am just very interested in the subject itself.
Cheers, thanks for the feedback. :)
Sir can you make water rocket can go at altitude of 1.5km. you are very close to 1 km .so plz🙏🙏🙏🙏🙏🙏❤️❤️
Just visited this comment ... Yes it is now possible to go over 1.5km :) See our latest video.
Interesting analysis.
Love that t-shirt!
Live streams might be an interesting thing to watch, it would be cool to be able to engage directly with the build and testing process
That was the idea to get a bit of interaction happening, and let people get an idea of the process we are doing, and perhaps suggest other things to try.
@@AirCommandRockets I think a combination of these edited videos, and some live streams here and there would be a good idea
Also. Wondering why exactly a hydraulic ram ti force water out wont work?. I would have thought that sustained low g's would mean less wind friction and more efficient?
Not sure what you mean by hydraulic ram? In terms of low Gs, the problem is that most of the flight the rocket is coasting, so theoretically if you only achieved 1 or 2 Gs, then the rocket wouldn't go very high in the coast phase.
@@AirCommandRockets a hydralic ram such as a bike.pump. it provides leverage.
@@AirCommandRockets the formula for drag is square root right? So speed needs to be reduce to optimise for drag
@@willyouwright Drag is proportional to the square of the velocity, but drag is only part of the whole picture. If you had zero speed, drag is 0, but you also aren't going anywhere. You need to balance the induced drag against the speed of the rocket to maximize altitude. That is what we are doing here by limiting the size of the nozzle to spread out the thrust phase and reduce the overall top speed.
@@willyouwright Again, I am not sure I am following what you mean here. Do you mean that there is some kind of piston in the rocket that pushes the water out? ... What pushes on the piston?
Thanks a lot for your videos! I am wondering how to calculate the nozzle orifice for a hydropneumatic rocket. I googled but couldn't find it. I am planning to make a rocket 5 or 7 cm in diameter and 1 meter long.
It really depends on a number of things. First is what kind of launcher you are using will limit the size of the nozzle you can use. Also what kind of a flight profile are you after, fast and short burn, or a long and slow burn? It's best to use a simulator and enter various sizes of the nozzle and see how that will affect the flight of your rocket. cjh.polyplex.org/rockets/simulation/
@@AirCommandRockets Thanks!
I love it! Your videos are amazing !! I would love to see some streams
; - )
Keep up the great work ;)
Cheers :)
Very cool! It's good to see re-usability as one of your priorities :-)
Just curious, do you guys plan to use chemical motors in the future?
As in regular solid model rocket motors?
@@AirCommandRockets Solid or liquid. You guys are so capable I asked in general. I wouldn't be surprised to see you build your own liquid or hybrid rocket motors :-)
@@BlisterHiker We do fly with regular commercial solid motors, but Hybrid motors certainly would be interesting to work with. A few club members have built decent sized hybrids and they are always impressive. They're also a good engineering challenge.
@@AirCommandRockets In my humble opinion, hybrid motors are the future. I hope to experiment with them some day, but first I will have to move to an area where I will not be arrested for doing that :-)
I'm looking forward to your future projects.
Edited, please.
Why not both ?
Thanks for the feedback. :) The intention was to continue the edited videos, the live streams were in addition to those.
Good to see you back again. Do you think that this year the full two stage rocket will be launched? Also what is the name of the lathe that you are using? The parts you guys make with that mini lathe look very good. i am looking for a (small) lathe for my workshop as well.
It all depends on when the launch opportunities occur this year when we have club launches at the high power launch site and the weather also has to co-operate. The next launch opportunity is in September which is too close and the rocket won't be ready by then, and then there are covid lockdowns to consider as well.
The lathe is a Sieg C3 mini lathe. There are many copies of this lathe made or re-branded by different manufacturers. It's a little on the small size, but good enough for small parts.