2 Stage Water Rocket - Part 29 - Successful Tests

Successful tests of the third test pressure chamber for the Horizon booster. We cover some of the changes we made to the pressure chamber since the last one, and show some highlights of the tests performed during a live stream earlier in the week.

[offroadprogrammer]

I love your construction investigations and revisions. It's been quite enjoyable watching ACR progress to this point. Looking forward to the maiden flight!

Last weekend, I made a pressure test on a 125mm (diam.) pressure chamber with 3 layers of 200g/m² carbon cloth. For security and to avoid scaring neighbours if it explodes, made it in my garden in a cavity, 25cm under the earth. I reached 53.5BAR for 10 minutes without any leak. But after 10min the co2 slowly dissolved in the water and the pressure decreased. So I made sparkling water. ^^

[simonabunker]

Amazing engineering as usual. The newer design looks so much better than when you started!

[aqimjulayhi]

I can’t believe I found your channel again! I remember 12 or 13 years ago I would visit your website daily because I was a 12 year old who wanted to have the wildest hobby. So many years go by and you’re still doing what you love. I really admire your work back then and now I feel like your projects should be the gold standard for water rocket engineering. Stay safe and have fun, George.

[rizin]

This is crazy to think I use to worry about 300psi in a sugar rocket motor design with PVC. Can't wait to see the heights you guys reach!

[Mongoa]

Its truly amazing how small construction details affect the MAWP.

[JulioGhigi]

Nice results! Congratulations! And I need this t-shirt!

[marcdubois]

Still following you for many years... hand shake from Québec.

[toamastar]

Great to see testing went well! Can't wait to see the finished thing, i know its going to be epic! :D

[lucasttngrr]

Incredibly cool project keep up the great work.

[Shangoo]

This is kind of a weird thing to say, but I really like your shirt in the intro, thought it was hilarious!

[michaelwni]

I'm wondering if you created a honey comb type insert, that reduced the chamber expansion, if you could get a significantly higher max PSI?

[istvanfrank]

Ez már nem játék, komoly hobbi, sok sikert Sopron Hungary! By the way, nice Blue tongue lizard a brave one 😃🚀👍🏻

[makerbeelab]

The lizard was just inspecting the safety precautions :)
In regards to use of fibreglass and carbon fibre around the nozzle.
Fibreglass has high strength but relatively low young module, it will stretch 6 times that of a carbon fibre before breaking.
Carbon fibre - the opposite, very high rigidity, so in principle all the fibreglass should go on the inside and ensure the seal while all the carbon fibre should go on the outside and ensure the mechanical strength. Indeed you do have a lot of fibreglass around the nozzle and it should be fine, but that's just a small consideration I would use.

What would be very interesting to see is what happens to the chamber lengthwise while you pressurise it. Does it expands lengthwise proportionally to the circumference expansion or not? The stress that acts diametrical should be D/2*pressure. while the stress in axial direction is D/4 and the chamber that is equally strong in all directions should expand proportionally to those stresses. The ideal case scenario is, obviously, when the chamber is twice as strong in perpendicular direction in comparison with the axial direction.

[russellauger]

Use of a reuseable nano gel tape might be more appropriate for creating an inner bead. Application might be made to each side and then pulled out of the nozzle during partial cure. Alternatively, a dual silicon balloon mould would assist to negate rotation during mating of the end cap to the body.

[prietjepruck]

Hi George, love how meticulously you build your rockets. I was wondering what would happen if you disolve a gas in the water like CO2. Keep up the good work. Greetings from the Netherlands.

[VentureWelding]

Perhaps I missed this, but why construct the pressure chamber from scratch? Versus carbon fiber wrapping several layers inside and outside of a SCH20 OR SCH40 PVC pipe? Or even aluminum? Obviously there would be a weight difference but you'd make up for it with the amount of pressure it could sustain?

[Danielastronomo]

Thank you for sharing with us the lessons that you have learned George. How are you planning to fill the pressure chambers with water? I can imagine that filling the booster might be cumbersome.

[RocketTech_Stars_YT]

Interesting missives. I never thought that such rockets could be so powerful. I still have a question how and with what do you pump this airde to such pressures?

[rlaghals]

Was there a case of leakage due to banding during the test? If there was, I wonder why.