Nova Water Rocket - Part 1 of 3 - Pressure Chamber

In this 3 part series we build and fly a mid-powered water rocket called Nova that can fly to 1000 feet (300m). In this episode we cover how to build the pressure chamber as we simplify some of the construction techniques we've used previously.
0:00 - Introduction
1:00 - Making Body Tube
4:51 - Coating Inside of Body Tube
6:15 - Making Endcaps
11:46 - Nozzle retaining ring
12:20 - Launcher / Test adaptor
12:48 - Pressure Test
14:29 - Outro

[@laurence4051]

I always like to watch the construction process of your rockets. I cant wait to see it fly!

[@AirCommandRockets]

Thanks Laurence.

[@arro_rockets]

Nice, a new video!

[@jimadams7765]

Built with SOAS (Sock on a stick) Technology.

[@skysurferuk]

Really interesting construction, thanks for posting.

[@mdk2127]

Very interesting to see how you optimise and simplify your designs. Also, I've noticed you can make very lightweight pressure chambers with this construction method and materials. Maybe I will try this in the far future. Looking forward to the next video's!

[@TonyLambregts]

Thank you for the update.

[@istvanfrank9201]

I like you how helping each other during work , comfortable to see awesome good work. Really profi.

[@sandeepkapare]

As always a very informative video. Can't wait for remaining parts now.

[@AirCommandRockets]

Cheers Sandeep.

[@rfdave3980]

Very interesting. Enjoyed it so much. Your construction techniques are simple but effective. KISS principle. Thank you !

[@AirCommandRockets]

Thanks!

[@arro_rockets]

You'll be glad to hear that CRG has now converted to water rockets for the summer, since we can't launch pyro rockets for the obvious fire risk!

[@AirCommandRockets]

Great! I'll have to check out any photos/videos from the launches. The more water rockets the better! :) NSWRA usually doesn't fly in December and then restarts again at the end of January.

[@arro_rockets]

@@AirCommandRockets Well that might be something to suggest to them, or you could come down to Canberra :)

[@alienbeef0421]

Nice!

[@Shreyam_io]

Ahh... You are back with build videos... I love them , specially carbon work😅

[@AirCommandRockets]

Cheers. :) Yup, we have the three videos for this rocket ready. It flew a couple of weeks ago. We'll release them each week while we work on the Horizon project.

[@Shreyam_io]

@@AirCommandRockets that will be grate

[@old_guard2431]

Well done - compact, complete, to the point. Pressure testing to less than the working pressure set off some alarm bells - "pressure vessels" are normally hydro-tested to 1.5 x working pressure. But I concede that it makes sense: 1. You have air in the system, although one hopes not in the pressure chamber itself. However, high-pressure water pumps are a bit expensive. 2. The pressure chamber will only be at high pressure when the reasonable blast radius is clear. (Not so much with boilers, HP air tanks etc. on a ship or in a factory.) If existing data is not available I would want to test one to destruction in a safe area just to make sure assumptions on blast radius are correct.

[@AirCommandRockets]

The philosophy here is we can test it to destruction on the launch pad trying to launch it. The safety margins are a lot lower in rockets simply to conserve weight. Hydro testing only gives you a part of the picture, as it doesn't take into account the compression heating of the air during pressurisation that can weaken the epoxy. It also doesn't take into account the dynamic load applied to the bottom of the pressure chamber under acceleration. A 50G launch can exert quite a bit of force from the water that is still in the rocket. The payload on top of the pressure chamber can also apply compressive loading on the top of the pressure chamber during high acceleration. Here is a good example of a rocket being destroyed by the dynamic loads after launch. The pressure chamber was hydro-tested before launch. kzbin.info/www/bejne/ameYm3-ppNl3r6M

[@overturetool]

As ever great videos from down under! Looking forward for parts 2 and 3! Question on nozzle and endcap, why not petg in stead of pla?

[@AirCommandRockets]

Really good question. We had plenty of PLA on hand, and because it is such a common printing material that a lot of people have, we wanted to see if it would work with it. I'm sure if you are really trying to push the limits of the design you probably would want something a little stronger.

[@TobyRobb]

Really enjoy watching your updates! I wonder could you make the original mandrel in the final shape? Really fantastic engineering!!

[@AirCommandRockets]

Cheers. :) The problem in doing it in the final shape is that you wouldn't be able to extract the mandrel. You may be able to get away with shaping one end, but then you would have trouble removing the tube because the baking paper wouldn't be able to shape itself over the end well and you would get wrinkles.

[@TobyRobb]

@@AirCommandRockets I admit that would be a problem ! :-) I can see from your methods that you have so many things well thought out, the engineering you are applying is fantastic!

[@fmacdonald3559]

Hi , another great series of videos are you selling or offering the 3d print plans?

[@wforider4786]

Are you sharing the stl files for the 3d printed parts? Love the design

[@adoumouang-namouemmanuel3507]

Great job again. Please would you share the information on the different dimensions? Thank you

[@RogueMaverick_]

Can you put materials and the place you buy in description?

[@rorypenstock1763]

That 3D printing process really looks like it saves some time. Are you going to be incorporating parts of the technique when you build Horizon's booster, or do you need better performance?

[@AirCommandRockets]

That's a really good question. It would certainly be worth investigating by doing a small test pressure chamber. The major concern is the higher pressures and the larger diameter that Horizon uses.

[@federicoschirru3957]

Hello AirCommand team! I would like to ask some questions regarding the video content; what exact type of west system epoxy is the one used in the video? 105 resin with 205 hardener? what is the expected curing time without any heating apparatus in hours? what safety equipment should be used?

[@AirCommandRockets]

We use 105 resin and the 206 slow hardener to give us enough work time. The cure time depends on ambient temperature. On hot days it cures a lot faster than on cold days. Normally we wait around 10 hours before removing it from the molds/mandrels, but it is still very slightly soft. I always wait at least 3 days before testing it with any loads. In terms of safety equipment, we just use gloves, the epoxy doesn't give off any odours like polyester so no need to wear a mask.

[@MatthewMenze]

Would wrapping the tube with peel-ply tightly while it was curing provide a meaningful benefit in the final strength to weight? Or vacuum bagging it even?

[@AirCommandRockets]

Yes vacuum bagging would definitely help improve the strength to weight ratio. We don't have the equipment to do that .... yet. :)

[@MatthewMenze]

@@AirCommandRockets What about peel ply? it gets close to vacuum bagged results, without any equipment, just a extra step of layup.

[@Mongo63a]

How about blow molding the inside of the rocket from PET. Then cover it with CF? The hard part would be the mold to blow mold the PET but once it was made the construction simplicity would be easier. Being on the inside it would also insure that you did not have to worry about pin holes in the CF wrap. Love the engineering you guys put into your designs.

[@AirCommandRockets]

That's something that could be feasible. I'm not sure what equipment would be needed to make that happen in terms of heating the preforms and then making the molds so they don't come appart when blowing into the preform, and do that at the full length of the rocket. My guess is it would only be economically viable if you were making dozens and dozens of them.

[@Mongo63a]

@@AirCommandRockets A new family business, time to retire from that boring job that pays the bills to do something to ruin your love of your hobby :) I would think you could 3D print the outside blow mold in sections that split vertically and would be bolted together. Obviously the entire central body would be pretty much identical with the ends for the nozzle and head cap being different. Maybe even use a piece of tubing to form the central cylindrical section blow mold and just split it lengthwise and use outside clamping brackets made from normal pipe hanging hardware or 3D printed ones.

[@DavesRocketShop]

Question about what you refer to as baking paper: is this a simple parchment paper, or are you using a waxed paper?

[@AirCommandRockets]

It is actual baking paper that has a waxy coating. They are not all created equal though, Glad Bake is recommended by many club members.

[@DavesRocketShop]

@@AirCommandRockets Just needed an Australian to English translation :)

[@halo_tuhh]

Going to try this method :) What's the diameter of that mandrel?

[@AirCommandRockets]

The mandrel is 60mm

[@herzigfrancois5444]

Hello George !!!!

[@AirCommandRockets]

Greetings from Sydney François :)

[@RogueMaverick_]

How you make the air compressor?

[@AirCommandRockets]

We use a scuba tank with an adjustable pressure valve to fill our rockets.

[@seann9]

Can you release the 3D printing STL file for the nozzle and end cap?

[@AirCommandRockets]

All STL files are available here: www.thingiverse.com/thing:5502347

[@suspendedsuplexchannel1000]

What kind of resin do you use, make another video on types of resin or reply me🍜🎄

[@tcsyme]

He mentions in the video that they are using West Systems epoxy. As another West Systems customer, I expect they are using 105 resin and 206 hardener, for its increased working time over the 205 hardener. Or possibly even the extra slow 208 hardener. More info available at www.westsystem.com

[@kpmmasskarthi]

what is length of pressure chamber?

[@AirCommandRockets]

1 meter.

[@ruthdoyle9085]

Have u tried LPG instead of water?

[@AirCommandRockets]

No, we have not.

[@Peter-pu7bo]

😂 nice end card

[@user-sd7gr9xh5d]

can you make a step by step build guide

[@grininventor]

Why do you use a brass nozzle seat and not aluminum?

[@AirCommandRockets]

It is stronger and easy to machine. Weight reduction isn't an issue since it stays on the ground. For us also it is cheaper because we have lots of brass stock on hand.

[@Shreyam_io]

That 3d printing saved lot of work and time....

[@AirCommandRockets]

The best part about 3D printing is you can work on something else at the same time that it's printing.

[@Shreyam_io]

@@AirCommandRockets indeed

[@otaviomoreto6615]

i chalenge you to create a reusable rocket space x style (no use parachutes)

[@AirCommandRockets]

Challenge accepted. No parachute: kzbin.info/www/bejne/h3W9e5eEo7aFrLs ... also no glue or tape or anything else. :)

[@otaviomoreto6615]

Thank you

[@j.y.j9297]

What is the outer diameter of the pipe???

[@AirCommandRockets]

60mm

[@kaminelson1277]

A faster way to drain the rocket is swishing the water around to create a vortex

[@AirCommandRockets]

That's true. but the size of the hole here is 7mm so it is difficult to get the vortex going to let air pass through it and drain at the same time.

[@grininventor]

Why are you using only a 7mm nozzle ? Don't bigger nozzles go higher?

[@AirCommandRockets]

That's a good question. As the video says this rocket was specifically designed to fly within the permissible altitude range for our launch site in Sydney. Club rules state that we have to keep to around 1000 feet so making it go higher really wasn't an option. So then if we can go that high with a big or small nozzle. we chose to go with the small nozzle in order to keep the acceleration and stresses down on the rocket. The slower take-off is also easier to film. A small nozzle also means that it is easier to hold the rocket down on the pad at higher pressures.

[@grininventor]

@@AirCommandRockets And if you use a bigger nozzle like 10-12mm and lower pressures like 18-23bar ? Also, with a smaller nozzle you can’t use a launch tube right ?

[@suspendedsuplexchannel1000]

Where do you live are you American

[@sharadthecurioustardigrade1533]

What about a liquid CO2 powered rocket? Your rockets can already support 2000 PSI

[@AirCommandRockets]

Liquid CO2 would certainly be worth investigating. I can imagine icing at the nozzle would need careful attention.