This blog covers the day to day progress of water rocket development by the Air Command Water Rockets team. It is also a facility for people to provide feedback and ask questions.

Tuesday, October 18, 2011

So how big is The Shadow?

Now that we have most of the components made, we are in the process of assembling them into the actual rocket. Here is a picture of the pressure chamber with payload bay and nosecone fitted on top. The entire rocket is 2580mm tall (~8.5 feet).

 I've added some more progress photos from the last week of construction here:

There is still lots to do on this rocket, but it's good to see it finally in context so that we can finish designing the launcher and figure out how we fill it with water and launch it. We're hoping to assemble the pressure chamber over the next week and pressure test it. For the pressure test we are going to need to finish the launcher, as it will be the only thing that will seal against the nozzle.

Otherwise progress on other projects is on the back burner for now as my regular daytime work has been extra busy lately.


Unknown said...

Hey George,

The project is looking fantastic, i'm really looking forward to the overall results of the thing when it all comes together :) Sun in the eye's? made you pull a very serious face :P

I really must get back into doing some work to the rockets i have around 4 splices lying around at different stages and a half finished reconstruction of the in-line deployment cone. And Hope you dont mind the copying im making the deployment pod for the bigger parachutes in much the same way as your G2 pod is made.

Regards Doug

Anonymous said...


I'm really curious what will happen on launch.
It could be like an explosion.
500psi is really high pressure to release suddenly.

- Formation of ice in the rocket or on the nozzle because of expansion of the air? Are the materials resistant to temp below 0°C.

- Will the water boil in the nozzle (law of Bernoulli + water boils at lower temp with lower pressure) and causing cavitation?

-(Sonic) boom of the air at launch?

I'm not sure the air, water and rockets will behave in the same way in The Shadow as in an ordinary water-rocket.
Although I wish you a great success and I'm looking forward to the first flight.

Anonymous said...

I wrote the comment above
Jan from Belgium

George Katz said...

Hi Doug, hee hee ... building rockets is VERY serious business. One can't just stand there and grin all the time. :)

I was wondering if you had been doing any more development. I hadn't seen any recent updates on your blog. Good to hear though that you are going to get back into it. ... onwards and upwards I say.... :)

George Katz said...

Thanks Anonymous/Jan,
We're pretty curious too what the launch will be like. I think it will be pretty loud I imagine. You are right it will be a lot of air going through a fairly large nozzle very quickly. There shouldn't be any problems in terms of temperatures in getting the water and air out. From what I remember of the sims it's all over in under 1/2 second.

Our biggest concern is the stress put onto the components during the boost phase. The first shakedown flights will be at lower pressures again, but if all works well, we'll increase the pressure on subsequent launches ... or rebuild it if it fails. :) Because this is a completely new rocket for us with a new launcher and deployment mechanism, we fully expect there to be a few failures along the way.

Hopefully not too far off to the first launches.

Rodrigo said...

A really interesting proyect, but, George, I have a question: You will deploy the parechute with a Pyro charge or with a spring?


George Katz said...

Hi Rodrigo,
We are initially aiming to deploy the parachute with a spring loaded piston. If that proves to be too unreliable then a pyro ejection is always our backup plan. Pyro works real well for normal rockets, so we know that works. We are trying the spring method first because it is cleaner, and we can test it as many times as we want.