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, April 12, 2011

Polaron G2 CATO

We had an interesting weekend this week. We finished the new Polaron G2 rocket, and took it out for a launch. Unfortunately things did not quite go according to the script.

The full flight day report gives details how we created a nice sculpture for the rocket range.

The report includes a highlights video including the CATO in slow-mo.The rocket and launcher are already being rebuilt and we will have another go again soon. The website update also has more detailed photos of the new side deploy mechanism and payload bay with a backup parachute.


Thomas Pete said...

Wow... This can be extremely dangerous is someone is standing nearby the area whn the explosion occur... May cause serious injuries...

cyril said...

courage, I'm sure the next flight will be good ;)

a +

(message translated with google translate) ...

Unknown said...

Hey George,

That really is a shame :( not had much luck with G2 really have you.

Whats your next step do you reckon?

Regards Doug

George Katz said...

Hi Doug,

Actually our Acceleron V has had a similar history of several CATOs and several wayward flights and crashes before it started flying well. I think the G2 rocket as is is fairly sound, so we are rebuilding it in the same configuration, but will use lower pressure first on the next launch, and then start to raise the pressure again after we get some flights under our belt and see how it performs. This was actually our highest ever pressure launch attempt, so I am not too surprised at the malfunction. This way we get to learn where the edge of the envelope is. :)

George Katz said...

@Thomas Pete.

Indeed it can be quite dangerous, so that's why no one is near it when we pressurise the rocket. We arm and launch it remotely. The rocket also has no metal components in the pressure chamber in case it does let go.

Vicente Junior said...

Dear George, I was thrilled by this release, it was for me a traj├ędia, have struggled to build rockets and simpler (in terms of you), I thought when I saw the explosion of work hours. But do not lose the passion for fireworks, I'm sure when it goes right will be another show. Good job.

MariusD said...

Hi George,
Sorry for this, but this shows how dangerous can be. It is good to have continuous elements connected in may points in your launcher, so they will not fly in many many peaces.
Filling slower the rocket, and with some breaks above 150 psi will help you, with a lower temperature at the end. Haw much? Probably you will need some testing.
But maybe you had a weaker point who become even wheaker at previous 270 psi test.
Anyway is good to rise the pressure slowly, with slow speed air intake, to have some positive results for you.
I liked the new ejection system, with side deploy. :)


MariusD said...

Above was "many points", not "may". The idea is to stay in one piece, more or less, connected.
I have a sugestion for you : before cover with the big piece of fiber glass, cover the joints with a band of fiber glass, around 7 cm wide, 50 % overlapped, 180 degrees apart all three.
Also, after seeing 2 times photo Day103_10_s.jpg, that "spike" form of the bottle may cause a weak point also. Maybe it started there.
Good luck next time.

George Katz said...

Thanks Marius,

We do need to fill the rocket slower to give it a chance to cool down. We too were thinking at pausing during the fill to let the temperatures equalize. We are looking at other ways of cooling the rocket as well.

Having damaged the launcher is also giving us an opportunity to build a new one. This one will be quite different with the main design criteria that it is easy to setup and pack up again.

Anonymous said...

Just some questions...
What exactaly means CATO?
Do you know if the air get hot just when it reach the rocket, or do it get hot already in the Hose? If it get hot in the hose, you could try adding some kind of thermal switch in the middle, so only cold air could pass...

George Katz said...


CATO stands for "Catastrophic Take Off", basically a major failure during a rocket launch.

The air gets hot inside the rocket as you compress the air, even if cool air is flowing into the rocket through the hose.