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.

Wednesday, February 02, 2011

Polaron G2 - Flight report

I’ve finished uploading the flight report from last weekend. The report has information about what we think went wrong and includes photos and a highlights video from the day.


We are in the process of rebuilding the rocket, so hopefully it won’t be too long before it’s up in the air again. It’s always easier to build the rocket a second time, because we know how to build it and what materials we need. The first build always takes a while as we try different prototypes.


Unknown said...

Sorry about the crash, but you mentioned using a drogue activated by the MAD and a side deploy mechanism?

George Katz said...

Hi Alex,

Yes that was the plan, however, we just ran out of time to fit it for this launch opportunity. It may have saved some of the damage. We are going to use it as the back up system on the re-build though.

With a limited number of favourable launch opportunities throughout the year sometimes you just have to fly them to see how things behave under the load stresses of a real launch.

As mentioned in the update, we did get quite a few positives out of the launch so it wasn't a complete failure.

Anonymous said...

Great Work George!! Success next time. Charlie

MariusD said...

Hi George,

Sorry about this crash, after a LOT of effort to make this rocket! I know how disappointing can be !

At the nosecone you can increase the lip, but very little, so it can get out on the right time. However, at that speed with rocket straight up and well balanced, with some lip for sure, I don't think is the cause.

You don't have an explosion force like in regular rockets to get the nosecone out, with a big and safety lip. I believe side deploy mechanism is better! You must only improve the door.

And also I think you have (like other times) an early start of timer. You must double the trigger mechanism with timer + mad, or with timer + that early switches mounted on the side of rocket and a pin bounded to earth which get off when the rocket leaves the lunching system.

Good luck

Todd said...

Hi George,

Nice video, I like the comedy sketch as well ;)Also the time lapse of setting it all up was great.

Sorry to see it didnt go exactly to plan but thats rocket science :)

Good luck with the next launch of G2


MariusD said...

Hi George,

I took a closer look at your logs. At altitude log you cannot identify the moment of deployment. At acceleration and velocity, you are saying that nosecone fly off after the burst, when G become negative. Maybe you are right. Is it heavy, enough ?
That is another reason for side deployment !
Protecting your big work, I say you could increase g value on g-sensor (ASLS5/ASLS10) to eliminate any false trigger signal. You have way more g' there! And backup it, with MAD signal coming in a fair designated delta (+/- 1.5s) of time, deducted from deployment time!

Anyway, easy said than done! ;)
Good luck with the next one!

George Katz said...

@Todd: Thanks Todd :), We are well into making repairs to the rocket now.

Good luck with the dragster record attempts!

@Marius: Hi Marius, we are actually working on both nosecones approaches. We are repairing the one that we just flew, and also doing a side deploy version. We'll test them both again before flying it on a big rocket. We are also mounting the MAD in the middle of the rocket with a smaller parachute to bring it down sideways should the main one fail again.

We are fairly confident that it was a mechanical issue rather than an early deploy on the last flight.

MariusD said...

Hi George,

Good idea! It will complicate your electronics because you must have some time reference for both systems, for checking against time and a door switch. For both situation, early deploy and not deploying at all. You will have a nasty situation when does deploy early and the rope will not broke!
Parachutes will tangle!

I saw on day 99 the small lip and the weight (361g). Probably you will need to change something.

I started building the new bigger one. 8l is big enough for me :) ! Only with Robinsons and not splicing, where I have a problem!


Anonymous said...

Perhaps some hot water in the rocket - superheated but kept from boiling due to the high pressure. As soon as the pressure backs off below the appropriate superheat temp - it will instantly turn to steam. 18mls turning to 24.4 ltrs of steam. The reason why the old locomotives use to explode so well

Anonymous said...

Steam Rockets - they is.

Very nice short clip below. Nice accent. Good Power and Similiar size to Polaron G2


George Katz said...

Yes, that's correct we'll be carrying more electronics, but as we want to use the backup system then that's what needs to happen. We're going to power the backup flight computer, altimeter, Craig's flight computer and the MAD from the same LiPo batteries so we will save some weight there.

The 361g is made up of about 70grams parachute, the nosecone is about 120 grams and the base with electronics and battery that is attached to the rocket is the rest.

Do you have any pictures/video of your 8L rocket? It sounds like a fun build. :)

MariusD said...

Hi George,

I will glad share some photos, like with the last one, that was destroyed due to the broken parachute cord! :( (late deploy with a too thin cord, as I discovered)

As soon as I will have something that resembles a rocket, not just a long tube :)