The Water Rocket Returns ... with an onboard camera

[TwoOnnies]

Hello,

This is my first post: some pictures and a video of my first water rocket with an onboard camera.

[youtube][/youtube]

Kind regards,

TwoOnnies

[rockets-in-brighton]

Hello,
This is my first post: some pictures and a video of my first water rocket with an onboard camera.

Excellent! A very tidy looking rocket, there. May we ask about the construction details, size/weight/deployment system etc?

i

[Spaceman Spiff]

I agree. That is a very clean looking design. I do not see a lot of protrusions or machanical tidbits on the exterior of the bottles, and there does not look to be a great deal of wasted mass inside. I am tempted to make a rocket from colored bottles now too, because they always look nicer to me for some reason.

[TwoOnnies]

Thank you for your replies.

I kept the design simple and the weight low.

The rocket is approx. 68 cm long and it weighs 180 g.

It's an SST rocket constructed from 0,5l Gini bottles (my favourite).

Parachute deployment works with a Tomy Timer released by a small cardboard airflap.

The only protrusion is the camera hook (which I should try to eliminate).

The interesting thing about water rockets is that there is always room for improvement: my next rocket will be perfect

Best regards,

TwoOnnies

[rockets-in-brighton]

The rocket is approx. 68 cm long and it weighs 180 g.

Very light, I guess this is glued rather than mechanical connectors?

It's an SST rocket constructed from 0,5l Gini bottles (my favourite).

Not certain what SST means in this context. I came across http://www.karl88.com/zenoamerica//wate ... index.html "Super Simple T Nozzle" - is that it? I am often frustrated by US sites which refer to materials unavailable in Europe. Were you able to adapt this design?

I guess that also means you use a launch tube.

Parachute deployment works with a Tomy Timer released by a small cardboard airflap.

I found some references to some of your other projects on a French-language site (it helps that you have a distinctive user-name which you use elsewhere honestly, I'm not stalking you) which included somehow using magnets as part of the deployment mechanism. Was this the same rocket?

Many thanks for all the information.

[TwoOnnies]

SST refers to the "symmetrical splice technique", i.e. the glueing of PET bottles using an internal PET ring as "connector". I use PU glue.

Although my German is not so good, I sometimes post on a German water rocket forum and they have real SST specialists: http://www.raketenmodellbau.org/forum?a ... eadid=7451 But you will need PET-bottles with a sufficient wall thickness.

I use a 20 mm launch tube. The rocket is launched at 8bar.

You rightly point out that I also post on the French forum. I guess you refer to my tomy timer system with "inertial" release flap with a magnet. The magnet prevents the inertial release flap from blocking the tomy timer after the launch. It was not a success, so I abandoned that idea. But I might pick it up later.

Best regards,

TwoOnnies

[U.S. Water Rockets1]

SST refers to the "symmetrical splice technique", i.e. the glueing of PET bottles using an internal PET ring as "connector". I use PU glue.

Although my German is not so good, I sometimes post on a German water rocket forum and they have real SST specialists: http://www.raketenmodellbau.org/forum?a ... eadid=7451 But you will need PET-bottles with a sufficient wall thickness.

I use a 20 mm launch tube. The rocket is launched at 8bar.

You rightly point out that I also post on the French forum. I guess you refer to my tomy timer system with "inertial" release flap with a magnet. The magnet prevents the inertial release flap from blocking the tomy timer after the launch. It was not a success, so I abandoned that idea. But I might pick it up later.

Best regards,

TwoOnnies

Beautiful looking rocket! One question for you... you mention needing bottles with sufficient wall thickness for your SST joint. What thickness are available to you and what size is required? Thanks.

[TwoOnnies]

I work with PET bottles with a wall thickness of approximately 1 mm.

PET that is to thin tends to crease when you try to glue a PET segment into an other segment.

The 0,5 l Gini bottles that I use don't crease.

I never used the German (or Dutch?) deposit PET bottles that are considerably thicker than the bottles available in Belgium.

Best regards,

TwoOnnies

[Spaceman Spiff]

I work with PET bottles with a wall thickness of approximately 1 mm.

PET that is to thin tends to crease when you try to glue a PET segment into an other segment.

The 0,5 l Gini bottles that I use don't crease.

I never used the German (or Dutch?) deposit PET bottles that are considerably thicker than the bottles available in Belgium.

Best regards,

TwoOnnies

My bottles are much less than 1mm. you guys are lucky to have much thicker bottles.

[MB water-rockets]

I really like the design of your rocket! Slim and tidy. It weighs much less than mine made of heavy (German) bottles. The coefficient of drag must be pretty low due to the nice shape.

One question regarding the camera: It looks like the camera is located close to the outer rim of the rocket, not to the center (which makes sense). Does it affect stability to have such a heavy part outside of the rocket's center? Or did you use a counter-weigth which I can't see?
Until now I didn't launch a rocket with payload so I can just guess...

Thanks and keep them flying!

MB water-rockets

[U.S. Water Rockets1]

The weight of the camera tends to be a small fraction of the weight of the rocket when under thrust (filled with water), so it doesn't make a significant difference in the balance of the rocket until the coast phase. At this point the rocket is rapidly approaching weightlessness where only aerodynamic forces are acting on the rocket.