Hi from London, UK

[Rusty]

Hi all!
I'm completely new to water rockets so have no idea about much at all
Any help you could give me with my current project would be nice. Don't ask how it got started, but a friend and I have made a maths project in which we want to build some sort of device to transport a mouse from one side of the river Thames to the other, which we figured out was about 60-70m. I thought a water rocket would be good because its cheap and they seem powerful. So, is it possible to
a. Fire a water rocket that far
b. Have the mouse still alive when it gets there (probably won't use a real mouse, but we'll find a humane substitue
c. Fire it straight enough to not land in the water
d. Do it cheap! (we're students so don't have that much money :P )

So, any help would be greatly appreciated!

[Andrewlee]

I think it could be possible, especially if you decide to make a glider base out of it. I will get back on here later, and show you some pictures of the RC Airplane that we are working with. We strapped a water rocket to its under side.
Also, if you angled it right, and used a tommy timer, you may be able to get it accross, and then deploy a parachute. So, either way, I think yes.

[WRA2]

Hi all!
I'm completely new to water rockets so have no idea about much at all
Any help you could give me with my current project would be nice. Don't ask how it got started, but a friend and I have made a maths project in which we want to build some sort of device to transport a mouse from one side of the river Thames to the other, which we figured out was about 60-70m. I thought a water rocket would be good because its cheap and they seem powerful. So, is it possible to
a. Fire a water rocket that far
b. Have the mouse still alive when it gets there (probably won't use a real mouse, but we'll find a humane substitue
c. Fire it straight enough to not land in the water
d. Do it cheap! (we're students so don't have that much money :P )

So, any help would be greatly appreciated!

Hello Rusty,

Welcome to the forum.

Here are some answers to the questions.

a. A water rocket should be able to go that far. You may have to experiment with different launch angles until you get it right (hopefully you don't get in trouble for littering as you are bound to lose a few in the drink).

b. Don't use a real mouse, it won't survive the g-forces of launch. The substitute is a good idea.

c. You may need to experiment with different launch angles and volumes.

d. It should not be very expensive and you will have lots of fun


Are you planning on using a parachute or is the goal just to land it on the other side.

[Rusty]

We wanted to keep the mouse alive so overcoming the g-force was one of the big problems. A pod attached to the rocket with a long elastic band was an idea that we had, but it might throw the rocket off target. Can you explain or point me to a l ink that explains what a tommy timer is/how it works and how to attach it with the parachute and the rocket. The glider idea seems good too so any information you could give would be of great help/

[Tim Chen]

We wanted to keep the mouse alive so overcoming the g-force was one of the big problems. A pod attached to the rocket with a long elastic band was an idea that we had, but it might throw the rocket off target. Can you explain or point me to a l ink that explains what a tommy timer is/how it works and how to attach it with the parachute and the rocket. The glider idea seems good too so any information you could give would be of great help/

Welcome Rusty!

Water rockets easily can fly 60-70 meters. You should have no trouble getting one to go that far. You will probably need to use a really small nozzle on the rocket to make sure that the acceleration forces are minimized. A large nozzle always results in rapid acceleration, so the smaller the better.

If you have the wind direction correct you may be able to use a simple "nose comes off at apogee" system (basically the nosecone is just resting on the top of the rocket and when the rocket launches the air flow holds it on top until the rocket stops going up and then the nose falls off and lets a Parachute come out). This system only works for a vertical flight because an angled flight will always be in motion, but I said above the wind direction could help you because you could deploy a really large parachute and the wind would blow the parachute across the river as it descended.

[Rusty]

The parachute idea is a really good one. It looks like the easiest and simplest to make/use on the rocket, as long as it doesn't come off too early during the flight! if i use a small nozzle, will i still get enough thrust to lift the rocket off the ground?
Also, do you know any links to good basic guides on the internet on how to build a rocket, because as I mentioned I am a complete novice at this :P

[Tim Chen]

The parachute idea is a really good one. It looks like the easiest and simplest to make/use on the rocket, as long as it doesn't come off too early during the flight! if i use a small nozzle, will i still get enough thrust to lift the rocket off the ground?
Also, do you know any links to good basic guides on the internet on how to build a rocket, because as I mentioned I am a complete novice at this :P

Even with a small nozzle you will be able to get off the ground. You should run a simulator program and look at the flight profile to see how high/fast a given nozzle size would be for a given weight. You can pick one that has sufficient power to get the altitude you want. The only caution I can give you is you may need to use a launch rail or guide to keep the rocket going straight up while launching. The purpose of these guides is to hold the rocket in line until it leaves the launch rail because it will need a few feet of travel to get going fast enough for the fins to keep it flying straight.

I think there's some more info on building in the Advanced Rocket Topic, but I think there's a number of posts you need to contribute to the forum before you can get in there.

[Rusty]

I've run a few figures through a simulator, but I can't seem to get the distance with a reasonable acceleration. I'm willing to go up to about 15g (about 150 m/s^2), but then I can't seem to get the 70m. And are there any REALLY basic guides out there on how to build a basic water rocket? For example, I don't have any idea about how I'm going to pump it up and launch it, so do you know where can I find specific details on how to make REALLY basic launchers? I've had a look around these forums but it's all way over my head :P

[U.S. Water Rockets1]

I've run a few figures through a simulator, but I can't seem to get the distance with a reasonable acceleration. I'm willing to go up to about 15g (about 150 m/s^2), but then I can't seem to get the 70m. And are there any REALLY basic guides out there on how to build a basic water rocket? For example, I don't have any idea about how I'm going to pump it up and launch it, so do you know where can I find specific details on how to make REALLY basic launchers? I've had a look around these forums but it's all way over my head :P

Welcome to the water rocket forum, Rusty. You might need to add some boosters to your water rocket to get the altitude and distance you want. We did some experiments years ago when we were first trying to set the world record and there was a lot of promise in this method. We abandoned them after a few tests because the rocket was getting too heavy to be competition legal. A large rocket would suit your objectives and wouldn't be competing so you wouldn't need to be rules compliant.

Additionally, we have some more good news for you. We had worked in the past on a tutorial on how to build a basic water rocket launcher. We had almost forgotten about this tutorial until your inquiry here on the forum. We've dusted off the instructions and we are posting them to our water rocket website on Multiply. Check out http://www.uswaterrockets.com for our tutorials (hint: if you sign up for the group you get access to the updates a week before non members)

Good luck with your water rockets!

[Rusty]

You might need to add some boosters to your water rocket to get the altitude and distance you want. We did some experiments years ago when we were first trying to set the world record and there was a lot of promise in this method. We abandoned them after a few tests because the rocket was getting too heavy to be competition legal. A large rocket would suit your objectives and wouldn't be competing so you wouldn't need to be rules compliant.

Additionally, we have some more good news for you. We had worked in the past on a tutorial on how to build a basic water rocket launcher. We had almost forgotten about this tutorial until your inquiry here on the forum. We've dusted off the instructions and we are posting them to our water rocket website on Multiply. Check out http://www.uswaterrockets.com for our tutorials (hint: if you sign up for the group you get access to the updates a week before non members)

Wouldn't adding boosters have the same problem of too much acceleration and g-force?
And thanks for the link, but I can't find out any basic tutorial there. Am I looking in the wrong place or do I have to be a member?

[Andrewlee]

http://dogrocket.home.mindspring.com/WaterRockets/

This is the site that I started from many years ago. It gives a whole lot of basic information, that is really helpful. It describes what a Tommy Timer is, and how to make it, what an Air Speed Flap is, how to make it, and what a FLC rocket is.
I think, for your purpose, you would be better off making a regular Soda bottle rocket. For a container to carry the mouse in, you could always extend the body of the rocket, and make a pod for it to ride in, that has rubber bands inside to help allow the pod to move, with out letting the g-forces to become to great. I'll draw up a picture, and scan it in for you here in a bit.
Although, I still think a glider with a rocket attached may be best, the only problem is controlling it.

[Andrewlee]

Here is a quick doodle of what I was talking about, as concerns to the mouse pod. I think I will try and build one this up coming week.
If you do do this, I would suggest test all ideas with a chicken egg first. Te egg is fragile, so if you can do it with out it busting, and with out suffocating it, you should be able to do it with a mouse

[Andrewlee]

Sorry it's not a better picture....i did it in only 30 seconds. haha

[Rusty]

Unfortunatly most of the links in the website you linked to 404, so not much information gained there, but thanks for trying!
The Pod idea seems great though. As I understand it, the pod is made out of the bottom of two bottles which are Velcroed together, and elastic bands attach the pod to the front of the rocket and the tip of the nose cone. Am I right or is there something I've missed from the drawing ;)
If it works, it could solve the G-force problem.

[Andrewlee]

Actually it is the neck or nozzle end of 2 bottles. And yes, you understand the rest quite well.
My grandmother is in the hospital, and i am staying there with her, so i cant do much from here. But, as soon as I can I will try to build a full scale model with an air speed flap parachute deployment system. As far as cheap and effective goes, I think they are the best for straight up launches. But, I do think you should look into the Tommy trigger, since you will be doing a launch of less than 90 degrees. The Tommy timer is made using a wind up toys winding device. Google Tommy Timer/Trigger and it should bring up some good searches for you.

If you want to see an air speed flap at work, i have a video of STF-TV1's flap in the experimental stage.