Jello.. erm, Hello from Pennsylvania

[Michael Wescott]

Hi everyone.

I just got back from a flight to Neverland, and boy are my arms tired. Heard it before, huh?
Would you believe two 3-liter bottles in my armpits, and a rudder clenched in my buttocks?

Well, I'm a 50 y/o step-dad to 4 teenagers, and recently the youngest (6th grader) announced to me that she needed 2 soda bottles for school. When I asked why, she said there's a water rocket fair coming up, and they had to construct one each.

3 guesses as to what I chose as a new family hobby... no points for third place.

I went online and viewed 6 videos on construction, 12+ web pages explaining rocket and launcher design, and even the NASA water rocket site. This was the only TRUE forum that seems to cover a diverse number of topics. Kudos guys.

I took the best from all I saw (1/2" S-40 PVC), and the one thing that I believe is not to be compromised on is the design of the seal between launcher and rocket. I need to find something supple and conical, or maybe made of soft neoprene with a rubber washer at the tip. This would add durability and allow for "springiness" of the bottle for ease of locking into launch position.
I had thought of a spring, topped with a metal washer, then neoprene glued in place.

Any thoughts?

[WRA2]

Hi everyone.

I just got back from a flight to Neverland, and boy are my arms tired. Heard it before, huh?
Would you believe two 3-liter bottles in my armpits, and a rudder clenched in my buttocks?

Well, I'm a 50 y/o step-dad to 4 teenagers, and recently the youngest (6th grader) announced to me that she needed 2 soda bottles for school. When I asked why, she said there's a water rocket fair coming up, and they had to construct one each.

3 guesses as to what I chose as a new family hobby... no points for third place.

I went online and viewed 6 videos on construction, 12+ web pages explaining rocket and launcher design, and even the NASA water rocket site. This was the only TRUE forum that seems to cover a diverse number of topics. Kudos guys.

I took the best from all I saw (1/2" S-40 PVC), and the one thing that I believe is not to be compromised on is the design of the seal between launcher and rocket. I need to find something supple and conical, or maybe made of soft neoprene with a rubber washer at the tip. This would add durability and allow for "springiness" of the bottle for ease of locking into launch position.
I had thought of a spring, topped with a metal washer, then neoprene glued in place.

Any thoughts?

Welcome to the forum

Did you consider using an o-ring to seal the rocket on the launcher. Here is an excellent tutorial:

http://www.wra2.org/forum/viewtopic.php?f=46&t=270

An outer seal as you suggest may be prone to leaking.

[thampson]

Welcome Michael

You may want to consider a gardena style nozzle and quick release launch fitting as well. These components can be purchased from most local hardware sores or irrigation type stores. These types of nozzles and fittings work well and will provide an airtight seal to 180+psi which should be more than enough for a school competition.

Here are a few links with pictures of how we use them on our launcher.

Nozzle links
http://wrocket.hampson.net.au/?p=948
http://wrocket.hampson.net.au/?p=243

Launcher Links
http://wrocket.hampson.net.au/?p=1254
http://wrocket.hampson.net.au/?p=1238
http://wrocket.hampson.net.au/?p=1132

hope these help. Good Luck

-todd-

[Aquafire]

It is really hard to seal the bottle against the bottom of the launcher. You need to get the seal inside of the threaded part of the bottle. If you try and seal at the lip you will discover the pressure will push the rocket away from the seal and it will leak as very litttle pressure. Try putting a rubber stopper or oring inside the bottle end, the pressure will be acting at perpendicular to the seal and not straight against it.

[U.S. Water Rockets1]

Hi everyone.

I just got back from a flight to Neverland, and boy are my arms tired. Heard it before, huh?
Would you believe two 3-liter bottles in my armpits, and a rudder clenched in my buttocks?

Well, I'm a 50 y/o step-dad to 4 teenagers, and recently the youngest (6th grader) announced to me that she needed 2 soda bottles for school. When I asked why, she said there's a water rocket fair coming up, and they had to construct one each.

3 guesses as to what I chose as a new family hobby... no points for third place.

I went online and viewed 6 videos on construction, 12+ web pages explaining rocket and launcher design, and even the NASA water rocket site. This was the only TRUE forum that seems to cover a diverse number of topics. Kudos guys.

I took the best from all I saw (1/2" S-40 PVC), and the one thing that I believe is not to be compromised on is the design of the seal between launcher and rocket. I need to find something supple and conical, or maybe made of soft neoprene with a rubber washer at the tip. This would add durability and allow for "springiness" of the bottle for ease of locking into launch position.
I had thought of a spring, topped with a metal washer, then neoprene glued in place.

Any thoughts?

Since you are from the US, you will be able to easily get all the materials needed for duplicating our launcher design and adapting it to your own use. Follow the link above to the topic regarding our tutorial and let us know what you think!