How would you rocket?

My little girl got estes rockets for her 4th birthday, maybe that won’t end well but.... it happened. 

4 years old?

How about a cardboard Sonotube with a plexi window she can climb inside and look out?

In reply to SVreX :

It would take a lot of Diet Coke and Mentos to get her airborne.

Woah, go big or go home, huh?  Pretty slick looking rig.  One of these:  kept me occupied for hours as a kid.  Reasonably safe in comparison to the other stuff I played with.   

Had a lot of fun messing with water rocket kit I got as a birthday present, till one landed on the hood of dads new 65 Mustang. Yes, they were red. The water rockets disappeared after the hood incident. Moved on to Estes rockets a few years later.

Herbie Handcock showed me how to rockit.

Short test video. The launcher release is sticking. Dana shot it, sorry for vertical video

Dang dude, good job!  Now I want to build one.

In reply to paranoid_android :

Took about an hour to put together, including the 3 times I had to take it apart, maybe $25 worth of fittings. The most expensive part was a pack of air fittings from HF that I needed anyway. I highly recommend it to kill am afternoon. Although now I wanna learn about fins and stages.

Small update today. My end caps came in so I got to fix it. With the bulge pipe instead of an Oring I seem to be limited to 80psi. With water, that means about 120 feet, without water about 90 feet. So next upgrade is going to be an o ring setup. 

It sounds like a gun shot without any water in it though, which is fun. 

Now I'm wondering if I just ran pipe off my compressor drain line what would happen when I open that up.

PVC is not recommended for air pressure. It can explode and turn into a giant frag grenade. Black pipe is not much more money and you can get all the bits you need at your local plumbing supply.

Some PVC has a pressure rating.

If you use a sprinker valve, you have an electric launch release. Man, I think my 3 and 6 yo nephews would dig this very much.

The weak point on mine is the bulge where the bottle sits. It won't build enough pressure to pop the bottle, which will(should) break before the PVC does. 

If I still had access to a thread cutter, I would agree on black pipe, but the short pieces needed  for something like this add up very very quickly. 

If it was constantly under pressure, or being used in cold weather, I'd be a bit more concerned about the pvc bursting, and while I'm sure there's an argument to be made about it filling and emptying rapidly weakening the walls of the pipe, I'm more worried about the falling 2 liter bottle. 

I pulled this back out today too blow off a little steam from this weekend. I've learned a little bit.

From sitting outside in the sun before use, the pvc seemed to have swelled or something. On my first shot, without water, I hit 85psi, a personal best. Second shot was 80. Then I added water, from the creek so maybe 70 degrees? it felt cold on an 84 degree day, and could barely pull 70psi. 

The bulge in the pvc is definitely my weak point. I think, to distract me from other stresses, I'm going to make an o ring style launcher

What I see most people doing is putting the o ring on a piece of something hard and rolled up, then gluing that in between 2 pieces of pvc. They get good results, reports of 120+ psi and no bursting. So I know it will work.

I'm curious though about just carving a channel in the pipe wall to mount the o ring in. Will it reduce The integrity enough to become a bomb, or will it just hold on? I'm guessing there's a reason I haven't seen many people doing it this way. 

I could also try to find the right quick connect hose fitting and use it inside the launch tube, not the cheapest way to solve this, but if I can find one that fits, definitely the easy button. 

I also took a trip to the fair and checked out the 4h kids rockets. Lots and lots of duct tape, heavy looking card board and fiber board wings. I noticed all of their bottles were 2 spliced together, and the top portion was sealed off with weight inside. Nobody was around for me to pick their brain, but looking at the winners from this year's contest versus the competitors I saw some very distinct differences. 

One winner in particular had 4 fins that looked more like legs. That was the hang time winner at just under 4 seconds. Unfortunately it was blocked off from each and under blacklight so I couldn't get any good pictures. 

This particular 4H group has programs starting for kids age 5, so next summer I think we're going to join them.