Water Rocket Record

On YORF, Joe Wooten posted:

Homemade Rocket Hits Record-Breaking 2,723 Feet Using Only Water and Air

Your move, Diet Coke and Mentos.

To see the video: CLICK HERE
The launches happen at 11:30 on both videos.

There's a fairly robust community that builds and launches water rockets. You know, regular rockets in pretty much every way except for the fact that they use pressurized water and air to launch into the sky. One such water rocket from a South African team of students​ at the University of Cape Town just broke the world altitude record with it's most recent launch.
The university team managed to grab the record thanks in part to an extremely lightweight frame. The rocket's frame weighs just over three pounds counting the on-board camera, parachute system, flight computer, and carbon fiber skeleton. The team had tried for the record two times before but had been plagued by equipment failure and air leaks. The third time took.​
The group launched their rocket, which clocks in at around nine feet in height, two different times on August 26th to get an average between the two. The first made it to 2,740 feet and the second to 2,707 feet for a world record of 2,723 feet, averaged. That handily beat the previous 2,044 foot record, set in 2007 by a U.S. group​.

Source: University of Cape Town via Toyland

Some Water Rockets - Variations

From the Air Command Rockets website:

And these are just the smaller ones!

Check them all out CLICK HERE

Water Rocket Launch, May 10, 2015

My first two water rocket launches were at the last Orlando R.O.C.K. launch.
I had attached just the top of a second bottle to act as a nose cone. No parachute yet, I was hoping the nose would fall off at apogee and prevent it nosing in.
On the first launch the bottle floated in slow and landed on it's side. No nose section separation.
The second launch the bottle nosed in and landed hard! I had to work on a more reliable recovery.


The Stratofin instructions tell you to cut off a bottle top 4" from the tip. For me (and the bottle I used) that was too tight and prevented the nose from falling off.
I trimmed back the bottom of the nose section a bit shorter.

Today I tried with a 12" Odd'l Rockets parachute.
The tape on the sides was to keep the nose cone in place while I walked to the schoolyard.


I had five attempts. On the first try the rocket wasn't fully locked down and went up 20 feet during the first pump. I'll have to adust the friction fit of the lock ring over the cable ties.

The second launch was at 40 psi. Straight and true to about 150 feet. The nose cone stayed on and the rocket nosed in!
I popped the dents out of the nose section. These PET bottles are tough!

On the third launch the nose cone did separate. The parachute opened about halfway down for a soft landing.

The fourth try was like the first, the rocket popped off the launcher on the first pump. From now on I'll have to double check the cable tie release before using the air pump.

The fifth launch was perfect!
45 psi got the rocket up fast to about 200'. At apogee the nose cone fell off and the parachute opened - Success! This was how they should recover.

Water rockets leave the launcher very fast and decelerate to almost a standstill at apogee. They seem to hang in place before coming down.

Three girls were kicking around a soccer ball asked about the rocket.
They were surprised by how high it flew and how simple the launch mechanism was. It was nice to have some success in front of a small audience.

www.aircommandrockets.com describes the recovery method I tried as:
N.O.A.A. or Nosecone - Off - At - Apogee. 
"A parachute deployment technique where the nosecone is suppose to fall off as the rocket reaches apogee allowing the parachute to fall out".

This deployment looks to be reliable, simple and effective:
Squashed Balloon Parachute Deployment
http://www.h2orocket.com/topic/balloon/balloon.html

StratoFins Water Rocket, Launcher Assembly Part 4

Dry fit all the PVC pieces before using any glue!
When using PVC glue you only have a moment to get the tube pieces lined up before the glue grabs!

Get very familiar with all the pieces and how they go together.

I used very thin strips of masking tape to line up the tubing. Adjoining pieces were marked with letters.
When sliding the glued pieces together I just had to line up the tape strips and matching letters.

This was especially important with the vertical launch tube! I wanted to be sure it was straight up.






After the PVC launcher is glued together it is attached to the flat plastic base with the two remaining cable ties.

Cut off the excess tails.

Here's the finished launcher.
The pink cord is tied to the release ring and threaded under the tubing to one side of the base.

You may have to adjust the tube clamp so when the trigger collar is slid up over the cable tie ends it is held up with a friction fit over the ties.


To launch the water rocket -
Stake down the launcher base with tent pegs (included with my set)
Fill the rocket (bottle) with water, 1/6 to 1/3 full.
Lay the release cord straight and away where no one can snag or pull on it until you are ready to launch.
Tip the launcher on it's side and slide the rocket over the vertical launch tube.
Slide the rocket down the tube, onto the bump (raised area on vertical tube) sealing the bottle.
Be sure the cable ties "click" and lock over the large ring on the nozzle.
Slide the trigger collar (with the cord attached) up and over the cable tie ends. This should be a friction fit locking the cable ties over the nozzle ring.
Turn the launcher and bottle up so the launcher base is flat on the ground. Stake down the launcher base.

Connect a bicycle pump (with pressure gauge) to the valve on the launcher base.
Pump to 30 PSI to start. ((Maximum pressure is 120 PSI!)
Don't stand over the rocket when pumping air into the launcher.
Countdown and pull the trigger collar release cord. LAUNCH!

StratoFins Water Rocket, Launcher Assembly Part 3

The low ends of the cable ties and tape are cut off 3 3/4" down from the top. The instructions say to use scissors, I used a sharp blade and straightedge.

The tape and ties were scored and cracked in half down the cut line.

Wrap the assembly around the vertical tube with the bulge on the low end. I used a small piece of tape to hold the ties closed.

Center the hose clamp on the tape and tighten the screw.

You assemble the fins onto the nozzle.
Notice how the fins are locked onto the center nozzle by the bottle lip.

The bottle is slid down until the ties just latch onto the bottom lip of the StratoFins nozzle.

StratoFins Water Rocket, Assembly Part 2

Before assembling I sanded off any printing on the PVC tubes.

You don't have to do this, I just wanted the launcher to look cleaner.

Nine of the cable wraps are used on the release ring.
Line up the tops with a straight edge, the flat sides are down.

For now it helps to hold these in place with a piece of masking tape.

A 5" long piece of duct tape is set over the ties, 4 1/2" down from the top.
Don't tack the tape on your work surface, just stick it to the ties underneath.

Lift up the cable tie assembly and turn it over.
Apply another 5" piece of duct tape directly over the top of the first piece of duct tape.
This is set down sticky side to sticky side.
Set it down carefully, it will stick quickly and very strong.

Press a fingernail between the strips making trenches between the strips.

StratoFins Water Rocket, Assembly Part 1

Here's the parts for the StratoFins launcher.
My "kit" came unassembled.
I'll have to supply duct tape, PVC glue, scissors, screwdriver and a ruler.







The StratoFins slide onto the "Nozzle" and the assembly screws onto a 2 liter soda bottle.
The plastic fins are made from high impact plastic and should survive some hard landings.






Parts of interest:

The vertical launch tube with the swelled ring. (The lip of the bottle sits on this enlarged area of the tube)
A Shrader valve already attached to a PVC cap.
The launcher base is cleanly cut from hard black plastic.