Camp Airbender: Water Rocket Derby

[bugwubber]

Well it is almost here! Camp Airbender will be held next Thurs/Fri. I will be running the water rockets station where scouts will get 35 minutes to build and fly water rockets. On the second day, I will do a demonstration launch that will include an attempt at the Unreinforced 2-liter class world record for Team SPEW, and depending on how time goes, a couple FTC rockets and the blinking LED/Servochron equipped Thingamajiggy.

I will have the scouts building rockets modeled after Just Add Water since our time will be so short and it will also help that we'll be launching them 5 at a time. Over the course of the day I expect we'll put over 200 rockets into the air!

Anyone who has run a water rocket event have any last minute advice or observations to pass along?

Thanks,

Bugwubber

[bugwubber]

Today the Scouts built and launched 200 rockets- most launched at least twice!
In the picture below, the Scouts wanted to know how altitude would change if the bottles were mostly water.

DSC00119sm.jpg (572.45 KiB) Viewed 61 times

I'll post some more pictures in a day or so. For now, must sleep!

Bugwubber

[arjan]

Very cool picture!!!

[bugwubber]

Alright well all I can say is wow!

We had initially planned to introduce the Scouts to the two bottle, self jettisoning water ballast rockets that I came up with along with the USWR box fins similar to this:

photo.JPG (134.11 KiB) Viewed 44 times

But, you know what they say about the best laid plans of mice and men...A check the morning of the event determined that we were well short of the needed 400 bottles to pull that design off. So instead we improvised and went with 1 bottle rockets for most of the day with simple cardboard nosecones and fins. Of course they did not fly well but regardless, we all had a blast. The goal of not having a bunch of lawn darts was met. Only a couple rockets came down at a high rate of speed. And believe it or not, only 1 car was hit, with no damage. The second day was too windy and the wind was blowing in the wrong direction for us to do a high altitude demonstration launch so that had to be scrapped.


It was quite the day-
The Scouts came in groups of 20-30 and had 35 minutes to build and launch before moving on to the next station at the camp. To save time and reduce waste, we started pre cutting the fins and nosecones for the Scouts. As soon as 5 scouts had rockets built, we started launching. This fast pace meant that most rockets were launched at least 2 times. In total, we definitely hit the 400 launches mark- probably closer to 450. Should have kept tally marks in the log book!

After the camp was over, a Scout walking past me raised his hand for a HI 5 and said "Hey Rocket Dude"!

Yeah I had a lot of fun.

Some things that worked really well-
1. 5x rocket launcher. I don't think we could have launched them all 1 or 2 at a time.
2. Water tower. The lower pressure of the water tower filled the rockets to the right level every time, hands off. Made for a great visual effect as well.
3. Full bore launch tubes. At 50-60 psi, there were no underpowered rockets
4. Nozzle reamer/bevel tool. This was absolutely indispensible. You must make or get one!
5. Sunscreen. SPF 50
6. 32 gal air compressor tank. Only filled it 3 times.

Learned some valuable lessons along the way myself-
1. Confirm your bottle count the week prior. Leave yourself time to get more if needed.
2. Get two more rolls of duck tape than you think you'll need.
3. A ground/support crew of 5 would be a good ideal minimum.
4. Cut the fins ahead of time. A large event is not the best time to ask everyone to come up with their own design.
5. While an emergency escape zipline like the kind NASA has on their launch pads would be really cool to incorporate, it'd be a really big distraction. Glad I left that idea on the table.
6. Wash the bottles before the event
7. Launcher building tip: for full bore launchers- make your launch tube removeable! Use screw on valves and couplers.
8. Keep a bowl of water at the launcher to dunk the nozzles of the rockets in prior to loading. Verify they are sand/dirt free before loading on the launcher.
9. If a rocket jams because of sand, you'll be glad you can remove the launch tube and if you brought a spare, the show can continue.
10. Everyone has a hard time understanding the box fins. Just cut them ahead of time and show by example.
11. Don't forget a hat!

So anyway, here is a slideshow of pictures my ground crew took:

[youtube][/youtube]

Thanks,

Bugwubber
a.k.a. Rocket Dude

[Spaceman Spiff]

Today the Scouts built and launched 200 rockets- most launched at least twice!
In the picture below, the Scouts wanted to know how altitude would change if the bottles were mostly water.

DSC00119sm.jpg

I'll post some more pictures in a day or so. For now, must sleep!

Bugwubber

That picture and your launcher are really cool. You have made a really wonderful design! I'm glad I spotted this topic! One thing I think is really fascinating about this image is that all of the rockets have the air pulse at the same altitude and time if we go by the size of the burst cloud, but the rockets a fraction of a second later when this picture was taken are all at different heights! That's really interesting!

[bugwubber]

That picture and your launcher are really cool. You have made a really wonderful design! I'm glad I spotted this topic! One thing I think is really fascinating about this image is that all of the rockets have the air pulse at the same altitude and time if we go by the size of the burst cloud, but the rockets a fraction of a second later when this picture was taken are all at different heights! That's really interesting!

Thanks! That was an interesting launch. We used the water hose (instead of the tower) to load the rockets as full as possible and then added air pressue. That's how we got such massive water columns for the size of bottles used.

Since they were full of water they launched relatively slowly. Aerodynamics of the fins/nose cones and potentially friction differences on the launch tubes may have played a factor in the height differences.

Bugwubber

[Spaceman Spiff]

That picture and your launcher are really cool. You have made a really wonderful design! I'm glad I spotted this topic! One thing I think is really fascinating about this image is that all of the rockets have the air pulse at the same altitude and time if we go by the size of the burst cloud, but the rockets a fraction of a second later when this picture was taken are all at different heights! That's really interesting!

Thanks! That was an interesting launch. We used the water hose (instead of the tower) to load the rockets as full as possible and then added air pressue. That's how we got such massive water columns for the size of bottles used.

Since they were full of water they launched relatively slowly. Aerodynamics of the fins/nose cones and potentially friction differences on the launch tubes may have played a factor in the height differences.

Bugwubber

I found that putting extra water in the rocket allows it to take off more slow and gives it a much longer water column, and this helps if you want totake a picture of the rocket lifting off. It is hard to catch the rocket with water still coming out if it moves quick.

[bugwubber]

I found that putting extra water in the rocket allows it to take off more slow and gives it a much longer water column, and this helps if you want totake a picture of the rocket lifting off. It is hard to catch the rocket with water still coming out if it moves quick.

Definitely. Most of the time I just use video frame grabs. This time I had a helper taking pictures with my dslr.