In the past week I shrunk the system considerably:
And I managed to get 24(!) 1 liter bottles with the heavy, and I mean heavy quality PET. These bottles easily hold up to 15 bars (217 psi). And I built a 5 liter booster with Robinson couplings (bottom to cap). The whole assembled thing weighs a whopping 723 grams and is over 160 cm long (over 5,5 ft). I have no idea what will happen, but I will launch at 10-12 bar... and 1,6 liter of soapy-water... The blue rocket in the picture below is the one that crashed last week. I rebuilt it and it’s half the weight of the white one, but holds only 8 bar (116 psi) I’ll launch that too with about 1,3 liters of soapysud water.
New rocket!
Heavy?
Robinson Coupling
Old and new...
Fins and nozzles...
The famous nozzle (below) from the mini dartrockets (that are comercially available) These screw right on the bottle, the washers suck, but hey! No more fidgeting like above!
Simple launcher, a reverse valve from a bicycle... It sticks through the gardena and thus makes it possible to tighten that to the baseplate of the launcher. You can see the steel rods left and right that I simply stick in the Dutch mucky soil. Better than tent spikes! Left of the gardena a thin iron rod of 4 ft (120 cm) with a small pipe around it, that pipe gets connected to the rocket: vertical guidance! I guess you guys don’t have these reverse valves (fietsventiel in Dutch, the fun thing about clicking the link is: these Google results are 50% about simple waterrockets (page two)!!! ). These ventieltjes are the best, they hold up to 20 bars maybe more, never tried higher, the tires kept exploding... and they are super cheap, like 50 cts each!!! If you guys want some let me know... they are great!
