Challenge: build an improvised rocket.

[Halo_003]

1 hour ago, PB666 said:

Yes, indeed lets not encourage people to build rockets unless they can get some expert help, seen a couple of deaths associated with home-made explosive and one fellow missing the end of his foot.

 

Additional warning: Be safe and don't get SWAT'd if you take up the challenge here. Especially if you're in America.

[fredinno]

9 hours ago, Spaceception said:

I don't think that's as strong, it'd need to be pressurized, are there other (More powerful) chemical reactions?

Coke and Mentos?

[p1t1o]

2 hours ago, magnemoe said:

The rocket effect is just by the expanded gasses, you would get an larger effect with steam. The fireball happen afterward as the gass mixes with air. 
Normal gas leaks are les dangerous as the gas is not so well mixed with air. 

I see what you mean, I was assuming air would be part of the equation. It would probably be very difficult to build a chamber to do this.

[Nothalogh]

11 hours ago, SinBad said:

I'm not sure this is a socially responsible challenge...

If "socially responsible" ruled the day we'd still be climbing trees

[Temstar]

9 hours ago, sevenperforce said:

Would it be able to use a converging/diverging nozzle and achieve supersonic exhaust velocities?

As others have said, water doesn't expand so there's no need for the diverging part of the nozzle. But some sort of nozzle is useful! If you look at the video @magnemoe linked where they used det cord to blow wide open the bottom of their water rocket the rocket kind of just release its entire load of water in a puff and doesn't travel very far. If you instead look up videos of water rockets made from soft drink bottles you can see they get much more delta-V out of their propellent because the mouth of the bottle forms a nozzle that increase the Isp.

In fact, because soft drink bottles have that handy thread on it's mouth you can create a range of nozzle attachments that screws onto the end and further constrict the water flow to further increase the Isp by trading away thrust.

In a two stage rocket, I imagine the first stage will no nozzle attachment for high thrust low Isp, then your upper stage would have a constricted nozzle for high Isp low thrust.

Edited February 25, 2016 by Temstar

[Temstar]

I know KSP like to joke about "parts found lying by the side of the road", but here really is a rocket built out of such parts.

[FishInferno]

We're not allowed to use hobby model rocket engines, correct?

[QuesoExplosivo]

Right. But Zn/S or rocket candy is allowed (just make sure you know what you're doing). I happen to have the materials to make both in my house right now (although I probably won't have time to actually build an improvised rocket until March).

Edited February 25, 2016 by QuesoExplosivo

[Camacha]

1 hour ago, FishInferno said:

We're not allowed to use hobby model rocket engines, correct?

How about full size rocket engines? Or a spare Saturn V?

Edited February 25, 2016 by Camacha

[magnemoe]

2 hours ago, Nothalogh said:

If "socially responsible" ruled the day we'd still be climbing trees

We would not gotten up in them in the first place, some will fall down, that is it break and so on. An very radical idea. Coming down was easier. 
 

[FishInferno]

23 minutes ago, Camacha said:

How about full size rocket engines? Or a spare Saturn V?

I'll take that as a yes

[Camacha]

1 minute ago, FishInferno said:

I'll take that as a yes

"I built an improvised Saturn V with this duct tape and a spare Saturn V I had lying around."

[p1t1o]

Ooh I've remembered something, I read it here:

http://library.sciencemadness.org/library/books/ignition.pdf

" One of the oddest combinations to be investigated was tried
by RMI, who burned d-limonene with WFNA. d-limonene is a terpene
which can be extracted from the skins of citrus fruits, and all
during the runs the test area was blanketed with a delightful odor of
lemon oil. "

 

That oil that squirts into your eye when you are peeling lemons or oranges? Almost pure Limonene, although you are going to need a lot of lemons... Also you can legitimately say "Argh! I got rocket fuel in my eye!"

We're talking legit rocket engines here, so I wouldn't try launching anything made of plastic bottles with it!

(Safety note kids: flammable liquids are dangerous - Don't run with lemons.)