Dangerous rockets

[insanity]

My team's rocket is going up hopefully this weekend! It should be a big one. We built the fins out of Plexiglas and used PVC molding glue to put them on. We're going to build the eject assembly today and I've got to figure out the launch pad.

We solved the launcher issue using a youtube hack (cut the top of a christmas light and fill it with gunpowder. All of the ground tests have been deemed a 'go' with one more big one to go until we try and go for vertical flight.

 

[Warthaug]

Though I wonder why high powered rockets are not launched at a slight angle? They could go up a few hundred feet off course, then if the parachute fails then it will land a ways away, and if the parachute goes correctly, it can drift back to where it launched.

Sometimes they are, but its fairly rare (at least up here). The reasons are pretty simple:

1) High-powered rockets are both heavy (compared to consumer-types) and can have extremely high thrust. So stabilising a pad at anything other than vertical can be a challenge. Back in my EX days I had an angled pad tip during a launch - not cool.

2) Surface winds seldom flow in the same direction as winds at altitude. as such, a "good" angle can be hard to figure out (especially when engine performance is not entierly known; often the case with experimental rockets).

3) People often shoot for max altitude; so anything other than vertical takes them away from their goals.

As for safety, its common to place the launch areas up-wind; this generally keeps things quite safe. But you do get the odd launch that goes haywire, at which point there is no "safe" place, only vigilance keeps you safe.

Bryan

---------- Post added at 04:02 PM ---------- Previous post was at 03:54 PM ----------

Has anyone ever tries a hydrogen-fueled rocket? I've thought about it, but I'm not sure how to pressurize hydrogen and an oxidizer that much... How about liquid or gaseous fueled rockets?

Liquid/gas rockets are extremely complex, and have quite complex engines. As such there is not many experimetal/hobbiest types using them. That said, hybrid rockets - gas oxidizer (usually nitrous) with a solid fuel - are becoming more common. These take advantage of the fact that its pretty easy to build a tubing/orifice system that can provide nitrous at a useful rate, while vastly simplifying rocket design by avoiding the difficulty of having to do the same for a liquid or gaseous fuel.

As for the fuel, different people use vastly different mixes. I've seen sugar-fuel like mixtures (minus the nitrates), epoxy-metal mixes, and many others. ISP's tend to be better than sugar-KNO3, but less than AN-based propellants.

Bryan

 

[Blacklight]

My step brother was a member of a high powered rocketry club for a while. He had a 6 foot tall rocket that took an engine the size of a soup can (it was like a bigger version of those rocket engine you buy for the little flying models). He could only launch WITH the club and before every launch, the club had to clear the launch with local air traffic control. Also, you had to stand QUITE A LONG distance away from where the rockets were primed to launch (WAY the hell out in the middle of a field so far away that you could barely see them on the ground). The club was extremely safety concious and the several times I went, I didn't see anyone's lives get put in danger. NOW... a lot of those people in those videos..... IDIOTS.:uhh:

 

[Warped]

It looks like fun!

 

[supersonic]

It looks like fun!

As long as you aren't one of the idiots in the above videos.

 

[Brycesv1]

or if you ARE one of those idiots, at least get it on video so we can laugh as we watch it on youtube... just try to stay off the evening news :thumbup:

 

[River Crab]

Has anyone ever tries a hydrogen-fueled rocket? I've thought about it, but I'm not sure how to pressurize hydrogen and an oxidizer that much... How about liquid or gaseous fueled rockets?

Estes has actually sold gaseous Hydrogen-fueled rockets, but not what you're thinking. They work by combusting the hydrogen that is separated from water in a Hoffman apparatus, which is kind of cool but not really. I've never tried one though.

If anyone's going to do something stupid, go find a discarded oven and use the door as a shield. Of course, don't get smug about it, that would just add to the comedy if the rocket comes and does a loop into your behind.