Rockets

[Dr Jekyll]

Would it be possible in principle to scale up a firework style gunpowder rocket to reach orbit? If so, how big would it have to be?

[IJWS15]

No



The physics means that you can't carry all the fuel (weight) so you have to have stages and leave part of the rocket behind on the way up (like a Saturn 5).

[eharding]

Even for a multi-stage solid rocket, gunpowder would be a bad idea as it has a fairly low specific impulse of around 80 seconds. The best performing solid rocket fuels have a specific impulse of over 300 seconds.

[Eric Mc]

IJWS15 said:

No



The physics means that you can't carry all the fuel (weight) so you have to have stages and leave part of the rocket behind on the way up (like a Saturn 5).

You don't carry all your propulsive fuel all the way to orbit. Most, if not all, of that fuel is consumed during the climb to orbit. The weight you are mainly getting rid of is not fuel but the structure of each rocket stage. That is doubly important with solid fueled rockets because the rocket casings for solid rockets are a lot more substantial and weighty compared to the fairly lightweight aluminium or composite rockets used for liquid fueled rockets.

As has been said, old fashioned gunpowder is pretty rubbish as a solid fuel. After all, it's 1,000 year old technology. What was good for 1100 AD isn't so useful for 2019 AD.

[Lynchie999]

... watch the Doc on BBC4 - Revolutions... about rockets.... it explains it all!

(and watch all the others too, one about cars etc... )

https://www.bbc.co.uk/iplayer/episodes/m00071ql/re...

[anonymous-user]

With what payload?


Solid fuelled chemical "rockets" are used to provide massive thrust to weight ratio, which is perfect for helping a system off the pad, but they don't have a very high specific impulse so can't carry a significant payload into orbit. Hence lots of systems use solid fuel "boosters" to assist, and these are jetisonned once they burn out at a relatively low altitude. For example, the Space Shuttle used a pair of Soild Rocket Boosters (SRB), each developing 13,800 kN of thrust and seperation post burn-out occurs at 'just' 45km altitude.

Solid rockets are used for small payloads:

https://en.wikipedia.org/wiki/Long_March_11


and for low altitude sounding rockets:

https://en.wikipedia.org/wiki/Sounding_rocket

[MartG]

There are actually quite a few solid fuelled multi-stage rockets which can put a sizeable payload into orbit - ESA's Vega for instance

https://en.wikipedia.org/wiki/Vega_(rocket)

[Smeeeeeg]

Not scaling up, but if you stick 'em together you could in theory reach space, but not orbit.

Oblig. and interesting XKCD link: https://what-if.xkcd.com/24/

[Alias218]

As already alluded to, I would imagine the Tsiolkovsky Rocket Equation would hit hard in this particular instance.

I bet it would be quite smoky though! Could even add various metal salts across varying strata to give us a pretty firework light show as it ascended.

[monoloco]

there are plenty of solid propellant rockets in use but these use far more complex/efficient fuels which are all held as a single solid block rather than the loose black powder of a firework. A firework charge burns as a simple 'cigarette burner' -ie from the bottom end which is very problematic for a large version as it would expose the casing to severe heat issues and also upset the balance of the rocket as it loses weight at the bottom. 'Proper' solid fuel rockets burn outwards from a star-shaped central tube which ensures the burning area remains constant, weigh loss is more evenly distributed and it avoids the heat hitting the casing until the last possible moment.