I've always wondered why large fireworks use explosive 'lifting charges' rather than a proper rocket design (slower burning fuel). Is it a legal limitation against creating missiles?
In contrast, rockets are very inefficient. Except in the special case where the exhaust velocity equals the rocket’s velocity, a large amount of the engine’s energy ends up as kinetic energy in the exhaust.
>Simple stick stabilized rockets work out well for small pyrotechnics, but don’t scale well. If you want bigger bangs and larger bursts in the air you need to get more payload up there. A larger rocket, with a few pounds of excitement at the front end, would require a stick 20-30 feet in length; not very practical.
En essence, rocket like designs are less stable, less predictable, and more complicated.
It is hard to have something simpler and cheaper than a ball.
While I can't seem to find any specific rules from the FAA, Tripoli, or NAR specifically prohibiting the launch of a rocket that deliberately explodes in mid-air, my impression from my recollections of talking to expert rocketeers at launches (and asking them the sorts of questions a 10-year-old might reasonably ask, like "can I launch a rocket from an RC plane?" or "Can I launch a rocket from another rocket?") is that this would be thoroughly frowned upon my launch officials and/or regulatory bodies, and if the rocket exceeds the specifications for "Class 1" it'd require prior FAA authorization (and I can't imagine "Hey I'm gonna strap an H motor to this explosive ball and hope for the best" to go well on that front).
Yes, it's possible to stabilize bottle rockets with fins (to adjust the CP), but as the article hints, the stick is multipurpose in helping with launch, as well as stability (plus being easy to manufacture with low precision).
I just published a follow-up article talking about bigger rockets. http://datagenetics.com/blog/july22020/index.html
Aeronautics is a complex science and my articles are intended to pique interest, not oversimplify or belittle. It's a hard balance to explain things in a few hundred words. I hope you enjoy them and, if there is interest, they become the catalyst for you to learn more. It's a fascininating subject.
Re: the stick...
> the stick is multipurpose in helping with launch, as well as stability (plus being easy to manufacture with low precision)
True. Model rockets achieve mostly the same, except instead of keeping the stick attached to the rocket, the stick is instead attached to the launchpad, and is stuck through two (or more) holes on the side of the rocket (fancier/bigger rockets typically opt for rails, but a simple metal rod is typically good enough for smaller rockets).
Like I mentioned, if such a rocket were to be built to be disposable (i.e. with a "recovery system" that just disintegrates the rocket instead of something like a parachute), they could probably be cost-competitive and performance-competitive with mortars (probably a slightly-higher upfront cost due to the launchpad and electric ignition system instead of a traditional fuse, but not by a whole lot); that they ain't typically used for pyrotechnics seems to imply a regulatory issue with doing so.