All of the "large" BP rocket motors I have seen in the last century used BP
modified with AP and compatible burn rate suppression chemicals to create
manageable burn rate exponent.
Does that count?
The perpetrators of the BP-AP tech were located in Pyrotechnics side of world.
Brothers from Indiana made & sold 29/38mm motors in 90's, forget their names.
Most popular was called Silver Streak, thanks to heavy load of metal flake that
showered launch site with burning metal. Dr "Rocket" Barr (in MI?), pioneered
BP-AP stick rockets up to ~2.5" OD, but lack of large BP success pushed him to
use silicone binder AP composites in late 90's, early 2000's. Large BP only
rockets fight a huge thrust to weight challenge as they get larger, thanks to
weight of pressure vessel. Folks quickly dumped the low ISP fuel with modern
composite options readily available via amateur rocket hobby.
NAR used to have a branch that kept records for largest/highest using BP. The
were massive clusters of Estes motors ignited using flash pan of BP. Wild site
to see first hand, when nearly 100 estes motors rip into sky. :) Sort of
remember the largest record was several hundred Estes motors?
NAR Highest Rocket used to be one using the non spark producing version of 38mm
Silver Streak BP-AP motors. I used to fly clusters of (7) 38mm BP-AP motors
for giggles in my early days of joining HPR hobby. Back then ~20% blew up
randomly as they were finicky beasts, despite using a high pressure composite
Al/paper casing.
Pryo history claims that Chinese used NC modified BP to make largest 'rockets'
for early BP war rockets, again using modified BP for same reasons modern
rocketeers switch to composite fuels.
Have several Pyrotechnic books and journals with details on historical BP
rockets stashed away. Most of the historical BP information I learned was
published by Pyro folks such as: "Journal of Pyrotechnics" published by
Kosanke, or "American Firework News" articles published by Drewes.
Distribution used be very limited to only certified pyrotechnic operators or
verified responsible adult members of large pyro clubs like PGI. Supposedly
this keep neighbor kids from getting hurt?
The biggest challenge with BP rockets is there were not the end product for
Pyro world. So the motor information is co-mingled inside details on stick
rockets with special high altitude display shells on top. Makes BP rocket motor
data hard to find.
Apologies in advance if you already know this history. Your post triggered one
of my few remaining memory cells that works, to spew useless old information of
little value to most folks.
Cheers!
On January 8, 2021 at 2:03 AM Dr Edward Jones <RocketPioneer@xxxxxxxxx> wrote:
I am supposing that black powder has been the most popular amateur
rocketeer's propellant since time out of mind. (I've read first-hand
accounts of Sum Ting Wong's experiments with giant bamboo thrust
chambers that static-tested Isp of >60 seconds.)
So what's the biggest, or heaviest, or highest-flying BP rocket anyone
has heard of? I bet it wasn't an Aerojet-Rocketdyne reaction motor.
Thanks
Edward
Rocket pioneering historian