Yasothon Bangfai Festival
On Fri, Jan 8, 2021 at 5:09 AM JAMES ROSSON <jmrosson@xxxxxxx> wrote:
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