[SS2S-Main] Re: Rocket help request

  • From: "James Jason Wentworth" <blackshire@xxxxxxxxxx>
  • To: <sugarshot@xxxxxxxxxxxxx>
  • Date: Wed, 1 Jan 2014 16:43:26 -0900

Hello William,

Thank you for replying to my query.  Actually, I'm looking to replicate the 
paper-cased, single-use Rapier jet motors that Dr. Jan Zigmund ("Dr. Z") makes 
in the Czech Republic; they are "drop-in" replacements for Jetex motors, but 
they can no longer be imported into the U.S. now that the Czech government has 
re-classified them as fireworks rather than as smoke generators.  But there are 
still many original Jetex motors (as well as the Japanese "Tiger" Jetex motors, 
and the Jet-X motors of the 1990s) in use, and those modelers would welcome a 
replacement propellant that would work in their motors.  Also, new Jetex-type 
motors (particularly the steel-cased HT ["High-Thrust"] ones) would not be 
difficult for a machine shop or a metal-working shop to make.  I will pass your 
information along to the Jet-Ex-Press forum on Yahoo.com--thank you again!

-- Jason
  ----- Original Message ----- 
  From: william colburn 
  To: sugarshot@xxxxxxxxxxxxx 
  Sent: Wednesday, January 01, 2014 8:22 AM
  Subject: [SS2S-Main] Re: Rocket help request

  Beware of the site on ebay that offered a formula for loading Jetex Engines. 
They gave the Micrograin formula which would not only melt the aluminum motor 
casing but probably would first disassemble it  instantaneously.

  Terry McElheran developed a castable formulation for Jetex. I have his 
complete set of lab notebooks. I will search them for the right formulation.

  IIRC his formulation used AN which is a. not so available now and b. In AZ 
worked fine but in higher humidities would show its hygroscopic nature.

  There are workarounds however for that one fault.

  More later.

  Gravity is a Stern Mistress..
  The Tick.

  From: James Jason Wentworth <blackshire@xxxxxxxxxx>
  To: sugarshot@xxxxxxxxxxxxx 
  Sent: Wednesday, January 1, 2014 12:57 AM
  Subject: [SS2S-Main] Rocket help request

  Hello All,

  Yesterday and today I have received numerous messages on the SS2S e-mail 
list.  I was wondering if anyone here could offer suggestions to solve a 

  I am a Jetex and Rapier model jets enthusiast (see: http://www.jetex.org/ ).  
While Jetex motors and fuel haven't been made since 1972, Dr. Jan Zigmund ("Dr. 
Z") in the Czech Republic has developed the Rapier motors, which are single-use 
replacements for the Jetex motors (see: www.jetex.org/motors/motors-rapier.html 
).  Unfortunately, they can now no longer be imported into the USA because the 
Czech government has re-classified them as fireworks instead of as smoke 
generators.  Also:

  Recalling David Sleeter's "Incredible Five Cent Sugar Rocket" which could be 
made safely--and in quantity--at a kitchen table using ordinary household 
materials (see: http://blizzard.rwic.und.edu/~nordlie/rocket/nickle.html , 
http://www.youtube.com/watch?v=sk3RV0lLygk , and 
http://nineball.ve.carpathiahost.net/zero/Articles/Sugar_Rockets.html ), 
something similar to this but optimized for model jet use (an end-burner 
producing 1/10 of a newton or so of thrust, for 10 - 20 seconds or more) would 
enable Jetex and Rapier flyers in the western hemisphere to enjoy our hobby 
with no worries about being unable to obtain jet motors for our models.  Could 
anyone here suggest propellant formulas for such low-thrust, long-burning jet 
motors?  (The Rapier motors link above includes performance figures for the 
various Rapier motors.)  Many thanks in advance to anyone who can help!

  Sincerely Yours,

  James Jason Wentworth


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