[SS2S-Main] Re: Rocket help request

  • From: Peter Johansson <rockets4kids@xxxxxxxxx>
  • To: sugarshot@xxxxxxxxxxxxx
  • Date: Wed, 1 Jan 2014 13:22:07 -0500

On Wed, Jan 1, 2014 at 3:57 AM, James Jason Wentworth
<blackshire@xxxxxxxxxx> wrote:

> 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
> problem:

Before we get to that, Is there any news on the migration of the
SugPro list to the new mail server?  That list would be far more
appropriate for this discussion than ss-main.

> 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?

Sugar propellants are generally not suitable for end burners because
it is difficult to get the burn rate fast enough for them to generate
sufficient thrust -- at least for rocketry applications.

However, I just attempted some simulations based on your requirements
and it does seem theoretically possible to hit that ballpark.  A 5mm
diameter grain (about the smallest you want to work with) will produce
about 3/10 N, and 40mm length will provide a 5.4 second burn time.
Total impulse is 1.68 Ns, 42% A.

-p.

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