17 replies to this topic

[marknotts]

When I was a kid at school my Physics teacher told me he used to make rockets from a Zinc Sulphur mix.
Has anybody used this and is it succesfull?

[Arthur Brown]

With no oxidiser there would be no propulsion! As part of a compound then possibly.

[johndee]

ROCKET PROPELLANT #7 (ZINC/SULFUR)

Source: rec.pyrotechnics
Comments: Burns very fast, producing lots of smoke. It is not a very effective propellant due to its low energy density.

Zinc..............................................67.1%
Sulfur............................................32.9%

[wjames]

erm, ive actaully heard of this before, and seen one in action

its not a great option though, the thrust to composition weight ratio is way off......


http://www.dark.dk/E...m/SmallTom.html


You can also make flash powder using is....6:1 zinc:sulphur

(IIRC.....could be slighlty differnt...i remember a 70/30 mix too - nasty fumes though)

Edited by wjames, 31 October 2008 - 09:03 PM.

[wjames]

ah, 70/30 was rocket prop.

[spanner]

It's called "Micrograin". Was popularized back quite a few years ago when Scientific American (IIRC) ran a series of articles on it. It has since fallen out of use because "friendlier", more powerful fuels have been developed.

The VRO Belgian Amateur Rocketry folks had a project on casting a zinc/sulphur/aluminum propellant, don't know how it turned out.

This is a variation. I'm 90% sure this came from Alan Yates:
"AJK Zinc SBR Article Part 3, PGI Bulletin #144, May/June 2005
percent component
53.00% Zinc (dust)
36.00% Potassium Nitrate
11.00% Sulfur
Screen together pre-milled components well. Milling the Sulfur and Potassium Nitrate together works quite well, followed by screening in the Zinc.
This propellant is designed for Steve Majdali's SBR tooling.
The PGI article has much paranoia about the properties of this propellant. In my experience it is less treacherous than conventional Micrograin and significantly less powerful than BP. It will not be affected by moisture in a dangerous manner as suggested; in fact it isn't much different safety wise than my Zinc Flash."

Please use due caution if experimenting w/this or any zinc/sulfur comp- they have a spotty reputation in regards to sensitivity and stability.

Edited by spanner, 31 October 2008 - 09:32 PM.

[Gillard]

With no oxidiser there would be no propulsion! As part of a compound then possibly.

Zinc sulphur rocket do definately work - these were the first rockets that i ever flew and got me into model rocketry.

There was nothing fancy about them
The design was a bic pen barrel, with the nib end blockeb, a mixture of zinc powder and sulphur powder in the barrel. fins were added from thin plastic (margarine tub)
and a bit of straw as a launch lug.
the ignitor was a match, with nichrome wire wrapped around it, attached to a 9v battery.
they worked about 50% of the time, occasionally they would explode on the pad - always fired them from behind a safety screen.
the pen rocket would get to about 150 foot, and then come in fast and hard.

i got the design from a chemistry club handbook. i'll get the exact Zn to S ratio tomorrow and post it.

[Gillard]

go to here

http://resources.sch.../SCC1_Demo3.pdf

it has the full description of the pen rocket
ratio was 3g of S to 1g of Zn.

[icarus]

zinc and sulphur does not need saltpetre adding as a low impulse fuel . Rockets that used it had what was called a burst diaphragm over the end ,This was typically a single layer of aluminium foil tightly taped over the end of the rocket motor . this ensured a sudden high pressure burst from the motor at lift off . i do not know if the increased pressure increases the burn rate of the motor significantly or not They are wonderfully messy throwing out a fine white dust cloud

[dr thrust]

hmm.. a burst diaphragm to build up pressure in a low powered motor, thats a great idea would the fuse pass though it?

[wjames]

arnt Zinc/Sulphur motors normally top ignited ?

[Mortartube]

http://www.pyrosocie...p?showtopic=963

[spanner]

arnt Zinc/Sulphur motors normally top ignited ?

The ones I've seen diagrammed have the leads passing through the burst diaphragm (brass or aluminum).

They were initiated by an e-match type ignitor. Because the leads are small, pressure still builds up despite the "leak" in the diaphragm.

[Andrew]

Haven't actually tried it in a rocket, but the two certainly do react!

[Gary]

Interestingly, the reaction product (zinc sulphide) is a solid, as opposed to a gaseous product.
How it manages to generate enough thrust, I do'nt know.