12 replies to this topic

[Loci]

Ok, this maybe a stupid question, we'll soon see.... Could I possibly turn this upside down and use it as a rocket?

Fraser

[Richard H]

Yes, that is a stupid question You could use it as a gerb on a rather scary catherine wheel but I would very much doubt that you could use one as a rocket. It just simply does not generate enough average thrust.

[RegimentalPyro]

Just out of interest, has anyone on this forum actually built Clarks GSF? Did it work as intended?

I've heard that the successful firing of this monster is a bit of a Holy Grail...

[Loci]

Shame, would have had a very impressive tail! hey one day, i might try it, if i'm really that bored

[italteen3]

I would like to know also because BP and fountains will be my first projects. In IPP by Tom Perigrin though he just gives directions and a formula found online, no real safety tips or trouble shooting help because he himself as not made one.

If anyone has made one let us know!

[Mortartube]

If you wanted to build a big rocket, you should do some research on the Congreve rocket. The big ones were about 6 feet long and 12inches ID. BP propellant that was rammed by 3 people taking turns to hit the wooden drift with sledgehammers, in a fashion reminiscent of the old fairground workers taking turns to hammer in a post.
I am NOT suggesting you make one, even if you could get enough chemicals for this experiment, but it's certainly worth some research. Also look up Hale rockets while you're at it.

[Loci]

I've never heard of them I will have a look for them on google when I finished work tonight

[adamw]

There was a tiny bit on Hale rockets on a show called Chris Barrie's Massive engines (the guy from Red Dwarf / Brittas Empire) on Discovery which was about rockets. I've got it taped but it was simple stuff and a bit boring actually..

[italteen3]

WOW 6 feet 12" ID. That is one massive rocket. I wonder what the payload that rocket is able to carry! Not to mention a tube to guide it and the amount of BP used.....

EDIT: Back on topic. Clark's Giant steel fountain is taken from Tennyson L Davis, The Chemistry of Powder and Explosives.

"The Giant Steel Fountain of Allen F. CLark is charged witha mixture of saltpeter 5 parts(200 mesh), cast-iron turnings 1 part (8 to 40 mesh), and red gum 1 part (180 to 200 mesh). For loading, the mixture is dampened with 50% alcohol. The case is a very strong paper tube, 20 inches long, 4 inches in OD, and 2 inches ID (1 inch thick walls). The bottom of the case is sealed with a 3 inch clay plug. The composition will stand tremendous pressure without exploding, and it is loaded very solidly in order that it may stay in place when the piece is burned

The charge is rammed in with a wooden rammer actuated by short heavy blows, as heavy as the case will stand, from a 15-pound sledge. The top is closed with a three inch clay plug. A 7/8's in. hole is then bored with an augur in the center of the top, and the hole is continued into the charge to a total depth of 10 inches [note -. caution while boring into a live charge]. The composition is difficult to light, but the ignition is accomplished by a bundle of six strands of black match inserted to the full depth of the cavity and tied into place.

This artifice produces a column of scintillated fire, 100 feet or more in height, of the general shape of a cedar tree. It develops considerable sound, and ends suddenly with a terrifying roar at the height of its maximum splendor."


Description is taken from Tom Perigrin, Introductory Practical Pyrotechnics who took the description from Tennyson L Davis, The Chemistry of Powder and Explosives..


I would love to one day make and watch such a stunning site go off.

I will not be attempting this soon but it says the mixture is dampened with 50% alcohol and 50% water combination. So for a lot of comp to be all dampened with this how long of a drying time would be recomended? Or would one ram in 3 or 4 inch increments, wet to reduce risk of accidental ignition or possible explosion, let dry for a few days, ram more again until finished?

Edited by italteen3, 01 May 2004 - 05:46 PM.

[bobconan]

roughly 200 pounds of bp. basing that on 1- 1.5 pints per pound of bp. 258 pints giving 1/2 foot lost to plugs/nozzles.
I really want to make the clarks but im afraid ill light the forest on fire. i have everything to make it except the tubes. i even bought a 20lb sledge. My friend goes rabid at the mention of the clarks. He really wants me to do it.

Edited by bobconan, 01 May 2004 - 07:45 PM.

[Kembang Api]

Size is huge, anyone dare to care it to the site?, look like you are caring a big b**ms. Make sure don?t drive to the down town man?.

The size and amount of BP is huge, the nozzel would be a big problems depending on what you used but if BP only, without any metal I believe it will work. Only BP the flame would not be very nice so it has to have some kind of metal powder in the composition, right!!

The debris, the un-burn metal ect. Will start building up at the nozzel and causing the nozzel smaller. At certain stage, I believe it would make a big bang?.

[Phoenix]

I've been turning some rammers and fountain tools and stuff, and felt like using them, so last night I fired a "Moderately Large Steel Fountain." ID was 25mm, nozzle was 12.5mm, and length of case was 10cm (a short one, I just wanted to get glimpse of how it performed without using too much material).

I rammed it with 50g of the following:

Rough Meal (ie pulverone w/o dextrin)........75
Fine Briquette Charcoal..............................12.5
Cast Iron Borings, passing 10 mesh...........12.5

The effect was quite pleasing. It produced about a 3m high spray of sparks, though it was higher to start with due to the short core formed by the spindle. Duration was about 10 seconds, though, as usual, I forgot to time it.

[Jerronimo]

giant steel fountain

I think Dan Williams gives some good info about this ambitious project.