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Questions on Rockets


billofca

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I've been looking at some stickless missiles on you tube and was wondering if anyone can elaborate on how they work,the ones I've seen seem to have a lift charge that blows them of the launch pad and on their way,are these spigot launched,I want to have a go at making them so any help would be appreciated,here's a video http://youtu.be/as3Gr5eHjJY would they possibly work the same way as a double voiced firecracker lauches its payload.

 

 

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At first I thought you were talking about a stinger, but that video basically just shows a finned BP rocket with a small header. It's basically the same as a BP motor with a stick, but with fins instead of the stick. Shooting those kinds of rockets in the middle of a parking lot full of cars is just kind of begging for trouble.
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yeah its not my video just an example,they don't take off like a normal rocket though do they,seems to explode then the rocket ignites.
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  • 11 years later...

The information below is borrowed from the March 2005 PGI Bulletin with permission from the author:

 

Graphite Nozzle Mix

55 fireclay

35 graphite powder

10 boiled linseed oil

+40 campstove fuel

 

First sieve the clay and graphite powders together into a stainless bowl. Next mix the linseed oil with four times it's weight of hexane (Coleman fuel or white gas). Mix the dissolved oil into the clay/graphite mixture; this should be done outdoors, in the shade and away from any source of ignition. Mix thoroughly with gloved hands and spread it out to dry on a non-stick tray to dry.

 

To speed the drying time (usually 3-4 weeks if air dried), a few drops to a 1/2 cap full of Japan Drier (available from the paint section of a hardware store) added to the linseed oil/stove fuel mixture before mixing with the dry ingredients, will speed the drying time to about three or four days!

 

This mixture, after the linseed oil polymerizes, goes plastic under pressure and flows around the clay and graphite grains and into the tube fibers to bond everything together, PLUS the graphite helps prevent chemical reduction of the oxides in the clay by the products of combustion from the propellant.

 

 

This mixture smells funny but works and resists erosion very well.

 

WSMcool2.gif

 

  • No. ingredients explanation
  • ratio
  • =============================================================================
  • ① fire clay | graphite powders Sieve the clay and graphite powders together in a 55:35 ratio.
  • 55 | 35
  • _________________________________________________________________________________
  • ② boiled | white gas Mix the boiled linseed oil and white gas in a 10:40 ratio.
  • linseed oil | (Add a few drops of white gas.)
  • 10 | 40
  • _________________________________________________________________________________
  • ③ Mix ② into ①.
  • ④ Dry for 3-4 days.
  • ⑤ Take a cardboard motor casing and snuggly fit it on the base spindle.
  • ⑥ Insert the funnel into the motor casing and add a ④
  • ⑦ insert the hollow drift into the casing until it hits the clay at the bottom
  • ⑧ Tap the ④ with the dead-blow hammer.
  • (or Press ④ to ? psi by hydraulic press)

 

Thanks for the great article you wrote. I am an amateur rocketeer living in Japan.

I'm trying to build Estes' A8-3 grade rocket. I molded the nozzle with about 1 ton force by hydraulic press using a Dr.Elsey Ultra clay, and I got erosion.

While looking for a more harder nozzle, I found your post.

 

1. Can I understand what you wrote above (03 Nov 2010) as an Excel sheet that I have organized? (above the table)

2. When performing molding according to the above method, can I do it by hand ramming?

3. If using a hydraulic press, how many kgf is appropriate?

4. I contacted PGI to purchase past bulletins, but PGI says they don't have them(the March 2005). If you don't mind, can't you take a picture of just this part of the bulletin(the March 2005) and send it to me? (gongsuni@yahoo.com)

 

p.s. If anyone knows how to insert an excel table, please let me know.

Edited by gongsuni
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  • No. ingredients explanation
  • ratio
  • =============================================================================
  • ① fire clay | graphite powders Sieve the clay and graphite powders together in a 55:35 ratio.
  • 55 | 35
  • _________________________________________________________________________________
  • ② boiled | white gas Mix the boiled linseed oil and white gas in a 10:40 ratio.
  • linseed oil | (Add a few drops of white gas.)
  • 10 | 40
  • _________________________________________________________________________________
  • ③ Mix ② into ①.
  • ④ Dry for 3-4 days.
  • ⑤ Take a cardboard motor casing and snuggly fit it on the base spindle.
  • ⑥ Insert the funnel into the motor casing and add a ④
  • ⑦ insert the hollow drift into the casing until it hits the clay at the bottom
  • ⑧ Tap the ④ with the dead-blow hammer.
  • (or Press ④ to ? psi by hydraulic press)

 

Thanks for the great article you wrote. I am an amateur rocketeer living in Japan.

I'm trying to build Estes' A8-3 grade rocket. I molded the nozzle with about 1 ton force by hydraulic press using a Dr.Elsey Ultra clay, and I got erosion.

While looking for a more harder nozzle, I found your post.

 

1. Can I understand what you wrote above (03 Nov 2010) as an Excel sheet that I have organized? (above the table)

2. When performing molding according to the above method, can I do it by hand ramming?

3. If using a hydraulic press, how many kgf is appropriate?

4. I contacted PGI to purchase past bulletins, but PGI says they don't have them(the March 2005). If you don't mind, can't you take a picture of just this part of the bulletin(the March 2005) and send it to me? (gongsuni@yahoo.com)

 

p.s. If anyone knows how to insert an excel table, please let me know.

 

I spent a week with WSM at PGI convention last month on the rocket line, really nice guy.

 

Yes, when WSM notes, "Insert the hollow drift into the casing until it hits the clay at the bottom.

Tap the drift with the dead-blow hammer.", he means, hand ramming.
We generally press to 5000-8000 PSI on the nozzle and fuel, you are using a 1/4" ID tube which is 0.049 square inches of area so 245-392 PSI will suffice.
As a rule, we do NOT allow bulletins to be copied, they are a copyrighted item.
On a final note: You say that you had erosion when using Dr.Elsey's Ultra Litter? I have spoken with Ed from ESTES whom helped design and care for "Mabel", the machine that made the rockets for ESTES and he states emphatically to just use bentonite clay. This is what Dr.Elsey's Ultra Litter is, bentonite clay.
Here is a picture of my current D12-0 ESTES copy with a Dr.Elsey's Ultra Litter nozzle (Left) and an unfired ESTES B4-4 motor. Almost no erosion in my nozzle so no, there is no reason to make such a complicated nozzle unless you feel the personal need to copy WSM.
gallery_9798_35_161471.jpg
Edited by dagabu
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