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KWB
Postmaster
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Reged: 09/30/06

Loc: Westminster,Co Elev.5400 feet
Re: Awesome Amateur Rocket Launch new [Re: Achernar]
      #4856827 - 10/11/11 11:42 PM

Liquid fueled rockets can be shut down,maybe not on the "shoestring budget" of this design but the solid fuel rascals can't AFAIK. I'm still stunned this was the propulsion system chosen,and yes I'd vote for a very sophisticated image stabilization system used,and maybe not so-consumer grade.

Maybe I didn't look hard enough but I only saw 150 pounds of propellent used,but not the specific type.


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deSitter
Still in Old School


Reged: 12/09/04

Re: Awesome Amateur Rocket Launch new [Re: KWB]
      #4856835 - 10/11/11 11:49 PM

Also amazing is that the rocket, going as fast as it was, did not spin about its axis at power-drill speeds. This testifies to extremely accurate machining of the chamber and the guidance fins.

-drl


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KWB
Postmaster
*****

Reged: 09/30/06

Loc: Westminster,Co Elev.5400 feet
Re: Awesome Amateur Rocket Launch new [Re: deSitter]
      #4856892 - 10/12/11 12:55 AM

Quote:

Also amazing is that the rocket, going as fast as it was, did not spin about its axis at power-drill speeds. This testifies to extremely accurate machining of the chamber and the guidance fins.

-drl



And in my mind testifies to the this overall project as being one in having a very good overall master plan-as in funding and in creative genius.


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Shadowalker
Apocaloptimist
*****

Reged: 11/23/04

Loc: Bay Saint Louis, Mississippi, ...
Re: Awesome Amateur Rocket Launch new [Re: KWB]
      #4857223 - 10/12/11 09:42 AM

Quote:

Liquid fueled rockets can be shut down,maybe not on the "shoestring budget" of this design but the solid fuel rascals can't AFAIK. I'm still stunned this was the propulsion system chosen,and yes I'd vote for a very sophisticated image stabilization system used,and maybe not so-consumer grade.

Maybe I didn't look hard enough but I only saw 150 pounds of propellent used,but not the specific type.




Kenny, there is another type of rocket motor that has much of the simplicity of solids, but the control of liquids. The Hybrid Rocket Motor.

They use a solid core of fuel, usually butyl rubber and pumped or pressure fed oxidizer at the front end. It can be throttled and shut down by controlling the oxidizer valve. Also, the solid fuel isn't nearly as dangerous as the Ammomium perchlorate/Powdered aluminum mix in true solids.

Here is a video of a 10,000 lb thrust hybrid we tested at Stennis Space Center some years back. Later, we tested a 250,000 lb thrust motor built by Lockheed.

Hybrids were all the rage for a while, but nobody seems to have picked up on them for an operational rocket.


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Scott Horstman
Vendor - Backyard Observatories
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Reged: 03/11/04

Loc: Here, There and Everywhere
Re: Awesome Amateur Rocket Launch new [Re: KWB]
      #4857224 - 10/12/11 09:42 AM

Awesome video, thanks for posting. I hope they qualify for the 5k. They certainly deserve it.

Reminded me of the Top Gear space shuttle launch, which had a slightly different outcome.

http://www.youtube.com/watch?v=Da3bk-b6yn4&feature=related


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llanitedave
Humble Megalomaniac
*****

Reged: 09/26/05

Loc: Amargosa Valley, NV, USA
Re: Awesome Amateur Rocket Launch new [Re: Scott Horstman]
      #4857492 - 10/12/11 12:17 PM

Just read the page. The hybrid rockets do seem pretty cool. From looking at the simplified diagrams I seem to see the possibility of some efficiency losses if part of the oxidizer passes through the combustion chamber without ever making contact with the fuel. I'm sure there are ways of ensuring fairly complete contact, though.

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Shadowalker
Apocaloptimist
*****

Reged: 11/23/04

Loc: Bay Saint Louis, Mississippi, ...
Re: Awesome Amateur Rocket Launch new [Re: llanitedave]
      #4857518 - 10/12/11 12:34 PM

One of the things they were testing for is combustion efficiency. They tested various sorts of injectors.

Potential efficiency is similar to Gas Generator cycle hydrocarbon engines. All of the ones I've seen are steel cases, which adds significant weight. Aluminum is out because at those temperatures, Aluminum will burn.


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shawnhar
Post Laureate
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Reged: 06/25/10

Loc: Knoxville, TN
Re: Awesome Amateur Rocket Launch new [Re: Shadowalker]
      #4857684 - 10/12/11 02:03 PM

What I found much more interesting was the link Carmack uses as an example of documentation.

http://www.rrs.org/main.1.0/index.php?option=com_content&task=view&id=80&Itemid=93

8 Years of work for an 11 second flight right into the ground at Mach 0.6!


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Shadowalker
Apocaloptimist
*****

Reged: 11/23/04

Loc: Bay Saint Louis, Mississippi, ...
Re: Awesome Amateur Rocket Launch new [Re: shawnhar]
      #4858416 - 10/12/11 10:23 PM

@shawnhar - yeah, that had to be discouraging.

I admit I'm not up on the state of the art in amateur rocketry. Is anyone using guidance? Vectored nozzles? Roll control? I sure would like to see amateur solutions to those things!


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KWB
Postmaster
*****

Reged: 09/30/06

Loc: Westminster,Co Elev.5400 feet
Re: Awesome Amateur Rocket Launch new [Re: Shadowalker]
      #4858501 - 10/12/11 11:19 PM

Tom

2 of those abilities you stated seemed to be a bit on display in this video as I watched it.

Once again,any guess what do you think this little fun filled experiment might have really cost?


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nytecam
Postmaster


Reged: 08/20/05

Loc: London UK
Re: Awesome Amateur Rocket Launch new [Re: KWB]
      #4858722 - 10/13/11 05:00 AM

That was a fun ride - good stuff

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FlorinAndrei
scholastic sledgehammer


Reged: 09/28/10

Loc: California
Re: Awesome Amateur Rocket Launch new [Re: EJN]
      #4861836 - 10/15/11 03:35 AM

Quote:

Propellant is Ammonium Perchlorate Composite Propellant (APCP)
in a rubber binder with 8% metal powder using a Fin-O-Cyl
grain configuration.




The first model rocket I made back in school (much much smaller than this one) used the perchlorate / aluminum mix for fuel. It burns with a beautiful brilliant white flame. There's almost no residue left.

Also, it's so hot it roasted the bottom of the rocket's tube. The motor itself (a shotgun shell) was destroyed.


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Ghost7
member


Reged: 10/14/11

Re: Awesome Amateur Rocket Launch new [Re: Achernar]
      #4863651 - 10/16/11 06:15 AM

Great. It's always cool to see amateurs achieving something like this. How much can it cost to this?

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Matthew Ota
Hmmm


Reged: 04/30/05

Loc: Los Angeles, California
Re: Awesome Amateur Rocket Launch new [Re: Ghost7]
      #4871861 - 10/20/11 11:06 PM

I dabbled in amateur rocketry from 1981 to 1984. My motors were purchased from a vendor and used ammonium perchlorate in a hydroxyl terminated polybutadene binder (HTPB).

What got me out of continuing it was the political infighting from the rocketry associations and the sheer cost of building and flying the things.

Amateur astronomy is easier on the pocketbook, once you have your equipment in place.

Edited by Matthew Ota (10/20/11 11:06 PM)


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jkaiser
member


Reged: 01/07/13

Loc: Wood River Junction, Rhode Isl...
Re: Awesome Amateur Rocket Launch new [Re: Matthew Ota]
      #5651668 - 01/30/13 06:43 AM

Rocketry associations actually drove the fun out of the hobby, I still design and build my rockets periodically, but don't have the so called certifications. In fact where I live there is nobody around to certfy you, you would have to travel to the closest rocketry club, I dont have time for that and I been building and launching model and high powered rockets for over 30 years.

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GlennLeDrew
Postmaster
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Reged: 06/18/08

Loc: Ottawa, Ontario, Canada
Re: Awesome Amateur Rocket Launch new [Re: jkaiser]
      #5655508 - 02/01/13 02:41 AM

I don't feel that there is all the vibration feared, requiring image stabilization. The great speed through the air will either induce more vibration than from the motor, or nicely steady out the ride (the likely scenario, methinks.) A clue pointing to the lack of stabilization is provided by the 'stuff' appearing in the window, which is never differentially shifting about in response to an image stabilization scheme.

My first thought regarding the 'stuff' appearing in the window was that it's condensation, not melted material.


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