posted 01-24-2000 05:27 PM         

and PsychoKitty:
http://hive.lycaeum.org/ubb_board/Forum5/HTML/000631.html
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Never one to leave good enuff alone, following is the simple construction detail of a device to enable pressurization of the proceedings, with the usual anticipated yield enhancements:

also the closed nature of the instrument anticipates its utilization in the Lone Ranger "Shake and Make" process: without having to resort to "wiring down the stoppers of flasks" which he so brazenly advocated.

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a 2" PVC slip coupling is fitted with a flat bottommed "end plug" on one end, and a 2" X 1/2" threaded female bushing on the other.

Said fittings are prepared, and cemented together with the appropriate solvent cements.

Into the bushing a 2.5" threaded PVC "Pipe Nipple" is inserted.

At the end of the pipe the appropriate fittings are attached to fit your popett valve, rated to release up to (say) 140 PSI.

[I use 60 PSI]

==============
USE

In use the appropriate chemicals as described in the above threads is added through the pipe, and a pre-made fiberglass WAD (technical term), wrapped in saran wrap or equivalent, with small pinholes in it, is inserted into the pipe.

With the popett valve stem raised, the valve is attached and well sealed using teflon tape, at which time the stem is released, shutting the spring-loaded valve.

(NOTE: the "WAD" is to restrict the release rate of the H2 overpressure, and to keep the valve from being "fouled" when using the sander. Without this, when the overpressure vents the H2 pressure will drop down to almost atmospheric)

===========================

For the Ultrasonic Cleaner -challenged folks amongst us:

Take piece of metal or plastic thin metal sheet, just the SAME SIZE AS A PIECE OF SANDPAPER that fits on your handy-dandy vibratory sander, cut a hole in it
to accept the pipe, (or glue it to it!), mount the sander upside down in your vice and the rest is pretty obvious.

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The above constitute the DUAL NATURE utilization potential of this device (and thus it's Gemini Nature) : the following is a "BONUS APPLICATION". (??? MAYBE???)

==========================

NOTE THE FOLLOWING HAS NOT BEEN TRIED: IT IS PURELY EXPERIMENTAL; IT IS PRESENTED FOR YOUR THOUGHTS AND RECOMMENDATIONS or other salient response.

=======================

I've considered the 60 second microwave stimulated quick cookerie described by ( I think) PsychoKitty:

I've seen microwave units in thrift stores for $20.

I do not greatly enjoy the prospect of generating flammable , EXPLOSIVE H2 in my kitchen microwave.

I've already had a WEENSIE fire in my wife's new microwave ( don't ask) and I have no spare NUTS to contribute should another mishap occur.

Being masculine is my favorite gender-role.

So anyway, I was thinking, the identical unit could be used in the microwave.

The metal valve would not get hot enough to cause a problem in the 60 seconds or so: the rubber seal would not be affected.

So you put a balloon over the pipe and valve, and when the balloon starts to fill up you know its time to quit, take out the unit, and check the contents.

Now if I'm wrong, and it arcs with a ½ filled balloon of H2, and with H2 having the broadest explosive range going with the exception of acetylene (if I recall), I sure would like for someone else to tell me about it instead of me knowing first hand, so I'm soliciting volunteers, or at least your opinions.

ASSUMPTIONS:

=======================

brass valve with hex wont generate EMF that will jump 3" (minimum) to microwave walls in 600 watt microwave.

Also, it will not heat enough (no current flow I HOPE ) to matter to the rubber seal.

Balloon (or latex) won't heat up : and will retain H2 well enough to avoid "loose" H2 gas floating around in the microwave.

=========================

Hate to unleash a potentially explosive idea such as this but how else would I get the input of all you sagacious people???

posted 01-24-2000 07:26 PM         

"One essential aspect to the reaction that I forgot to mention is that the flask or beaker used must provide a shallow liquid base."

posted 01-24-2000 07:47 PM         

Cost of the unit is $5 + your choice of popett valves: around $10.

It can be made of 3" PVC also, if you can find the fittings.

Volume is 200 CC or so: can be larger if you want to insert a piece of pipe to tie together two slip-fittings. (Above 400 CC or so and it gets pretty "top heavy". )

Construct it as indicated and your wall thickness will be about 1/4 inch: probably well over the schedule 40 advertised 450 PSI cold water rating.

posted 01-25-2000 05:42 PM         

=================

Hell, after raquetball I'll stick the unit in the micro with water in it and see what happens: however, my spare blow off is 140 PSI: I do not want to run the PVC to that temp/presure in wifey-poo's microwave. (Nut anxiety)

so I'll just check for sparking. betcha $25.00 no problemo.

The gold rim sparked because it was close to the metal box-ground.

======================

Akcnalb, the mirror man, was gwin'e test the NI: He stated in crystal that he had no luck: but what he did and how he did it i do not know as of yet.

========================

I've got a $5 bet that copper dissoved in HCl, and then precipped, would work (under pressure) : wouldn't that be nifty:

I'm more inclined to try that 'cuz it is totally uncharted territory, but since i have the NiCl hexa hydrate I guess reason demands that I try that firstest.

======================

i git excited ez: why Stoni even posted my high pitched sound when I do:

but seriously I think this might be the eziest technique ever. Buy brass foundry stocks: those blow off valves are gonna take a lot of it: sell mexican mafia stocks.

==================

Talk is cheap.

Time will tell

posted 01-27-2000 12:42 PM         

I believe that the first experiments should be conducted in a cheap microwave at the end of a long extension cord in the middle of a large lot.

I further believe that there will be no problem: but when the failure mode involves significant hazard it is far better to be safe than sorry.

Truth is that a 1/2 inch hole could be cut in the microwave box, and plastic pipe run out the side on which the safety valve is located, thus eliminating the spark hazard arising from metal in the cavity. The exiting pipe could be sealed from spurious microwave emission with grounded screen door wire.

In an experiment performed with the valve on top of the Gemini Bottle, 30 seconds at full power with some water inside did not generate sparking. Neither did the valve get warm.

However, with conductive liquids inside, and saturated (and presumedly conducting) gas volume connecting the brass to the liquid volume, the insulation from ground is only the 1/4 " PVC: i suspect it's breakdown V is sufficient, but i further speculate that it might be smart to have the insulation further enhanced, through placing on a glass plate.

posted 01-31-2000 01:54 PM         

having no access to a machine shop: and with carbon fiber not yet invented, by crackee, he used master brake cylinder pistons, further drilled an polished to approximate the appropriate entrance and divergence angles.

The aluminum was eroded by the exhaust gases. Water cooling (water jacket) was employed: was decided to use new nozzles every time.

Just as well: usually the rockets would be trashed afer one flight anyway. almost got to 10,000 feet once: probably a piker's height these days.

Digging the rockets out of the sandy soil was always a treat: hell FINDING the rockets was always a treat.

Ah,nostalgia.

=============================

Microwave molasses/popcorn next weekend.

posted 02-02-2000 02:07 AM         

I used AP/Al with HTPB. The trick is to allow for the void spaces by computing a 15% void space. This allows you to get the pressure ratios correct WITHOUT degassing the mix, as it is a real bitch to do that shit.

Nozzles were machined graphite, you can order up a killer lathe from sherline for about $300 or so that will do what you need... There is some ceramic inserts that one can use, have to look up the data, the old milspec tungsten, but the graphite are the best..need to make sure you insulate before you wrap carbon around them as the heat conductivity is high.. Propep has been reincarnated in a windows formulation for ease of use..

If you wanna have the best time of your life, contact the Reaction Research Society in So Cal. They do a killer 3 day class on building your own motor from scratch, show you how to mix propellant, pack, load drill, and you get a reusable 2.5" 3 foot long motor to take home with you! You get blueprints also...and all the answers to your questions!

The nozzle angle and throat are all wrapped up in the propellant rate of burn, the propellant area, area of the chamber, operating pressure and temperature.

Rocket propulsion elements is the bible on all of this, but hard to pull the equations.. I have some simplified ones... if your serious get my email addr from Rhodium and I'll answer all...

as to your fantasy, I don't think you'll get a 270 practical ISP, my best was 245, but to support your ideals...
...would be happy to give Osmium the killer AP/Al/HTPB mix ratios that require NO degassing...and then point him to the GPS + 3 axis homebuilt accelerometers in Circut Cellar magazine to enable his Butylene Oxide (more brisance than EthylO) Fuel Air Explosive to do it's mass conversion job on the appropriate audiences, although Starlite prefers the micro turbine powered cruise model approach with the Ramsey Electronics 10 gm color video camera transceiver in the nose so you can insure that it goes right up the appropriate orifice for maximum terminal effect..

re: Chem guy...

posted 02-02-2000 05:22 AM         

I know about Firefox and the other pyro suppliers, but AP and HTPB are export restricted, and I don't know what my government will say when they discover I'm ordering rocket propellants and explosives (AP is regarded an explosive hazard in my country)
I even might get access to a heated vacuum propellant mixer, but this is not really necessary when you use the right binders. Interesting concept to use 15% void space, but what about the burn rate? I guess it will be rather high with such a porous grain. Polypropyleneoxide is a very good binder for such propellants (low viscosity, high reactivity and oxygen content, no need for heat curing, availability and price). Check out this patent: http://www.patents.ibm.com/details?&pn=US05076868__

I've never seen graphite stock for sale, and I don't really want to work with old 747 brake disks as my graphite source, because they can't be found easily either. I know firefox sold instructions and tools on how to cast your own graphite nozzle. I guess they use graphite, some phenolic resin and bake it afterwards, I could probably try that myself, but I'd like to have these instructions.

posted 02-02-2000 06:51 PM         

[url]http://www.geocities.com/CapeCanaveral/Campus/5361/basechem.html[\url]
Electrolyze to your hearts content!

now lessee where we were... yah you wanted..

re: concept to use 15% void space, but what about the burn rate
It's factored in as part of the calculation for the total surface burn area...that normalizes the burn rate across the propellant... you mix this in one of those 20 lb a shot bread dough mixers for about 15 minutes for homogenity..

re: I know firefox sold instructions and tools on how to cast your own graphite nozzle. I guess they use graphite, some phenolic resin and bake it afterwards, I could probably try that myself, but I'd like to have these instructions
Firefox provided you with a standardized nozzle form. you pressed your own. The mix was a high temp epoxy resin and the graphite powder. Graphite blocks shouldn't be too hard to find... but the mix as they say, will do... They sell instructions, which you can order, I don't have them though...

re: Re propep, are you talking about the guipep front end? Or is there a new version? Any ideas about software which can calculate/estimate p/T graphs? I know there's a dutch company somewhere selling such software
Several new incarnations have been done on the rocket list. Chemical Propulsion Research [CHEMROC@LISTSERV.UGA.EDU]

Nozzles:
Here's the data points ( starlite is now reaching for his wizards manual of black arts ...) Ah..well the nozzle design angles are pretty standard pg 69 of RPE gives the 1/2 angle as between 12 and 18 degrees ( i used 17.5) this is dependent upon chamber pressure, mass flow rate and temperature, the tweek is to avoid laminar boundary layer separation along the sides but this is in the .03 to .05 correction factor to the design... The Area (throat) to Area (exit ) optimum is about 25 for a 15 degree 1/2 angle and that puts the length to throat diameter at around 8 or so. We used a 43 degree external 1/2 angle

re: Phenolic: Cast your grains into that, then load the motor case with the grain segments. Carbon fiber will also work as well. Using a bates grain, the propellant insulates the chamber and the nozzle should butt up to the grain. Add an additional thicknes of carbon filament and it will char and protect for the time frame.

re: Mach numbers: My rockets usually hit mach one at about 8 meters. Mach 4 + is typical.. The three foot 2.5 inch AP motor will hit 20k feet altitude. Cheap is relative... when I find a microgram balance for under $700 I think Cheap! But, yes... you can wack together the propellants and materials for a reloadable system, (especially if you make your own AP via that link) for about $2-300.00, then figure about $25-30 per flight for new propellant load.

re: Mass Ratio... Everyone wants to stuff their motor to the gills...problem is getting your system pressurized and burning in a stable mode and having a constant mass flow rate. Now, you'll have a high propellant to weight ratio, you'll be amazed at how big your bates core hole is though..

re: Butylene Oxide: Depends upon what your targets are...the typical method is as follows:
(ballistic trajectory)
-eject a parachute retarded ignition system from the warhead
-release the warhead containment which will expand with forward velocity to achieve a cone shaped coverage of the target area
- have the sensor or timer in the ignition system detonate at the cloud apex
- the ignition system propagates multipoint ( Zirconium/Mag/Oxidizer) pellets for multipoint detonation of the cloud.
- Apex detonation creates a Munroe effect pressure wave with peak overpressures @ ground level.

re: RDX - Your better off with the Acetic Anhydride NH4NO3 method to generate HMX @ 12-14%. Balance your Oxygen with the Al at the molar level...it will reduce brisance but increase overpressure and blast.

re: Guidance. Basic stamps are cheap and work well. Terminal telemetry with color video cams the size of a .25 piece coupled with R/C obviate the need for terminal guidance, although that article on gps guiding a toy car was interesting in Circut Cellar...with ButlyO , precision is anything within a 1/4 mile

re: Helicoptors:.. Use a pulse jet ( plans on the net ) along with the above guidance system. ( it flys faster than the chopper and slow enough to guide. Use the motor to boost up to jet start. Then your going 175 - 325 mph and you have them on your sony handycam... speed is of course adjustable...

Oh well...catharsis of previous incarnations... All of the above only increases karmic debt load and results in more trips around the wheel if implemented... if the Jackboots KNEW what we do, then they wouldn't be who they are..they would be us, ( actually they are us, they just don't know it...most don't find out till they are about to die...too late for regrets then..), or as the dali lama said, "... there is only ignorance or enlightenment..."

Thkr

posted 02-03-2000 12:28 PM         

dwarfer: What the hay have you done with psychokitty? I'm worried.

Osmium: Where bee ya', baby?

posted 02-03-2000 11:09 PM         

In my misspent youth, I combined 50% H2O2 and Anhydrous N2H4 in a makeshift 304SS tube rocket. Needless to say, it didn't work, but it made a hell of an explosion

posted 02-04-2000 02:09 AM         

One of the great things about working through Prentisses, chemicals in war and then creating all sorts of HE ( although I need that PETN receipe from you Osmimum, I could never get mine to drive to completion) is that I know (usually) what goes boom..and not much scares me anymore...

If you all search around the web you can find the RRS website with the 120 sec onboard video camera of their 9" diameter 15' rocket that went 55 miles up! you can see the stars at apogee! They assembled the entire motor on site in 2 days! ( thats why nongassing propellant is soo cool ).

posted 02-04-2000 12:35 PM         

How is it going?

posted 02-04-2000 06:16 PM         

We were pretty careful with the hydrazine, just not too smart in seting up the rocket. I ttthhinnnnnk ttthat I'mmmmstiiiilll OK

posted 02-04-2000 08:33 PM         

Hexamine is much better used to create HMTD as primary initiator systems are more difficult to construct... although that is moot give you can take apart a disposable flash camera and hook up a copper or tungsten filament ( or even a copper etched 1 mm chip ) and have an exploding bridgewire that obviates any need for a primary or a booster in the det train...

( geeze you guy's sure know how to drag out all the forbidden knowlege... next thing I know you'll be asking me how to make microfission nukes...)

posted 02-04-2000 09:22 PM         

Damn - we're just asking for a lockdown of this topic

posted 02-04-2000 11:50 PM         

I think the Gemini will be even MORE successful than some of the rocket experiences described: I'll have to read them again I did not notice hydrazine mentioned.

I DID get ahold of some solid rocket propellent which had been used in a NIke rocke (if I recall) .

The cast rubbery propellent (monlithic when in place) had been ground up by a special machine, under water, and then dried, preparatory to being used as cement kiln fuel, which is a disposal technique:

ANYWAY, I "High-graded" some, but could never reasonably think of a good use ofr it, so i burnid it myself: pretty decet flame spread rate, I MUST say.

Here's one for you rocketeers that I've NEVER had answered: Howzecome zinc and sulfur gets to a certain desireable pressure, and then self regulates??

I for get the pressure, but at ??100PSI?? or some other number it does not burn as fast??

Pressure INHIBITING a molecular combination??

Whyzat, boss??

posted 02-05-2000 03:14 AM         

re: Nike propellant - Lets see what Propellant Chemistry - Sarner has to say 'bout that...Nope nuthin there... if you were able to use it as a Kiln fuel, I am guessing that it was a dark gray to black. That would make it one of the Guanandine nitrate or Triaminonguanadine nitrate type fuels... these were developed before they got the AP/HTPB fuels sorted out...they burn with no residue to C02 N2 etc.. Otherwise you might have had a double base propellant but the specific impulse is too low on that for a Nike...what color was your stuff?

re: Zn/S This is called micrograin...was a favorite until a good AP method was developed...basically what happens is ALL the fuel instantly combusts, and you have a pressure vessel sitting on the pad prior to liftoff. So the reason it gets to a certain pressure ( depending upon the fuel load 1-2k psi is what you design for ) is that's all there is...then it goes up...

( I am assuming your talking about the Zn/S dust loadings )... if you have low pressure you didn't get it all started, 'cause according to my guru's ( who've launched a few thousand or so ) it's just a pressure vessel. ( ever see one of those household water heaters go into orbit from jammed relief valve?...had no idea you'd get a two mile range on one till I saw the video..)

As to why pressure is important... The regressive surface burn rate of a propellant is directly proportional to the pressure.. if you don't get it right your motor goes into oscillation and 'chuffs' as it tries to get up to steam... Worse yet is when you get a harmonic resonance with the supersonic exhaust flow and the motor cavity..you only want to transition that space not live in it...That is why the ignition system is critical, because most grains will not ignite unless pressurized, and most certainly will not perform at nominal specs... Resonance and chuffing can crack your grain if it persists, at which point your surface area just expanded by 1x10E3, and you have runaway catastrophic failure as your burning area expands exponentially along with the internal pressure!

I remember on a military base I grew up on the younger kids found loads of unburned zuni 5" rocket propellant that the eod left on the burning ground... We grabbed a lot of it an played around with carving it into shapes and lighting it off... then some idiot threw a 5 lb chunk in the dumpster that went to the base incinerator. The detonation was heard 2 miles away and it blew the whole thing up! We spent countless hours being grilled by the CID looking for the culprit...