Quartz

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Mark
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Post by Mark » Wed Jan 28, 2004 3:01 am

Mark wrote:
Mark wrote:
brunoogorelec wrote: Here's a quote from an early 1950s study (I think by NACA) on pulsejet temperatures. 1 degree Reaumur is equal to 1.25 degrees Celsius.
http://www.csc.liv.ac.uk/~frans/COMP101 ... aumur.html
http://www.rayotek.com/Technical-1.html ... -WHY-49575
1965 Experimental Aircraft Assn. "The construction materials for pulsejet tubes should be 347 stainless steel because of the corrosion and high temperatures. In our experiments, we have measured temperatures as high as 1790 F. However, most experimenters cannot afford such expensive materials. We found that 16 guage cold rolled steel works quite well for static experiments. A this temperature the cold rolled steel has very little strength, but it is ample to withstand the combustion chamber guage pressure of 20 psi."

Tharratt, "If we assume the mean operating temperature of a duct is 1,000 K. we are in the surprising position of being able to determine the dimensions of a duct capable of developing a given thrust literally on the back of an envelope."

Pulsejet theory by Franco Marcenaro "If the temperature in our engine is assumed to be (average) 1750 F the absolute temperature will be 2210 R...
The more scientifically minded among you will probably demand how I came up with the temperature value of 1750 F. ....... Scientists must make things complicated but all you have to do is to add the temperature as usually expressed in degrees Fahrenheit and add 460 to get the Rankine degrees (R) used in scientific calculations."

Another pulsejet article "Nickel steels are used in the commercial pulse jets manufactured in this country to resist the effects of the high combustion temperatures which may top 2000 F in the chamber."

Anyway, if you were to use methanol, the combustion temperature would drop and a pulsejet of quartz glass might be feasible. And perhaps a pulsejet could be coerced to run with a blend of alcohol and water making the combustion even cooler.

Mark

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Post by Bruno Ogorelec » Wed Jan 28, 2004 6:15 am

Very informative sites! Thanks.

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Post by Mike Everman » Wed Jan 28, 2004 7:35 am

Speaking of methanol, I had a very productive night with jam-jars. I was joking with Bruno recently about pointing jam jars at each other to see if they phase up, BCVP style, and they do! (or did). It was wild, much louder than two running seperated.
Best spacing of 5 positions longer and shorter was 1.9", caps off. I band-clamped two Pint jam jars to a stick with 1/2" lid holes (wood spade drills work well, hold tight to a wood block).

It ran for about 2 sec. Jam jars won't run long on their sides because the mixing is off when the fuel pools along one of the sides, so I needed a way to get them to run longer. I made circle pad of red shop towel and soaked it in methanol. It sticks naturally to the bottom of the jar and the jar can then function on it's side; it can even be inverted(!) A small feed hole in the base could keep the cloth saturated easily.

I tried this on a quart jar, and it ran on it's side, accelerated steeply, and was still increasing in energy when it shattered about 2.5sec later (usually you can run 8-10 sec before it cracks. It was fascinating, it didn't pop; more like collapsing. I'll be making a set of water cooled glass jars for sure now! Well, Friday maybe, got to hit the road/air to Minnesota in the morning.

When I pick this up again, I'll likely just rig some water flow in the garage sink to cool the two jars.
Mike
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Post by Mark » Thu Jan 29, 2004 5:15 am

Mike Everman wrote:Speaking of methanol, I had a very productive night with jam-jars. I was joking with Bruno recently about pointing jam jars at each other to see if they phase up, BCVP style, and they do! (or did). It was wild, much louder than two running seperated.
Best spacing of 5 positions longer and shorter was 1.9", caps off. I band-clamped two Pint jam jars to a stick with 1/2" lid holes (wood spade drills work well, hold tight to a wood block).

It ran for about 2 sec. Jam jars won't run long on their sides because the mixing is off when the fuel pools along one of the sides, so I needed a way to get them to run longer. I made circle pad of red shop towel and soaked it in methanol. It sticks naturally to the bottom of the jar and the jar can then function on it's side; it can even be inverted(!) A small feed hole in the base could keep the cloth saturated easily.

I tried this on a quart jar, and it ran on it's side, accelerated steeply, and was still increasing in energy when it shattered about 2.5sec later (usually you can run 8-10 sec before it cracks. It was fascinating, it didn't pop; more like collapsing. I'll be making a set of water cooled glass jars for sure now! Well, Friday maybe, got to hit the road/air to Minnesota in the morning.

When I pick this up again, I'll likely just rig some water flow in the garage sink to cool the two jars.
I love simple experiments like the above. I have toyed with twin jam jar set-ups using these liter-sized steel jars. I bought a set of 6 of them on ebay one time, they are very shapely babes that hold about a quart. http://www.vollrathco.com/custom_spinning.jsp If you watch the beginning of the movie "Young Frankenstein", you will see one of these very same jars too on the table in the classroom as Gene Wilder is giving a medical lecture.
I burned the #$(%_+@$ out of my finger one time trying to hold the domed lid on with a hole in the center that I drilled on my lathe, and the medical jar frosted my finger with a jet of fire. No real harm but I hate when I burn myself needlessly. Yes, I even have a mark now on the inside of my arm where I grazed a red hot hydraulic jam jar tank that had just run a liter of fuel. I guess I might need Combustors Anonymous after all as I have jam jar marks on the inside of my arm. "Hi, my name is Mark, and I am a jam jar junkie."
If anyone knows of a company that sells little steel jars with screw-on lids, it would be very helpful for jam jar experimenting. My chrome-plated syringes work very well as jam jars but I have as yet to find an ideal steel jar with air/fuel tight sealing lids. Some company out there must make them for something. I once saw some beautiful stainless steel containers for ice core samples that were kept frozen in a vault. Hundreds of these cylinder shaped rods/canisters that held ice core samples, they were about 4 inches diameter by a few feet long with screw on caps. Another time I saw some military mortar tube canisters that would have been nice. Alas, I didn't buy the tubes in time.
Mark

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Post by Mike Everman » Thu Jan 29, 2004 12:43 pm

Nice link, Volrath. I like the 18-8 funnels, for obvious reasons. I didn't find the quart steel jars, though...
I'll be searching for metal jars harder than usual. When I get home though, I'm going to rig the water cooling on glass so we can watch what happens inside when they are brought close, then through a tube, etc.
Mike
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Post by Mark » Thu Jan 29, 2004 2:48 pm

[quote="Mike Everman"]Nice link, Volrath. I like the 18-8 funnels, for obvious reasons. I didn't find the quart steel jars, though...

On the link I posted, the bottle/medical jar is pictured to the left of that funnel. It has a lid/cap that just lifts off and if topless, you can see the medical jar has a nice fluted curved lip the lid rests on. The lid has about a 1.5 inch side that just slides into the jar, not real snug, but they are nice shapes. I couldn't find where they have a price for ordering the jars on their site if that is what you mean. I wish they had a picture of the jar with the lid off or to the side, it looks like such a good shape for a mini Reynst body.
Mark

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Post by Mike Everman » Thu Jan 29, 2004 3:07 pm

that's a sugar dispenser! the coffee pots and malt cups for Hamilton blenders are good too. I think there are some good espresso accessories with screw caps.

http://www.home-espresso.com/product/6016B Nice shape, screw top, spendy though... Think I'll just use small mutilated propane cannisters.
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Post by Mark » Thu Jan 29, 2004 5:04 pm

Mike Everman wrote:that's a sugar dispenser! the coffee pots and malt cups for Hamilton blenders are good too. I think there are some good espresso accessories with screw caps.

http://www.home-espresso.com/product/6016B Nice shape, screw top, spendy though... Think I'll just use small mutilated propane cannisters.
I bought an interesting Italian espresso device at a junk store, I have used it for several experiments but nothing earth shaking yet. In my college days, I bought an Isi brand whipped cream maker made in Austria, similar to the one you posted, for about $35.00. I still have it but it is made out of aluminum, good for those nitrous oxide thoughts. I kept all the spent nitrous cartridges too, I might find some use for them. They can be drilled and putt putt for a few seconds jam jar style with methanol, but that's about it, not bad though for so tiny I guess.
Where is the link for the "sugar" dispensers? Where can I buy one? Here's some forceps jars with a weighted base, elegant but pricey.
http://www.medicalresources.com/shoppin ... subcat=131
For some reason I hate using propane canisters for jam jars, they are just so ugly, I suppose that's foolish to say, but presentation is everything they use to proclaim in my advertising design class. It just doesn't motivate me to work with them the way a silvery smooth vessel does. I guess it's that I want to make the jam jar an art form as well as an engine of sorts. I might change my mind, I use a propane torch all the time for experimenting and I just throw the canisters away.
I'm thinking of trying some bar stock and just boring a 1.75 inch hole down the middle and making my own lid and self contained fuel tank all in a neatly disguised svelte gleaming cylindrical body. Smaller holes drilled around the main hole would hold the fuel and cool the body as it evaporated and gets ingested, with a flush disk of metal for the top and hole in center the entire jam jar would appear nothing more than a section of round bar stock. I have some tiny jars that run furiously, and I want to improve on them. With a platinum catalytic ignition, you might just add your fuel and wait a few seconds for it to magically start reving on its own.
Mark

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Post by Bruno Ogorelec » Thu Jan 29, 2004 6:20 pm

Mark wrote:I hate using propane canisters for jam jars, they are just so ugly, I suppose that's foolish to say, but presentation is everything they use to proclaim in my advertising design class. It just doesn't motivate me to work with them the way a silvery smooth vessel does.
Ha-ha-ha... this is, really, why I've stayed in the forum for all those years. It's a place all unto itself. Somehow, I just can't imagine anyone in the turbojet forum writing anything of the kind. It made my day.

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Post by Mike Everman » Fri Jan 30, 2004 1:06 am

LOL! I enjoyed that alot, too! I however have not been around long enough to focus on the subtleties. I am far from turning this into an art form, though as a media, it rocks! I have always thought that I would do kinetic sculpture in my dotage, but I think by then it will sculpture in flame!

As to the propane cannisters, I think they are brazed together at the mid-length; I'll unbraze one and see because I want to get the fuel pad in the base, for liquid fuel, then close it up again. The fit before brazing looks good enough to seal if compressed axially. I propose to cut the hole(s) in the bottom, and use the normal outlet for fuel input. Thinking about using propane for fuel, too.
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Re: Quartz

Post by dynajetjerry » Thu Jun 21, 2012 7:19 pm

Hi, Guys,
Can anyone guide me to information on a PhD being awarded (in 1947?) for a disertation on a Pyrex Dyna-Jet? Bill Tenney told me about it in 1951 but I can find nothing about it. (NYU, I think.)
Jerry
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Re: Quartz

Post by Mark » Fri Jun 22, 2012 3:06 am

I recall reading a study under Project SQUID, it was a paper on the Dynajet where they were going to use a quartz-walled engine where just one side of the Dynajet was glass the length of the engine. But the quartz cracked, from vibration I think, but later they found they could use borosilicate glass and run it for several seconds while recording the combustion, a to and fro of the gas clouds using schlieren photography. It was a university study and the paper was about 10 pages long or so but don't quote me.
http://en.wikipedia.org/wiki/Project_SQUID

This isn't the same paper I read, but it does have a report of the Dynajet and schlieren photography, no glass though. NYU stuff. The paper I read had photographs of the glass window Dynajet and gas clouds or charges as they progressed down the duct. The inflow phase showed how the charge was choked down and inflow occurring around the edges at the same time a charge was exiting the duct.
"Figure 11. Schlieren photographs of gas motions from
the exhaust end of the tailpipe of a Dynajet over a single
cycle. Note the necking down of the jet beginning at
frame 6 and the return flow beginning at frame 9."
page12
http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA952980
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Re: Quartz

Post by dynajetjerry » Fri Jun 22, 2012 3:42 pm

Guys,
I've been trying to locate information on a Pyrex/quartz combustion pipe for a Dyna-Jet. I was told about it by Bill Tenney in 1951 but the successful work was done earlier, perhaps 1947, for a PhD candidate. I've brought up nothing on the internet.
Can anyone aim me in the right direction? I'd like to include such material in my Dyna-Jet book.
Jerry
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Re: Quartz

Post by Mark » Wed Jun 27, 2012 6:02 pm

Jerry, this is the info I have on a quartz-walled dynajet. Top and bottom of the dynajet body were plaster-of-paris and the sides were Pyrex but they cracked, and quartz was used for 6 months but subsequently they found that pyrex worked after all. I don't think they ran it for very long. The head of the jet was the typical dynajet head. The body the same shape as a dynajet including the flare on the tail. I assume the plaster was very thick, to me the picture looked like a long retangular box housing a typical dynajet shape if you didn't know better. The long rectangular box must have been filled with plaster leaving only a dynajet shape . Again, this with two side having quartz walls.

United States Navy
Project Squid
Technical Report No. 16
"Flame and Partical Motions in a Small Pulsejet Engine"
By Paul Elias
July 1948
New York University (for partial fulfillment of the requirements for the degree of doctor of engineering science)
21 pages including the bibliography
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Re: Quartz

Post by Mike Everman » Mon Aug 20, 2018 4:40 pm

Hey Mark, hope all is well! Getting ready to cut some of that Quartz tube you sent me lo these many years hence.

I wonder if scoring it in the lathe with a glass cutter and break will work? I do need to grind the ends flush to a specific length, too.

As I recall but can't find it was you were a fan of diamond wheel in a dremel?
Mike
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