[Turtle]

Originally Posted by UncleAl

Kinetic Temperature, Thermal Energy

Mach 20 = 6806 m/sec. For air with average molecular weight = 29 daltons, Mach 20 gives 80,000 C (most probable speed) to 52,000 C (RMS speed) as the apparent relative temperature of the surrounding atmosphere. What difference does surface "lubrication" make when sitting in a plasma furnace?

As soon as I get a plasma furnace, I will check that out. In the mean time I'm guessing the answer is 'not so much'? *

Originally Posted by Alexander

ooh i wonder if i could make a prototype for this for a car, obviously paper straws are out, but i am wondering if and how much it would increase the amount of air that is pushed into the engine by streamlining it's motion.... perhaps this would be interesting with a turbo?

Your creativity is enjoying a major spike these last couple weeks I have observed. I'm thinking this is going to be interesting with a lot of subsonic air velocity things.

Here's the control experiment vid with the open fan.

YouTube - Laminar Flow Experiment - Control Run

*Reading the link I gather that passing a plasma through my ductedy-duct would not produce a laminar outflow because a plasma's motion can't be properly desribed by point-particle means, but rather requires atomic parameters such as spin?

[alexander]

lol off to break my dad's tdi jetta....

lol i have always been creative, just that recently i have had some time and money to put into that.... doing some photography, lots a modifying things, making some music, etc, amongst other projects.... i am interested in this though, i have seen the laminar flow for water prototype on a show not too long ago (one of the original ones) and i was amazed at how nicely that looked, so i was thinking that with that, you could probably create a turbo-like pressure effect, granted you have a thicker pipe of filtered air coming into a laminar flow control thing, and then a coupler stepping down the tube size to the size of the normal air hose going into the intake manafold. I bet i could probably get a couple of lb of pressure out of the system without adding any moving parts to it, and i can almost guarantee that this would be way better then a "tornado". Also you can still create a tornado-like effect if you spiral the tubes a little bit, though i dont know if that would be needed considering the fact that you will have air pressure built up by the system anyways...

[Turtle]

Originally Posted by alexander

lol off to break my dad's tdi jetta....

lol i have always been creative, just that recently i have had some time and money to put into that.... doing some photography, lots a modifying things, making some music, etc, amongst other projects.... i am interested in this though, i have seen the laminar flow for water prototype on a show not too long ago (one of the original ones) and i was amazed at how nicely that looked, so i was thinking that with that, you could probably create a turbo-like pressure effect, granted you have a thicker pipe of filtered air coming into a laminar flow control thing, and then a coupler stepping down the tube size to the size of the normal air hose going into the intake manafold. ...

Sounds like the same show that got me interested. I have done water versions like on the show, and the step down need only be a flat plate with a centered hole sized to fit your application. I plan to experiment with this by using interchangeable plates (coffee can lids with holes ) situated in front of the outflow side of the duct.

Here's experiment run #2: blowing out the candle with the empty duct attached to the fan. As I earlier surmised, the result is worse than the control, that is I had to get closer. The maximum distance for blowout is ~5.5 feet, which is 27% closer. ........

YouTube - Laminar Flow Experiment - Empty Duct Run

[alexander]

hmm... *ponders for a second*

perhaps i should contribute... smaller though, i should get a computer fan (use battery to power it), and then attach a soup can to that, fill it with straws (got plenty of those at work, thin ones too) and yeah see what it is going to do, then i can use more soup cans to make different shape step-down adapters, and its more of the size of a car intake duct...

sounds like a project

[CraigD]

Some unsolicited suggestions and ideas for folk experimenting with air flows:

• Smoke is useful. Try injecting smoke from a lit cigarette, punk, etc, into your contraptions to visualize (ie: make visible) laminar and turbulent airflow.
• Terminology-wise, a device to assure that all of the air in a wind tunnel is moving in more-or-less the same direction is called a collimator (its use in aerodynamics is less common than in optics). “Laminar” (“layered”) refers to air moving at different speeds in the same direction remaining parallel. It’s usually of most interest when one of the layers of air is contacting some surface, in which case it’s called a boundary layer, but you’ve got another significant case of it where the fast-moving, roughly cylindrical body of air emerging from a ducted or unducted fan meets the still surrounding air.
• The main purpose of the collimator in a wind tunnel is to eliminate artifacts, particularly the rotating effect of the driving fan. Try holding a model airplane in front of a fan, and the need for this is obvious – the plane will try to roll fast.
• Square or hexagonal grids made of paper, plastic, metal, or thin wood are, I think, better for a wind collimator than packed together straws. I suspect you’re getting some pretty complicated turbulence from those straws. The only wind tunnel I ever built, from plans from Estes (the model rocket company) published in the 1970s, used glued-together paper milk cartons.
• Fan duct length and taper can be optimized for a given medium (eg: ambient/ humidity/temperature/pressure air) and fan. An example of this is the design of the bypass duct on a turbofan jet engine.
• Blowing out a candle doesn’t necessarily require a large volume of air, or even any net air movement. One of my childhood toys was a sort of pistol with a strong spring-powered piston that drove air through a tapered plastic chamber to a small (about 2 cm) nozzle. One of its tricks was that it could blow out a candle at an amazing distance, 3 meters or so if I recall correctly, even though it expelled only a fraction of a liter of air in a single shot. It also could damage eardrums when discharged directly into an ear (or so legend had it – I never tried that trick), which is why, I suspect, it’s no longer a popular toy.
  A Mythbusters episode demonstrated blowing out flames (ultimately a big gas flame) with little rubber diaphragms and loudspeakers.

[alexander]

ooh i just had an idea of how to produce the contraption for the car

ok, i take clay and model the duct structure, surrounded by a can, grease up the dried clay or putty (i have yet to investigate what would work best) but take a bunch of industrial hot glue sticks (they are thicker and have ratings on hardness of plastic) melt a package of those together in a pot and then poor the plastic mixture into the mold, shake it a little bit to expell any air that may be in the mold, let set, remove the mold (hopefully that will work), trim and i should have a test-ready mold, ready for installation in a car or device i want to use.... at the cost of sactificeing a pot, i think i will start with making a mold... gotta stop at some artist store an pick up some clay of some sort... i may need some sort of an enamel, or something to keep the plastic from sticking to the mold.... anyone have any ideas? i think this way would be easier then creating hexagons from paper probably more reliable for real testing, too?

[Turtle]

Originally Posted by alexander

ooh i just had an idea of how to produce the contraption for the car ...ok, i take clay and model the duct structure, surrounded by a can, grease up the dried clay or putty (i have yet to investigate what would work best) but take a bunch of industrial hot glue sticks (they are thicker and have ratings on hardness of plastic) melt a package of those together in a pot and then poor the plastic mixture into the mold...

Now we're cookin'! The holt-melt glue mold idea is interesting and it's in the back of my mind now for future use.

Originally Posted by Craigenator

Some unsolicited suggestions and ideas for folk experimenting with air flows:
-Smoke is useful. Try injecting smoke from a lit cigarette, punk, etc, into your contraptions to visualize (ie: make visible) laminar and turbulent airflow....

I'm stocking up on the Nag Champa as we type. I think the other variations you mention are great, and give other experimenters more options for materials at hand as well as providing new results for comparisons to other designs.

Beisdes using the candle blow-out in initial tests, I have in mind to hang an array of ribbons/string as a target and so be able to 'see' the shape of the stream as it disturbs them.

I have the second row of straws nearly installed in the can, and because the straws aren't all from the same place (I scavenged them over the last few months from my roommates who eat out), they do not closepack as does the ideal theoretical model. Still, I have used straws before to build one of these for water and with good results. (threw it away in a minimalist multifunctionistic binge. )

In building these, I have noticed they have unusual accoustic properties, and I intend to affix a speaker in the fan end at some point and experiment with that. (The speaker will replace the fan, not add to it). There are some disorienting/interesting visual properties as well I've noticed when trying to look through the array of channels and that will get a look sooner or later.

Great ideas fellas, and I'm off like a dirty sock to watch some glue dry.

[alexander]

-Smoke is useful.

from my history with smoke, it can be a little hard to work with it, i mean last time when i set off a smoke bomb in my friend's shed as an april fools joke, it took us 2 hours to get back into the shed....(it was not well vented)


neighbors were like "do you want us to call the fire dep-t?", i was like "naaw, don't worry, i only used 600g of to 400g of sugar, it finished burning a long time ago and i set it on a big piece of sheet metal, this is just the smoke that is left over....", my friend was like "you are one sick m&*3r f#&^$r". But hey, it was pay back time

took a little long to get, had to order it and wait for it to come in, then had to poor the smoke bomb in stages, like get one batch all nice and cooked, poor it, go to next batch.... it was funny though

[Turtle]

Originally Posted by alexander

from my history with smoke, it can be a little hard to work with it, i mean last time when i set off a smoke bomb in my friend's shed as an april fools joke, it took us 2 hours to get back into the shed....(it was not well vented)

I was thinking dry ice might work to good effect?

Here's a snapshot of my construction so far.

[Pyrotex]

Originally Posted by arkain101

LOL,...Now, if one was to build such a plane where the engines were located in such a posistin that they provided substantial thrust of air over the fusilage even while the plane/flying machine was at rest relative to the ground, would it, could it fly, and even maybe hover?...

Well... yes.
Mississippi State University, back in the 70's I think, built such a plane.
It had two engines, one on each wing. The wings themselves came straight out of the fusilage, then curved in a semi-circle (down and then up) and ended in a second straight section at the tips.

The engines were mounted at the axis of the semi-circular wing sections, and each had a propeller that pushed all its air "through" the semi-circular wing section.

With engines revved to max, about ~90% of plane's weight was gone. The plane only needed to move forward at about ~40 mph to take off.

Can't find a picture online. And all numbers are guesstimates.