The Cheerios contest?

[sbs]

1) Regarding the difference in surface area. Can that variable be removed if the hose is held from above, and the distance from the ground at which the Cheerio is inhaled, is the determining factor? ie. dust collector pulled cheerios from 14" while shop vac sucked them up at 8". This would remove the questionable smoothness of the surface area from the equation, no? Simply support hose end and measuring stick in the same hand, make mark on the stick if not ruled, and report findings. Just a suggestion.

Indeed that is a much better experiment.

Here is my cheerio lift tester, patent pending:



(It handily converts into a horizontal cheerio displacement tester - two tools in one!)


My results:

Fein 9.55.13 with a very dirty filter.

Experimented with different hoses (2-2.5" x 15-18') and various nozzles, differences were insignificant.

Horizontal (on tempered hardboard) about 2.5"

Vertical about 1"

The cereal in question was Wal-Mart brand plain cheerios. They appear to be slightly larger and a lot rougher than the real thing.

Next time it gets above freezing here I'll try to remember to wash the filter and repeat the test.

[LCHIEN]

The vertical lift test I think would be more variable due to the cross-section shape of the cheerio. In order for it to lift, the air rushing at the sides must get underneath and that would depend more on the shape of the sides. Imagine a cheerio blown up as a donut - cut the donut in half across the hole. the two edge profiles could either look like circles for a round donut or like rectangles if the donut was more "washer" like. In the case of a true rectangular cross section, it would not lift at all as there would be way for the air to get under any part of it and lift.

In the horizontal pull test, the air comes from the side and the push comes from the side-view cross section of cheerio which is more consistent and less dependent upon the variation in squareness or roundness. It will still vary some but not as much.

We should stick with the horizontal test.

[sbs]

The vertical lift test I think would be more variable due to the cross-section shape of the cheerio. In order for it to lift, the air rushing at the sides must get underneath and that would depend more on the shape of the sides. Imagine a cheerio blown up as a donut - cut the donut in half across the hole. the two edge profiles could either look like circles for a round donut or like rectangles if the donut was more "washer" like. In the case of a true rectangular cross section, it would not lift at all as there would be way for the air to get under any part of it and lift.

Lift occurs due to low pressure above the cheerio. The pressure on the bottom is roughly 1 atm regardless of shape (as applied to cereal, at least.)

I think the vertical test is the much more controlled test. But we're talking about one test with 99% of variables uncontrolled and another with 98% of variables uncontrolled, so they're as good as equal.

[onedash]

OK....What will these tests actually tell us? Who doesn't connect their hose to the tool? Are we trying to get dust to jump a gap before they enter the hose? Most tools seem to launch the dust in a certain direction. Some want to go into the dust colletor/vac others that avoid it at all costs. The CMS saw for example has a bag connected to a tiny hole that is supposed to catch the dust. I noticed if the bag is empty and the saw is allowed to reach full speed and the cut is slow it collects more dust. Im sure certain blades are better than others that create more airflow that will go towards that tiny hole. And a router fence directs airflow across the bit (depending on cut and bit) and into the collector. my planer will make my DC bag blow up to full size so that is creating airflow as well.
so if we can pull a cherio 2 inches or 48 inches means what exactly?
A shop vac can suck up a pile of bolts as long as you move the hose to the bolt, The dust collector can't but it moves 6-12 times more CFM which is great to collect tiny particles from a greater distance like the CMS unless you restrict the airflow in which case it doesnt do as good.

[mpauly]

One more idea. Seeing as we're using uniform boards, we may want to place the Cheerio 1" from one end, and then advance the hose from the other end. Once the Cheerio gets sucked in, stop and measure from the current hose location to where the Cheerio started.

This thread is too funny!!!

I would think though that steadily moving the cheerio towards the hose (rather than suggested above) with your finger would kind of help negate some of the surface/friction dependencies as the motion would already be overcoming most of the static friction component between the cheerio and the board.

[cgallery]

Lift occurs due to low pressure above the cheerio. The pressure on the bottom is roughly 1 atm regardless of shape (as applied to cereal, at least.)

I think the vertical test is the much more controlled test. But we're talking about one test with 99% of variables uncontrolled and another with 98% of variables uncontrolled, so they're as good as equal.

Absolutely pull test. Not only do I think it is more similar to real-world conditions, but the #'s yielded will be larger and easier to compare.

[Stytooner]

Okay, what about if we tie some fishing line to hold the Cheerio to a nail acting as an anchor. At what distance does the cheerio become airborne with the hose above? This would be sort of a misinfo thing with regard to all the forces mentioned above working on a Cheerio that is not in motion.

The key to get a more accurate reading would be once the Cheerio is suspended in mid air and anchored by the line, how far away can you pull the hose until the Cheerio drops back down?
Of course we would all have to use the same guage line. "Well I used 50 lb test. I used 5 lb test." etc....
Since this isn't a permanent test, standard cotton thread could be employed as an anchor.

[LarryG]

Owners of Harbor Freight dust collectors are cautioned not to try this test with the stock bags ... otherwise that Cheerio is going to come flying out and nail you right between the eyes.

[Stormbringer]

Owners of Harbor Freight dust collectors are cautioned not to try this test with the stock bags ... otherwise that Cheerio is going to come flying out and nail you right between the eyes.

Just open your mouth and you have some breakfast

[LCHIEN]

Forget the fishing line, it should be no problem at all to find the equilibrium height for the hose above the cheerio, at which point the cheerio will remain suspended and floating in air, neither rising nor falling.

[L. D. Jeffries]

I don't like cherrios', can I use corn flakes?

HAHA

[mikel]

****, I can only find fruit loops...

...mikel

[MilDoc]

HEY!

Unless you specify the weight of the Cheerio you used as well as its diameter and the size of the hole, how can we compare results???

[WoodButcher26]

And I thought the rocket scientists I work with were bad...

Due to the inconsistencies in size of Cheerios, I propose that the aforemetioned test articles be limited to .438 +/- .007 inches in diameter and .129 +/- .004 inches in thickness (11.125 +/- .177mm, 3.275 +/- .100mm for Mr. Kirby and anyone else used to working in real measurements...), having mass between 3.5 and 3.65 grams measured at standard temperature and pressure.

I would also suggest that voltage and current measurements be taken of the power supplied to the pressure lowering device before and after each phase of the test, to ensure that fluctuations in local power did not unduly influence the test results.

(Sorry, I write this kind of thing on a regular basis as part of my job... )


Kim

[TB Roye]

I think this tread will end up giving the Song Game a run for it's money. It must be a long cold winter with no shop time. But I do enjoy reading about this contest. Keep it up, can't wait for the results and the winner. Does the winner get the Thong?

Tom