1. O.k guys, so now my teacher told me I have to have a possible real world application for my project, so I told him that the information gained through this report could lead to advancments in travel, things like hovercrafts. He said that I would then have to compare the different flight patterns of a spining card vs. a non-spining card given the same initial forward driven force. He also told me that I would have to have some way of measuring the force of the cards spin, he suggested using a blender and some sort of balance.

My question this time is "Does anyone know how I could measure the revolutions per second of the cards, as well as measuring the amount of lift created by the rate of revolution?"

Please help me. My teacher couldn't talk to me about it very much as he is also helping about 40 other kids so any advice more helpful than, "Use a blender to create a controled amount of spin," would be very helpful. Thank you everyone.

2.

3. Also anything anyone can tell me about laminar flow beyond what it is would also be greatly appreciated.

4. Houm...

I think I can help with the rpm matter.

First you need to measure the rpm of the blender. I assume that you haven't access to a rpm counter so I'll suggest you a way to measure the rpm of the blender.

you'll need a blende rof the type which have got the motor inside the handle and a removable "head" with the blades. This blenders usally have a drive shaft to conect the motor with the head, and thsi dirve shaft will be your power source.

In order to measure the rpm of the blender without a rpm counter, you may try to link the blender shaft with a kind of disk, maybe a wooden disk, to which you can roll a fishing wire. The purpose of this is to measure how many fishing wire can the blender wrap in, say, 5 seconds. You only need to mark a point in the fishing wire, then turn the blender on and roll the wire around the disk. Make a second signal in the point were the outer layer of wire coincides with your previous signal. Then unwrap and measure the length of the rolled wire, and you'll get how many circunference lenghts of the disk have "rolled in" in 5 seconds. Multiply by 12 and you'll get the rpm of the disk, thus of the blender. FAI, a disk 10 cm in diameter will have a circunfernce of 31.4 cm; so if the blender rolled 31 meters of wire in 5 seconds this means that it has made 100 revolutions in 5 seconds=1,200 rpm.

Then you just may like to link your original disk to disks with smaller/larger circunferences; a disk with a circunfernce of 15,7 cm (diameter 5 cm) will make 2 revolutinos in the same tiem as the alrger one rols one; providing twice the rpm. Then if you link the disk with a free axis which spins the cards... The only enxt tign would be how to propel the spinnign cards. Mayeb someone else can figure a jury-rigged device for this.

(Alternatively, you may use Lego Technic gear wheels, just bear in mind that the relation of speeds is between the circunferences measured at the base of the gear teeth... and woud be smart to use soe kind of reduction between the blender shaft and the Lego gears, FAI a smaller wheel on the blender shaft spinning a larger wheel on the axis of the first Lego gear)

5. Originally Posted by Lucifer
Houm...

Multiply by 12 and you'll get the rpm of the disk, thus of the blender. FAI, a disk 10 cm in diameter will have a circunfernce of 31.4 cm; so if the blender rolled 31 meters of wire in 5 seconds this means that it has made 100 revolutions in 5 seconds=1,200 rpm.

Why would I multiply by 12?

6. Originally Posted by biohazard87
Originally Posted by Lucifer
Houm...

Multiply by 12 and you'll get the rpm of the disk, thus of the blender. FAI, a disk 10 cm in diameter will have a circunfernce of 31.4 cm; so if the blender rolled 31 meters of wire in 5 seconds this means that it has made 100 revolutions in 5 seconds=1,200 rpm.

Why would I multiply by 12?
We've measured 5 seconds of rolled wire, and minute=60s, whcih divided by 5s=12. So we need to multiply the turns made in 5 seconds for 12 to get the rpm, or how many turns (revolutions) would it do in a minute.

BTW, the 5 seconds figure is arbitrary, but of course the longer you run the blender the longer wire you'll need to measure to estimate the rpm... :wink:

7. Thank you lucifer for the advise, I will most likely be using a blender, but now I need a way to measure laminar flow. I have been loking on line for about an hour and sll I can find is machines that measure the lamiar flow of water, mostly for streams.

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