Egglet24
Posts: 7
Joined: Sun Jan 18, 2004 3:38 pm

I'm doing a project on what object produce the most lift. I have tested them already. Well some of them and i only get like a 2 to 3 oz. differnece. I'm wondering if that would be a big enough differnece to make a sciecne fair project out of. I have a scale within a cardboard box and i place a 5 pound stand on the scale and a clip. And i'm using a leaf blower to produce the air. And i'm wonder if is a good enough project for me and if there is any way to make it better i would like to know. The scale display the weight and it changes up to 3 oz. So i'm wonder if there is a better way to do this or is it good enough or do i need to change something. If you have any ideas let me know Thanks

Matt D
Posts: 13
Joined: Mon Dec 22, 2003 3:08 pm
I would guess that you would probably need much more accuracy than to the nearest ounce, probably to the nearest gram to actually measure something. You could probably do this best by tying a string to the leading edge of the "wing" and a sting coming down from the wing. Have a basket at the bottom of the sting that's hanging down and attach a basket that you can add weights to (pennies work good for this). See how much mass the wing can support.

(ignore the periods--the spacing messed up without them)

...........---------------------------------------
leaf
blower---string------<==wing=>
here................................|
..........---------------------- | ---------------
| (string that runs thru hole in wind tunnel)

I think I understand your current design. If I'm right it looks something like this:

........... -------------------------------------
leaf
blower..........}~~~~~<==wing=>
here...........[5lb]
................(scale)
...........-------------------------------------

I'm not sure how well this method works. One thing that worries me is the turbulence caused by the weight. You could probably fix this by putting a metal rod in and putting theweight and scale underneath the wind tunnel. This is an interesting method. Perhaps you could do both and see the difference.