Intro: The 50 Cent Toy Hovercraft / Helicopter- Demonstrate the Magnus Effect
I really liked how simple the original project was, but I got to thinkin... bigger is better, right!? Hoopajoo's is quick and easy, mine requires a little more time but it is still very simple to build and it will stay in the air a bit longer too!
Ready to build? Me too, but lets talk a little first about this "Magnus Effect".
The 50 cent Hovercraft:
Step 1: What the Heck Is the Magnus Effect?!
So what the heck is the Magnus Effect? According to Wikipedia:
The Magnus effect is the phenomenon whereby a spinning object flying in a fluid creates a whirlpool of fluid around itself, and experiences a force perpendicular to the line of motion. The overall behaviour is similar to that around an airfoil (see lift force) with a circulation which is generated by the mechanical rotation, rather than by aerofoil action.
See the complete article here: http://en.wikipedia.org/wiki/Magnus_effect
Turns out, the Magnus Effect is what is usually responsible for curve balls in just about all types of sports- you now have something to blame for that nasty slice in your golf game!
To be totally honest, until I saw this project, I'd never heard of it... but lets see if I can enlighten y'all
Bernoulli discovered that fluids moving fast create low pressures, and fluids moving slowly create high pressures. Air flowing over the top of the wing moves faster than the air flowing underneath, so you have a high pressure underneath and a low pressure above causing the wing to rise.
A SPINNING object- a ball, or our little hovercraft thingamabob here- causes air to move. When the spinning object moves, the spinning air around the object speeds up in the direction the object is moving and slows down behind it, creating a low pressure in front and a high pressure behind. Clear as mud?!? Took me a few tries to understand it too! Check out the picture below for a little more help.
Okay. Lets get to it.
Step 2: Gather Supplies
Real simple. You need:
2, 4, 6, 8, or however many styrofoam cups
20" of thin dowel
Tape (scotch, masking, duct tape, whatever!)
Hot glue Gun
Something to cut the dowel with
Pencil or other sorta sharp object
Step 3: Build!
Build the cylinders. You will need to repeat this step once, leaving you with two sets of cylinders.
Start by taping two cups together at the top as shown in Picture 1.
Using your pencil or other sharp object, poke a small hole in the bottoms of the cup right in the center, as show in Pictures 2 and 3.
Slide the dowel through the holes so that about an inch is sticking out one side as shown in Picture 4. Using the hot glue gun, Glue the dowel to the cup as shown in Picture 5
Poke another hole in the bottom of the next cup as shown in Picture 6.
Slide the 3rd cup over the part of dowel that sticks out as shown in Picture 7. Hot glue helps, but it isn't necessary because this cup also gets taped to the other two.
Viola! Half done. Repeat the above steps for the other side, but make sure to LEAVE ABOUT 3 INCHES between the two sets as shown in Picture 8.
Step 4: Flying Tips and Tricks
Once you have the rubber band wrapped, hold it down low, let go of the stick, and yank up all at the same time. Takes some practice but you should be able to get a good launch after about 5 tries or so.
The video is not real great quality, but I think it's pretty good considering it was shot by my 8 year old son!