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The Super Cool Flying Propeller

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I was inspired to make this because once again i was scratching my head and thinking "What the heck can i do to keep my grade 8 metal work students interested?" I am often doing this perhaps to keep myself interested, too.
I like stuff that flies and have about 10 RC airplane wrecks to prove it. :-) So when i think of things to build i often do something that flies... or at least tries to.

This project was inspired by the old wooden toy that is basically just a propeller on a stick. You spin the stick between your palms and it flies.... do it the wrong way and it attacks your hand. I thought that it must be simple to make a launcher that spins a prop really quickly and after all sorts of really complicated ideas the simplest as always was the best.

The project is made of simple steel tubing with a long bolt going through the middle, a couple of discarded skate bearings and nuts. A string wound around the bolt spins it as it is pulled. The spinning motion is transferred to a propeller and WHOOSH off it goes. It even makes that sound! seriously!

here's a youtube link of the prop in action...

http://www.youtube.com/watch?v=iy-BiMZP3Fc ( just copy and paste into your browser)

Anyone can make it with very simple tools. During the steps I will suggest both simple and more complicated methods so that you can challenge the beginners and advanced students in your class.

Turns out that the project has TONS of teachables in it. Here are some learning objectives...

History.... The students will research and apply the information gained about historical approaches to flight to investigate propellers and helicopter blade design
Design... After research has been compiled the kids will use that information to creatively design three propellers.
Geometry... Students will learn how to use a compass to subdivide a circle into even parts.
Using the Scientific Method... Students will evaluate the performance of the propellers after first writing a hypothesis, testing the props and drawing conclusions based on their observations
Pattern-making... The students will develop a pattern than transfer the pattern to metal.
Metalwork... Basic metalworking skills will be learned and applied to produce the parts required to build the project. Simple skills will involve a drill press, hacksaw and aviation snips as well as files and sandpaper. More advanced skills could be applied to increase precision such as the use of a lathe, MIG or oxyacetylene torch. (the examples i use are  all with simple tools)

Vocabulary:
-Pitch
-Diameter, Radius
-Bearing race
-Flush
-Leading edge
-Trailing edge
-ball peen hammer

Materials:
-1 1/4" x .120 steel tube. About 6" long. You can use any pipe at all... any material as long as the ID is the same as the OD of the skateboard bearings.
-1/16" welding rod
-5/16" aluminum rod
-aluminum tube... 5/16" ID... about 1/8" wall thickness. Steel is usable, too...
-0.50 aluminum... Very thin aluminum... 6" square.
-5/16" 6" carriage bolt
-5/16" washers (3) and nuts (3)
-File folder
-Sharpie, Pencil
-Compass
-JB Weld or Epoxy

Tools:
-Compass, Ruler, pencil, sharpie
-Center-punch
-Drill press or Hand drill
-1/16, 1/8", 9/32" drill bits
-aviation snips
-assorted smooth files
-Bench vice (or some kind of clamp...)
-Hacksaw




Or you can just follow the steps and build a cool flying thingie. Your choice...  :-)

Submitted by HD Stafford Middle School  for the Instructables Sponsorship Program

 
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glorybe1 year ago
At the end of WWII the US had Mustang fighters with two different props. One was a three bladed prop while the other was a two bladed design. The third blade added torque but reduced speed and flight quality. At a certain point the plane wants to rotate when the prop gets too good a bite. So the pilot has to compensate for all that extra torque. But extra torque meant heavier payloads and probably shorter runways as well.
this is along the same lines as the early bi planes and tri winged planes that needed almost no runway and launched so easily but were so very, very slow in the air. Too much power or too much lift always cause penalties.
Never seen a P-51 with a 2 bladed prop, most had 4 blades with adjustable pitch and "cuffs" at the base of each blade for giving the propeller a broader base and more thrust at higher altitudes and lower revs. The rest of the prop was more like that of any other fighter of the time and gave better low speed torque for better maneuverability in dogfights.
stumitch (author)  glorybe1 year ago
interesting.... it makes sense, really. I'll share that with the kids next time i do this project!
-stu
maximzodal2 years ago
Another great project! Wish my grand kids had you as a teacher. As for safety, parents should check out the book "50 dangerous things you should let your kids do" (Actually, I didn't find them all that dangerous. We did much more dangerous things as kids!). But I know what you mean. Our litigious society means a lot of fun things I was able to do in the classroom 35 years ago almost impossible today. Too bad.
stumitch (author)  maximzodal2 years ago
thanks so much... and you are absolutely right about our litigious society! we are SO protective of our kids... for good reason but we do need to know where to draw the line.... they have to fall to learn!
Kiteman2 years ago
Yay, grand fun!
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