hey everyone.
i have a a physics project due next monday and i need some suggestions on how to get my "fan" mobile started. the fan mobile consists of some sort of self-created body, a self made propeller, and a 9volt batter with a small motor.
i am allowed to use a 9 volt battery with a small motor. the rest has to be made from scratch. no premaid wheels, propeller, etc.
my goal is to be the fastest car within an 8 meter span.
does anybody have any suggestions in how to make this mobile work and hopefully win?
Self Propelled "fan" mobile
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Craig_Bridge
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bradleyshanrock-solberg
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25 years doing IT, various roles, for multinational manufacturing company - Project Due Date: n/a
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Interesting. It sounds like you are not allowed to use the engine to just spin the wheels like on most ground vehicles.
As the prior poster stated, you want to build some kind of frame for it, leaving aside the problem of the fan. Your vehicle needs wheels (unless your vehicle is so light that it flies, which is unlikely - wheels will reduce friction resistance better than anything else). You need a frame sturdy enough to hold the motor, the battery and the fan itself. It also needs to be stable enough so the rotation of the fan doesn't cause it to vibrate apart or tip over.
To make something stable, you make it kind of low and flat. This lowers the "center of gravity". You can get this concept by thinking about a brick. If you stand the brick up [] it's easy to tip over. If you put it on its side, on the narrow end, it's harder to tip over but not that hard. If you lay it flat (widest side on the ground), you can't really "tip" it at all...you have to lift up a side and flip it over.
As for fan design - I'm not sure how I'd begin on that in a project where I had to machine anything myself. Probably I'd inspect the fan blades of anything I could get my hands on - actual fans, blow dryer, vacuum cleaner etc, and look for something that isn't too hard to make (unplug before inspecting them and don't disassemble unless you've got permission from somebody who understands you may not be able to put it back together).
Most propellor or fan blades are curved plastic or metal, carefully shaped. This isn't an easy thing to just find or make. There are some though that are essentially flat blades stuck onto rods and they're just set at a particular angle. That seems possible.
As the prior poster stated, you want to build some kind of frame for it, leaving aside the problem of the fan. Your vehicle needs wheels (unless your vehicle is so light that it flies, which is unlikely - wheels will reduce friction resistance better than anything else). You need a frame sturdy enough to hold the motor, the battery and the fan itself. It also needs to be stable enough so the rotation of the fan doesn't cause it to vibrate apart or tip over.
To make something stable, you make it kind of low and flat. This lowers the "center of gravity". You can get this concept by thinking about a brick. If you stand the brick up [] it's easy to tip over. If you put it on its side, on the narrow end, it's harder to tip over but not that hard. If you lay it flat (widest side on the ground), you can't really "tip" it at all...you have to lift up a side and flip it over.
As for fan design - I'm not sure how I'd begin on that in a project where I had to machine anything myself. Probably I'd inspect the fan blades of anything I could get my hands on - actual fans, blow dryer, vacuum cleaner etc, and look for something that isn't too hard to make (unplug before inspecting them and don't disassemble unless you've got permission from somebody who understands you may not be able to put it back together).
Most propellor or fan blades are curved plastic or metal, carefully shaped. This isn't an easy thing to just find or make. There are some though that are essentially flat blades stuck onto rods and they're just set at a particular angle. That seems possible.
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bradleyshanrock-solberg
- Former Expert
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- Occupation: Software Engineer/QA Lead - Quality, Risk Assessment, Statistics, Problem Solving
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Research in Traffic and Ceramic Composites
25 years doing IT, various roles, for multinational manufacturing company - Project Due Date: n/a
- Project Status: Not applicable
For the rest, a lot depends on the tools you have and the materials you are allowed.
If you have a machine shop available, it's not too hard to make wheels and most of the rest of the frame. (a lathe makes round things...axles and wheels easily enough). But really, a "wheel" can be something as simple as rubber bands wound around the ends of an axle. As long as you have a round piece of wood or metal to be the axle, you can get roughly circular stuff to serve as wheels just by wrapping enough material around the axle (electrical tape might work too). This works better if your entire vehicle is small. If it's large, you will need some kind of real wheel.
You might also just consider finding something round that already exists - bottle caps or jar caps for example, or even something like a prescription drug container...slice off the bottom and you have a nice round piece of plastic.
If you have access to round materials of any size, you can take a narrow stick and that's the axle, take a fat one, slice off the end, and that round thing is the wheel. Then drill a hole in the wheel and stick the axle through. Either the axle or the wheel needs to rotate, and you want the connection between whatever rotates and whatever holds it to be smooth. Grease might prove helpful here.
For the frame, wood, aluminum and plexiglas are all easy to machine and pretty easy to work with even with only hand tools. Wood is usually best assembled with a mix of glue and something mechanical (screw or nail), plexiglas can simply be glued together with the right solvent-based adhesive (it will be as strong as one piece of plastic if you use the right adhesive). Aluminum usually needs to be screwed together. Steel can also be used if the holes are already there (like from an erector set) but it is much harder to machine and nearly impossible to manipulate with hand tools.
Cardboard might be used for some components, it is light, easy to work with and strong for its weight, but the basic frame, wheels and whatever you attach the moter to must be pretty sturdy. I don't recommend cardboard anywhere near the electric motor - it will get hot..not enough to burn wood but paper or cardboard....maybe. best to be safe.
If you have a machine shop available, it's not too hard to make wheels and most of the rest of the frame. (a lathe makes round things...axles and wheels easily enough). But really, a "wheel" can be something as simple as rubber bands wound around the ends of an axle. As long as you have a round piece of wood or metal to be the axle, you can get roughly circular stuff to serve as wheels just by wrapping enough material around the axle (electrical tape might work too). This works better if your entire vehicle is small. If it's large, you will need some kind of real wheel.
You might also just consider finding something round that already exists - bottle caps or jar caps for example, or even something like a prescription drug container...slice off the bottom and you have a nice round piece of plastic.
If you have access to round materials of any size, you can take a narrow stick and that's the axle, take a fat one, slice off the end, and that round thing is the wheel. Then drill a hole in the wheel and stick the axle through. Either the axle or the wheel needs to rotate, and you want the connection between whatever rotates and whatever holds it to be smooth. Grease might prove helpful here.
For the frame, wood, aluminum and plexiglas are all easy to machine and pretty easy to work with even with only hand tools. Wood is usually best assembled with a mix of glue and something mechanical (screw or nail), plexiglas can simply be glued together with the right solvent-based adhesive (it will be as strong as one piece of plastic if you use the right adhesive). Aluminum usually needs to be screwed together. Steel can also be used if the holes are already there (like from an erector set) but it is much harder to machine and nearly impossible to manipulate with hand tools.
Cardboard might be used for some components, it is light, easy to work with and strong for its weight, but the basic frame, wheels and whatever you attach the moter to must be pretty sturdy. I don't recommend cardboard anywhere near the electric motor - it will get hot..not enough to burn wood but paper or cardboard....maybe. best to be safe.