Can a homemade hovercraft be built using bicycle inner tubes?

[lokeo13]

My friend and I are ambitsious(sp) people and we are currently looking into making our own hovercraft. I know it can be done, But how I wonder... I like physics very much and i know there are physics involved. Has anyone ever attempted in making a hovercraft from scratch ( or mostly scratrch)? What are the main physics one would need to know to build a working hovercraft? I hope someone out there can help me...

 

[chroot]

I assume you mean a normal air-powered hovercraft.

The most important part of the hovercraft is the skirt, which directs airflow downwards around its perimeter.

I'm sure the web is full of information.

- Warren

 

[anomaly]

Yes, I made a hovercraft just last year. I made it for my senior applied technology class at CSU. The object was to design a hovercraft that is powered by 9V batteries and is capable of moving in a straight line.

I designed the hovercraft using two 9V batteries wired in parallel to two motors with propellers - one facing down, the other facing to the rear of the hovercraft. The chasis of the hoovercraft was made from a styrofoam meat tray (the ones you find a T-bone steak on at the supermarket). I cut a hole in the center of the tray for one propeller to sit in and built up from there.

This was a simple enough design to pursue and it worked. I can post pics of it if you like.

You can make a personal hovercraft using a leaf blower as well. This is actually easy to do. You will need a sheet of thick plywood (thick enough to support your weight), trash bags, and a leaf blower. You cut the plywood into a circle that is approximately 3' in diameter. Then cut a hole in the plywood for the leaf blower to push the air through and chamfer the hole so that it looks like this on the bottom side ___/ \___. Secure the trash bag on one side of the plywood and cut small holes into the bag (for the air to escape from). Construct the hovercraft, and go for a spin.

As for some equations that will help you to determine the requirements of the system, I would begin with drawing free body diagrams to determine the forces involved. Then utilize the equilibrium equations to derive the conclusions.

 

[chroot]

I had the impression that the critical feature of a hovercraft's skirt is that the air is blown out only around its perimeter...

but I could be wrong.

- Warren

 

[lokeo13]

ok, thanks for replying. anomaly >> when you described the hovercraft you made, i imagine it was a model... downsized any way... do you know what the best materials one would use to make a very effective hovercraft for a person to ride? what would be the most effiicent power source for a larger hovercraft? thanks for the leaf bloer idea. We will probably start wiht that.

 

[jcsd]

THey made hovercrafts on that tv program Scrapheap Challenge/Junyard Wars (UK/US versions), seeing as how both of them were made out of scrath it might be worth getting hold of a tape of that episode for a few pointers.

 

[anomaly]

Yes, the hovercraft I made was a model (sort of). The chasis was no bigger than 12" x 9" (lxw) and it stood maybe 8" (h). Again, the chasis was made of styrofoam. The motor mounts were made of 1/4" balsa wood. And the entire operation was powered by 2 9V batteries. Give me a day or two and I will post a picture of the model.

To make a personal transport, I would suggest using materials that offer a high strength to weight ratio and are rigid (to help eliminate chasis flex with live loading). Carbon Fiber would probably be ideal, but for cost and availability one could probably go with fiberglass, plastic, or maybe thin gauge sheet metal (Al.).

For an engine, you should be looking for one with variable speed control. So it does not run at full throttle all the time - Afterall, you do want to be able to control it. I would suggest looking at how swamp fan boats are made and powered (in addition to the junkyard wars video mentioned above).

 

[anomaly]

As promised: Here is the link to the pics of the model hovercraft.

http://f1.pg.photos.yahoo.com/bc/toddveloni/lst?.dir=/Miscellaneous&.src=ph&.order=&.view=t&.done=http%3a//f1.pg.photos.yahoo.com/


And to reply to chroot:
Yes, you are correct with that critical feature. The hovercraft does need to use the perimeter of the skirt, but it is not as critical (in some situations) as thought. That description of the function/workings of the hovercraft are more for the balance aspect. By the air forced around the perimeter of the skirt, the hovercraft is better able to 'float' evenly. But Newtons laws apply here as well. Provide enough force to lift the mass of the hovercraft, and it will float. More thought must go into the design in order to control how well the lift is affecting the hovercraft - hence the pressures at the perimeter.

 

[lokeo13]

Thanks for posting the pics. I think its easier to understand with a visual. I'm going to try a simple hovercraft before trying to improve it (obviously). M abe it'll help to start with a smaller model. thanks for the help.

 

[bergie]

Hovercraft

I need help designing a hovercraft skirt for a model hovercraft using a leaf blower. It is an oval shape and about 32 X 24. How do I make a skirt for It??[?]

 

[NateTG]

Bycicle inner tubes come to mind.