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What to do with those screamers?

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Batteries wise, you want ni-cads. Alkaline batteries don't handle the high current very well, thats why the 9v's got very hot. R/C Racing batteries are ni-cads and they only get warm while dishing out 30amps continous load. NiMH batteries are better than alkaline but still not as good as ni-cads.
 
Nickme90 said:
Batteries wise, you want ni-cads. Alkaline batteries don't handle the high current very well, thats why the 9v's got very hot. R/C Racing batteries are ni-cads and they only get warm while dishing out 30amps continous load. NiMH batteries are better than alkaline but still not as good as ni-cads.

Yeah, but Nicads only last half as long as alkalines or NiMH. And NiMH batteries are lighter than alkaline or nicads.
I suppose you could always go with Lithium Ion... but that's quite expensive and hard to find.
 
Caffinehog said:


Yeah, but Nicads only last half as long as alkalines or NiMH. And NiMH batteries are lighter than alkaline or nicads.
I suppose you could always go with Lithium Ion... but that's quite expensive and hard to find.

Laptops generally run on lithium ion. Just steal a laptop battery...
 
True NiMD do have a higher capacity. I would say that if the fans and everything else, draw close to 10 amps go ni-cads else NiMH will be fine. Thinking about it more, hovercrafts proablly don't draw half as much as R/C cars so NiMH would proablly be a better choice.

On to the actual design of the hovercraft, I noticed in the picture, that your skirt went all the way to the middle with a few holes. You might find it better if the skirt didn't go as far in and had far more area to allow the air to escape. You probably know this, but the idea is that the skirt makes a loose seal to the ground and that air escapes all around the skirt. By making less flow restrictions, you might find that with the computer fans, it might hover better.

Heres some pages I thought you might find useful:-
http://www.freenetpages.co.uk/hp/dave_jesse/Hovercraft.htm
http://members.aol.com/modelhov2/index.html

Edit: One last thing, Also make the base bigger. You will not need a really high pressure fan if you make the base bigger. Specially if you use polystrene for the base, since the bigger the area, the more the weight is spread out.

Pressure=weight/area

You might have to add more fans if the base gets to big, but I leave you to experiment with that.
 
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that fan is loud though, i dont think id be able to stand it, but it would have excellent cooling power. As for the blades there is a moving set of blades which actually moves the air the blades that are on top in the picture are vanes which straighten (sp?) the airfolw and increase throughput.
 
Good luck getting NiMI's for this project.

For that money you can double NiCad's and add two more lifting fans and a drive fan :\

It's nice to dream though ;)

The old philisophical question.

Expencive NiMi's with special hardware that have a long life, but drop off in power like a rock

Inexpencive NiCad's that require cheap basic chargers with less life, but a more drawn out and pronounced dropoff
 
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