Spinning disk question

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Carlman
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If i had a spinning disk that measured 8cm in diameter and i wanted the outside to be moving at 300km/hr how many RPM would the disk have to be spinning at?
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jackssmirkingrevenge
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So, the disc has a circumference of (pi x diameter) around 0.00025 kilometres, so at 1 rpm the outside is travelling at 0.015 km/h

You want 300 km/h however, which means that your disc is going to have to be spinning at (300 / 0.015) the grand rate of 20,000 revolutions per minute.

Do I sense a centrifugal launcher in the works...?
hectmarr wrote:You have to make many weapons, because this field is long and short life
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SpudFarm
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mabe he is making something like the steam cannon mythbysters made?

(i saw only 3minutes of that episode)
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Carlman
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jackssmirkingrevenge wrote:Do I sense a centrifugal launcher in the works...?
maybe...

your too good JSR! :roll:
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SpudFarm
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you will need one hell of a thing to spin it.
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Carlman
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spudfarm wrote:you will need one hell of a thing to spin it.
rc airplane motor and gears
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SpudFarm
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frakin NICE!!
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jackssmirkingrevenge
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Carlman wrote:rc airplane motor and gears
That will have to be quite a substantial motor, considering the load it will be under, I suggest you read up on the theory before attempting anything, or simply use the biggest motor you can find and go from there :wink:
hectmarr wrote:You have to make many weapons, because this field is long and short life
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Carlman
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just found this on ebay

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worth getting?
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SpudFarm
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oh i thought you was using a nitro engine
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Carlman
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jackssmirkingrevenge wrote:
Carlman wrote:rc airplane motor and gears
That will have to be quite a substantial motor, considering the load it will be under, I suggest you read up on the theory before attempting anything, or simply use the biggest motor you can find and go from there :wink:
yea well that is the thing im debating on a hard slog at a centriugal lancher like the PEST or a tennis ball laucher style used for bbs.
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jackssmirkingrevenge
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Looks good for the price.
Load Speed (rpm) : 39000
That should suit you fine, probably without a gearbox... now get your hands on some epoxy and carbon fibre matting and make yourself a lightweight yet strong disk :)
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Carlman
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this could be fun :D
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POLAND_SPUD
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put some pics when it's ready...
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Hook it up to a Dremel, those things run at a clip of around 30,000 RPM at max speed.

I've even seen some knock-offs that claim to go up to 40,000 RPM.
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