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| TwitchTheAussie |
 Posted: 06/07/2008 8:40 AM Post subject: |
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Brigadier General
Joined: 06 Feb 2007
Posts: 923
981.27 Spud Bux
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Just a bit of an idea thatl probably never happen but use a V8's crank  |
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| Philbob1 |
| Posted: 06/07/2008 9:27 AM Post subject: |
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Private First Class
Joined: 29 May 2008
Posts: 31
70.46 Spud Bux
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| Or maybe a grinder... those things MUST turn fast. |
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| starman |
| Posted: 06/07/2008 10:10 AM Post subject: |
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Big Daddio
Joined: 12 Dec 2007
Posts: 1333
2437.02 Spud Bux
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| Philbob1 wrote: | | Or maybe a grinder... those things MUST turn fast. |
The fast ones run up around 11000 rpm ...here is an example. To spin something of any size at 20,000 rpm is going to require a high level of precision and balance, and probably a gear box...not to mention a beefy motor. |
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| Spitfire |
| Posted: 06/07/2008 12:21 PM Post subject: |
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Sergeant Major
Joined: 16 Nov 2007
Posts: 193
17.86 Spud Bux
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| Why not use a nitro engine? A .40in sized motor drives a 10" prop at about 30 000rpm. Thats what my engine averages at |
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| THUNDERLORD |
| Posted: 06/07/2008 13:18 PM Post subject: |
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Loose Cannon
Joined: 28 Mar 2008
Posts: 707
1319.08 Spud Bux
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IMO, anything spinning that fast is usually not designed for large diameter wheel or rotor due to safety dangers.
The slightest unbalance of weight causes a lot of stress on the bearings and creates a lot of woble and noise as well.
That's why IMO seperate bearings/ pulley or gear is much more durable, safer.
There is also a danger of the spinning part actually breaking apart and flying off ,as has occurred on aircraft propellors at high speed sending large parts of props through several buildings even due to high stress on the metal.
Brass (or Bronze?) "drill bushings" (w/out ball bearings) are available at hardware stores and come in 1/4" and 3/8" ID I know of.
Or also bearings similar to skateboard or rollerblade wheels(w/ball bearings) Would be very useful.
Because the axle can be held in place by one on each side. And the end of the axle on one side can be fitted with a gear or pulley.
This method will greatly save wear on the motors built in bearings and provide a more sturdy mount.
A thick cover shield should be added around the diameter.
If a gear or pulley is used torque is more desirable than innaccurate "no load speeds"
Like I've written before, electric boat motors seem excellent candidates because they're waterproof, high torque, DC powered already, quiet running and have a shaft for mounting propellor already.  
BTW not really my favorite subject, but since it's out there, Have you ever looked at a 7 ball pendulum? Where you pull one and the one on the other side goes almost as far, or pull 2 and 2 on the other side go almost as far. Pretty good kinetic energy transfer and extremely simple design. |
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| Carlman |
| Posted: 06/07/2008 13:26 PM Post subject: |
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The Aussie
Joined: 24 Nov 2007
Posts: 1107
288.94 Spud Bux
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thanks for the comments guys
| THUNDERLORD wrote: | | BTW not really my favorite subject, but since it's out there, Have you ever looked at a 7 ball pendulum? Where you pull one and the one on the other side goes almost as far, or pull 2 and 2 on the other side go almost as far. Pretty good kinetic energy transfer and extremely simple design. |
ages ago i was going to order some magnets to try this with like line up 50 or so then let er rip  |
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| Hotwired |
| Posted: 06/07/2008 13:49 PM Post subject: |
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UK Spudgunner
Joined: 13 Oct 2006
Posts: 1679
3543.47 Spud Bux
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They don't however say how unhelpful 30,000 rpm can be when (just as a random example...) a copper fitting you're grinding down the inside of comes free from it's clamp and starts whizzing around the tool bit...
I had to flail around like a maniac to hit the mains switch because the dremel was thrashing about in my other hand too much to hit its controls. |
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| Carlman |
| Posted: 06/07/2008 13:54 PM Post subject: |
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The Aussie
Joined: 24 Nov 2007
Posts: 1107
288.94 Spud Bux
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| Hotwired wrote: | T
I had to flail around like a maniac to hit the mains switch because the dremel was thrashing about in my other hand too much to hit its controls. |
thats neva good mate  |
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| THUNDERLORD |
| Posted: 06/07/2008 14:16 PM Post subject: |
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Loose Cannon
Joined: 28 Mar 2008
Posts: 707
1319.08 Spud Bux
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Seriously, my mind could go a thousand directions with this one.
Well nearly every modern invention would not be possible without motors.
Things change like seasons too.
If I know of something it probably isn't secret because if it was"secret" how would I know of it?
It's also like the hundred monkeys theory that a group of 100 monkeys on one island isolated from 100 on another island will advance at the same rate (tool use, eating etc.).
I was designing rollerblades with a gas motor for 2-3 years, then one day I found one on the internet. 
Here's another of the thousand directions, I was at the batting cage and the ball machine had two wheels and a magazine.
Also I was watching football practice with a football launcher similar.
Those little motor scooters are cool too, ride it, pick it up and use it for a buzz saw maybe. Speed all depends on it's use. Sort of like firearms or archery or missiles, there are claymores, muskets, bows, rpg's etc. each using totally different configuration/designs and speeds.
Well that's my rant about that. |
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| POLAND_SPUD |
| Posted: 06/07/2008 15:01 PM Post subject: |
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Brigadier General
Joined: 13 Oct 2007
Posts: 849
2093.82 Spud Bux
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| Quote: | | I had to flail around like a maniac to hit the mains switch because the dremel was thrashing about in my other hand too much to hit its controls. | LOL the same thing happend to me |
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| s&w45 |
| Posted: 06/07/2008 15:15 PM Post subject: |
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Private
Joined: 06 May 2008
Posts: 3
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| Being a brushless motor, the one linked would have to have a speed controller (esc) to make it run. They work on a different principle than your standard brushed motors that can just be directly hooked up to a power source. |
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| Spitfire |
| Posted: 06/08/2008 11:32 AM Post subject: |
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Sergeant Major
Joined: 16 Nov 2007
Posts: 193
17.86 Spud Bux
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| s&w45 wrote: | | Being a brushless motor, the one linked would have to have a speed controller (esc) to make it run. They work on a different principle than your standard brushed motors that can just be directly hooked up to a power source. |
Computer fans are brushless, and can be hooked up to any power source and stilll run. The same goes for Airplane brushless motors |
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| TurboSuper |
| Posted: 06/08/2008 12:00 PM Post subject: |
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Colonel
Joined: 16 Jun 2005
Posts: 646
972.40 Spud Bux
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| Uhh, a brushless motor does need a controller, but I think in most motors that is already integrated. |
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| Spitfire |
| Posted: 06/08/2008 12:17 PM Post subject: |
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Sergeant Major
Joined: 16 Nov 2007
Posts: 193
17.86 Spud Bux
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| TurboSuper wrote: | | Uhh, a brushless motor does need a controller, but I think in most motors that is already integrated. |
oops, all my brushless motors can be hoked up directly, didnt think that controlers would be built in |
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| Sticky_Tape |
| Posted: 06/08/2008 13:53 PM Post subject: |
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Brigadier General
Joined: 31 Jan 2008
Posts: 819
1009.07 Spud Bux
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| This was on mythbusters before they had a really short barrel they couldn't get it to fire through balistics gell I think if you do make this use a long barrel. |
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