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Unread postPosted: Sat Jun 07, 2008 8:40 am
Author: TwitchTheAussie
Just a bit of an idea thatl probably never happen but use a V8's crank :twisted:

Unread postPosted: Sat Jun 07, 2008 9:27 am
Author: Philbob1
Or maybe a grinder... those things MUST turn fast.

Unread postPosted: Sat Jun 07, 2008 10:10 am
Author: starman
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.

Unread postPosted: Sat Jun 07, 2008 12:21 pm
Author: Spitfire
Why not use a nitro engine? A .40in sized motor drives a 10" prop at about 30 000rpm. Thats what my engine averages at

Unread postPosted: Sat Jun 07, 2008 1:18 pm
Author: THUNDERLORD
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. :wink: 8)

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. 8)

Unread postPosted: Sat Jun 07, 2008 1:26 pm
Author: Carlman
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. 8)


ages ago i was going to order some magnets to try this with like line up 50 or so then let er rip :D

Unread postPosted: Sat Jun 07, 2008 1:49 pm
Author: Hotwired
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.

Unread postPosted: Sat Jun 07, 2008 1:54 pm
Author: Carlman
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 :shock:

Unread postPosted: Sat Jun 07, 2008 2:16 pm
Author: THUNDERLORD
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. 8)

Unread postPosted: Sat Jun 07, 2008 3:01 pm
Author: POLAND_SPUD
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

Unread postPosted: Sat Jun 07, 2008 3:15 pm
Author: s&w45
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.

Unread postPosted: Sun Jun 08, 2008 11:32 am
Author: Spitfire
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

Unread postPosted: Sun Jun 08, 2008 12:00 pm
Author: TurboSuper
Uhh, a brushless motor does need a controller, but I think in most motors that is already integrated.

Unread postPosted: Sun Jun 08, 2008 12:17 pm
Author: Spitfire
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

Unread postPosted: Sun Jun 08, 2008 1:53 pm
Author: Sticky_Tape
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.