I can do science, me!

[c_dug]

So today I was bored at work (on my lunch, boss) and decided to have a go at making a simple homopolar motor, I have seen these done before like this:

https://www.grand-illusions.com/images/articles/articles/homopolar_motor/mainimage.jpg

https://upload.wikimedia.org/wikipedia/commons/a/a5/Homopolar_Motor_Large.jpg

But I substituted the screw for a bearing as I found it spun up a lot better.

Video here: https://www.youtube.com/watch?v=8BOIqD2doOA

Anyway, I have the rest of today (today's breaks, boss) and all of tomorrow to do more experiments so if anybody has any suggestions of things I can actually knock up and do please suggest away! I have my eyes on a self flowing flask:

https://image1.frequency.com/uri/w234_h132_ctrim_ll/_/item/3/6/7/1/self_flowing_flask_36712181_thumbnail.jpg

Example of one here: https://www.youtube.com/watch?feature=player_detailpage&v=287qd4uI7-E#t=43

So may have a go at that next.
____________________
I am a bellend, I am a man of constant sorrow, I am a gummy bear, I am a rock.

[Tungtvann]

Can't work a camera though, can you!

[c_dug]

Meh, phone propped up on my desk, it does focus a little better half way through. Also majorly compressed to email it to my work pc.
____________________
I am a bellend, I am a man of constant sorrow, I am a gummy bear, I am a rock.

[G]

Rail gun.

(You should have enough stuff lying around to make a basic one at least.)

[hellkat]

https://cdn.bikechatforums.com/files/msy.jpg
____________________
Not nearly as interesting in real life.

[scorps]

weird thumbs
____________________
Do not presume that I am male.

[hellkat]

[Nexus Icon]

Needs balancing.
____________________
Greetings from Shitsville!

[c_dug]

My thumb got caught in a door when I was 3, nearly lost the end of it!
____________________
I am a bellend, I am a man of constant sorrow, I am a gummy bear, I am a rock.

[c_dug]

[G]

Bit rusty on it all.
But if we say a metal 4.5mm bb (.32g) launched at very pedestrian 50 fps, presuming you have access to a vacuum, super conductors and other materials to get it near 100% efficient, I make it:
https://www.google.co.uk/search?q=30+meters+per+second+per+second+*+3.2+newtons+*+0.5+second

Seems in reality the efficiency is more like 1%.
So about 4.8kw for one second. Go and have a look for some ultracaps lying around.
(And if you find some spare, I want to use some to replace my truck starter battery .)

[c_dug]

None of that means much to me. So far I have my rails mounted on wood, wires attaches and a pp9 battery for go juice. Ok getting sparks but no movement. Take it the capacitor is needed? Some basic ones online didn't use a capacitor but they were firing bits of tin foil.
____________________
I am a bellend, I am a man of constant sorrow, I am a gummy bear, I am a rock.

[Ariel Badger]

You do realise that the self flowing flask does not work?
____________________
Bikers make great organ donors, get 115 on your licence today.

[c_dug]

Even if set up correctly? I know it wont be perpetual but I assumed it would circulate a bit?
____________________
I am a bellend, I am a man of constant sorrow, I am a gummy bear, I am a rock.

[G]

I'm not sure how you're making it; my calculations were purely theoretical.

It seems a decent 9 volts battery can put out 4 amps. 9v*4v=36w.
So you'll need about 134 9v batteries for 4.8kw without a capacitor.

With your 134 batteries you should be able to get maybe 2-300 shots. (10.2 minutes worth of one second shots, but that's for the total possible capacity of the battery, which you can't really use due to the voltage dropping.)
Speed probably would fall off towards the end as it is too.

[c_dug]

Ok, well, I have some pretty damn powerful capacitors here, but im using as powerful as i dare without properly soldering them and attaching them to something. I dont much fancy getting electrocuted by the big fuckers.

I think ill try a coil gun instead.
____________________
I am a bellend, I am a man of constant sorrow, I am a gummy bear, I am a rock.

[G]

Go look for some 'ultra capacitors' if you can.
These should have terminals you can bolt together and are massively more powerful than the normal capacitors you'll likely hav lying around.

[c_dug]

Yeah definetly not got anything like that. I have masses of 25v capacitors and a proper power supply, I could make a whole bank of them up but that's more effort than im willing to put in to it!
____________________
I am a bellend, I am a man of constant sorrow, I am a gummy bear, I am a rock.

[G]

Bah; oh well.

As an idea, for this ultra-cap...
https://i.ebayimg.com/t/Maxwell-650-Farad-Ultracapacitor-Super-Capacitor-Qty-30-/16/!CCCiJTgBWk~$%28KGrHqMOKp!E0UqF%28K,iBNJ29-GVZQ~~_3.JPG

You'd need 5416 of these 'normal' capacitors!...
https://img251.imageshack.us/img251/9384/capyc.jpg
(I may be wrong there and it may only be 1000, as not sure how the voltage plays when comparing them - either way, the ultra capacitors are rather good for delivery a lot of energy very quickly.)

[Im-a-Ridah]

[G]

[c_dug]

Just curious, would a welder give enough power make it work? (not going to try, probably)
____________________
I am a bellend, I am a man of constant sorrow, I am a gummy bear, I am a rock.

[scorps]

you have too much free time at work, can I get a job there please
____________________
Do not presume that I am male.

[G]

Depends the type of welder.

You can't get more power out than in.

If your welder is plugged in to a 13a fused plug, it can't give out more than 3120w, which from the above calculations, would be enough for a well designed coil gun to reach 50fps if you're lucky.

However, having capacitors seems like a much better idea - no reason to continuously provide the energy it only needs for half of second or something,

[c_dug]

Pretty sure its plugged into a 415v outlet in the other workshop if that makes a difference?

Scorps, weekends are a real mixed bag, sometimes I won't get 10 minutes for lunch without being called to the other end of the museum because some kid got his foot stuck in a bench or something
____________________
I am a bellend, I am a man of constant sorrow, I am a gummy bear, I am a rock.