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How to Almost Build an Engine With Only Parts From the Hardware Store [video]

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Re: How to Almost Build an Engine With Only Parts From the Hardware Store [video]

#41

Post by noonespecial »

mikeash wrote: post #28
vacri wrote: post #27

Earlier quoted context omitted.

I'm not sure about totally won - here is a demonstration of a gasoline-powered flashlight, which might create a resurgence of this method for power tools. At 0:30 he expounds on the advantages of the device. https://www.youtube.com/watch?v=OcdVaslktBE

And let's not forget compressed air, which is still a very popular way to run power tools. Electric vastly outnumbers it, of course, but compressed air is still used in a significant portion of tools.

Compressed CO2 and nitrogen are gaining favor in the tool space as well.

Re: How to Almost Build an Engine With Only Parts From the Hardware Store [video]

#42

Post by mangamadaiyan »

speeder wrote: post #25
JoshTriplett wrote: post #21

Earlier quoted context omitted.

Assuming the track was designed so the cars go forward no matter which direction you place them, the cars likely had a small diode-based circuit to always feed the current into the motor with the same polarity. When you fed an AC current into the track, that circuit in the cars would have acted like a rectifier, turning the AC into poor-quality, high-voltage DC. The sparks would come from feeding way too much voltage…

Diodes! Great idea, I should have thought of that.

I'm guessing your mains supply would've been 230v/5A - in which case I have to say I'm surprised that it didn't blow the diodes out :) I remember plugging a 1N2001 (or similar) into a wall socket, and turning the switch on to watch the diode blow out as a schoolboy.

Re: How to Almost Build an Engine With Only Parts From the Hardware Store [video]

#43

Post by ganeumann »

ars wrote: post #24
SwellJoe wrote: post #5

It's kind of fascinating, to me, that internal combustion engines won the car war for so long. Electric motors are so much simpler to build, and so much more efficient from an energy usage perspective. I understand why electric lost out (energy storage, range of vehicle), but I think it could have gone a different way had there been just a couple of nudges in the electric direction at the right time. And, what a diff…

> but I think it could have gone a different way had there been just a couple of nudges in the electric direction at the right time Gasoline cars were popularized before electric power generation was widespread. It would be decades before the power grid could possibly have supported electric cars. The Model-T started in 1908 (and there were of course cars before that), the War of the Currents was in the late 1880's.…

When Henry Ford finally made it big with his Model T, his wife Clara made him buy her a fancy car: a 1914 Detroit Electric.

Electric cars were the 'good' cars, easier to run, not as dirty or hard to start, more luxurious. But they were an expensive luxury. The Model T was cheap, easy to fix, and adaptable to many other uses (like hooking a wheel to a belt and running a saw to cut wood.) The Model T was a classic disruptive invention: less good but much, much cheaper; it created an entirely new market of car buyers.

It may be that that electric is a better option now: oil is expensive and non-renewable, and burning fuel pollutes. But neither of these reasons were very compelling a century ago.

Re: How to Almost Build an Engine With Only Parts From the Hardware Store [video]

#44

Post by [deleted] »

vacri wrote: post #27
jasonwatkinspdx wrote: post #16

Earlier quoted context omitted.

Yeah. It's worth noting that for engines in stationary devices like fabrication tools and machinery, electric totally won. So what made the difference with cars wasn't just the engines themselves, but rather the energy storage/distribution network. Now that we have batteries that are good enough at a cheap enough price, electric is gaining fast despite a lot of cultural opposition.

I'm not sure about totally won - here is a demonstration of a gasoline-powered flashlight, which might create a resurgence of this method for power tools. At 0:30 he expounds on the advantages of the device. https://www.youtube.com/watch?v=OcdVaslktBE

[deleted]

Re: How to Almost Build an Engine With Only Parts From the Hardware Store [video]

#45

Post by ricardobeat »

mikeash wrote: post #28
vacri wrote: post #27

Earlier quoted context omitted.

I'm not sure about totally won - here is a demonstration of a gasoline-powered flashlight, which might create a resurgence of this method for power tools. At 0:30 he expounds on the advantages of the device. https://www.youtube.com/watch?v=OcdVaslktBE

And let's not forget compressed air, which is still a very popular way to run power tools. Electric vastly outnumbers it, of course, but compressed air is still used in a significant portion of tools.

There was a french company that built compressed-air vehicles, and they were supposed to be much more efficient. The comment you replied to is tongue-in-cheek though.

Re: How to Almost Build an Engine With Only Parts From the Hardware Store [video]

#46

Post by ricardobeat »

jessaustin wrote: post #17
larrys wrote: post #11

Earlier quoted context omitted.

Aerosol can. Spark. Gasoline.

Meh. You folks should have misspent more of your youth burning shit down. Gasoline is highly flammable, but it doesn't light without a spark. Also, the small amount of gasoline he's got in his carb will only produce so much flame. I'm glad he appears to be running this outside. I probably would have worn safety glasses, but then I only have one eye.

http://www.youtube.com/watch?v=8TCe9NKtP90

Re: How to Almost Build an Engine With Only Parts From the Hardware Store [video]

#47

Post by nhebb »

mikeash wrote: post #28
vacri wrote: post #27

Earlier quoted context omitted.

I'm not sure about totally won - here is a demonstration of a gasoline-powered flashlight, which might create a resurgence of this method for power tools. At 0:30 he expounds on the advantages of the device. https://www.youtube.com/watch?v=OcdVaslktBE

And let's not forget compressed air, which is still a very popular way to run power tools. Electric vastly outnumbers it, of course, but compressed air is still used in a significant portion of tools.

In shop operations most compressors, in turn, run off electricity.

Re: How to Almost Build an Engine With Only Parts From the Hardware Store [video]

#48

Post by matthiasl »

speeder wrote: post #20
WalterBright wrote: post #19

Earlier quoted context omitted.

You don't even need a magnet. I made an electric motor as a kid out of nails, wire and a battery. It worked pretty good. But, being a boy, I wanted it to work better. So I replaced the battery with a lamp cord and plugged it in. It promptly burst into flames. Awesome!

Once I plugged a toy race track to the outlet (in portuguese we call it "Autorama" I dunno the name in english), I knew enough of physics to expect it to burst in flame... But instead the car got REALLY, REALLY, REALLY fast, shoot out of the track and smashed into the wall. Of course, I happily put a second car on it, and changed the track so that the car does not end smashed, and indeed, I could launch cars all over…

As a sibling comment mentioned, it's possible there was a diode somewhere in the system.

Another possibility is that the motors in the slot cars had electromagnets for the stationary field instead of permanent magnets. That's what an ordinary power drill, especially one without electronic speed control, has. Such a motor will run pretty much the same on AC or DC. When running on AC, the rotor and stator both change their magnetic fields in perfect sync so the net effect is substantially the same as running to same motor on DC.

Wikipedia has an article on "Brushed DC electric motor" with a section on "wound stator". It doesn't specifically mention running the motor on AC, but there's enough there to show you what's going on.

Re: How to Almost Build an Engine With Only Parts From the Hardware Store [video]

#49

Post by KMag »

JoshTriplett wrote: post #21
speeder wrote: post #20

Earlier quoted context omitted.

Once I plugged a toy race track to the outlet (in portuguese we call it "Autorama" I dunno the name in english), I knew enough of physics to expect it to burst in flame... But instead the car got REALLY, REALLY, REALLY fast, shoot out of the track and smashed into the wall. Of course, I happily put a second car on it, and changed the track so that the car does not end smashed, and indeed, I could launch cars all over…

Assuming the track was designed so the cars go forward no matter which direction you place them, the cars likely had a small diode-based circuit to always feed the current into the motor with the same polarity. When you fed an AC current into the track, that circuit in the cars would have acted like a rectifier, turning the AC into poor-quality, high-voltage DC. The sparks would come from feeding way too much voltage…

Or, they could have used electromagnets for the stator and the rotor. The stator would reverse polarity at the same moment the rotor reversed polarity (modulo differences the transfer functions), so the force would still be in the same direction, despite the alternating current. One could make A/C motors this way, it's just that A/C induction motors are much more efficient.

Re: How to Almost Build an Engine With Only Parts From the Hardware Store [video]

#50

Post by bradleyland »

mikeash wrote: post #28
vacri wrote: post #27

Earlier quoted context omitted.

I'm not sure about totally won - here is a demonstration of a gasoline-powered flashlight, which might create a resurgence of this method for power tools. At 0:30 he expounds on the advantages of the device. https://www.youtube.com/watch?v=OcdVaslktBE

And let's not forget compressed air, which is still a very popular way to run power tools. Electric vastly outnumbers it, of course, but compressed air is still used in a significant portion of tools.

Compressed air is not an energy source, it's a short term energy storage medium. The same static/non-static correlation between electric and gasoline exists. Most compressors in static installations are electric. Compressors that must be used in the field are frequently powered by a small internal combustion engine.

Compressed air is used because the powerhead is much smaller and lighter than an electric motor (at available voltages) of comparable power. This makes it suitable for handheld tools. Otherwise, compressed air represents a NET loss of energy, and would be avoided.

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