InigoMontoya

You're missing the point. The question isn't whether or not a generator could charge the battery. It could. The question is whether or not doing so would be an efficient use of the gasoline in question. Let me try a different approach..... Suppose you have a big rock. We'll say it weighs in at 100 pounds. The rock is sitting in your front yard. You want it moved to your back yard. Which of these two scenarios would be most efficient: A) Picking up the rock, putting it in a wheel barrow.... and moving it directly through your side yard into your back yard. B) Picking up the rock, carrying it by hand, walking all the way around the block, through the back yard of the guy who lives behind you, and then heaving it over the back fence into your yard. If you vote 'A', then skip all the generator/battery BS and just power your bike with the 80 cc motor you already have. If you want to impress girls with your manly muscles (even if all the guys think you're an idiot), then by all means vote 'B' and use the generator to charge the battery to power your bike via electric motor (Rube Goldberg would be proud!).

You run into the same problem.... It will take more energy to drive the alternator than you'll ever get out of it. This is doubly true since you're charging a battery THEN using the energy (each step has it's own losses).

And THAT is where I disagree. I don't believe that a blimp would scale well. You're talking about a very large, very fragile object. If a blimp is reasonably small, it can be simply taken indoors to weather storms. But if it's sufficiently large, where are you going to park it? And don't say that you can simply avoid storms by moving around. That works for a while but sooner or later you'll find yourself in a situation where you simply can't run and you MUST weather some level of a storm. I simply don't believe a blimp large enough to classify as a small "town" could also withstand anything that resembled bad weather. The square/cube law just bites such systems in the arse.

When you start talking about farms and the like, the amount of materials (read: water, etc.) required to keep one person alive quickly become too much to keep in the air. At that point, you're no longer talking about a "city" in the air or anything and are instead just talking about a glorified RV. That's a very different proposition. Could you make a home out of a blimp? Sure. Could you make anything that resembles being self sufficient (ie, a city)? I maintain that the answer is "no." I further note that your linked to design is vaporware.

Another point: Watts is a measure of power, not energy. So if you're looking for energy (and it sounds like you are) and your units come out watts, then you've definitely screwed something up.

I strongly suspect a plain ol' recumbant bicycle would be much better. Something like those shown at the bottom of this page.

No, it isn't.

Another issue I've not seen addressed.... Heat. Even electric motors generate heat. Where do you plan on dumping the heat? In the cold vacuum of space, spacecraft can have problems keeping cool. Now you ditch the cold expanse of space as a radiative heat sink (you lose the Sun as a source too so maybe it's not THAT bad) and you have to keep some seriously powerful motors rather than simple electronics cool.

D'oh! Disregard the above. Apologies. Somehow I got it in my head that we were dealing with a servo motor, not a stepper. So it's OK if it takes three weeks to complete the scan? 'Seems normal enough to me.....

Not really. PID loops are positively marvelous.

Rock tumblers are pretty cheap. Buy one on ebay or craigslist or similar. Done.

And about which axis are you rotating the rod?

Placebos are addictive and overdoses of placebos can cause death. Huh. I learned something new today.

I think they're laboratory curiosities; nothing more.

Don't forget cost and availability.

A DPDT switch is really two switches in one. Which switch is being used is controlled by which direction you flip it. So you wire it just like you would with two separate switches... Just remembering that the two switches are housed in the same unit.

Look for DPDT switches. edit: Would this one work? http://www.grainger.com. Part number: 774104

As a teenager, I was digging around in my parent's garage and I came across a rather curious photograph. I was looking at it trying to figure out what it was when my father walked in, saw what I was doing, and explained.... Once upon a time he'd been an engineer on the team that designed/built the very first FLIR. When the team was ready, they'd driven the FLIR to the top of a local mountain, turned it on, and viewed the surrounding valley. At night, of course. It was the first time a FLIR had ever been used. They took a picture of the display. That picture was what I held in my hands. Cool. Two weeks ago, my father passed away. Yesterday, while going through his things, I came across the picture and figured folks here might be interested in a bit of history. I also spent some time on google maps trying to figure out exactly where the photo was taken. It wasn't easy given that the photo would have been taken nearly 50 years ago and much has changed, but I believe I have found the location. Note that the FLIR would have been facing west.

Ramjets extract their energy from fuel; typically JP-8. There's no violation of the 2nd Law. As presented in the OP, the car in question does not have an energy source other than it's own drag (if you consider drag an energy source).

Been doing the Mech Eng thing for about 18 years now. Never a dull moment. OK, I exaggerate. There ARE dull moments. But by and large I love my job. I work in the ordnance industry and get paid to design/conduct tests of new weapon systems (translation: I blow shit up...albeit in very specific ways). Great fun. And no two assignments are the same so if I don't like the project I'm working on... No big deal, in 3 months I'll be doing something different.

The 2nd Law of Thermodynamics. You should look into it.

I'll take a stab at it.... Assume: Keyboard press takes 0.5 N of force and the stroke is 0.01 m. Work performed pushing key is in therefore 0.5 * 0.01 = .005 J. Assume: Magical keyboard converts 10% of that energy into "output" energy. So for each keystroke we get 0.0005 J of useable energy. When someone says they type at 40 wpm, that classically means 200 keystrokes per minute, or 3.33 keystrokes per second. So each monkey is generating 0.0005*3.33 = 0.00167 W of useable energy. Therefore a 40 watt light bulb would require 40 / 0.00167 = 24,000 monkeys to operate.

Do they make butane powered cells? With just a very small amount of pressure you get a liquid fuel (energy density goes way up).

A 1.5' x 1000' x 150' slab of steel weighs in at about 55,000 tons. You're telling me that on the *conservative* end of the spectrum that the deck accounts for over 50% of the mass of the ship? How does such a ship stay right-side up? Don't get me wrong, decks are armored, but not like that. Not against heavy/hard penetrators. Agree to disagree. Agree that it would punch a hole in the bottom as well (thus my prior comments in this thread). Disagree on total damage.

I highly doubt the missile in question pushes an inert payload. First off, carriers aren't particularly hard targets requiring such penetrating capabilities from a missile. Secondly, merely punching a hole through the hull of any modern warship won't sink it. That's doubly true for a large ship such as a carrier.