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They already do. Giros power lights as you ride(we can debate if that a machine ofcourse)
Quote from: Wiybit on 30/03/2011 01:28:43They already do. Giros power lights as you ride(we can debate if that a machine ofcourse)We can definitely debate if it is a "washing machine" per the question  - and it's dynamos not giros.
An energetic cyclist can maintain an output of about 200 Watts, enough for spinning and churning no doubt but heating would take a long time.
No no no! You cannot create extra energy by using pulley systems or levers. You can give yourself a mechanical advantage using a lever or a pulley; but you can never generate more power or get more energy. And if it gets easier you are, on the whole, putting less energy into the system and thus less can be extracted.
and infact it's always less effort over all to use the highest gear you can (less frantic going-round-and-round per amount of useful effort)
Nope. Lower gearing can make it easier on your legs to turn a dynamo, but you'll only turn it ve-e-e-ery slowly, and the amount of power you generate depends on how fast you can turn it.You can't increase the power out of your legs beyond a certain point. It's an "energy in is always less than energy out thing again". Do you own a pushbike? With gears? You can try it... if you change down a gear when going up hill, you don't have to work so hard to turn the wheels by one turn, but you don't go so far per turn either. It all balances out... and infact it's always less effort over all to use the highest gear you can (less frantic going-round-and-round per amount of useful effort).
There are ways to do that, that take less energy, to achieve a a good spin.
The most efficient long period method of cycling is with a high(ish) cadence low(ish) effort - you can keep your legs turning over quite rapidly for long periods when the resistance is low
QuoteThere are ways to do that, that take less energy, to achieve a a good spin.Up to a certain limit.You cannot get out more energy than you can put in. And the peak energy that you can put in is less than the peak energy required by a washing machine (certainly if you're trying to heat the water too). If you could charge a battery and then use the stored energy to run the machine, then you could certainly do it.
It's easier to maintain a speed once your going, That's why I was suggesting a system to assist at the begging to get you going.
Quote from: Wiybit on 31/03/2011 15:37:04It's easier to maintain a speed once your going, That's why I was suggesting a system to assist at the begging to get you going.I believe most bikes come with gears 
Quote from: peppercorn on 31/03/2011 16:50:06I believe most bikes come with gears I was making the point that if you connected up a few dynamos it would be a hassel to get going, so some assitence might be needed, gears or not.
I believe most bikes come with gears 
The most efficient way to heat the water would be to turn the drum, so the water tumbles inside it and is heated by work done against viscosity.
The issue of gearing is related to the issue of impedance matching.
QuoteThe most efficient long period method of cycling is with a high(ish) cadence low(ish) effort - you can keep your legs turning over quite rapidly for long periods when the resistance is low Really? I'm prepared to believe that in principle, but it doesn't accord with my experience in practice (tho' perhaps that's because my bike's not geared excessively high, and I live in Cambridge, which is dead flat, so mostly I reach top gear a few yards out of the traffic light and stop there... and I'm not generally trying for very high speeds, because in town that would be basically suicidal).Cycling on the flat, of course, once you're up to speed you're only working against friction and air resistance, and air resistance gets worse in a non-linear way (I think?) if you go faster, so distance-for-distance I'd expect you'd use less energy going a bit slower? Up hill (well, up-the-side-of-the-railway-bridge), though, (it feels like) it's less effort to maintain a higher gear, go faster, and get to the top sooner, than to change down and welly the pedals, provided I'm going fast enough initially to get embarked on the slope and keep up the momentum.But I've not really thought about any of this in depth..