human powered tractor?

I have always thought that aside from propelling oneself around, the other
best use of human power is growing food; but stooping over and grubbing with
ones hands isn't very efficient. Having played with a small single blade
wheel plow as a kid, including taking turns pulling it with my sister, the
idea seems a reasonable way to get a good workout after work and on weekends
through much of the season.

Has anyone seen such a thing? Ideally you could make one that mounts and is
powered by a conventional bike. You could model present tractors or
tillers and just reduce the forward speed and width of till until it matched
the fraction of a horsepower we produce. For lots of people in the 3rd
world who don't have enough land to support a horse, such appropriate
technology makes sense.

I wish colleges would have competitions for useful things like this rather
than concrete canoes and solar powered cars.

--
Robert Haston
Satellite Beach, FL

Robert Haston wrote:

Has anyone seen such a thing? Ideally you could make one that mounts
and is
powered by a conventional bike. You could model present tractors or

tillers and just reduce the forward speed and width of till until it
matched
the fraction of a horsepower we produce. For lots of people in the
3rd
world who don't have enough land to support a horse, such appropriate

technology makes sense.


Would you settle for a human-powered lawnmower?
http://www.art.net/Studios/Hackers/Tower/hpvs.html

Jeff

On Tue, 25 Jan 2005 02:08:12 GMT, "Robert Haston"
wrote:

I have always thought that aside from propelling oneself around, the other
best use of human power is growing food; but stooping over and grubbing with
ones hands isn't very efficient. Having played with a small single blade
wheel plow as a kid, including taking turns pulling it with my sister, the
idea seems a reasonable way to get a good workout after work and on weekends
through much of the season.

Has anyone seen such a thing? Ideally you could make one that mounts and is
powered by a conventional bike. You could model present tractors or
tillers and just reduce the forward speed and width of till until it matched
the fraction of a horsepower we produce. For lots of people in the 3rd
world who don't have enough land to support a horse, such appropriate
technology makes sense.

I wish colleges would have competitions for useful things like this rather
than concrete canoes and solar powered cars.

Dear Robert,

A bicycle's gearing trades force for distance to take
advantage of the tremendous reduction of friction by wheels
on bearings. On flat ground, the gears can increase one foot
of pedal movement to almost nine feet of wheel movement
(with the force spread out over nine feet).

So it's not well suited to forcing a plow through the
tremendous friction of the ground. Here, you'd want to trade
distance for force and have gearing that turned one foot of
pedal movement into an inch or two of wheel movement (with
the force concentrated into an inch or so).

Your arms and legs need the increased mechanical advantage
of the handle of a shovel to do much digging, not the
reduced mechanical advantage of bicycle gearing.

To make a bicycle work (ineffectively) as a plow, you'd need
to start by reversing the gears.

An 11-tooth front and a 53-tooth rear might let you drag a
plow through some loose sand, but it would be exhausting to
plough a single furrow.

The solar-powered car is more practical.

Carl Fogel

On Tue, 25 Jan 2005 02:08:12 GMT, "Robert Haston"
may have said:

I have always thought that aside from propelling oneself around, the other
best use of human power is growing food; but stooping over and grubbing with
ones hands isn't very efficient. Having played with a small single blade
wheel plow as a kid, including taking turns pulling it with my sister, the
idea seems a reasonable way to get a good workout after work and on weekends
through much of the season.

Has anyone seen such a thing?

Attempts have been made in third-world nations, and there is a reason
why the people there either use fuel-powered machinery or draft
animals if they don't just do the work by hand. There's no advantage
in trying to run the motion of human limbs through a bunch of
conversions to do a task that they are better suited for with just the
direct implement. The extra machinery cannot reduce the amount of
work that has to be performed in order to do a specific task; indeed,
it generally will have the opposite effect, increasing the amount of
work that must be done in order to perform that task through the
addition of the inefficiencies of the machinery itself.

The riding mower shown by another poster is an example of an
exception; the draft effort needed to pull that mower around is not
particularly high, and the usual method of propelling it (by pushing)
is actually not all that efficient. I once demonstrated that such a
push mower could be made much easier to push on level, firm ground by
lengthening the handle, lowering its angle, and increasing the mass of
the mower head. At ten feet of arm, with a 20-pound sack of
fertilizer strapped to the top, it pushed much more easily and cut
more effectively...but it was a pain in the neck to use because it was
near to impossible to maneuver usefully. This doesn't imply that more
power conversions would make a better result, it just shows that the
way to make things more efficient usually involves looking at where
the losses and problems are, and addressing those, rather than trying
to artificially apply a specific arbitrary technology to the task
simply because it exists and is available. Doing that is like driving
screws with a baseball bat; it may work, but there are better ways to
produce hardwood kindling.

--
My email address is antispammed; pull WEEDS if replying via e-mail.
Typoes are not a bug, they're a feature.
Words processed in a facility that contains nuts.

"Robert Haston" wrote in message
nk.net...
I have always thought that aside from propelling oneself around, the other
best use of human power is growing food; but stooping over and grubbing
with
ones hands isn't very efficient. Having played with a small single blade
wheel plow as a kid, including taking turns pulling it with my sister, the
idea seems a reasonable way to get a good workout after work and on
weekends
through much of the season.

Has anyone seen such a thing? Ideally you could make one that mounts and
is
powered by a conventional bike. You could model present tractors or
tillers and just reduce the forward speed and width of till until it
matched
the fraction of a horsepower we produce. For lots of people in the 3rd
world who don't have enough land to support a horse, such appropriate
technology makes sense.

I wish colleges would have competitions for useful things like this rather
than concrete canoes and solar powered cars.

--
Robert Haston
Satellite Beach, FL


While I have never seen such a device, it does sound like a good idea,
however it think it would be impractical. The tiller blade would have to be
extremely narrow due to the drag of the soil and the relatively low power
output of human legs.

Ken

wrote:
Robert Haston wrote:

Has anyone seen such a thing? Ideally you could make one that
mounts
and is
powered by a conventional bike. You could model present tractors
or

tillers and just reduce the forward speed and width of till until
it
matched
the fraction of a horsepower we produce. For lots of people in the
3rd
world who don't have enough land to support a horse, such
appropriate

technology makes sense.


Would you settle for a human-powered lawnmower?
http://www.art.net/Studios/Hackers/Tower/hpvs.html

Jeff

Or a chicken powered tractor?
http://nc.essortment.com/chickentractor_rjpo.htm

Cam