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COMMUNITY : FULLBELLYPROJECT


pedal powered tractor

I'm no designer but here's an idea I've been stewing on for some time. I've hunted but not found any designs for a pedal powered tractor. The very early tractors were very large;could to lots of work; but they only had 2 or 3 horsepower. They ran so slow you could count the piston strokes. The designs were simple and they were work horses. Our new high horse powered gas tools often cann't do nearly as much. The old machines used heavy flywheels; slow to start but they kept on rolling. With the improvements we've made in bike gearing systems why not make a pedal powered tractor that could do serious work with that same heavy flywheel technology?

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solarbobky says: Jul 1, 2010. 3:57 AM
One alternative that was developed by Rodale many years ago, with other versions by others since, is a stationary pedal powered winch to pull small implements. It is moved along the edge of the garden and reels in the implement with a steel cable. Use Planet Jr type wheel hoe or small garden tractor implements.
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jtobako says: Feb 2, 2008. 8:08 AM
Here's a japanise catalog of human powered items, including a fork lift.

AAAaand the google version.
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jtobako says: Apr 24, 2007. 8:08 AM
A human only produces about 1/4 horsepower and a tractor requires a constant source of power. Flywheels are good to even out applied power-if the load is intermittent or needs a higher starting torque but otherwise runs easily, then you can store enough in a flywheel to use a smaller power source. When the load is consistently larger than the power source can handle, a flywheel won't help-it just can't keep up. Old tractors (up to WWII or so) were traction engines and portable power-they ran slow ONLY when idling, they ran much faster under load (I grew up with one). An old tractor/equipment combo could handle a 10 foot wide swath where the new(est) equipment can handle 7 to 10 times that (and at greater speed). It's cheaper to have a machine sit with an engine in it for most of a year than have to worry about a single engine fitting multiple pieces of equipment-and if the single power source tractor breaks down, ALL activity stops. And last, how many people do you know are willing to do a marathon EVERY day, year after year? There is a reason that animals were used, and were replaced by machines-human power is a lot of WORK.
Michael Fletcher (author) in reply to jtobakoJan 23, 2008. 8:27 PM
I think your points about the difficulty of the work load are valid for our culture which is not accustomed to physically working that hard but there still remain many cultures in the world that do work that hard everyday. Look for photos of the small farmers in Asia, Africa or Indonisia. The use pedal power to move the quantities of goods that in our culture we'd insist on having a pickup truck for. They pedal power in tandem to pump irrigate their fields. For many of them an oxen or work animal is an not an affordable luxury and the sort of modern machinery we take for granted is totally out of the picture. It is for these that I wonder if our engineering couldn't come up with a very cheap but more efficient use of human power.
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jtobako in reply to Michael FletcherJan 24, 2008. 6:32 AM
I'm having a hard time explaining this. I think that human power is great for transportation. I don't think that it's a good source of long term high power applications. A low head pump works well with low power, but when the well needs to be 25 to 50 feet deep, you don't use human power to irrigate (human consumption is different-it requieres high power but low time-important point).
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killerjackalope in reply to Michael FletcherJan 23, 2008. 9:42 PM
Actually if there's people already pumping water electricity could be made by adding water spun generators in the flow and add generators to the cycling setup making electricity to be used for other work... like building stuff with powered tools... or electric processing machines for grains and stuff, generally add functions and outputs to prexisting items for minimal input cost, so the guys doing the work are doing very little extra work for a good return
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jtobako in reply to killerjackalopeJan 24, 2008. 6:34 AM
Now I know why I can't explain-you don't understand physics at all. Here's a hint-anyone who claims perpetual motion is lying.
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killerjackalope in reply to jtobakoJan 24, 2008. 10:20 AM
No you've completely misatken what i've said here, I'm talking about taking extra work from things being done, not some kind of perpetual motion, just generating power from the already working pedal power bit and is by some chance there was a point where the water flow was sufficient it may aswell do an extra job while it's going down hill or whatever (unless it's always going uphill) By the way I actually take in all sciences pretty easily at GCSE I got my half assed double A in double award science (wanted to to all three seperate but school had no option) When I said minimal input cost I'm talking about making the absolute most of whats there without increasing the input by much... You do realise I was never really arguing so much as saying that there are possibilities, sure that human powered tractor could do plowing but it has merits, surely you can understand that?
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jtobako in reply to killerjackalopeJan 24, 2008. 3:41 PM
And you should have noticed that I was very careful to limit my lack of power arguments to jobs that require large amounts of (physics) work, not transport (overcoming inertia, for the most part). If you look at Michael Fletcher's post, he specifically said that they don't have the money to use anything except human power-where are they going to get the money for generators and power tools? Second part, human power is very low power-you get very careful not to 'waste' any power. For instance, the human power pumps mentioned only lift the water a few inches over the edge of the irrigation canal and into a secondary canal that waters the plants (if I'm remembering the images correctly). The builders know very well that there is no 'extra' power available.
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killerjackalope in reply to jtobakoJan 24, 2008. 9:19 PM
I'm giving up, I don't think you understand hypothesising very well.
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jtobako in reply to killerjackalopeJan 25, 2008. 9:55 PM
I generally skip to the "what problems are we going to encounter" stage not in a 'we can't do it' but 'how can we get around it' way. If you want to be serious about a human tractor, you have to rethink farming in a lot of ways-most of which eliminate the need for a tractor...
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killerjackalope in reply to jtobakoJan 26, 2008. 5:56 AM
Hmmm I suppose it does eliminate itself quites easily, however the idea could be good for moving heavy stuff and generally being an easy way to transport really heavy loads compared to other pedal powered stuff, also it might be able to replace animals being used at lower cost leaving animals to do other stuff.... I'll admit I wouldn't want to ploguh a field on a pedal tractor when there's an oxen or such sitting there but if I was building my house I'd be very glad of the tractor, maybe it's not a tractor so much as a pickup truck or loadall...
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jtobako in reply to killerjackalopeJan 26, 2008. 2:20 PM
I've seen plans for hand-powered forklifts (vintageplans.com i think). Biggest problem is that farmland isn't smooth and you need a slow speed-no chance to get inertia on your side. If you need to plow-skip it and use a shovel and hoe, only turn over what you absoutely have to-I don't remember what it's called, but there is a name for minimal plowing farming.
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killerjackalope in reply to jtobakoJan 28, 2008. 1:14 AM
maybe it's minmal plowing farming... the hand powered forklift probably wouldn't be too bad an idea, though it would have to be a bit different from the ones in warehouse, sure they can move 1 tonne but trying get and epmty one up a curb is futile never mind a loaded one, but there might be some merit there...
Michael Fletcher (author) in reply to killerjackalopeJan 28, 2008. 7:48 PM
I believe the term you are looking for is "no till" farming. Tractors are used for many things besides plowing. They are the mechanical workhorse. Even if one assumes plowing is out, might there be other means of utilizing more pedal power for those many workhorse task?
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killerjackalope in reply to Michael FletcherJan 28, 2008. 8:15 PM
yeah, that's why the forlift style idea seems better off... all the lifting can easily be done by hydraulics, the work isn't hard that way...
2
jtobako in reply to killerjackalopeJan 28, 2008. 6:14 AM
Now you know why I didn't think a tractor was a good idea : )
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killerjackalope in reply to jtobakoJan 28, 2008. 6:44 AM
Hmm tractor's never going to plough, a forklift design would be the way to go for usefullness but not like the warehouse ones, something along those lines for lifting but moving about would need to be very different... I guess the tractor would be useless if it couldn't plough...
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killerjackalope in reply to jtobakoJan 20, 2008. 6:00 PM
It's not a bad idea but the flywheel isn't great, however humans produce more than that, in physics we tested ourselves and I put out 1.693 Hp now I'm definitely fitter and stronger than then... Also it depends on how we use our strength, in terms of direct torque we have a hell of a lot, take the fact that the torque is the force we actually move with, If I did 130KGs on a squat press plus body weight then each of my legs has a minimum of about 60Kgs of torque to use if pedalling with your back against a chair now thats 140lbs of torque in about a foots length so about 140lbs/ft of torque and if they're super fit say 2HP peak now using the right gearing we could move alot and go quick, ever pulled someone on a skateboard with your bike, they lose inertia slower than you, then you go faster than them during the stroke, but even in top gear you can go on pretty well with 80KG pulling you back at the start of each stroke ...
2
jtobako in reply to killerjackalopeJan 21, 2008. 6:47 PM
A 5 horse rototiller bogs down at times trying to till a small garden (depending on soil and depth). Can you constantly do leg squats for 4 hours? (I'm giving you a break here, a farmer can't afford anything less than a 12 hour day during planting and harvesting seasons) And then do it again tomorrow? For the 2 weeks that it's going to take to plow a tiny 5 acre plot?

Flywheels are great at storing short bursts of energy, but it takes a lot of energy to plow with. The bike analogy is good IF you can save some of the energy in inertia-a tractor is there to SPEND inertia. Horsepower is spent over hours-how many hours are you going to be able to store?

140ft*lb...(33000ft*lb/min)/(60sec/min)=550ft*lb/sec...say a lift takes 1 second...you are at about 1/4 horsepower (140/550)=.2545. Now, can you do those lifts, without resting, for the hours it's going to take to plow?
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killerjackalope in reply to jtobakoJan 21, 2008. 7:20 PM
Also just realised I can do that for four hours, and more, used to a tyre fitter and moving scrap by hand involved lifting every tyre up from squat (if you did a lazy furniture mover here you'd have slipped discs in fifteen minutes) and these were lorry tyres, chiefly super singles... I had lunch then had two hours going like hell in the forklift which has hydraulic steering powered by you (spinning the wheel turns the pump) and I wasn't dead to the world. 12 hours though, would kill...
2
jtobako in reply to killerjackalopeJan 23, 2008. 5:49 AM
Thats one squat PER SECOND EVERY SECOND for four hours, not one every minuet or so. Think about loading the scrap truck, by yourself, as fast as you can, without a break. Horsepower is in units of time-the longer it takes to do something, the less horsepower you produce.
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killerjackalope in reply to jtobakoJan 23, 2008. 2:20 PM
No you're cycling to power the tractor... thus making a large difference... though as a small proof of concept check out the crapheap challenge episode with human powered trains... Remember also that belfast has famous tyre bonfires, I've worked with three guys that come round every year... In a matter of minutes a twenty foot container is filled... The big difference is the fact that you're cycling the machine, not squatting the point about squats was to get the point that there is a large amount of power in humans but it's not outputted handily, unfortunately we unlike a landrover don't have a power takeoff option
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jtobako in reply to killerjackalopeJan 23, 2008. 4:22 PM
When you are plowing there is no inertia to keep it going. There is a lot of resistance. Try biking in 70 or 100 cm of water over sand. How far will your bike coast?
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killerjackalope in reply to jtobakoJan 23, 2008. 4:33 PM
I used the train example because four men had to make a train capable of moving several tonnes of load, due to the nature of their machines it took them most of the course to actually get inertia. I'm not saying this is an idea that would work well for ploughing in particular (as they would have to have a risiculous amount of reduction gearing to keep the wheels driving the thing moving and that would make it slower than animals... However for other stuff it could work, the principle could be used to build handy fueless machinery... but ploguhing is a great example of a bad use for this idea...
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killerjackalope in reply to jtobakoJan 21, 2008. 7:15 PM
Nope my idea was a cycling setup similar to leg squats for maximum force from minimum effort, maybe a four man one or something with a gearbox man could work but then you might aswell just use the oxen... I think a flywheel would waste engery because if would be god awful to get going and you'd have to take 'goes' at what you're doing to keep intertia up... Maybe a bit of recycling is a better idea for this idea... ie reappropriated machinery from scrap.
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Goodhart in reply to killerjackalopeJan 23, 2008. 4:40 PM
I think a flywheel would waste engery because if would be god awful to get going

That's true if driven "directly", but if a simple gear box and transmission are added, it could work. I am not saying it would work "well" but it could be gotten to work.
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killerjackalope in reply to GoodhartJan 23, 2008. 6:44 PM
What I mean is, you could store your energy by spinning it up and hae intial inertia but every time it slowed down you'd have to work it back up to speed...
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Goodhart in reply to killerjackalopeJan 23, 2008. 6:51 PM
yes, if you let is slow, one would have to "down shift" and get it going again. In any case a lot of energy is waisted with this set up.
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Goodhart in reply to GoodhartJan 23, 2008. 6:55 PM
The Oil burner tractor I posted about further down, had a tremendously large flywheel, and a one cylander engine....it didn't use gears, but a slip clutch of sorts. It was slow as hang, but it also was moving quite a massive piece of metal with a simple, bang, bang output.
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killerjackalope in reply to GoodhartJan 23, 2008. 7:18 PM
Sorry I remembered something about people in africa or such... so ignore that point but someone mentioned that... For my wonder tractor I would suggest a hamster wheel system like the human powered trains in scrapheap challenge, there's your big flywheel...
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Goodhart in reply to killerjackalopeJan 23, 2008. 7:22 PM
I agree, it would be impractical for anything but a small garden maybe :-)
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killerjackalope in reply to GoodhartJan 23, 2008. 7:16 PM
I don't think pedal power is the answer for the original question though, engines don't get tired... How about a project using scrapped cars, most diesel cars (every 1.9 diesel) have thousands of miles of life left, why not make super cheap scraptors that are simply a slow small engined tractor, If the wimpy mistsibushi pickup truck we had could drag a 12tonne shovel out of a hole simply by shifting to the extra low set surely a similar Idea could be applied here. Give the people fuel in a big bunker, a thousand litres could go pretty far if the engine was running half assed because the gearing did the work. Also the people that would power the tractor are starving from lack of food, this would increase their food consumption by enough to make it useless for up to a year...
attick in reply to jtobakoJan 20, 2008. 12:44 PM
good idea...looks like it will work

http://www.pedalcarplus.com
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jtobako in reply to attickJan 20, 2008. 4:10 PM
To bad those are WAY to small and don't have any gearing for speed. Otherwise they might be a good 'bad weather' bike for short trips.
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robbtoberfest in reply to jtobakoMay 14, 2007. 12:27 AM
http://www.theoildrum.com/story/2006/10/7/12055/9120

http://www.renewables.com/Permaculture/SustAgri.htm

Check out these solar powered tractors.
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Goodhart says: Jan 21, 2008. 6:56 PM
I can't say for sure, but the tremendously heavy "oil burner" my grandpap had when I was younger, I remember well, pop, pop, pop about 1 and a half strokes per second unless you gave it a little fuel, then it could Pop at about twice a second, but anyways, I think it was a two cycle engine, or else much like a diesel. The flywheel alone was a massive several hundred pounds and the wheels, made of iron, were about 12 foot high and about 2 foot wide. This machine, taken to the local steam engine rallies, was also used mainly to steam tobacco beds. What a piece of wonder that was for a 12 year old (and he let me "steer" too ! which was really just a brake on one or the other flywheel to slow down one side or the other)
attick says: Jan 20, 2008. 12:38 PM
looks like it will work. Nice idea

http://www.pedalcarplus.com
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