Limitations on Tractor/Combine Design 4

[gontek]

I have never had any experience with farming or tractor design per se, but I was trying to figure out what limitations are placed on design of Farming machinery, and why not go way bigger. With farms becoming corporate, are we looking at farming machines going the way of mining/quarry machines and becoming superhuge? I figure size limitation probably has to do with the requirement of being able to drive down a narrow dirt road with overhead wires, is there a standard weight limitation or other limitations to sizing a new tractor or combine design?

I am wondering it an aircraft could be designed to do some serious farming. I am thinking about a low speed flyer, with about 4 engines, and multi-tailboom design. It would be heavy and have a ton of drag, but you could have an enormous wing with controlled attachments for doing the cutting/tilling/ whathaveyou. Nothing like it has been done before to my knowledge, but I would compare it to a slow B-52 with no wing sweep, narrower & shorter fuselages, and huge tires. I honestly don't know enough about the ag market to find out if it would be cost effieient do design a fleet of these beasts, but I think it would be a cool option to go bigger.

Thoughts? Comments? It is a totally crazy and impractical idea? Assinine to even pursue marketability?

If anyone could provide some resources online I might not be aware of, or some good specific references to get an idea of the mechanical terminology, mechanical systems and design parameters of tractor/combine/ farming machinery, that would be helpful, especially dealing with price/cost parameters associated with tractor design. ($/acre, section; $/hr; $/year, lifecycle, etc)

 

[drkillroy]

I do have anbother question along the same subject. I have read about low flying air plains that fly just above the water and are capable of carring heavy payloads. I read the military want them for moving tanks faster than a ship for rapid deployment. Would the same principle work over land? Could the plain clear the trees in the hedgerow? How fast or short a distance can it land?
Thanks Drkillroy

 

[gontek]

drkillroy,
what you are referring to is called ground effect. It applies over land as well as water. Ground effect vehicles (GEV) can operate only in this area. I think the height above groud in which GE occurs is about half the wingspan.

 

[Slugger926]

For the tractor end of things, there is a lot going on in the No Till farming of wheat. There is lots of fuel saved by not tilling the soil which requires the big 4 wheel drive tractors to pull the plowing and sub-soilling equipment. A smaller tractor can pull the air powered seed planters and the spraying equipment for killing weeds.

There is also less fertilizing required due to not exposing as much topsoil for erosion loss during the off season.

The smart sprayers will also minimize the amount of herbicides put down on the fields as well in the future.

It is funny to see the big corporate 4x4 tractors sitting around rusting away.

 

[Pressed]

The Ruskies designed a flying tank. Maiden voyage with thier best pilot, yes, he made it but they collectively descided to scrap the project because of risk. This was around WW2 time when tanks were thier main force. It might have been a glider, anyway they were sweating bullets or artillery shells till the flight was over.

The thing I would think important is the loss, not using a real runway. Those quick deployed equipment of the military get ruined alot. I don't know what the numbers are but insurance might be a problem.

_______________________________________
Feeling frisky.........

http://www.tailofthedragon.com

 

[drkillroy]

Slugger926
"Smart Sprayers" Tell me more about the way they work? Years ago I heard of mounting microphones next to the nozzle to send an alarm if the sound of the spray changes! What else is going on?
Drkillroy

 

[gontek]

There are remote sensing tecohologies that use satellies and remote sensing/ GIS to determine hte moisture levels in the soil. I have heard of airborne sensors that can identify crops vs weeds, and only apply the spray where it will be most utilized, instead of blanket spraying the entire field of crops. The way aircraft control systems work, taking measurements every millisecond, it would be pssible to spray the chemicals selectively, to only the areas that need them. Instead of "dusting", it is more of a seek and destroy squirt gun application, saving bundles in chemical costs.

 

[gontek]

Addendum - crop dusting technology currently used has not changed since WWII for the most part. My senior year, the AIAA individual design project was based on improving crop duster technology. I started a project, but then started working full time, and never finished it. It was initially a UAV/RPV crop duster using this technology. There are still a LOT of issues with getting UAV's with this type of technology certified by the FAA for civillian use, but I believe it has a lot of merit for crop dusting among other things like aerial photography, remote sensing for agriculture, and photogrammetyr. Crop dusting is one of the most pilot-intensive activities that exists in an aircraft anymore, and one of the most dangerous because of this. Automating most of the procedures involved would save many $$$ as well as taking many pilots out of risk, in my opinion.

 

[Slugger926]

Smart Spayers identify weeds and only spray the herbicide on the weeds. There is a light sensor that is mounted a few feet in front of the spayer nozel that tells the difference in ultra vilot light from the weeds and the actual crop. When weeds pass the sensor, the computer squirts the weed with herbicide when the sprayer nozzle is over the weed. The computers keep track of the ground speed and account for the delay in time from when the weed passes the sensor and then the sprayer nozzel.

Several universities and experts in agricultural/biosystems engineering are working together to master this technology to where it can be economically feasable for the average farmer. The faster computers of today compared to 15 years ago is helping this technology a lot.

 

[IceStationZebra]

"The John Deere 9620 has about 500 HP and weighs about 40,000 lbs. So you are saying a large tractor roughly of that size and power cal pull about 360,000 lbs? Good to know."

Hold up -- not even close. The coefficient of friction between soil and rubber is ~0.7. A 40,000lbs tractor can only exert a constant pull of ~28,000lbs, give or take. I used to use this fact to verify that my load cells were working correctly. And then the soil can only "hold" a certain amount of force before the tires begin to spin. After you have enough rubber on the ground to avoid excessive spinning (~7-10% is optimum for tires, 3% from tracks) more tires can be used to minimize compaction. You generally get higher draft loads when the machine first engages the ground due to momentum, but that only lasts a split second. As you can see, if ground drive is utilized you would need a lot of weight to pull a large ground engaging implement.

As for turbines, IH built two prototype turbine tractors sometime in the 70's. From what my coworkers said they were ungodly loud, it was difficult to modulate engine speed, and they required lots of fuel. They donated one to the Smithsonian and I think they still have the other in their private collection.

 

[gontek]

Hello I am back. Thank you all for teaching me and/or entertaining my crazy idea. I have not thought much about this since I started my new job back in August, they are keeping me plenty busy and pleasantly challenged.

http://gontek.blogspot.com/

at this link to my new blog I posted a couple images of my preliminary configuration attempts. I would probably normally do about 20 more configuration layouts before I considered weight, balance, pros and cons, and went with one. I would pretty much have to do a whole detailed design before I could estimate costs with any accuracy, and it would probably be more than 10 billion for 500 machines, I would wildly guess. enjoy, and thanks everyone for your comments, shared knowledge, and time.

 

[gontek]

ps I believe those are turboshaft props as it finally turned out. Optimal for slow vehicles. remember those crazy headers fold up into the shaft, and would likely have hinges to conform to uneven ground.

Dang it, I'm doiing it again, I am thinking about it.

 

[corang]

I'm not sure we are heading this way at all

With fossil fuels becoming ever more expensive we will
I think downsize tractors as the emphasis will be placed on no-till.
I'm moving that way and saving money already.
The other changes in future will be more sun-migration and more people growing their own food on small holdings as the traditional role of cities diminish due to the cost (and lack) of oil affecting all transport systems.
There may be a role for smaller planes in agriculture but certainly not for primitive activities such as ground engagement.

EJ

 

[softley]

Mention is made of turbine in a tractor design early in this thread. Can a turbine engine use a heaver grade of fuel that kerosene or light diesel? The concept of turbine electric power intrigues me. IF we could apply power to more drive wheels on our ag equipment maybe we could reduce soil compaction.