Posted by LenNH on February 03, 2010 at 14:34:19 from (24.60.236.239):
If you are an armchair engineer (I confess I am), you might like to search the web with terms like "tractor plowing speeds." I found the complete text of an old IHC booklet on plowing (but no pictures). There are summaries of some modern research on plowing done at universities, but the academic jargon is about as understandable as some of the stuff written by computer programmers. I have a copy of an article published in 1920 by Oliver Zimmerman (apparently of IHC) called "Tractor Plowing Speeds." It is fairly long and goes into a lot of different conditions, but one of the graphs clearly shows why steel-wheeled tractors could pull their "rated load" at about 3 mph, but not much faster. As speed increases (a straight line on the graph), plow draft rises faster than the speed (a curved line going upward on the graph). A plow that takes 4.5 hp at 2 mph requires about 12 hp at 4 mph. At 4.5 mph, the plow needs almost 15 hp!!It is easy to see that if your tractor is rated at 10 drawbar horsepower (which might put out 14 or 15 maximum hp), it will run out of steam around 3.5 mph (plow requires almost 10 hp at that speed). Anybody who has ever worked with steel-wheels will remember that the lugs really rob the power, and that increasing speed takes a lot away from the drawbar hp. I remember very well that our 10-20 would pull through anything in second gear, but would pull almost nothing in third. An F-20 that I used to plow with sometimes had been converted to 36" rubber. It would plow in second at close to 4 mph (h.p. of the 10-20 and F-20 are close enough to make a reasonable comparison), sometimes in third (estimate 4.5 mph) and even in 4th (over 5 mph) in very light soil. If you are an avid reader of Nebraska tractor tests, you can see the loss of power to the wheels with steel-wheeled tractors (I'd put it at about 35% loss on average; this helps explain the old ratings like 10-20, with the higher number for belt hp). Today, four-wheel-drive tractors are probably putting around 85-90% of the engine power to the ground. I'm sure modern plow bottoms are shaped for the new speeds, too. In "my day," I believe the moldboards were actually designed to do a good job of turning over the soil at about 3 mph. In the old tractor brochures from the 20s and 30s, they often talked about "plowing speed," which was usually in the neighborhood of 3 mph.
We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today. [ About Us ]
Today's Featured Article - The Cletrac General GG and the BF Avery A - A Bit of History - by Mike Ballash. This article is a summary of what I have gathered up from various sources on the Gletrac General GG and the B. F. Avery model A tractors. I am quite sure that most of it is accurate. The General GG was made by the Cleveland Tractor Company (Cletrac) of Cleveland, Ohio. Originally the company was called the Cleveland Motor Plow Company which began in 1912, then the Cleveland Tractor Company (1917) and finally Cletrac.
... [Read Article]
All Rights Reserved. Reproduction of any part of this website, including design and content, without written permission is strictly prohibited. Trade Marks and Trade Names contained and used in this Website are those of others, and are used in this Website in a descriptive sense to refer to the products of others. Use of this Web site constitutes acceptance of our User Agreement and Privacy Policy
TRADEMARK DISCLAIMER: Tradenames and Trademarks referred to within Yesterday's Tractor Co. products and within the Yesterday's Tractor Co. websites are the property of their respective trademark holders. None of these trademark holders are affiliated with Yesterday's Tractor Co., our products, or our website nor are we sponsored by them. John Deere and its logos are the registered trademarks of the John Deere Corporation. Agco, Agco Allis, White, Massey Ferguson and their logos are the registered trademarks of AGCO Corporation. Case, Case-IH, Farmall, International Harvester, New Holland and their logos are registered trademarks of CNH Global N.V.
