Horsepower needed for bushogging

Sure I could use a larger mower, but that means I can fit between fewer trees, fences, rocks, etc., and I would have to go slower...this time of year I like to keep my ground speed up in order to stay ahead of the dust and chaff! Yes these are basically big fans and they kick up a miserable cloud when it's dry out!

I believe a larger diesel (at least to a certain size) is much more efficient than overworking a smaller one and is a lot easier on everything mechanically. I also found that running loaded tires uses less fuel as they act as a big flywheel and help power the mower thru the tough spots.

As to a 7 foot mower, it costs 50% more than a 6 foot, is longer and heavier (so it will scalp more often) and takes more room to turn around and haul on a trailer.....I'll stick to a 6 foot! There's a reason they don't sell many 7 footers! An 8 foot would be a better upgrade as it has twin gearboxes making it much shorter and the rotation of the blades picks up the grass smashed down by the tires.....but it is 4 times the price of a 6 footer and HEAVY!

Mitch

Here's some data on one of Deere's most efficient diesels - that does miserably when not loaded down and used for too small a job. At 22 horsepower, an 8N Ford gas tractor is more efficient.

An 8N gas tractor can be loaded to 25 horsepower and run at an efficiency of 11.1 horsepower-gallons per hour.

A John Deere 414 engine when only loaded at 22 horsepower runs at 8.7 horsepower-gallons per hour.

Deere 6603 with a 414 cubic inch diesel - Nebraska Test # 1809

Fuel efficiency expressed in horsepower-hours per gallon of diesel fuel.

Loaded to 101 horsepower at 2100 RPM - 18 HHG
Loaded to 97 horsepower at 2100 RPM - 17.1 HHG.
Loaded to 85 horsepower at 2100 RPM - 16.1 HHG
Loaded to 65 horsepower at 2200 RPM - 15.5 HHG
Loaded to 44 horsepower at 2200 RPM - 14.7 HHG
Loaded to 22 horsepower at 2200 RPM - 8.7 HHG
Loaded to 1 horsepower at 2200 RPM - 6/10 HHG

One big advantage to diesel - is the fuel weighs more than gasoline - i.e. there is more fuel in a gallon and more BTUs.

My main point was - and is - most diesels are only efficient at certain power loads and RPM ranges. You might have a large tractor that is highly efficient when being worked at 100 horsepower, but the same tractor when only worked at 20 horse is likely to use a lot more fuel per work done - than a smaller tractor doing the same job - gas or diesel.

Didn't think anybody would try to argue that point. Most farmers I've worked with or known - always had small tractors for light work due to fuel efficiency. My neighbor - year ago - bought two brand new Deere 4020s (still has one). He loved the tractors for heavy work, but always griped about what fuel hogs they were on his silo blower which only needs about 20 horsepower. He finally bought - new - a little 30 horse British Allis Chalmers ED-40, and it did the same job on almost half the fuel.

That's why I posted the Deere specs showing what a dog it becomes when not worked hard. And, those specs are with PTO work loads and have nothing to do with excess tractor weight.

Another example is that of electric gensets. If you take a 60 horsepower 20KW genset and use it to make 500 watts, it is highly inefficient. That because the engine is too big for a small job. A little gas generator rated a 750 or 1000 watts max will make 500 watts using much less fuel - than the large diesel genset.

Rod

steveormary