power required for logging

[fabian]

in our german ox forum is a link to this article:

http://zugrinder.de/Zugkraftbedarf.pdf

where Tim Harrigan a.o. compare the power which is required for logging with oxen with different methods.

also a link to this video:

http://www.youtube.com/watch?v=b5tf1iUROWY

But I find nowhere informations about the power which is required by logging with a short chain, as seen here:

http://www.youtube.com/watch?v=hXVZuY92P6s&NR=1

here:

http://www.youtube.com/watch?v=wvKQFYKxWjc (especially the third team)

or described here:

http://www.gilbertroad.f2s.com/documents/oxlogman.pdf

(page 16)

Are there any informations about the required power ?
Thank you for the answers.

Wolfgang

[Tim Harrigan]

Wolfgang: Thanks for the videos and articles. The short chaining is an interesting way to take advantage of a high hitch angle and the power that is concentrated in the neck and shoulders of an ox team. I have not tried that method of skidding, you will notice that it requires a wide-span yoke so the team can straddle the log. There are clear advantages in keeping the log off the ground in front, cleaner log, less danger of hitting obstructions, etc. It would also require some training for the team to maneuver and turn the log in tight quarters, and the wide span could limit access in some wood lots. The advantage of a high hitch angle is that the team can carry some of the load in addition to pulling it. When they carry part of the load it reduces the part of the load they have to pull and the pulling draft is reduced.

When I have time I will do some calculations to estimate a theoretical draft with thay method, but in general I would guess the draft would be about the same as with a logging arch. The problem with that is that the arch is carrying the load, not the team, which eases the burden of the team. So the question is really efficient use of power. This is an interesting use of an ox team in that it really captures the front end power and that is the primary power plant in many ox breeds.

Have you seen this by Professor Inns in the UK?

http://www.fao.org/docrep/w0613t/w0613t0g.htm

It is an interesting approach to hitching a single donkey for tillage whereby they take advantage of a high hitch point by modifying the harness so a portion of the load is carried on the hind quarters and the angle of draft is shifted from the front to the back of the animal. There are figures and images associated with the highlighted text, one of the graphs shows reduction in tillage draft when using the high-lift harness compared to their traditional harness, probably a breast harness if I recall correctly.

You can also download a report of the use if the high-lift harness in Bolivia from this site

http://www.cigrjournal.org/index.php/Ejounral/article/view/458/0

reporting on work by Brian Sims who I believe is a colleague of Inns in the UK.

[fabian]

@Tim Harrigan 17802 wrote:

but in general I would guess the draft would be about the same as with a logging arch.

That was also my consideration, adding some power (but how much ?) needed for lifting the load.

Thank you for your extensive answer.

Wolfgang

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