Need advice on a fetching arch build

[MillWeld]

I have read several threads on building a log arch but can't find one that addresses my issue. I'm building a small fetching arch (24" wide, 39" tall) which I plan to pull with a drag line via a truck or tractor. I am about to attach the draw bar and hooks and a design issue has come up: the weight of the log has to be supported at the rear of the arch otherwise the draw bar runs the risk of hitting the ground making pulling impossible. What I thought of doing is tilting the arch as shown on the pic to assure the center of gravity is always to the rear. Is this a good idea or will something rear up and bite me? I have looked at LogRite's arch and noticed their tong is mounted to the rear which accomplishes the same thing.
At this point I can go either way. Any advice?

 

[Baby Grand]

I think you'll want the tongs hanging from a point just forward of the axle when it's in the traveling position. That way the weight of the log will pull the arch down and the long beam won't try to lift the 3pt hitch - very few tractors have down force on the 3pt. Having the hitch lift on you, because the load is applied aft of the axle could be a real PITA or worse.

Edit: Looking at many of the commercially available fetching arches, the tongs are just aft of, or right over the axle. I guess that the long beam weighs enough and is long enough (it's CG is far enough forward) to offset any lift generated by the log on the other side of the axle. An advantage of having the tongs mounted slightly aft would be the added lift height you'd get once the tongs grab the log and the long beam rotates forward.

 

[bcp]

You could use two arches:
From:
http://www.forestryforum.com/board/index.php?topic=25941.20



Some rope pulling here:
Night Train's Logging Arch, with pictures! | Cycle Chat Cycling Forums


You could use a skid on the front of the log.
From:
http://www.tractorbynet.com/forums/attachments/22577-logging-arch.html




Do a Google Image search for

logging arch

and see hundreds of them.

Bruce

 

[MillWeld]

I think you'll want the tongs hanging from a point just forward of the axle when it's in the traveling position. That way the weight of the log will pull the arch down and the long beam won't try to lift the 3pt hitch - very few tractors have down force on the 3pt. Having the hitch lift on you, because the load is applied aft of the axle could be a real PITA or worse.

Edit: Looking at many of the commercially available fetching arches, the tongs are just aft of, or right over the axle. I guess that the long beam weighs enough and is long enough (it's CG is far enough forward) to offset any lift generated by the log on the other side of the axle. An advantage of having the tongs mounted slightly aft would be the added lift height you'd get once the tongs grab the log and the long beam rotates forward.

The lifting of the log is accomplished by the pull of the drag line. See LogRite video.
LogRite Fetching Arch - YouTube

 

[MillWeld]

bcp, your ForestryForum link led me to http://www.forestryforum.com/board/index.php/topic,23479.240.html

I will not tilt the arch; copying the slide out feature on the Mark 7 will allow me to adjust the mechanical advantage as needed. A very versatile solution and thanks for the link
Bob