Jim D.
I'm with ya......been talking about the concave coulter idea with dad and Travis for some time now...even have some parts to make one. Around here they were called Yetter coulters, which is what I typed in the original post...sorry for the confusion.
2 problems with it that I can see right from the start....
1) Like John said, not enough weight to make one cut...they pull much harder than a straight coulter would, especially in 1/4 scale.
2) Beam clearance. It will be hard to make the coulter lay over like it should and still keep it out of the beam.
BTW, a pulling hitch and a plow hitch are two different animals. Higher attachment heights are not the answer, just more beam clearance. The actual line of draft should still be below the rear axle height and idealy right thru the lower hitch point. The difference between plowing and pulling is that the plow needs to have the correct balance of downward suck (provided by the bottom) to keep it in the ground and upward pull (provided by the tractor) to keep it running level and transfer tractor weight. In pulling you have virtually unlimited downward force on the "implement", so much so that you can't lift it (at least not past the first few feet of the track) and can hang the whole tractor off of it......do that with a plow and the bottom will just pop out of the ground. We have penetration problems with plows as-is...higher hitch heights would only make that MUCH worse.
The plan for real plow development is as follows:
1) Get 12" bottom parts from Robb (within 2 weeks)
2) mock up furrow/land/etc with 2x6's on edge and some plywood...full width so that clearance can be seen/measured/photoed etc. at various points (hitch/tractor/plow).
3) design
4) test design and line of pull on the mock-up.
5) build
6) test in field
7) obtain desired results
8) Install front bumper on right front tire (to protect it from contact with 12" Brinly 3pt. plows on JD's that won't get out of the way)
....left turn singal for passing may also be an option......