Published April 7, 2008 | By admin
Orthman Looks Deeper!
QUESTION FROM THE FIELD:
Why do you with the Orthman 1tRIPr strip-till toolbar require 25 to 30 horsepower per shank compared to some others saying theirs requires 15 to 20 at most?
Answer:
Numerous engineering studies have shown when any ground engaging device such as a ripping/mole shank is engaged deeper than five inches there is a great amount of resistance in firm soil to resist the forward motion the tractor exerts. Soils with more than 24% clay can require 3090 pounds of force to cause soil failure in front of one shank (at 14 inches) which disrupts the soil upward and around the shank and behind. Same soils at 12 inches it is 2130 pounds of force and at 10 inches depth, it would take 1850 pounds of force to pull one shank. That is not counting the force to keep the shank(s) in the ground with vertical pressure, add that to the mix and we have 4490 lbs of total force exerted per shank at 14 inches deep. Take this times eight shanks in the ground, that is 35,900 pounds of force to cause forward motion, just think then to drive 4 or 5 mph?.
If soils are compacted at the depth where you want it to fail and fracture, the required force to overcome 300 psi multiplies what the lateral draft force is ahead of the shanks.
When someone tells you it may only take 10 to 15hp per shank, consider that soil has a great deal of resistance. And when we are trying to ready a seedbed and root environment it takes power. You want to do it correctly right?