Tractor Drawbar Power
Drawbar HP = (pull * speed) / 375; PTO HP estimate from public benchmark.
Example
You enter
- Drawbar pull (lb) 4500
- Ground speed (mph) 4.5
- Surface firm_soil
You get
- Drawbar HP 54.0
- PTO HP estimate 75.0
- Tractive efficiency 0.72
Details, formula, and sources
Drawbar HP = (pull_lb × speed_mph) / 375. PTO HP estimate = drawbar_HP / tractive_efficiency (typical 0.65 firm soil / 0.55 tilled / 0.45 soft).
ASABE D497 (Agricultural Machinery Management Data) by name; Nebraska Tractor Test Lab publications.
Nebraska Tractor Test data free at tractortestlab.unl.edu.
Estimate. AHJ and licensed professional govern.
Field names used by the API: pull_lb, speed_mph, surface, drawbar_hp, pto_hp_estimate, tractive_efficiency
- Tractive-efficiency table 0.65 firm / 0.55 tilled / 0.45 soft (engineering-practice values)ASABE D497