A winch turns hand-crank torque into rope tension at its drum. Compare ideal line pull from hand force, crank radius, gear ratio and drum radius. A separate holding-force reference is 1.25 times that result; it is an assumed comparison, not a brake rating.
Winch Interactive Calculator
Enter hand force, ideal gear ratio, crank radius and drum radius. Results assume lossless torque transfer and a single effective drum radius; they are not rated lifting capacities.
Equation Used
- Hand force is tangential at the entered crank radius.
- Gear ratio is an ideal torque multiplier.
- Drum radius is one fixed effective radius.
- One kilogram-force equals 9.80665 N.
- Efficiency, rope layers, dynamics, structure, hardware ratings and safety are omitted.
Ideal Winch Torque comparison
The NASA Glenn torque reference supports force times moment arm. Gear efficiency and hardware capacity remain outside this screen.
What This Calculator Represents
A lossless crank, gear and drum torque conversion.
Torque and Line Pull
L=Fhand MA
LN=9.80665L
B=1.25L
Worked Scenario
At 10 kgf, G=5, rc=250 mm and rd=50 mm, ideal advantage is 25 and line pull is 250 kgf or about 2,452 N; the fixed brake reference is 312.5 kgf.
Assumptions and Limits
No efficiency, rope buildup, rated capacity, structure, braking dynamics or lift approval is included.
Frequently Asked Questions
Is line pull rated capacity?
No.
Are losses included?
No.
Does drum radius change with rope layers?
In reality yes; this model holds it fixed.
Is 1.25 a universal brake factor?
No.
Are anchors and rope checked?
No.
Can this approve a lift?
No.
References
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