This partial calculator determines circumference and ideal surface travel from selected drum diameter and constant rotational speed. It does not predict actual rope speed under layering, acceleration, slip, load, torque, braking or hoist safety.
Steam Hoisting Engine - Selected Ideal Drum-Travel Ledger
Explore selected cylindrical-drum circumference and ideal constant-rate surface travel.
Equation Used
- Drum diameter and rotational speed are selected constant values.
- The effective radius stays constant with no rope layering.
- The rope has no thickness, elasticity or slip.
- The 1,000 ft time excludes acceleration and deceleration.
- Load, torque, power, braking, structure and safety are excluded.
The secondary figure is an abstract drum-travel ledger, not a steam hoist design.
Selected ideal drum-travel ledger
A cylindrical drum advances one circumference pi D at its surface per revolution. At selected constant speed N, ideal surface travel is pi D N. Miles per hour and ideal time for 1,000 ft are direct unit conversions.
What the calculator determines
Use it to inspect constant-radius kinematics and unit conversions. It cannot rate or operate a hoist.
Selected relationships
C=pi D; v=CN; mph=60v/5280; t_1000=60000/v seconds.
Selected-input example
At selected diameter 12 ft and 60 rpm, circumference is about 37.699 ft/rev, ideal surface travel is about 2261.947 ft/min or 25.704 mph, and ideal constant-rate time for 1,000 ft is about 26.526 seconds.
Not a hoist performance model
Rope build-up, groove geometry, elasticity, slip, acceleration, load, power, gearing, losses, braking, controls, structure and safety are excluded.
Questions
Is surface travel actual rope speed?
Only for an ideal single effective radius with no slip or layering.
Does the 1,000 ft time include acceleration?
No. It assumes the selected constant rate for the entire distance.
Can this size a hoist?
No. No load, torque, power, brake or structural inputs are present.
Authoritative references
- NASA Glenn angular-motion reference — relates tangential speed, angular speed and radius.
- NIST SI Units - Length — documents length units and conversion practice.
References & Further Reading
- Wikipedia contributors. Steam donkey. Wikipedia
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