“Rotary Engine (form 2)” is a historical catalog label, not a standardized eccentricity or performance class. The source-supported interpretation is a fixed circular casing around an offset drum with radial sliding members; the catalog does not establish a universal bore percentage, member count, port timing or output rating.
Historical Rotary Engine Form 2 Topology Visual
Inspect the historical fixed-casing, offset-drum and radial sliding-member topology without assigning unsupported sizing or performance outputs.
Equation Used
- The component grouping follows the historical catalog interpretation.
- The casing is fixed and the displayed drum center is offset.
- Four equally spaced sliding members are used only to make the topology visible.
- Dimensions, materials, ports, seals, pressure, temperature, loads, speed and ratings are unspecified.
The visual uses normalized illustrative geometry with four displayed members and is not a construction, restoration or operating drawing.
Historical topology
The illustrated interpretation places a rotating drum off the casing center. Radial members move in slots in the drum and extend to the fixed casing, so their exposed lengths vary as the drum turns.
The animation solves the ray-to-circle intersection for an illustrative four-member layout. Four is a display choice, not a historical requirement or recommendation, and the normalized proportions are not design dimensions.
What the visual demonstrates
The visual highlights the fixed casing, offset drum, radial sliding members and center offset. Every displayed member root stays on the drum and each tip meets the casing through a complete illustrative revolution.
It does not assign inlet and exhaust ports, working-fluid direction, seals, springs or a pressure cycle. Those system details must be defined before the geometry can represent a specific pump, motor or engine.
No universal eccentricity calculator is supported
The removed calculator converted two user-entered bore percentages into a claimed recommended offset range. The historical catalog label provides no basis for universal minimum or maximum eccentricity percentages, and equal angular spacing follows only from a separately selected member count.
Performance also requires a complete chamber-volume function and pressure-volume path. Work per cycle is W = ∮p dV; without ports, width, timing, pressure and losses, neither displacement nor power can be evaluated.
Reading the topology visual
Use the cycle control to follow the offset drum through one revolution and to change the highlighted component group. Member length changes are constrained by the illustrative fixed casing and drum centers.
The display checks internal consistency of one schematic, not whether its offset, drum radius or member count would operate as a real pressure machine.
Correction and safety boundary
The former article supplied universal eccentricity ranges, speeds, pressures, power bands, clearances, materials, port ratios, wear intervals, torque ripple, leakage, failure diagnoses and museum examples without primary support. It also linked an unrelated video.
Those claims and the fabricated worked example are removed. Historical rotary pressure machinery can involve hot pressurized fluid and stored energy; this page is not a construction, restoration, operating or steaming guide.
Questions
Is “form 2” a performance standard?
No. It is a catalog label used to distinguish one historical arrangement from other forms.
Is offset always a fixed percentage of bore?
No universal percentage follows from the label. A specified design must satisfy containment, chamber, port, contact, strength and sealing constraints.
Does the number of sliding members define power?
No. Member count alone does not define chamber volume, pressure, work, leakage or friction.
Does the visual specify inlet and exhaust timing?
No. No ports or working-fluid cycle are assigned.
Historical and technical references
- G. D. Hiscox, Mechanical Movements, Powers, Devices and Appliances — historical catalog of rotary-engine arrangements; useful for topology identification, not universal sizing percentages.
- T. W. Barber, The Engineer's Sketch-Book — period collection showing many distinct eccentric-drum, vane and abutment arrangements under broad rotary-engine and pump headings.
- OpenStax University Physics, Work, Heat, and Internal Energy — pressure-volume work is path dependent and requires a defined p(V) process.
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