Spring-Dimensioned Wind-Up Propeller Mechanism

MAINSpring — DIMENSIONAL MASTER: The entire mechanism MUST be designed around this REAL purchased metal mainspring: • Type: flat spiral/clockwork mainspring • Material: spring steel • Thickness: 0.30 mm • Width: 5.0 mm • Length: approximately 1.0–1.2 m; nominal 1.10 m • Barrel internal diameter at the outer winding region: 12 mm minimum • Barrel internal width: 5.2–5.5 mm • Arbor diameter: 6 mm • Intended winding: approximately 6–8 arbor turns from relaxed position The metal mainspring is the ONLY non-printed component. Do NOT model, print or substitute a plastic/compression spring. CRITICAL SPRING-BARREL SIZING: The spring barrel MUST be dimensioned from the actual 1.10 m × 0.30 mm × 5.0 mm spring, NOT from a predetermined housing or barrel diameter. Calculate the radial storage capacity required for the ENTIRE 1.10 m spring when wound around the 6 mm arbor. The wound spring must physically fit inside the barrel without overlapping the barrel wall, exceeding the available radial space, or being compressed axially. Treat the 6 mm arbor diameter as the inner winding diameter and the 12 mm dimension as the MINIMUM barrel internal diameter. Calculate the required OUTER winding diameter/radial depth from the spring's actual length and thickness, then add practical clearance. The final barrel may be substantially larger than 22 mm if required. The barrel must therefore have enough internal radial volume to contain the FULL 1.10 m spring at maximum winding. Do NOT simply make a visually plausible 12 mm ID / 22 mm OD barrel. The spring width is 5.0 mm. Provide approximately 0.2–0.25 mm axial clearance on each side, giving approximately 5.4–5.5 mm usable internal barrel width. SPRING CONNECTION: The inner end of the spring must positively attach to the 6 mm arbor. The outer end must positively attach to the rotating barrel. When the winding key rotates the arbor, the spring winds tighter around the arbor. When released, spring torque MUST rotate the barrel relative to the arbor. The rotating barrel must carry the first gearbox drive gear and therefore directly transmit the mainspring's torque into the reduction gearbox. Provide a removable barrel cover so the REAL metal spring can be installed, removed and replaced. Do NOT invent dimensions for the spring. Do NOT reduce the spring length to make it fit. Do NOT force the spring into a smaller barrel. If the calculated barrel size conflicts with the Spitfire nose dimensions, enlarge the nose/housing around the correctly sized spring barrel. SPRING DIMENSIONS TAKE PRIORITY OVER EXTERNAL APPEARANCE.

Parameters

Every value above is a live dimension. Open a model like this in the editor and each one becomes a slider you can drag before exporting.