Recent Blogs
Serpollet's Steam Tricycle Mechanism: How the 1887 Flash Boiler Steam Vehicle Works
Serpollet's Steam Tricycle used a flash boiler to power a 3-wheeled road vehicle in 1887. Learn the mechanism, formulas, and worked example for heritage builds.
Self-registering Tide Gauge: How It Works, Stilling Well Diagram, Parts, Uses & Orifice Calculator
How a self-registering tide gauge works — float, stilling well, drum recorder, and clockwork. Used in harbour engineering and coastal survey work.
Screw Propeller Mechanism: How It Works, Parts, Diagram, Formula and Marine Uses Explained
How a Screw Propeller works — blade geometry, pitch, slip, thrust calculation, and worked examples from marine, aviation, and submersible propulsion.
Sampler Sounding Weight Mechanism Explained: Parts, Diagram, Formula and Hydrographic Survey Uses
How a Sampler Sounding Weight measures water depth and grabs a seabed sample in one drop. Used by hydrographic survey crews, dredging contractors, and marine...
Round Turn and Half Hitch: Mechanism, Capstan Formula, Parts, and Mooring Uses Explained
Round turn and two half hitches knot explained — how the wraps absorb load, breaking-strength figures, and real mooring and rigging applications.
Rope Knots and Hitches Explained: How They Work, Key Parts, Knot Efficiency and Working Load Limits
Rope knots and hitches explained — how friction, bend radius, and load path determine holding strength in rigging, sailing, arboriculture, and rescue work.
Road Roller Mechanism Explained: How Vibratory Compaction Works, Parts, Formula and Uses
How a Road Roller compacts asphalt and soil — drum geometry, vibration physics, lift thickness math, and pass-count rules used by paving crews worldwide.
Road Machine Mechanism Explained: How Asphalt Pavers, Graders, and Milling Machines Work
How a road machine works — the asphalt paver, grader, and milling machines that build modern highways. Specs, formulas, and real paving examples.
Road Builders' Level Mechanism Explained: How It Works, Parts, Diagram & Surveying Uses
How a road builders' level works — bubble vial physics, sight tube geometry, and grade-staking math used by highway crews to set elevations within ±3...
Reversing Screw Propeller Mechanism: How It Works, Parts, Pitch Diagram and Marine Uses Explained
Explore a propeller pitch-control linkage. Calculate blade angle, zero-angle crosshead position and travel per degree from stroke and ahead/astern angle limits.
Reversible Road Roller: Hydrostatic Direction and Speed Calculator
Explore how swashplate angle reverses a hydrostatic drive. Compare ideal forward and reverse travel speeds using an entered full-stroke reference.
Railway Pneumatic Signal Mechanism: How It Works, Parts, Diagram and Uses Explained
How a railway pneumatic signal works — air pressure drives the semaphore arm, with stroke times of 2-4 seconds at 80 psi. Used across heritage...
Railroad Gates: Declared Constant-Speed Timing Ledger
Railroad gates protect grade crossings using counterweighted arms, DC gate motors, and track circuits. See how rail crossing gates work, with engineering specs and a...
Passenger Locomotive Eight-Wheeler: 4-4-0 Rolling Layout
Explore the American 4-4-0 locomotive arrangement. Calculate leading-wheel and coupled-driver rpm from wheel diameters and train speed under ideal rolling.
Overhand Knot: Declared Loose-Diagram Geometry
Explore a loose overhand-knot projection and trace its centerline. Adjust drawing scale, tails and sampling resolution without predicting rope performance.
Radial Paddle Wheel: Declared Immersion Geometry
Explore radial paddle-wheel geometry. Calculate radius, circumference, bottom-tip immersion and float spacing from diameter, immersion percentage and count.
Novel Steering Gear: Hiscox Meteor Yacht Screw Linkage
Explore Meteor's historical opposed-screw yacht steering gear. Calculate nut travel and rudder-cap angle for an illustrative symmetric equal-link arrangement.
Newport Cat-Boat: Gaff Rig and Declared Longitudinal Centres
Explore the Newport cat-boat's gaff rig and compare entered CE and CLR positions along a waterline. Calculate signed separation from a common bow datum.
Steam Locomotive–Tender Drawbar: Articulation Geometry
Explore steam locomotive-tender drawbar articulation and calculate longitudinal projection, lateral offset and geometric shortening from length and swing angle.
Light Electric Carriage: Grade-Force and Climbing-Power Calculator
Compare grade force and constant-speed climbing power with a stated battery input ceiling. Explore the effects of vehicle mass, slope and speed.
Lateen Rig Mechanism Explained: How the Triangular Sail Works, Parts, Geometry & Uses
How a Lateen Rig works, the geometry behind its upwind ability, and where you still see it today — from Nile feluccas to modern sailing...
Jib Topsail Sloop: Idealized Sail-Force Component Calculator | FIRGELLI
Calculate lift, drag and a forward-axis component from entered wind, sail area and assumed coefficients. The diagram does not predict vessel speed, heel or rigging...
Jacketless Carriage Motor: Illustrative Fin-Cooling Calculator | FIRGELLI
Explore ideal convection using a declared reference-area assumption, fin-depth and spacing multipliers, and entered temperatures. No historical engine rating or complete cooling design is calculated.
Ice Boat: Perpendicular Apparent-Wind Calculator | FIRGELLI
Explore Hiscox’s three-runner ice boat and calculate a perpendicular apparent-wind triangle. Sail forces, attainable craft speed and safe conditions are not calculated.
Hermaphrodite Brig: Sail-Area Coordinate Calculator | FIRGELLI
Compare an entered sail-area centroid with a lateral-resistance coordinate. This geometric comparison does not predict helm angle, sailing behavior or a suitable rig.