https://longearthsociety.com/ Builds, tests and batches from Long Earth Society. Every project starts with a question and ends with the data. en-us Sun, 18 Oct 2026 08:43:06 +0000 https://longearthsociety.com/engineering/experiment?e=displacer-build-8x6-flashing https://longearthsociety.com/engineering/experiment?e=displacer-build-8x6-flashing Fri, 25 Jul 2025 00:00:00 +0000 Can a lightweight 8" × 6" displacer be built from aluminum flashing and hold up in the free-piston rig? Yes. A DIY method for making a large displacer from aluminum flashing, shown step by step. https://longearthsociety.com/engineering/experiment?e=displacer-design-3ft-fpse https://longearthsociety.com/engineering/experiment?e=displacer-design-3ft-fpse Wed, 23 Jul 2025 00:00:00 +0000 Can a displacer for a 3-foot free-piston engine be designed and built in-house instead of bought? Yes. Building it saved roughly $700 after tariffs and shipping. https://longearthsociety.com/engineering/experiment?e=fpse-design https://longearthsociety.com/engineering/experiment?e=fpse-design Sat, 19 Jul 2025 00:00:00 +0000 What does the thermoacoustic work change about the free-piston Stirling design started two years earlier? Pending. Trial still ahead. https://longearthsociety.com/misc/experiment?e=corona-motor-concept https://longearthsociety.com/misc/experiment?e=corona-motor-concept Thu, 09 May 2024 00:00:00 +0000 Can a LaserSaber-style corona (electrostatic) motor be reproduced and made useful? Successful test. Next step is scaling it up to see whether torque increases with size. https://longearthsociety.com/engineering/experiment?e=thermoacoustic-turbine-test https://longearthsociety.com/engineering/experiment?e=thermoacoustic-turbine-test Sun, 21 Jan 2024 00:00:00 +0000 Can a 3D-printed Wells turbine extract useful work from a 2" thermoacoustic resonator? Not as built. The printed material, the turbine design, and its size relative to the 2" resonator all appear to limit output. https://longearthsociety.com/engineering/experiment?e=syringe-air-injection https://longearthsociety.com/engineering/experiment?e=syringe-air-injection Sun, 24 Dec 2023 00:00:00 +0000 How do amplitude and speed change as air is injected into a sealed Stirling engine? Measurable change. Injecting air with a syringe shifts amplitude and speed as internal pressure rises. https://longearthsociety.com/engineering/experiment?e=custom-high-temp-stirling https://longearthsociety.com/engineering/experiment?e=custom-high-temp-stirling Sun, 25 Jun 2023 00:00:00 +0000 Can a desktop-toy-inspired Stirling engine be scaled into one that does real work? Design frozen at this revision. Built to run hot and generate electricity; sold made-to-order. https://longearthsociety.com/engineering/experiment?e=collapsing-one-way-valve https://longearthsociety.com/engineering/experiment?e=collapsing-one-way-valve Tue, 06 Jun 2023 00:00:00 +0000 Can a collapsing one-way valve (balloon, then duckbill) manage the engine's excess pressure? Both worked. The balloon valve was replaced by a duckbill valve, which was later replaced by the water check valve. https://longearthsociety.com/engineering/experiment?e=temp-rpm-measurements https://longearthsociety.com/engineering/experiment?e=temp-rpm-measurements Wed, 17 May 2023 00:00:00 +0000 What are the hot-end, cold-end and RPM figures for the engine at steady state? Hot end 215 °F, cold end 100 °F, 2,699 RPM. https://longearthsociety.com/engineering/experiment?e=sbc2023-custom-stirling https://longearthsociety.com/engineering/experiment?e=sbc2023-custom-stirling Fri, 05 May 2023 00:00:00 +0000 How does the custom engine stack up in the 2023 Stirling engine building contest? Winner of the contest. https://longearthsociety.com/engineering/experiment?e=aluminum-spool-eddy-currents https://longearthsociety.com/engineering/experiment?e=aluminum-spool-eddy-currents Sat, 22 Apr 2023 00:00:00 +0000 Does an aluminum spool work as the former for a moving-magnet linear alternator? No. Aluminum is conductive, so the moving magnet induces eddy currents in the spool that brake it; the magnet can't pass through. Use a non-conductive spool. https://longearthsociety.com/engineering/experiment?e=water-check-valve-engine https://longearthsociety.com/engineering/experiment?e=water-check-valve-engine Wed, 05 Apr 2023 00:00:00 +0000 If excess pressure is bled off through a water check valve, does the remaining 1 cubic inch of air oscillate faster? Yes. Venting the extra pressure through the water check valve lets the small air volume oscillate more quickly. https://longearthsociety.com/engineering/experiment?e=no-moving-parts-thermoacoustic https://longearthsociety.com/engineering/experiment?e=no-moving-parts-thermoacoustic Wed, 05 Apr 2023 00:00:00 +0000 Is a thermoacoustic design with no moving parts except a disposable diaphragm the most powerful practical Stirling-class engine? Success. A working demonstration of how thermoacoustics converts heat to oscillation with no moving parts beyond the diaphragm. https://longearthsociety.com/engineering/experiment?e=3-foot-stirling https://longearthsociety.com/engineering/experiment?e=3-foot-stirling Sat, 01 Apr 2023 00:00:00 +0000 Does the thermoacoustic design keep working when scaled up to a 3-foot resonator? Yes. The scaled-up engine runs. The channel's most-watched build, ~50k views. https://longearthsociety.com/engineering/experiment?e=solenoid-generator https://longearthsociety.com/engineering/experiment?e=solenoid-generator Thu, 02 Mar 2023 00:00:00 +0000 Can an ordinary solenoid be run in reverse as a generator? Yes. Moving a magnet through the solenoid's coil produces electricity; the actuator becomes an alternator. https://longearthsociety.com/engineering/experiment?e=piezo-diaphragm https://longearthsociety.com/engineering/experiment?e=piezo-diaphragm Sat, 25 Feb 2023 00:00:00 +0000 Can a home-made piezoelectric diaphragm act as the engine's diaphragm and generate electricity at the same time? No. It flexes and produces a signal when moved, but not meaningful electricity, and it doesn't work as a proper diaphragm. The flexible concept is interesting; it fails at both jobs. https://longearthsociety.com/engineering/experiment?e=laser-cut-flexure-bearing https://longearthsociety.com/engineering/experiment?e=laser-cut-flexure-bearing Thu, 23 Feb 2023 00:00:00 +0000 Can a laser-cut linear flexure bearing guide a free-piston Stirling's moving parts without contact? Yes. The flexure works as a linear bearing. https://longearthsociety.com/misc/experiment?e=hydrogen-rc-car https://longearthsociety.com/misc/experiment?e=hydrogen-rc-car Mon, 20 Feb 2023 00:00:00 +0000 Can a battery RC car be converted to run on hydrogen generated on board from aluminum and gallium? Yes, it runs. Aluminum (soda-can tabs) alloyed with gallium forms reactive aluminum that splits water into hydrogen and aluminum hydroxide; the reaction is exothermic.