Gravity Engines and the Diving Engine

By Steve Baer. The CoEvolution Quarterly, Summer 1974, pp. 80–86 (Box 428, Sausalito, California 94965). Bio note in the original: “Baer, 35, is the head of Zomeworks in Albuquerque, NM, where you may buy skylids, solar collector plans, bead-walls, zome dwellings, zome toys, The Zome Primer, and stock in the company.”

What is a gravity engine

Baer defines a gravity engine as one that relies on gravity to function — not a perpetual-motion device, any more than a flywheel or spring-driven engine is. “Gravity engines don’t run off gravity, they need it to function.” Hydroelectric plants and waterwheels are gravity engines; wind is “part of the most enormous gravity engine.” Gravity engines require a specific orientation of their parts and use gravity as a spring that “doesn’t wear out… is an energy bank that can’t be robbed.” Baer states a preference for engines that are simple, easy to repair, and non-dangerous over complex/dangerous ones (nuclear power named explicitly), and proposes that some gravity engines — stationary, slow, silent — could be broadly useful even if commercially unfashionable.

The patent office (Crystal City, VA, spring 1973)

A firsthand account of researching prior art: examiners as “friendly,” a numbing “day and a half” of searching, discovery of two 1972–73 patents with whole drawers of un-searched prior art in section 60-22 (missed by the examiners), and a discussion of the diving engine’s own patent status (“I may… file a patent… within a year of public disclosure”). Baer’s assessment: US patent law is good on disclosure timing but “almost never worth the money” once filed, and enforcement requires expensive court defense.

Iske engine (US Patent 256,482, A. & A. Iske, granted April 18, 1882)

A wheel of paired chambers connected by tubes across its diameter; each chamber is heated at the bottom of a revolution, vapor pressure drives liquid to the paired chamber at the top, and the resulting weight shift turns the wheel — “like a water wheel which supplies itself with its own water.” Requires purging of foreign gas from the sealed system. Baer notes the design “has been invented and reinvented for years” — the most recent patent he found for the same idea was US 3,659,416 (1972). He suggests such an engine, solar-powered, could run public clocks. Judged fundamentally inefficient: the containers must be fully heated/cooled every cycle just to lift a small amount of liquid, and there’s no way around the requirement without abandoning the same-container-as-boiler-and-condenser design.

Dipping bird comparison: Baer identifies the dipping-bird toy as a related but more efficient gravity engine, because — unlike the Iske engine — the boiler stays the boiler and the condenser stays the condenser, avoiding the energy wasted heating/cooling the same vessel every cycle. Open problems he lists: purging foreign gas, sealing containers, building pressure-tolerant containers, wasted boiler gas on dumping, and pipe friction.

Bubble-wheel steam engines (O.C. Spofford patent; George O. Schur patent, “steam engine”)

Two more historical patent designs (illustrated, Figures 3–4) sharing the Iske engine’s core flaw: the top condenser keeps receiving heat that never powered the wheel, and pressure increasing with depth makes bottom-of-container boiling harder than top-of-container boiling.

Two-liquid bubble wheel (Baer’s own sketch, “Figure 5”): uses two immiscible liquids (e.g., hexane and water) — the higher-boiling-point liquid as the bath, the lower-boiling-point one as the propellant. Boiling at useless points in the bath is prevented and the machine’s rate is externally valve-controlled. A lighter propellant (like hexane on water) self-corrects by floating to the bath’s surface rather than stalling at the cold bottom.

Eduction pump variant (“Figure 6”): the same evaporation/condensation principle reconfigured as a forced-circulation pump rather than a rotating wheel — Baer notes this “could be useful in solar heating systems that require forced circulation.”

Baer’s diagnosis of what’s fundamentally wrong with bubble-wheel gravity engines: they must turn through resistive baths; sealing/coupling through the container wall while avoiding leaks and explosion risk (overheated sealed hexane, e.g.) is hard; and the wheel must turn slowly to keep friction low, which caps power delivery.

The diving engine (Baer’s own design)

A regenerator-based engine using two “divers” (weighted floats/pistons) connected to a flywheel by cables, submerged in hot and cold liquid baths respectively. As the flywheel turns, the hot piston/diver and cold piston/diver cycle through four phases (illustrated step-by-step, “air passing to hot” → “air rising in hot” → “air passing to cold” → “air compressing in cold”): air trapped between the two divers passes back and forth through a regenerator (a thermal-storage element in the connecting tube) and a flexible tube, being heated/cooled and humidified/dried on each pass. The volume/buoyancy difference between the warmer, larger air bubble on the hot side and the cooler, smaller one on the cold side is the source of usable work.

Relation to known engine types: Baer compares it explicitly to the Stirling engine — both pass gas between hot and cold pistons through a regenerator — but distinguishes his design because the gas moves at roughly constant pressure (the surrounding liquid doesn’t confine it with force beyond gravity) rather than the Stirling’s constant volume (gas caged between two pistons). He also notes the presence of evaporating/condensing liquid+vapor (not just gas) exaggerates the hot/cold bubble’s volume swing, and cites the lesser-known Ericsson engine (constant-pressure regenerator cycle) as the closer analogy.

Feasibility calculation (Carnot-bound)

Assuming 2000 Btu/ft² captured daily from a solar collector and a realistic 15% max theoretical conversion (Carnot: E_max = (T_source − T_sink)/T_source, evaluated at winter 45°F/135°F and summer 70°F/165°F tank-temperature pairs), Baer works through the mechanical-power target (300 Btu/day = ~240,000 ft·lbs/day ≈ 2.75 ft·lbs/sec per ft² of engine) and the resulting bubble geometry needed (~7⅝” of bubble depth-times-velocity product per square foot, achievable at multiple depth/speed combinations, e.g. a 30”-deep bubble moving at ¼ ft/sec). His conclusion: the required power density is “compatible with the possible density of production of mechanical power… using water and air and slow moving… containers” — i.e., no fundamental thermodynamic obstacle, though drag (through the liquid bath, through the regenerator tube, and mechanical-coupling friction) roughly doubles the practical requirement above the idealized calculation.

Built prototype (photographed)

A caption-described photograph shows a “counter-weighted diving engine”: hot tanks (wrapped in insulation) on the right, cold tanks on the left, flywheel made of four 25 lb weights plus 20-30 lbs of 1” washers, 1-gallon diving pistons suspended on 1/16” cable over pulleys. Measured operating conditions: hot bath 120°F, cold bath 60°F, running at 4-6 rpm with a 2-foot piston stroke; hot and cold divers offset ~60° in phase, front/back piston pairs 180° out of phase; no regenerator used in this first model. Result: “very little energy left over after overcoming its own friction, but it did run on the very first attempt, thus demonstrating that there are at least no thermodynamic contradictions in the theory of the diving engine.” Described as “almost completely silent.”

Closing framing

Baer closes with a broader argument for engines usable “if the world were desolate of equipment” — starting from waterwheels and windmills rather than nuclear reactors or internal combustion — and two short parable-style passages (in the “solar fiction” register also used in Sunspots) about a god unable to reach humans too busy building things, and about humans/creatures indistinguishable from “things” once their origin is forgotten.

Page scans

Seven consecutive page images (pp. 80–86), colocated with this record:

p. 80 — photo, “Baer with his demonstrator of the principle of the diving engine”
p. 81 — article opening, “Gravity Engines and the Diving Engine,” gravity-engine framing + patent office account begins
p. 82 — patent office account continues; Iske engine (Fig. 1), bubble wheel sketch (Fig. 2)
p. 83 — Spofford/Schur bubble-wheel patents (Figs. 3–4), two-liquid bubble wheel (Fig. 5), eduction pump (Fig. 6)
p. 84 — diving-engine 4-phase cycle diagrams (regenerator, flexible tube, hot/cold divers)
p. 85 — regenerator mechanics, Stirling/Ericsson comparison, Carnot feasibility calculation begins
p. 86 — feasibility calculation concludes; closing argument; photo of the built counterweighted diving engine prototype