The Gas Turbine: When the Turbine Finally Beat Its Own Compressor

No combustion here. Print a small impulse air turbine — a 60 mm wheel with 20 cupped buckets — on the shaft of a hobby motor used as a generator, with a 330 Ω load and the multimeter across it. Blow it with the air compressor through the regulator and a nozzle made from a short piece of tube. Measure the electrical power out (V² ÷ R). Then measure the power the compressor draws from the wall while it runs — the clamp meter on the live conductor, times the mains voltage. The turbine returns a tiny fraction of what the compressor took. That is the gas turbine's problem without the fuel: compression is expensive, and only by adding heat between compressor and turbine does the turbine get back more than it cost.

**Ægidius Elling, Norway, 1903** — the first gas turbine to deliver net power — more than its own compressor consumed. No patent number is asserted here, and the details of his machine are left to the sources; the principle is the payload. Earlier attempts had failed exactly as the notebook predicts: the compressor ate all the turbine's output. The line runs through Büchi's turbocharger (the next rung) — a gas turbine driving a compressor, fed by an engine's exhaust — to the Whittle turbojet and the power-station gas turbine. **Honest limits.** Efficiency depends on turbine inlet temperature, which is limited by materials and cooling; small gas turbines are inefficient; and part-load efficiency falls away. **Do not build a combustion gas turbine**: the parts spin at speeds where a failure is a shrapnel event, and the combustor is a blowtorch.