One public endpoint, no auth, CORS-open, cached at the edge. It runs the same blade-element momentum solver as the app (measured against UIUC wind-tunnel data for three reference props; see /methods), over the app's default planform scaled to your diameter.
https://propshaper.com/api/prop-math?diameter_in=5.1&pitch_in=3.6&blades=3&rpm=25000&fluid=air
| param | meaning | range / default |
|---|---|---|
diameter_in | prop diameter, inches | 1–40, required |
pitch_in | geometric pitch, inches | 0.5–40, required |
blades | blade count | 2–6, default 3 |
rpm | shaft speed | 100–60000; default 25000 air / 4000 water |
fluid | air or water | default air |
v_ms | advance speed, m/s | 0–80, default 0 (static) |
geometry: diameter/pitch (mm), P/D, disk area, solidity, helix
angle at 0.75R, activity factor, tip speed, tip Mach (air) or cavitation
number at 0.7R (water), Reynolds at 0.75R.
performance: advance ratio J, thrust (N and gf), power,
torque, CT, CP, efficiency (when J>0), and a convergence flag.
design_link: a deep link that opens the studio with this
prop prebuilt.
https://propshaper.com/?d=5.1&p=3.6&b=3&rot=CCW&fluid=air
Opens the designer with a basic prop already built. All optional except
d and p; values clamped to sane ranges.
More for machines: /llms.txt. Methods and validation: /methods.