What reaction-torque-to-thrust ratio do real small propellers have, and does the best rotor cant angle survive it?
research/codesign-aero-cant-propdata
What is the reaction-torque-to-thrust ratio of real small propellers, and does the best cant angle survive it? Measured static data for 77 propellers of 3.15–9.85 in give c = CP/(2π·CT) = 0.065–0.13 (median 0.081); in simulation cant still beats no cant in 5 of 5 seeds at every c, by 2.9–4.7°, and the joint design picks 36–41°.
What it found
Closes the open limitation of codesign-aero-cant-kappa, where κ = Q/T = c D used a swept c. Here c = CP/(2π CT) is computed from the UIUC Propeller Data Site static tests (160 propellers; 77 of 3.15–9.85 in): median 0.081, 10th–90th percentile 0.065–0.13, maximum 0.193, no diameter trend (r = −0.11); the parent's upper sweep value 0.25 is above every propeller. Joint CMA-ES over arm length, propeller size, cant and six PID gains (1920 evaluations, 5 seeds, 64 held-out episodes), bound 0, 35° or 80°, at those four c values. At 80° the held-out error is 12.50°, 12.46°, 12.22°, 12.00° against 17.22°, 17.06°, 16.12°, 14.91° with no cant: better in 5 of 5 paired seeds each, by 4.7°, 4.6°, 3.9°, 2.9°; chosen cant 36–41°. Limits: static coefficients only (hover), c is a median over test RPMs, cost, mass and plant ranges are inherited assumed fits, attitude steps only, no hardware.
A figure from its own output
Paper, code and results
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Produced with AI assistance (Claude). Results are from the code in this repository and are simulated or stylised unless the abstract says otherwise; nothing here implies affiliation with or endorsement by any lab, researcher or company cited. MIT licensed.