IO-320-C

Lycoming · Figs 3-7 / 3-8 · Physics Model

IN ENVELOPE
Manifold Pressure 24.0in.Hg
17.0 min— WOT
Engine Speed 2300RPM
18002700
Pressure Altitude 6000ft
SL24 000 ft
Inlet Air Temp (OAT) +20°F
−60 °F+130 °F
Brake Horsepower (temp corrected)
—BHP
% Rated Power
—%
Max MAP (envelope)
—in.Hg
Full-Throttle MAP here
—in.Hg
Critical Altitude
—ft
FF · Best Power
—GPH
FF · Best Economy
—GPH
FF · Full Rich
—GPH
Std Temp Tₛ / ΔT
—°F
MAP inHg
24.0
RPM
2300
ALT ft
6000
OAT °F
+20

Reproduction of Lycoming Fig 3-8 (Sea Level & Altitude Performance). Red solid: rated power · Red dashed: limiting MAP for continuous operation · Blue: constant-MAP lines · Green: your operating point (A→F construction). Point marker turns red when outside the envelope.

RPM
ISA Offset

Full-envelope engine map in the 916is markdown format. 1,224 operating points across all RPM × MAP × altitude × ISA combinations, physics model anchored to the digitized manual charts.

Engine — Lycoming IO-320-C Series · FAA TC 1E12 · 160 BHP @ 2700 RPM · 319.8 cu.in · 5.125″ × 3.875″ · CR 8.5:1 · 1-3-2-4 · 25° BTC · 1:1 drive · 100/130 min · Bendix RSA-5AD1

Model — Sea-level BHP = k·RPM·(MAP−MAP₀), k = 0.002808, MAP₀ = 7.75 in.Hg (LSQ fit, Fig 3-8) · Altitude: Gagg-Farrar 1.132σ−0.132 · Induction loss 0.127+0.532(N/2700)² in.Hg · Temp: √[(460+Tₛ)/(460+T)] · BSFC BP/BE/FR = 0.500/0.420/0.550 lb/BHP·hr (Fig 3-7) · Full-rich rated cap 15.2 GPH

Envelope — Below 2400 RPM: limiting MAP for continuous operation (red dashed line) · 2400+ RPM: rated power line · Both fitted from chart data, agreement ≤0.2 in.Hg

⚠ Planning aid only. Verify against the published Operators Manual charts. Not a substitute for the POH or engine instrumentation.