SAG CALCULATOR

Wire sag and helicopter load for wire pulls

PULL METHOD

PULL LAYOUT

Wire / Rope Wire Weight (lb/ft) Hardline weights are averages for 6×19 / 6×26 IWRC steel rope. Check your rope's spec and edit if needed. Span Length (ft) Weight on Hook (lbs)

Helicopter

Support heights (optional)

Structure A (ft) Structure B (ft)

Measure both from the same reference: height above ground on flat terrain, or elevation on a hillside. Leave closed or blank for a level pull.

SAG

— ft

Enter weight, span and tension

Sag = (W × L²) ÷ (8 × T) · T = horizontal tension

Wire in span is the wire hanging between attachments only. Add wire for tie-offs, dead-ends, sagging and reserve on the reel.

Estimate only. Uses the parabolic sag approximation with wire weight spread along the slope, the same horizontal tension in every span (frictionless blocks), a straight long line, and no wind, ice, rotor wash or aircraft motion. Accuracy drops on very steep or very deep spans. Load limits must come from the aircraft flight manual supplement for the equipment installed. Use with your own judgment, the equipment manufacturer's limits and the job's stringing plan. The pilot in command is responsible for the safety of the operation.

Provided free by Rubicon Aerospace