Payload-Range

A payload-range analysis is done to provide an indication of the usefulness of the helicopter as a load-carrying vehicle. Figure 4.45 shows the payload-range curve for the example helicopter at two takeoff gross weights. The conditions are listed on the Figure and are typical for studies of this type. The curves are based on the evaluation of two fundamental equations:

f g. w.t. o.

Range = (S. R.yG. W., N. M.

*’G. W.ldng.

where G. W.lndg = G. W.T0 — (Expended fuel + WUTO fuel) lb

and Payload = (G. W.T0 — G. W.min0P.) — (Expended fuel + WUTO fuel + Reserves + Aux. fuel tank wt.) lb

(WUTO stands for warmup and takeoff.)

The Figure shows that as a transport aircraft the example helicopter, taking off at 20,000 pounds, can carry its design payload of 6,600 pounds—consisting of 30 passengers with baggage averaging 220 pounds apiece—for 330 nautical miles at

sea level with adequate reserves. Offloading payload and replacing with fuel in auxiliary tanks can extend the range significantly.