| Abstract | Turboprop, turbo jet and various intermediate powerplants are compared on the basis of the total weight of engine plus fuel required for the following mission for a VTOL aircraft:
Aircraft all-up weight: 25,000 lbs.
Installed lifting capacity: 37,500 lb.
Hovering time (total): 10 mins.
Range: 500 miles
Cruising Conditions: a)200 m.p.h. at sea level b)4OO m.p.h. at 20,000 ft. c)6OO m.p.h. at 36,000 ft.
Cruising L/D (all): 10
Under all three cruising conditions, turboprop engines produce the lowest weight of engine plus fuel, although the difference is only marginal at the highest speed condition. Powerplants involving propellers for lifting and jet propulsion for cruising produce lower total weights than pure jet propulsion schemes. |
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