Models

AC 840 (690C) JetProp Commander

Major changes were made to the Twin Commander with the introduction of the model 840 in 1979. The wings were increased 30 inches and canted winglets were added to increase total wing area. The 254K variant of the AiResearch gas turbine TPE331 engines were used that generated 717.5 shaft horsepower each with new Dowty full feathering and reversible propellers. Wet wings were added outboard of the nacelles increasing fuel capacity from 384 to 482 gallons. The increased fuel capacity of the wet wings and fuel efficiency of the new engines allowed the 840 to have a maximum range of 2,040 nautical miles. It was the first Twin Commander to break the 2,000 nautical mile range barrier. Aircraft dry weight decreased by 507 lbs. over the 690B.

Specification Performance Kit Finder
840
840

Specifications

Dimensions

Wing span52.12′15.89m
Wing Area279.37ft²25.95M²
Length42.98′13.10m
Height14.95′4.56m
Tread15.42′4.70m
Turning Radius43.88ft13.37m
Cabin Entry Door2. 21’ x 3.92’.67 x 1.19m
Cabin Height (Inside Interior)4.48′1.35m
Cabin Length14.25′4.34m
Cabin Width (Inside Interior)4.12′1.25m
Cabin Volume224 ft³6.34m³
Baggage compartment height3.25′1.07m
Baggage compartment width3.82′1.25m
Baggage compartment length6.57′2.15m
Baggage compartment volume70 ft³1.98 m³
Baggage door height2.60′.79m
Baggage door width2.08′.63m
Baggage compartment load limit600 lbs272 kg
840

Propellers

Dowty Rotol, 3 bladed, full feathering and reversible

Power Plant

Honeywell TPE-331-5-254K single-shaft turbo-prop with integral gearbox, two-stage centrifugal compressor, three-stage axial turbine and single annular combustion chamber.

Weights - Aircraft

Ramp Weight:10,375 lbs/4,706 kg
Take-off Weight:10,325 lbs/4,683 kg
Landing Weight:9,675 lbs/4,389 kg
Standard Empty Weight:6,702 lbs/3,040 kg
Useful Load:3,673 lbs/1,666 kg
Zero Fuel Weight:8,800 lbs/3,992 kg
Baggage:600 lbs/272 kg
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Performance

Operating Speed

Maximum Cruise
(100% 12,000 ft.TAS@ 10,325 lbs/4,683 kg)334mph/290kts
Normal Cruise Speed
(96%20,000 ft.TAS@ 10,325 lbs/4,683 kg):330mph/287kts
Twin Engine Best Rate of Climb Speed (CAS):155mph/135kts
Twin Engine Best Angle of Climb Speed (CAS):97mph/84kts
Single Engine Best Rate of Climb Speed (CAS):130mph/113kts
Single Engine Best Angle of Climb Speed (CAS):110mph/96kts
Minimum Control Speed (CAS):107mph/93kts
Stall Speed, Clean (CAS):89mph/77kts
Stall Speed, Gear and Flaps Down (CAS):86mph/75kts

Cruising Ranges

Long range cruise at 288mph/250.3kts/463.4kmh (TAS) average at 31,000 ft., 9,449 meters, (96% rpm) with 45 min. fuel reserve:
Standard Fuel: 2,047 SM/ 1,780 NM, 3,295 KM
Optional Fuel: 2,346 SM/ 2,040 NM, 3,776 KM

High speed cruise range at 320mph/278kts/515kmh (TAS) average at 25,000 ft., 7,620 meters (96% rpm) with 45 min. fuel reserve:
Standard Fuel: 1,985 SM/ 1,726 NM, 3,196 KM
Optional Fuel: 2,272 SM/ 1,976 NM, 3,660 KM

840
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