Adjustable Center of Gravity for Rotorcraft

Pochari Technologies has invented a sliding center of gravity system for rotorcraft to eliminate limitations faced by “weight and balance” requirement in conventional rotorcraft. The turboshaft and main reduction gearbox are fixed to the fuselage, a proprietary shaft extension mechanism allows the 90′ bevel gearbox section and main rotor shaft to slide the desired length in the longitudinal direction of the fuselage depending on the CG range required. This innovation allows for greatly enhanced mission flexibility as a result of the wider CG range allowable and is especially complimentary to our VED technology. When a load is picked up in the VED capsule, it’s ideal to have the CG directly over the center of the capsule. Once the capsule is retracted, the load can be transferred to the fixed fuselage section on either side of the capsule, as this occurs, the CG is slowly shifted to either side until perfectly balanced. The implications beyond complimenting VED technology of RCG are enormous. As fuel is burned during flight, the CG changes, with this system, the fuel tanks can be placed in the rear of the aircraft rather than underneath the bottom of the fuselage as centering the fuel mass is no longer necessary. Attack helicopters can store munitions outside of the CG center range without concern of shifting CG as the ammunition is consumed. Utility helicopters, cargo or passenger carrying aircraft can carry the load outside the CG range by simply shifting the CG position. Loads of varying density can be carried in the aircraft with less constraint. Personnel, with relatively low density, can be placed in the forward half section of the CG range, then a load with higher density (a cargo pallet) can be placed in the rear half section of the CG range. The CG sliding range is designed to be between 20 and 24″ for an 8,000 lb GW aircraft. A rail the length of the desired CG range constructed out of carbon fiber is lined with a metallic liner. On this metallic liner, a high friction rubber liner is also placed. A mechanism connecting the drivetrain module and the rail allows for sliding and locking of the location. Multiple small roller retracts from the rail slide mechanism, once the rollers retract, a friction pad is extended, providing a tight connection between the friction pad in the rail mechanism and the high friction liner on the rail. The system has gone through feasibility analysis and found to add negligible additional weight and well worth any additional technical hurdles considering the immense performance gains.

“Helicopters are loaded, unloaded and reloaded with different cargoes. The center of gravity of a loaded fuselage changes in location from load to load depending upon the load position in the cabin. This often requires readjustment of load position or careful initial distribution of load components in order to end up with the position of the center of gravity within a limited field. When the center of gravity is thus positioned within the limited field, the aircraft may then be maneuvered within the limits dictated by its design with out difficulty. When a given ship is certified by the governmental authorities, the CG field, size and location are certified and specified. The ship, once certified, cannot legally be operated with loads such that the CG is outside the certified field”

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