Description:
OBJECTIVE: Develop and demonstrate advanced high speed seals for helicopter drive system application. The objective is to develop low cost, low friction, high speed seals as an alternative to existing seal technology. DESCRIPTION: There is currently a need in the Army for advanced seals in helicopter gearboxes. These seals are used to keep fluids from escaping the gearbox. The helicopter industry has typically used carbon face seals for high speed (surface speed) applications. These carbon face seals require cooling and a lubricant supply. They also have a low tolerance for misalignment and a low tolerance to debris on the sealing surface (i.e. grit on the face). Large diameter magnetic face seals are also used in the industry, and have problems with being very temperamental and causing significant leaks. Elastomeric lip seals are also used, but are limited in high speed applications, create sleeve wear, and generate heat. Experience has shown that seal failure is one of the leading drivers for gearbox removals. These failures impact not only costs, but also availability of aircraft. In order to reduce the occurrence of seal failures and improve aircraft reliability, an improved seal is needed. This topic seeks an innovative solution or a new approach in design in order to improve gearbox seals beyond the state of the art. The technology should be designed to be affordable, scalable and capable of application across multiple Army helicopter platforms. Minimal impact on the existing gearbox hardware is desired. The development, demonstration, and validation of a gearbox seal is required for this topic. The specific seal locations targeted for this topic are the: main gearbox shaft seals, nose gearbox shaft seals, intermediate gearbox shaft seals, and tail gearbox shaft seals. The proposed improved seal does not have to be developed for implementation in all locations, but the proposal must state the specific location targeted for development. Due to high shaft speeds, the proposed seal should be capable of speeds between 5,000 to 13,000 RPMS. Shaft diameters vary, and the seal design should be scalable between 2 to 5 inches. Due to the high temperature environment, the proposed seal design should be capable of temperatures up to 500 degrees Fahrenheit. Performance parameters can be established through models and/or experiments that would lead to the construction and demonstration of a seal to validate these parameters. PHASE I: During Phase I, the contractor shall design an improved gearbox seal for the proposed location. Specific metrics of this design are that it must be capable of speeds between 5,000 to 13,000 RPMS, be scalable between 2 to 5 inches, and be capable of withstanding temperatures of 500 degrees Fahrenheit. At the end of Phase I, the contractor shall demonstrate the feasibility of the proposed concept. This feasibility demonstration can be done through the use of modeling and simulation, or a prototype test. Experimental data (from testing) of materials and/or components should be provided to demonstrate that the proposed concept meets the metrics. PHASE II: The contractor shall further develop the prototype seal based on the Phase I effort for implementation on a relevant hardware platform. Offerors are encouraged to work with an Army helicopter OEM to tailor their design towards a specific application, and improve the chance for transition. The capabilities of the advanced seal will be validated by conducting additional bench or rig testing. This testing may be on a rig of the offerors choosing, but access to a Government test rig will not be provided. PHASE III: This technology could be integrated in a broad range of military/civilian aircraft where high speed seals are used. The potential exists to integrate and transition this system into existing and future Army gearboxes, such as those for the Apache, Chinook, Black Hawk, and Kiowa Warrior. This technology should also be applicable to ground platform PTOs and pumps.
