Description:
OBJECTIVE: Demonstrate an advanced forced induction system for UAS/UGS applications in the 50 to 150 HP range. DESCRIPTION: The benefits of greater power and efficiency are offered by using turbochargers and superchargers for small UAS propulsion systems which including rotary, piston, and other developing engines. Present day UASs suffer performance losses upon takeoff and at altitude. Therefore, the need for improved, light weight turbo and superchargers which eliminate the use of oil lubrication for the bearing system is needed. Furthermore, current UAS systems are experiencing durability issues with turbochargers due to oil coking. Light weight forced induction systems with improved bearing and lubrication circuits are sought for the 50 to 150 HP UAS class. The bearing systems in turbochargers and superchargers are normally oil-fed from the engine oiling system. The bearings in these systems run in an extremely harsh environment and are subjected to axial, radial and thermal loads that limit the life of the turbocharger system and can cause failures during important mission sorties. The elimination of the pressurized oil bearing system would greatly enhance reliability and durability and decreases losses of aircraft that are employing turbochargers and superchargers. There are a number of engines that could use turbocharger technology but some do not have pressurized oiling systems. Even systems that have pressurized oiling systems suffer from pumping losses due to the oiling system having to supply oil to the turbocharger and supercharger. Additionally, when operating at high angles of attack, the pressurized oil systems may not provide adequate lubrication for the bearing systems. Having a system that optimizes the ability to place the turbocharger or supercharger in airframe positions that are not possible with a pressurized oiling system is a must. Lastly, the forced induction system should be light weight and reliable. The weight should less than 5% of the overall engine system. PHASE I: Develop a design concept for turbo/supercharger systems that are light weight, durable, and self-lubricated including bearing and material selection. The design should consider forced induction loading, thermal loads, and operating speeds. Reliability and durability performance parameters should be part of the analysis and potential bench top testing of candidate systems should be performed in Phase I. PHASE II: This phase builds off the progress made in Phase I to incorporate the bearing system in an advanced turbo/supercharger and demonstrate it in an operational UAS propulsion system. This will include analytical modeling, the appropriate bench testing for system integration, and an engine demonstration. PHASE III DUAL USE APPLICATIONS: Military Application: Advanced turbocharger/supercharger technologies are directly applicable to the Army, Air Force, and Navy. This advanced technology allows for an increase in power for small engine classes, leading to more mission capability. It also allows turbochargers to be incorporated into current systems without pressurized oil systems that previously would not be able to increase power through a conventional turbocharger system. Commercial Application: The advanced turbocharger/supercharger technology is applicable to commercial applications. Lightweight turbochargers can be incorporated into small engines to increase power without significantly effecting engine size and weight. Further, the elimination of the pressurized oil bearing system on turbochargers would allow for enhanced reliability and durability on commercial engines.
