Efficient Electric Short Take-Off & Landing (STOL): Electric Lift Augmenting Slats (ELAS)

An underdeveloped technology that can meet the DoD's needs is eSTOL (electric Short TakeOff and Landing). eSTOL aircraft use distributed electric propulsion to enable fixed-wing aircraft to get in and out of small takeoff and landing areas. ESTOL research is in its early days with no "best" configuration. The technology used here, ELAS (Electric Lift Augmenting Slats) has the potential to dominate eSTOL market. CubCrafters has been developing ELAS with three years of NASA Phase I and II STTR support. ELAS is now TRL6 and has shown promise for filling DoD mission needs. ELAS uses enhanced Upper Surface Blowing (USB) to achieve efficient, simple, reliable, and quiet eSTOL. USB reduces the takeoff and landing performance and can increase cruise speed, reducing mission time. USB  was explored in the 1970s with Boeing's YC-14, an entrant in the United States Air Force's Advanced Medium STOL Transport competition. It was further developed with NASA's QSRA. ELAS is the electrification of USB technology using many small distributed ducted fans to accelerate air over the wing's top surface, augmenting lift. 2023 full-scale flight tests by CubCrafters used COTS ducted fans to validate the ELAS concept. Results showed very short takeoff distances and greatly reduced stall speeds, as did the YC-14 and the QSRA. The research proposed here capitalizes on this eSTOL promise with application to DoD needs. During the NASA-funded research, CubCrafters developed a suite of analytical modeling tools for eSTOL, eVTOL, and conventional configurations that will allow predictions of lift augmentation, takeoff and landing distances, cruise performance, payload estimation, range, and other key performance indicators. These models were proven during the NASA Phase II flight tests. The scope for the proposed CubCrafters Phase I engagement is a 90-day sprint to validate ELAS's capability for Air Force missions. Concepts can be developed and evaluated for new missions and aircraft using these models. Thus, for each potential US Air Force customer, their mission needs will be used to drive the models and the results shared to determine the value of continued development of eSTOL and ELAS. CubCrafters is a $40M manufacturer of backcountry General Aviation aircraft with a 44-year history of manufacturing top-performing airplanes. It has successfully developed and commercialized 7 aircraft models, bringing standout performance to the backcountry aircraft segment. CubCrafters has over 200 employees at its Yakima, Washington facilities. These include Engineering, Composites, Metal Fabrication, Welding, Assembly, and Delivery Center. CubCrafters holds an FAA Production Certificate compliant with 14 CFR Part 21, has gained Type Certificates for 4 aircraft models, and owns over 60 STCs. CubCrafters has 22 years of providing aircraft systems for Government use. The research team has an extensive history in aerodynamics and project management and holds three ELAS patents.