NASA GL-10 Greased Lightning
{{Short description|American unmanned aircraft}}
| {{Infobox aircraft begin
| name=GL-10 Greased Lightning | image=Gl10 test013 8-19-14.jpg | caption=GL-10 Greased Lightning 50% Scale Prototype }}{{Infobox aircraft type | type=Hybrid UAV | national origin=United States | manufacturer= | designer= | first flight=19 August 2014 (tethered) | introduced=2014 | retired= | status=In development | primary user= | more users= | produced= | number built=1 | program cost= | unit cost= | developed from= | variants with their own articles= }} |
The GL-10 Greased Lightning is a hybrid diesel-electric tiltwing unmanned aircraft.
Development
The wing has eight electric motor-driven propellers, while the horizontal stabilizer has two. In the future full-scale version, power will be generated by two 6 kW (8 hp) diesel engines which will charge lithium-ion batteries. The propellers on the leading edge of the wing provide high speed flow, and thus lift, on the wing even in low forward velocity flight allowing pitch, roll, and yaw control authority during the critical transition phase from hover to forward flight.
The VTOL capability of this new class of UAV eliminates the requirement for additional ground support equipment like launch catapults and landing catch mechanisms. In addition, the propellers are designed for a relatively low tip speed resulting in a marked reduction in noise.{{cite web|title=NASA's Greased Lightning Tests Vertical Takeoff But is it systematic, hydromatic, ultramatic|date=19 August 2014 |url=http://www.popsci.com/article/technology/nasas-greased-lightning-tests-vertical-takeoff|accessdate=25 August 2014}}{{cite web|url=http://www.avweb.com/avwebflash/news/NASA-Flies-Hybrid-Electric-VTOL222636-1.html|accessdate=25 August 2014|title=NASA Flies Hybrid Electric VTOL|date=23 August 2014 }}{{cite web|url=http://www.nasa.gov/aero/testing-electric-propulsion.html|accessdate=25 August 2014|title=Testing Electric Propulsion}} The aircraft is designed to complete several vertical take-off and landings during its mission with a loiter endurance of 24 hours in the forward flight mode.Fredericks, W. J., Moore, M. D., & Busan, R. C. (2013). Benefits of Hybrid-Electric Propulsion to Achieve 4x Increase in Cruise Efficiency for a VTOL Aircraft.Rothhaar, P. M., Murphy, P. C., Bacon B. J., Gregory, I. M., Grauer, J. A., Busan, R. C., & Croom, M. A. (2014, June). NASA Langley Distributed Propulsion VTOL Tilt-Wing Aircraft Testing, Modeling, Simulation, Control, and Flight Test Development. In 14th AIAA Aviation Technology, Integration, and Operations Conference, Atlanta, GA.Busan, R. C., Rothhaar, P. M., Croom, M. A., Murphy, P. C., Grafton, S. B., & O-Neal, A. W. Enabling Advanced Wind-Tunnel Research Methods Using the NASA Langley 12-Foot Low Speed Tunnel. The GL-10 performed transitions between vertical and horizontal flight in 2015.{{cite news |first=Kathy |last=Barnstorff |url=http://www.verticalmag.com/news/article/NASAsGreasedLightningUAVcompletessuccessfulflighttest |title= NASA's Greased Lightning UAV completes successful flight test |work=Vertical Magazine |date=4 May 2015 |accessdate=5 May 2015 }}
The Greased Lightning was followed by the Langley Aerodrome No. 8 (LA-8), a tandem-wing, deflected-slipstream (demonstrated in the late 1950s by the Ryan VZ-3 Vertiplane) design with four propellers on each wing for urban air mobility, tested in a Low-Speed Wind Tunnel before flight tests in late August 2019.{{cite news |url= https://aviationweek.com/future-aerospace/week-technology-may-6-10-2019 |title= The Week In Technology, May 6-10, 2019 |date= May 6, 2019 |author= Graham Warwick |work= Aviation Week & Space Technology}}
Full scale specifications (GL-10)
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See also
{{commons category|NASA GL-10}}