Investigating the Autorotational Performance of Scaled Samara Rotor in Vertical and Forward Flight

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Samara seeds are nature’s most efficient fliers, they can create twice the lift compared to translating wings by the creation of the Leading edge vortex (LEV). Realising this, numerous Samara inspired UAVs are being created. However, a number of research questions still need to be answered to be able to harness the benefit of the LEV for UAV applications. In particular, if scaling up the natural Samara degrades its aerodynamics performance and how well the scaled Samara wings perform in autorotation in both the forward and vertical flight regimes. This paper explores the effects of scaling by a series of drop tests and wind tunnel tests. It was found that the vertical aerodynamic performance of the Samara wing starts degrading as its scale reaches a ratio of 8:1 size to the natural Samara seed. In terms of forward flight, the natural Samara found it hard to cope with any slight deviations from vertical descent whereas the artificial scaled Samara were able to autorotate up to 80 degrees shaft angle relative to the wind direction. The effect of scaling in forward flight was also explored; a 1:1 to 4:1 scaling boosted the thrust by around seven folds whereas a 4:1 to 8:1 scaling increased the thrust by only around four times.
Original languageEnglish
Title of host publication42nd European Rotorcraft Forum 2016
Subtitle of host publicationProceedings of a conference held 5-8 September 2016, Lille, France
PublisherAssociation Aeronautique et Astronautique de France
ChapterAerodynamics 9
Number of pages15
ISBN (Print)9781510839144
Publication statusPublished - Jul 2017
Event42nd European Rotorcraft Forum 2016 - Lille, France
Duration: 5 Sep 20168 Sep 2016


Conference42nd European Rotorcraft Forum 2016


  • Samara
  • Autorotation
  • leading edge vortex
  • Samara seed
  • maple seed
  • leading edge vortex (LEV)
  • small rotor,
  • autorotation

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