SSA 2012—News from Jonker Sailplanes

Uys Jonker, co-founder of Jonker Sailplanes, makers of the 18 meter JS-1 Revelation, gave a well-attended talk at the 2012 SSA convention in Reno on how refinements in glider aerodynamic design can add up to significant gains in performance over the current generation of 18 meter sailplanes. Unfortunately, we are not able to publish the presentation at this time, but we hope to do so later this year. In the meantime, we include a summary of Uys’ presentation from the convention program and we offer this Soaring Café video interview with Uys. Thanks to Kempton Izuno for making the video.

Uys and his brother Attie placed 2nd and 5th, respectively, in the 2010 World Gliding Championships 18 meter championship in Szeged, Hungary. They were both flying JS-1bs. Four JS-1s finished in the top ten.

Pilots in the United States may contact Leo Benetti-Longhini via the JS contacts page for more information on pricing and delivery for the JS-1b Revelation.

Refinement of Glider Aerodynamic Design – a Glimpse into the Future     Johan Bosman/Uys Jonker

It can be difficult to imagine how today’s high performance sailplanes can be refined much further, but the historical trend predicts otherwise. So, what improvements remain for the efficient aerodynamic marvels we compete with? In their SSA 2012 presentation, Johan Bosman and Uys Jonker present some practical examples, case studies and validations, providing a glimpse into the future of glider performance enhancements. The talk includes a brief introduction in pilot’s terms about numerical methods followed by a discussion of computational fluid dynamics (CFD) and the ability of the latest computational tools to allow flow to be analyzed accurately in locations where it was previously not possible or impractical. The demanding computer hardware and software requirements are commented on.

The heart of the presentation revolve around several case studies and comparisons performed using the newest type of laminar-to-turbulent CFD transition modeling. These are followed by a discussion of validation tests to show that the computer generated studies can indeed be trusted. We can expect to see flow visualizations and hear about wing tip wheels versus wing tip skids, rudders with and without: control cable fairings, forebody laminar flow of gliders with nose-mounted tow hooks versus gliders with sharp noses, cockpit flow extraction, retractable tailwheels versus fixed tailwheels, mid-wing compared to high-wing configurations, fuselage aft-body shape contractions and possibly some other aerodynamic devices currently in patent preparation. The significance of apparently minor improvements over a record flight or series of contest flights are also revealed. The talk will quantify how even small improvements combined together rapidly become something measurable and meainingful to the competitive pilot.

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