The illustration of the control bar section (Fig. 1) summarizes the significant differences in effective drag area (= performance) and geometry between the older AT style airfoil downtubes and the new Slipstream and Litestream sections. The performance comparison graph (Fig. 2) shows the relative L/D performance of the three types of control bars (mounted on a Talon) at various speeds (in mph).
Wills Wing was the first to introduce an economical aluminum performance downtube, the Slipstream downtube, and to integrate an interchangeable streamline aluminum speedbar option with the pilot’s choice of either the carbon or aluminum Slipstream downtubes. The Slipstream aluminum downtubes, and the aluminum streamlined basetube, each retain a very high percentage of the performance advantage provided by the more exotic carbon tubes, while offering improved durability and substantially lower cost.
Slipstream 2 – In April 2005 we began using the Slipstream 2 control bar, starting with the new T2 hang glider. The only difference between the Slipstream 2 and the original is that with the Slipstream 2 the VG cord runs down the front of the tube instead of the back of the tube. With this change, swapping between Slipstream 2 and LiteStream Control Legs no longer requires moving the VG pulley on the keel near the Control Bar Apex. On the left side, Slipstream 2 and Slipstream downtubes are interchangeable. On the right side, where the VG cord is routed, Slipstream and Slipstream 2 downtubes are not interchangeable.
The illustration of the control bar section summarizes the significant differences in effective drag area (= performance) and geometry between the older AT style airfoil downtubes and the new Slipstream and Litestream sections. (Click on the image)
The performance comparison graph shows the relative L/D performance of the three types of control bars (mounted on a Talon) at various speeds (in mph). (Click on the image)
For 2003, Wills Wing released the Litestream control bar for performance oriented recreational pilots. The Litestream control bar combines the same low drag aluminum streamlined basetube used on the Slipstream control bar with a slightly shorter chord, lighter weight, easier to hold Litestream aluminum downtube.
The Litestream bar is standard equipment on our U2 High Performance glider and our Sport 2 glider, and optional on the T2. The Litestream control bar can also be purchased as an add-on accessory for the Falcon 3 145, 170 and 195 models. The best control bar for high performance recreational flying, the Litestream bar comes very close to matching the performance of the Slipstream bar, while saving 1.5 lbs in weight. The smaller profile makes ground handling and launching significantly easier, especially for pilots with smaller hands. (For comparison purposes, the performance given up by dropping down from a Slipstream to a Litestream control bar is approximately equal to the performance that would be gained back by removing the coating from the bottom side wires. By comparison, moving up from an AT style streamlined control bar with round basetube to a Litestream control bar does away with over 90% of the drag of the control bar, adding approximately one full point in L/D to the glider’s performance.)
The new carbon speedbar will fit all gliders fitted with Slipstream or Slipstream 2 control bars (Talons, T2’s). A Litestream compatible version is available for all gliders that have Litestream Control Bars. Features of the new carbon speedbar include a re-designed shape, with a deep offset planform. The grip positions are optimized for comfort, control and aerodynamics in all phases of flight. Specially designed flares in the grip area allow for effortless maintenance of optimum bank angle when thermalling.
Structural features include an extra thick laminate constructed from aerospace-grade carbon and Kevlar pre-preg, cured at 230 degrees Fahrenheit and 105 psi pressure. A stainless steel internal safety cable and corner fittings machined from solid blocks of wrought aluminum (Wills Wing has never used the far less reliable cast fittings) insure the structural reliability of the basetube.
The Wills Wing Tandem Control Bar is purpose built for, and standard equipment on the Wills Wing Falcon Tandem glider.With downtubes made from stout 1.25″ diameter by 0.095″ wall tubing , and featuring specially designed, strong and durable machined aluminum corner fittings, the super-sized Tandem bar provides the ideal complement to the Falcon Tandem glider.
AT Streamlined Downtubes With Folding Basetube (No Longer Used on Production Models)
The Wills Wing AT streamlined downtubes offer enhanced performance over conventional round downtubes in an economical streamlined profile. The folding speedbar basetube option shown speeds set-up and breakdown by eliminating the installation or removal of any nuts or safeties during the process. A more economical, non-folding speedbar is also available.
Conventional round downtubes and straight basetube offer the most economical control bar option for entry level and medium performance recreational flight.The round downtubes can be combined with either the conventional speedbar basetube (standard on the Eagle, for example), or with the optional folding speedbar basetube.
Wills Wing released the first commercially available ultra high performance control bar system in mid 1999. The Wills Wing “World Team Carbon Control Bar,” with 3.2″ chord / .77″ thickness profile carbon downtubes, featured the first high-pressure, high-temp, pre-preg composite airfoil tubes available for hang gliders. These carbon control bars added over a full point in L/D to competition class gliders and demonstrated such a compelling performance advantage that they were purchased by Moyes and Icaro for their top competition pilots.
The blended aerodynamic corner fittings, machined from a solid block of aluminum, were the first application of 3D CNC machining for hardware produced for hang glider applications. Although CNC machined fittings from wrought aluminum are expensive to produce, they are both stronger and more durable than comparable castings.