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In the Finnish culture, the term Sisu refers to internal fortitude, or courage. You’ll no doubt be pleased to meet a courageous new two meter sailplane that’s revolutionary in design and maxed out for thermal competition. Designed by veteran soaring pilot Jerry Robertson, the Sisu features a triple-taper crescent planform that is close to parabolic optimum shape, optional winglets that increase the effective span, and flaps that cover the largest possible span and area for maximum effectiveness. The ailerons are unusual as well - at the outboard end is a triangular shaped aileron called the "Robertson Trileron." This allows the movable surface to extend much closer to the wing tips without disturbing the airflow at the tips, thus maintaining performance while at the same time allowing greater roll forces out at the tip. The inboard section of the aileron can then be shortened. The end result is increased flap effect and improved aileron efficiency, because very little vortex is created when the Robertson Trileron is deflected.
The smallest cross section practical was one of the design objectives of the Sisu fuselage, and its unique shape aligns with the true airflow at thermalling speeds. The fuselage sports a nosecone for strength and utility. Rudder and stabs are generous and are built-up in construction to minimize nose weight. The all-up flying weight of the Sisu is 35 ounces. Airfoils are highly modified and transitional based on a blend of SD7037 and SD7035 airfoils optimized for the Reynolds Numbers in which this sailplane will operate. Sisu is maxed!
All wood, hardware, plans and instructions are included in the kit. The hardware is high quality and has been selected carefully to minimize weight and maximize
The composite Sisu is the ultimate in two meter soaring and launch performance. Because the wing is very accurate, its efficiency is greater, providing an amazingly flat glide that rivals an open class sailplane! The triple-taper crescent shaped Sisu C wing is carbonfiber sheeted and will withstand the hardest launches. The wing comes prepainted white and the bottom side of the wing shows the natural carbonfiber black for maximum visibility. The stabs are vacuum bagged fiberglass over Spyder foam and are ready to go. We build the Sisu wing in a two-piece bolt-on configuration. This two-piece wing has a carbonfiber spar installed. The two wing halves are joined with a 3/8" carbonfiber wingrod. For the best possible performance and strength a special carbonfiber cloth is used. This material is hard to acquire, but saves 4-5 ounces on this sailplane.
New! All the new Sisus come with the Kevlar hinges and all new designed light wing! This has reduced the weight another 4 ounces! Fantastic sinkrate and landing ability!
Sal Says:
If you want the ultimate in performance, this baby is the way to go! The Sisu C is the best 2 meter there is! Customers tell us their Sisu has been the only two meter they’ve ever flown that approaches open class sailplane performance - quite a feat for a two meter! I fly the Sisu C in competition because it has all the attributes I want: it can be launched hard and zooms very high, it has a great sink rate which stays good in a turn (so unusual in a two meter design), and it lands well under control right down to stall speed.
CD Says:
Sal, all this talk about carbonfiber are you sure you’re not getting too much fiber in your diet?!?
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