Dakota Cub’s extended slotted wing
Flight safety is something all pilots talk about. They live it, accept it and always hope to choose it in their day-to-day life in the world of aviation. For the Super Cub fanatic, the Dakota Cub’s extended slotted wing offers pilots the opportunity to improve their margin of safety as well as increase the aircraft’s climb performance.
Imagine flying your Super Cub at a high angle of attack with the airspeed indicator reading 20 mph, then rolling at a 60 degree incline and initiating an upward spiral while selecting a power setting that is less than full throttle! That’s the typical display that the Dakota Cub Extended Slotted Wing sells. The second most talked about quality of this wing is the ability to have full flight control authority at high angles of attack. No more smooth controls, dropping it or dropping the wings on the post.
Mark Erickson, the founder of Dakota Cub, began his mission in the 1990s. All he wanted was a puppy rib. Nothing from Piper was available at a reasonable cost and since Piper’s ribs were so fragile, he decided to build his own. He applied modern technology to an old Piper wing that was originally developed for the YL-14 link version of the J5C Cub. The YL-14 wing was a slotted wing. According to Erickson, only 14 of these aircraft were built before the end of WWII. They were specifically designed for short 100-foot takeoffs and ascents with high angles of attack. There are only two of these still on the air today: one in Spain; the other in Nebraska.
The Dakota Cub extended slotted wing has several variations compared to the original Cub wing and the L-14 wing for that matter. Erickson revised the original Piper US35B airfoil used for the L-14. He developed a custom “T” shaped extrusion with the same dimensions as when used to build a truss-style rib, it is lighter, easier to work with and more robust than the original wing. Erickson earned an STC for the new wing in 1993.
Erickson’s new rib only adds seven pounds to the weight of each original Piper wing. The new wing has been structurally tested at a 2,200 pound access, however the STC limits the gross weight to 1,750 pounds for the original wing or 2,000 pounds for those wings equipped with the Wipaire One Ton Cub STC. This artificial reduction is expected to change in the future. In the intervening years, Erickson has designed ribs and many other parts that are FAA PMA-ed for all Rag-winged Pipers. Erickson received the STC for the full-length leading edge groove in 1998. This groove helps preserve the boundary layer of airflow at slow speeds. On top of that, Erickson designed a square wing and got rid of the nose bow, giving the wing an additional 6% surface area, increased flaps, resulting in 44% more flap area, and pushed the ailerons out 23 inches toward the edge of the wing. He calls it the “extended wing.” The square wing adds around 8 pounds to the original Piper wing.
Adding a slot to the extended wing adds another nine pounds per wing, but the increased safety from which to fly is worth the compromise. The flight characteristics of the square and slotted wing, which Erickson calls the “extended slotted wing,” is the main advantage and emphasis regarding the choice of wings to include in your Cub project. The extended slotted wing is the best performance wing offered by the Dakota Cub. It has a 135-inch slot, a square wing with 102-inch ailerons, and a 90.25-inch fin. Dakota Cub also offers the standard Cub wing and a square wing without the slot.
The extended slotted wing is simply a more secure wing. It allows for a higher critical angle of attack, slower stall speed, and virtually eliminates sudden stall compared to a straight wing. It delays the separation of the airflow from the wing surface, thus maintaining the authority of the ailerons and in many cases the only sign of a stall will be a decent rate higher than normal. This phenomenon allows the rate of fall of the aircraft on approach to landing to be controlled with energy alone, allowing for a more precise landing point without fear of a wing choking or falling to one side. The wing also has an improved roll speed due to the ailerons extending to the end of the wing.
If you want to take full advantage of the extended slotted wing on your Super Cub, it is recommended to install a 3-inch gear extension. The train extension will allow the wing’s low speed capabilities to take full effect upon landing. Larger tires will also provide this. A low gear coupled with small tires will result in the rear wheel’s first landing and a longer than optimal takeoff run because that higher angle of attack is more difficult to achieve.
The end result of all this innovation is a Cub that has better climb performance, better sinking control, slower landings, and a much higher margin of safety. An Airframes, Inc wide-body fuselage features an extended fuselage, and when combined with the larger control surfaces and slot, a pilot can fly in a 45-degree nose-up attitude, land at 25 knots and still have a wing. hanging in the air.