SPA President Dan Weseman Says First Prototype Progressing Towards Completion
By Anthony Liberatore
Among the things AirVenture is known for is the introduction of new designs in the kit-built arena, and as the winds picked up a bit and a sprinkle or two hit fell outside his booth at AirVenture, Sports Performance Aircraft President Dan Weseman told me that single-seat Panther prototype is still 3 months away from completion, with a group of family and friends with strong aero-skills assist him in obtaining his goal. While looking over the design philosophy and construction methodology, you can't help but ask if this will be as good an airplane as it looks on paper.
With that said, let's take a look at the design. The Panther is a single seater LSA (there is also a non-LSA version) with the current engine being a William Wynne 120 hp Corvair Conversion. Weseman, who also makes his “5th Bearing” kit for the Corvair Conversion community, said that while they are gearing the Panther towards the Corvair, other powerplants and installation kits could potentially made available if there is enough customer demand.
As we step back from the engine, the fuselage center section (pictured) is a chrome-moly steel tube structure that serves multiple functions. This structure which will be part of a plans/kit offering, would ensure proper alignment for the landing gear, wing incidence, and dihedral. An adjustable rudder pedal assembly and multi-seat that can accommodate pilots from 5'4" to 6'6” is rounded out by an integral roll bar. With the rest of the structure being aircraft aluminum, the wings have been tested to 10.1g's positive. Just under this chrome-moly truss center section is the main landing gear legs in a taildragger configuration. Weseman noted the same gear legs can be used for the proposed tricycle gear version, but the legs themselves are most interesting. With the leading edge rounded and a tapered trailing edge with a machined groove for the brake-line, the leg design marries reduction in parts count and the elimination of landing gear fairings. Weseman did the machining himself., and
Weseman says Sports Performance will offer them to customers. But he noted it is something a builder could do with common tools.
Looking at the Panther's side view drawing (pictued), I mentioned to Weseman that he was taking advantage of “John Thorp's poor man's area rule,” and Weseman noted it sort of just happened that way. But he was influenced by Ken Paser's book “Speed with Economy”. Weseman also noted that prior to designing the Panther, he took a year to brush up on calculus as well learning the CAD software programs which were used in the Panther's design process. As the design progressed, Weseman incorporated some subtle features that may increase the Panthers appeal in these dollar-conscious times by either allowing the Panther to be taken home post-flight, or to share a hangar space with it's folding wing design.
But there is more to this folding wing feature. The Panther was designed to fit in a 16'-9” enclosed aluminum trailer often referred to as a “toy box”. The key enablers to fit in the toy box are it's 7' span horizontal stabilizer and it's folding wings that pull out and rotate up and back (leading edge down) along side the fuselage. The wing removal and rotation function is facilitated by a 4 pin a 4 telescopic tube system. The most interesting feature of this folding wing design is that there is no fuel in the fuselage and the leading edge fuel tanks will not spill in the folding-unfolding process. That's because the fuel systems design places the filler cap further back on the wings chord, and out on the wings span. Weseman also noted that while the Panther could be trailered on it's own gear below 45 mph, a simple boat type trailer to transport it was preferred, and gives the owner another transportation option as well.
For the Panther builder, Weseman (pictured, below) discussed the current direction Sports Performance is considering in supporting Panther builders. One would be the plans with a few components, such as the center section, for which no plans would be available for scratch builders. Second would be complete kits, and the third option would be the availability of pre-built spars and fuel tanks again for the scratch builders. Weseman's future plans also include a two-place tandem version of the Panther that he hopes will grace the grounds of AiVenture in 2013.