'Engine In Box' Option Allows Quicker Competition Times For Builders

By Anthony Liberatore

In the North Aircraft display area, Dan and Rachel Weseman of Sport Performance Aviation LLC debuted their latest engine option their 3.3 liter (3.3l) displacement Corvair Conversion. Mounted on their Panther single seat sport aircraft, the 3.3l saw one hour of flight time, and hours total of ground run and calibrated dynamometer testing performed by an independent dynamometer facility.

To get the 3.3l engine size, Weseman dovetailed off their previous 3.0l engine with it's bigger bore and further increased the displacement by increasing the engine stroke by .312”. This longer stroke variant uses the Weseman forged Timken 4340 billet crankshaft made in the U.S. This displacement increase requires some “clearancing” (material removal) from the engine case halves, as well as the camshaft. Weseman said a slightly different cam profile is used for the 3.3l, however the options available to the builder convert or assemble their 3.3l are numerous and geared towards the builder's needs.

These options include going the traditional Corvair conversion route, of the builder doing the work themselves (other than crankshaft and cam), and having work done by the various vendors in the Corvair Community (and the logistical coordination involved within), or they can choose to employ the Weseman's latest offering known as “Engine in a Box” (EIB). The EIB is an offering where everything you need to assemble your engine (except carburetion, intake manifold, oil cooler kit, and exhaust) either yourself, at a William Wynne Corvair College, or at the Finishing School. The EIB is ideal for the builder who wants to learn about their engine, but prefers one stop shopping. The Finishing School is a Weseman initiative of which they have established and it is geared towards final assembly of the EIB components up to and including test runs, were as the Corvair Colleges can facilitate engines in all phases of the conversion process.

While the 3.3l can be built up and assembled via these various options, the performance niche it fills is also noteworthy. At 2800 rpm the engine is rated for 118 hp, and 125 hp at 3300 rpm. Weseman noted that these dyno results are not only independent but are corrected (temperature, pressure etc), and they are real world numbers. Weseman said SPA's goal to was offer an engine in this horsepower class at a more traditional rpm (2800 rpm). Creating 118 hp at 2800 rpm the 3.3l will lend itself to aircraft that fly in a more traditional flight envelope ( including experimental LSA's) where a larger propeller diameter and longer landing gear lengths are often design characteristics of these aircraft.

The 3.3 liter SPA conversion engine can be seen at Airventure in booth N615, which is located in the North Aircraft Display area.

(Images provided by the author)

FMI: www.FlywithSPA.com