Maj. Numbskully

Folkerts SK-3_EA

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Folkerts SK-3

Designer: Clayton Folkerts
First Flight: 1937
Role: Racing Aircraft

The SK-3 was a midwinged conventional racing aircraft with retractable landing gear. Built by Clayton Folkerts of Bristow Iowa, the Jupiter SK3 was the winner of the Thompson trophy series air races of 1937.

The Thompson trophy race was one of the National Air Races of the heyday of early airplane racing in the 1930's. Established in 1929, the last race was held in 1961. The race was 10 miles long with 50-foot-high pylons marking the turns, and emphasized low altitude flying and maneuverability at high speeds. As the race was flown around a closed course, crowds in the grandstands could easily see much of the spectacle.

The Folkerts SK-3 Jupiter exemplified American 1930's trial-and-error design. It had a wooden propeller of very high pitch and one of the shortest wingspans in racing history. The fuselage was long and slender. The thin wings used spruce wood spars, plywood covering and split flaps. The fuselage was welded steel tubing with aircraft fabric covering, built in two parts that were bolted together. The manual retractable landing gear used a single lever, rather than earlier crank systems. There were two 11 U.S. gallons (42 L; 9.2 imp gal) forward fuel tanks, a 27 U.S. gallons (100 L; 22 imp gal) main, and an auxiliary of 12 U.S. gallons (45 L; 10.0 imp gal) mounted behind the cockpit. The Menasco C6-S was modified by Kling to produce 400 hp (298 kW) at 3300 rpm, versus the standard 250 hp (186 kW) output.

The Folkerts RC plane is a 74" wingspan scale reproduction of the original. Weights, power levels, throws, c.g., etc. , all reflect typical RC scratch built planes.
The landing gear mimics a solution for the complex cranked retracts seen on the original plane.

3D Design, Creation and Realization by : jeffpn
Body Paint and Graphics by: Maj. Numbskully
Physics by: Opjose and Boof69

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