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Foam Airplane From Ohio Makes World Debut
Aero modeler built airworthy ultralight from insulation board
By James Wynbrandt
July 26, 2018 - Dayton, Ohio, has been the birthplace of aviation innovators and innovative aircraft for more than a century now, and the latest of both have alighted at EAA AirVenture Oshkosh 2018. Aero modeler Peter Sripol, EAA 1283911, is debuting what he calls his “first real airplane,” the Sky Pupper, a homebuilt one-place, electric-powered ultralight made almost entirely of foam, which is on display just north of the Tall Pines Café.
“It’s like flying a wet paper bag,” said Peter, Sky Pupper’s designer, builder, and test pilot. “The stall speed is around 18 miles per hour, it cruises about 35 [mph], and the controls are mushy because it’s so slow, [but] otherwise it’s not too terrible.”
A small crowd continually circles the pale aquamarine and yellow twin-engine biplane, examining the markings on the unpainted foam board fuselage and empennage that read, “GreenGuard XPS extruded polystyrene insulation” and “Lowe’s.”
“I’ve been building models since middle school,” Peter said. “I’m in the new era of aero modeling: people doing ‘foamies.’ This is just a giant foam model airplane to me.”
Peter earned his pilot certificate when he was about 20 with the intention of becoming a commercial pilot, but abandoned that career path in favor of his current day job: YouTube star. He has a video channel he’s used to partially document the Sky Pupper’s development and flight-test program, a project inspired by Oshkosh last year.
“I was camping out here, watching ultralights, and I thought, ‘I’m not getting any younger; I’m just going to go and build an airplane,’” Peter said.
Using a simple 3D modeling program to design the aircraft, he built it in two-and-a-half months, using specialty tools like a laser cutter to reduce build time and spending “probably around $6,000 because I made a lot of mistakes and bought parts that didn’t work out.” The aircraft was “built very safely,” he said, with aviation grade hardware throughout. Empty weight, without the 30 pounds of batteries, is about 210 pounds, and it’s powered by 150 cc electric model airplane motors, producing a total of some 9.8 kW of energy, or about 13 hp. As an ultralight, it requires no certification.
The instrument panel, a study in minimalism, has only an altimeter and airspeed indicator, which he describes as “basically useless,” and a cutout where a radio or other avionics could be fitted.
The flight-test program was unconventional. “We just went for it,” Peter said. After high-speed taxi tests, on the (unintentional) first flight he found the aircraft was very nose heavy and the batteries weren’t providing sufficient power to lift the aircraft out of ground effect. The flight ended in a cornfield, leaving the fuselage with a still-visible ding on its underside. But after correcting those issues, the foamie took off on its maiden flight in October.
Sky Pupper has now accumulated about 20 minutes of flight time; it arrived at the fly-in on a trailer. Peter’s not sure how much more he’ll fly his creation, but “I definitely want to keep building airplanes, as a hobby, for fun,” he said. He has another, more traditional ultralight project in the works, and the concept for one built with chromoly 4130 tubing. Meanwhile, he wears his mantle as Dayton’s latest aviation innovator uneasily.“Everyone wants to get away from Dayton,” Peter said. “I put my plane together so I can get away.” The Sky Pupper has clearly achieved its design objective.