The Sling TSi first flew in 2018, with kits being shipped to builders in fall 2018. The aircraft was developed in 2018. The Sling TSi is an all-metal, low-wing, fixed tricycle gear homebuilt aircraft. The airplane is equipped with the new Rotax 915iS engine and was the inspiration for the designation of TSi. Parts of the wings and fuselage were reinforced and outfitted with flush riveting for increased strength and reduced drag over the Sling 4. The first Sling TSi in the USA was shown at EAA AirVenture Oshkosh in 2018. In a review for KitPlanes, writer Paul Dye said, "...it lives up to its design goals. We flew with four full sized adults from a field with a density altitude of 9,000' and had to throttle back to keep from exceeding redline when we leveled off at 10,000. Later, operating off of a dry lakebed in the high desert, with temperatures of 100 degrees, we never had to worry about engine cooling - and it handled like a fine touring machine." A company demonstrator Sling TSi flew non-stop from Torrance, California, to Tampa Executive Airport on its way to Lakeland, Florida for Sun 'n Fun 2019 in 13.5 hours. The aircraft carried an additional 30 U.S. gallons (110 L; 25 imp gal) of fuel over the normal 45 U.S. gallons (170 L; 37 imp gal) long-range tanks and benefited from tailwinds en route. In July 2019 the company did a ceiling expansion test and flew non-stop from Torrance, California to Wittman Regional Airport to attend EAA AirVenture Oshkosh for 9.75 hours. The aircraft reached a final height of 27,000 feet. During EAA AirVenture Oshkosh in 2019 the development of a new high-wing variant, the Sling HW was announced.
