The aluminum he chose was 6061 Aluminum Alloy. The Airplane Factory founders feel that the Sling airplanes and kits are the best on the market and believe that you will soon agree! In addition, each kit we produce is inspected and assured to be top quality before being shipped to the buyer. Every new design prototype is tested to its ultimate breaking points to ensure maximum reliability and durability, not too mention the extraordinary efforts The Airplane Factory goes to in order to make sure handling and stability are in the upper echelon of all airplanes on the market today. We know and understand the concerns of our fellow aviators and we would never build anything we did not 100% believe in or endorse. The reason for such meticulous design and construction is because most of us here at The Airplane Factory are pilots. We take every step to ensure that each aircraft produced, whether ready-to-fly or kit version, is held to the highest of standards, above and beyond that required by ASTM or the FAA. The Airplane Factory is proud to be the producer of high quality, high performance Light Sport and Experimental Aircraft. Nevertheless, The Airplane Factory believes that the Sling 4 Turbo enjoys a set of qualities that will fulfill the needs, at the highest level, of many pilots around the globe. No single aircraft can fulfill the special needs of every pilot. The Sling 4 Turbo comes with a variety of customization options that the builder can explore as well as the option for a Ballistic Parachute for safety purposes. Aluminum construction is used for ease of maintenance and construction as well as its proven strength and lifetime qualities. Her flying characteristics are very similar to the smaller Sling LSA, perfectly-coordinated with highly responsive controls that are not too sensitive! The Sling 4 Turbo is the perfect aircraft for the home builder who is looking for an affordable DIY 4-place airplane. It can comfortably seat 4 people, carry baggage and still cruise effortlessly and efficiently, making it the ultimate affordable cross-country aircraft. The plane is basically an elongated version of its sibling, the Sling LSA, however it uses the more powerful Rotax 914 Turbo and has Gullwing doors instead of a sliding canopy. The Sling 4 Turbo was designed with the aim of creating the most practical and desirable lightweight, 4-place Experimental aircraft on the market, a niche not previously filled.