This is My Heavy Duty version of my OA-40S hyper STOL cargo aircraft. It is a twin turboprop heavy lift STOL airplane. Its competitors include beefy’s PADC Tamaraw, which I made a modernized version of, and the Twin Otter. It is made of carbon composite materials and only weighs 9000lbs with fully fuel and little payload. With a maximum gross weight of the normal version is 11,500lbs but the heavy duty, that will go up to 15,000. you will be able to take any payload, anywhere, litterally. Takes off in 150ft and almost has the power to climb out vertically. The heavy duty version has twin 1220shp Pratt and Whitney Canada PT6A-65AR engines attached to MT 7 blade props you will never need more power than you have. Start up procedure: AG1 for master, wait for props to un feather, AG3 to start engine 2 wait for rpm to stabialize, AG2 to start engine 1, wait for rpm to stabalize, then begin taxi. For stol takeoff idle throttles, tap brakes, flaps full down, hold full up elavator, then full power. When above 150kts use trim for pitch control because it is a very large surface for rotation. Thank you and enjoy! The differences between V3 and V4 are larger flaps, extra bouncy suspension system, and larger wheels. Hint hint, this wasnt much of a change, but thats because this airframe is getting so good i dont know what to do. Recomendations in the comments please and i will not do more updates to this weekly anymore, but only when there is 2 more large ideas. There are more differences between the HD version and the normal, but they are minor. The extened range version adds more fuel, sacraficing some take off distance,Thank you and enjoy!