Convair NC-131H Samaritan

The Convair NC-131H Samaritan, also known as the Total In-Flight Simulator, was originally a C-131B aircraft that underwent conversion by the United States Air Force in the late 1960s. It was transformed into an in-flight simulator specifically developed to study aircraft handling characteristics. The NC-131H made its maiden flight in 1970.

Notably, the NC-131H was designed with two distinct nose configurations. One configuration featured a two-person cockpit that allowed for computer-simulated handling of various aircraft. The other nose configuration was equipped to carry a range of radars, cameras, and sensors. This setup enabled the NC-131H to perform a variety of data collection and analysis tasks during flight.

Design and simulation
The TIFS first flew in 1970, and its first research project simulated the B-1 bomber's flying characteristics. During its long and successful career, the TIFS simulated many military and NASA aircraft, including the Boeing X-40, Northrop Tacit Blue, Space Shuttle, Northrop Grumman B-2 Spirit, Northrop YF-23 and Boeing C-17 Globemaster III. Civilian aircraft development projects included the Boeing SST, McDonnell Douglas MD-12 and IPTN N-250.

Engineers found the TIFS especially useful for studying how large aircraft would handle during takeoff and landing. The Total In-Flight Simulator NC-131H has continually been upgraded through its 30-year history to keep it at the leading edge IFS technology. Since its retirement, it is still one of the world's most capable IFS aircraft.

Originally, a United States Air Force C-131B transport aircraft. It was then developed into the NC-131B Control Configured Vehicle, a variable stability aircraft with NASA. It was re-engined and redesigned as an NC-131H for the USAF Research Labs (AFRL). The "N" was to indicate that the aircraft had been permanently modified, this airplane underwent extensive modifications. With its spacious cabin and replaceable nose, TIFS is a cost effective test-bed aircraft, especially for programs with large equipment needs. The TIFS simulation cockpit is separate and completely independent. Ample space and modular design supports installation of all required controls and displays. An aft-cabin crewstation can also be provided.

The TIFS had two nose designs, one nose contained an additional cockpit for a test aircrew as the aircraft flight controls could be programmed to simulate various aircraft configurations. A safety crew occupied the production cockpit, ready to take control should problems, usually instability, occurred. The other available nose incorporated a large radome and could be used to test various sensors. During the Martin Marietta Smart Weapons Program, TIFS was modified to replicate an intelligent cruise missile.

The original piston engines were replaced by turboprop engines with nearly twice the horsepower, but the most noticeable modifications added the second cockpit on the nose and the vertical fins on the wings. The vertical fins on the wings generated side forces to simulate crosswinds and provided test data. It was owned by the Flight Dynamics Laboratory (FDL), but operated and maintained by The Calspan Corporation (originally Cornell Aeronautical Labs).

The aircraft often was used for FDL flight test with the flying done be Calspan test crews. It was also occasionally used for USAF or Navy Test Pilot School student projects, with the students in the test cockpit and the Calspan crew serving as safety crew and system programmers. The computers onboard TIFS are easily programmed and allow rapid turnaround and system changes. This makes hosting and checkout of customer software very efficient. Since the simulation is not critical to safety of flight, quick changes can be made without extensive verification and validation. Onboard flight test engineers can even reprogram the system in flight if necessary.