in spite of lower performance. The team that had designed the engine was now in the United States after being captured as part of Operation Paperclip. Many of them were setting up a new Army-funded research effort under the direction of Wernher von Braun. The company hired Dieter Huzel to act as a coordinator between NAA and the Army missile team. In September 1947, the company began the design of an engine incorporating the showerhead design, which they called the Mark III. Initially, the goal was to match the thrust of the Model 39, but be 15% lighter. Work on the Mark II continued and the detailed design was completed in June 1947. In March, the company rented a large tract of land in the western San Fernando Valley north of Los Angeles, in the Santa Susana Mountains, for use in testing large engines. A rocket test center was built, using $1 million () of corporate funds and $1.5 million () from the USAAF. The first parts began to arrive in September. Development of the Mark III proceeded in parallel using a scaled-down version developing that could be fired in the parking lot. The team made a string of changes to this and eventually cured the combustion problems. Evolving design Another set of German research papers received by NAA concerned work on supersonic ramjets, which appeared to make a highly supersonic cruise missile design possible. Bollay began a series of parallel design projects; Phase 1 was the original boost-glide design, Phase 2 was a design that used ramjets, and Phase 3 was a study for what sort of booster rocket would be needed to get the Phase 2 vehicle up to speed from a vertical launch system. Meanwhile, aerodynamicists in the company discovered that the A-4b's swept wing design was inherently unstable at transonic speeds. They redesigned the missile with a delta wing at the extreme rear, and canards at the nose. Engineers working on the inertial navigation system (INS) invented an entirely new design known as the Kinetic Double-Integrating Accelerometer (KDIA) that measured not only velocity as in the V-2's version, but then integrated that to provide the location as well. This meant that the autopilot simply had to compare the target location with the current location from the INS to develop a correction, if any, that needed to bring the missile back on target. So, by June 1947,