It was under Tim’s insistence that

It was under Tim’s insistence that led to the use of fused quartz (fused silica) with its low internal damping characteristics. It was this excellent insight that has allowed the HRG to achieve the high quality factors (Q’s), reaching over 10 million by the early 1980s, which enabled the gyro to reach its superior performance level. As part of the NAVAIR development program, the first on the HRG since the Boston Lab work, two designs of the “Sonic” gyro were completed and evaluated by the Navy6. These designs were the“Block 10” gyro which had a “true wineglass” resonator and the“Block 20” gyro which had a“mushroom” resonator with an internal stem (Figure 7)