Holt and Mock
November 6, 2017
Most of our blog posts focus on larger projects and themes, but today we’d like to feature the individual accomplishments of two Dahlgren scientists, Drs. Willis Mock and William Holt. Their research in naval ordnance began in 1971 and eventually resulted in “a new and revolutionary approach for using plastic polymer and plastic polymer/metal combination materials for Navy ordnance applications.” They paved the way for an important class of new weapons, and in 2005 Secretary of the Navy Gordon England granted them the Distinguished Achievement in Science Award.
Holt and Mock required a gas gun to study how new materials could be used in ordnance. It would provide the necessary amount of control over the test conditions they required. However, they had virtually no budget. Undeterred, they built the gun from scrap metal they found on base. For a 2002 profile of the pair in The Dahlgren Bullet, Mock said “we had a big challenge, because a research gas gun isn’t something that you could throw together and expect it to work right. To get meaningful data, everything has to be precision.” Neither Holt nor Mock had built a gas gun before, but did some research and based their design on gas guns other people had built, picking the specific features and experimenting with the design so that each part would work the way they wanted.
The two scientists designed the gun to “use compressed gas to launch items at speeds between 100 and 3,100 ft./sec in a controlled manner to investigate cracking in metals and other precision impact shock effects.” They also created a “soft recovery system” that catches the projectile and absorbs its momentum while leaving the projectile and impactor undamaged so the pieces could be examined. They also built the gun with the capability to take high-speed photographs to measure the target response. According to the profile of Mock and Holt in The Bullet, “the gas gun has been vital in helping the Navy understand what happens to objects such as certain metals and projectiles under shock, stress and fracture.”
The discoveries that resulted from their work included filling projectiles with a small amount of plastic that becomes gaseous upon impact. The reaction of the gas with the air and metal in the projectile results in catastrophic damage to a target. Their gun also offered “the promise of an initial stage to the experimental rail gun.”
On September 7, 2005, Holt and Mock were both awarded the Navy Award for Distinguished Achievement in Science for the three decades of work in shock physics they completed with the gas gun. The citation states,
“Their scientific endeavors have culminated in the last ten years in the discovery and systematic exploitation of various compounds that react under high shock loading to yield a new phenomenon of multi-phase flows. Their research has led to the development and application of plastic and polymer/metal combination materials that have resulted in significant advancement within the weapons community Dr. Mock and Dr. Holt were the first to recognize and demonstrate the potential use of an entirely new type of energetic material for warhead applications.”
Notably, the Distinguished Achievement in Science Award is not presented on a regular basis. It is only awarded “to recognize pioneering scientific achievements which are extraordinary and significant in nature and which contain a potential of far-reaching consequence.”