In the US, NDRC focused on radio fuzes for use with anti-aircraft artillery, where acceleration was up to 20,000  as opposed to about 100  for rockets and much less for dropped bombs. In addition to extreme acceleration, artillery shells were spun by the rifling of the gun barrels to close to 30,000 rpm, creating immense centrifugal force. Working with Western Electric Company and Raytheon Company, miniature hearing-aid tubes were modified to withstand this extreme stress. The T-3 fuze had a 52% success against a water target when tested in January, 1942. The United States Navy accepted that failure rate. A simulated battle conditions test was started on 12 August 1942. Gun batteries aboard cruiser tested proximity-fuzed ammunition against radio-controlled drone aircraft targets over Chesapeake Bay. The tests were to be conducted over two days, but the testing stopped when drones were destroyed early on the first day. The three drones were destroyed with just four projectiles.