Final answer:
The term 'Hover DCL' is not defined in standard physics, so we cannot directly answer how to adjust it. However, in aerodynamics, speed can be influenced by air drag, and adjustments to the speed of vehicles can be made via changes in power output or aerodynamic design. During the 1970s oil crisis, U.S. highway speeds were limited to improve fuel efficiency by reducing air drag.
Step-by-step explanation:
The statement in the question appears to mix terms from physics with an undefined acronym 'Hover DCL.' It is difficult to provide a direct answer as 'Hover DCL' is not a standard term in physics. However, if we interpret the question as related to controls that can adjust speed, in physics and aerodynamics, the speed of an object can be influenced by several factors. One significant factor at high speeds is air drag, also known as drag coefficient, which can depend upon velocity. When testing vehicles, such as cars or model planes, researchers like those at NASA will often use wind tunnels to measure the effects of air drag. Adjustments to the speed of an object, such as a car, can often be controlled by modifying its power output, aerodynamic design, or by using certain technologies or mechanisms that influence these factors. However, without clarification of the term 'Hover DCL,' providing a specific control mechanism is not possible.
During the 1970s oil crisis, to increase fuel efficiency, maximum speed limits on highways in the United States were set lower due to the relationship between speed and air drag. At highway speeds, a significant amount of a car's power is used to overcome air drag, which increases with speed.