Final answer:
High power requirements during hover are primarily due to induced flow and induced drag, as well as factors like blade tip vortices and environmental conditions affecting air density. Hovering demands significant power to generate the upward lift force needed to support the helicopter's weight.
Step-by-step explanation:
The question 'What causes high power requirements during hover?' pertains to the principles of aerodynamics and helicopter flight mechanics.
The power required during hover is significantly high due to several factors. One of the main factors is the creation of induced flow, which is the downward flow of air through the rotor system. When a helicopter hovers, its rotors must push a large volume of air downwards to create an upward lift force enough to counteract its weight. This action results in induced drag, which requires additional power to overcome.
Another factor contributing to high power requirements is blade tip vortices, which form at the rotor tips due to pressure differences.
These vortices create drag and require extra power to maintain the necessary lift. Furthermore, hovering close to the ground can lead to the 'ground effect', which can aid lift but may also introduce instability and necessitate further power to maintain a stable hover.
Finally, environmental conditions such as high altitude or hot temperatures can reduce air density, thereby requiring the rotors to work harder to generate the same amount of lift, increasing power requirements.