Hot and High - Improving Hot and High Performance

Improving Hot and High Performance

Some ways to increase aircraft performance in hot and high conditions include:

• Reduce aircraft weight. Weight can be reduced by carrying only enough fuel to reach the destination rather than filling the tanks completely. In some cases, unnecessary equipment can be removed from the aircraft. However, in many cases, the only practical way to adequately reduce aircraft weight is to depart with a smaller passenger, cargo, or weapons load. Consequently, hot and high conditions at the originating airport may prevent a commercial aircraft from operating with a load large enough to be profitable, or may constrain the firepower that a combat aircraft can bring to bear when conducting a long-range airstrike.
• Increase engine power. More powerful engines can improve an airplane's acceleration and reduce its takeoff run. However, more powerful engines are generally larger and heavier and use more fuel during cruise, increasing the fuel load needed to reach the same destination. The added weight of the fuel and engines may negate the potential performance gain, and the added cost of the extra fuel may constrain the profitability of a commercial aircraft. On the other hand, replacing an older, less efficient engine with a newer engine of more advanced design can both increase power output AND efficiency while sometimes even decreasing weight. In this situation, the only real disadvantage is the cost of the upgrade.
• Increase the size of the wings. However, larger wings weigh more and increase drag, making the aircraft slower and increasing fuel consumption during cruise.
• Add high-lift devices to the wings. However, these devices typically add weight and mechanical complexity, increasing manufacturing and maintenance costs. Furthermore, some high-lift devices increase drag during cruise.
• Utilize assisted take off devices, such as rockets, to increase lift and acceleration.
• Inject distilled water during takeoff in the engine (compressor or combustor). Evaporating water reduces the temperature, so more fuel can be added, increasing power.

Alternately, runway lengths may be increased to make up for reduced aircraft performance.