This article will describe:
- The thermal considerations in designing a nose cone tip
- A mathematical model to describe how hot the nose cone tip is expected to get
- The numerical method used to determine the temperature profile of the tip
- The final design choice made for Hermes II
Nose cone tip thermal consideration
Hermes II is expected to reach high speeds in low atmosphere: approx Mach 3.5 at just 10,000 ft when burn out occurs. At these high speeds, the stagnation point temperature of the air is extremely high:
$$ T_{stag} = T \left(1 + \frac{\gamma 1}{2} M^2 \right) = 268 \left( 1 + \frac{1.4 - 1}{2} 3.5^2 \right) = 924 K $$