Question:
Now that we've hit on figuring if our rocket will break mach, on to the next
question. When a rocket breaks mach, does the effect cause a change in CP
for the rocket with the wave resonance?
Second question, is there specific additional stress on an airframe etc.
caused from breaking mach speed? (Other than the obvious stress from
ultra-high impulse thrust)
Also, reading info at shadow composites, they comment on heat produced from
air friction at high velocity. Is there any information on the web or
otherwise that might give insight into how hot surface temperatures might
get in accordance with air friction given a specific aerodynamic factor?
Answer:
The CP does move negatively as the fins become engulfed more into a
shock wave. This effect occurs more as Mach nmber increases.
For vertical flight rockets with paint this is not a major factor. At
Mach numbers above 1.5 you can lose your paint layer. It takes rockets
that go over M4 to get into any materials issues, but a steel tip nose
cone is 80% of that solution.
The extra drag produced by the shock wave can be annoying to rockets..
but what's extra annoying and requires strong fins is if your fins stick
outside of your shock cone and end up producing their own shock waves
themselves. Then you need strong fins.
But once the sound barrier is broken the change in pressure (from the rocket
being in the shock cone won't induce structural stress.
