Tantalum
Final Approach
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- Feb 22, 2017
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San_Diego_Pilot
Reading the most recent "I learned about flying from that" link here made me think about something..
In the article they guy writes that his face was blasted with 310 knots windspeed at 25,000 when the windshield on his Lancair Evolution failed
He also writes that the 6.5 PSI cabin differential ensured that the glass blew outwards, that's why there were no pieces of glass hitting his face or the cabin
My question is 2 part:
A.) for a given square inch.. what force is greater, the 6.5 inches pressing outwards, or the 310 knots of wind pushing inwards. I imagine this would be a very easy calculation assuming the mass of air at that altitude is known (I recall from physics it was around 30 g/mol at sea level).. anyone know? Curious what the *actual* force is on the windshield is at that speed..
B.) If the cabin 6.5 PSI is in fact greater pushing out than the 310 knots of wind pushing in.. than surely those tiny pieces of glass can't carry that momentum so the minute they're presented with the 310 knots of wind and the pressure has been released they'd come back in the cabin.. right? 6.5 PSI is not insignificant, but spread across small pieces of glass? How much forward travel relative to the plane could a tiny piece of glass actually achieve? Maybe a quarter inch? Wouldn't it just get blown right back into the plane?
Anyway.. made me think about the actual physics that are at play here
In the article they guy writes that his face was blasted with 310 knots windspeed at 25,000 when the windshield on his Lancair Evolution failed
He also writes that the 6.5 PSI cabin differential ensured that the glass blew outwards, that's why there were no pieces of glass hitting his face or the cabin
My question is 2 part:
A.) for a given square inch.. what force is greater, the 6.5 inches pressing outwards, or the 310 knots of wind pushing inwards. I imagine this would be a very easy calculation assuming the mass of air at that altitude is known (I recall from physics it was around 30 g/mol at sea level).. anyone know? Curious what the *actual* force is on the windshield is at that speed..
B.) If the cabin 6.5 PSI is in fact greater pushing out than the 310 knots of wind pushing in.. than surely those tiny pieces of glass can't carry that momentum so the minute they're presented with the 310 knots of wind and the pressure has been released they'd come back in the cabin.. right? 6.5 PSI is not insignificant, but spread across small pieces of glass? How much forward travel relative to the plane could a tiny piece of glass actually achieve? Maybe a quarter inch? Wouldn't it just get blown right back into the plane?
Anyway.. made me think about the actual physics that are at play here