Originally Posted by
Nick Thomas
As I understand it due to friction heat caused by flying at mach 2 Concorde would expand by approx 6 inches. Some of this expansion could be seen between the FE panel and flight deck partition. Obivously the interior would be at a comfortable temp of say 21c; thus the exterior would expand but the interior linings etc would not. So finally to my question- How was this differential expansion dealt with? I have really enjoyed reading the clear answers posted answering many interesting Concorde questions.
"...due to friction heat caused by flying at mach 2 ..."
"Friction" is the "easy explanation", but not really true.
It was due to the air being
compressed, being "pushed sideways" by the aircraft trying to make its way through the air at Mach 2, if you like
Same as what happens in a bicycle pump, that get hot as you compress the air. The analogy is somewhat oversimplified, but the phenomenon is the same.
The hottest spots were actually the nose and the wing leading edge, not because of friction, but because that's where the air was locally brought to a total standstill, hence compressed the most. Temperature there could rise to +127°C, from the -50°C and less of the air at 50,000ft just ahead.
"How was this differential expansion dealt with?"
Mostly by attaching things like equipment racks (think of the hat) and floors, and other bits and pieces, to the outer fuselage structure only at
one end, and making sure they could move relative to the outer structure when it expanded.
Hope that explains it?