That aside I'm really fasicinated by those fast planes.
I mean, it's now public knowledge that the SR-71 leaked fuel between gaps in the fuselage onto the tarmac. Because of that they only fueled it up a little to get into the air without leaking too much.
Then after take off, speeding up until the thermal expansion closed those gaps, and full aerial refueling directly after that.
How did they solve that with the Valkyrie I wonder? Did similar things occur there, or were of no concern because of different materials, dimensions, make, etc.?
My understanding is that the fuel in the SR-71 was also the coolant, so it might not have been the fuel-loop that was leaking, but the coolant loop, as the coolant necessarily must go to hotter parts of the aircraft.
I doubt that the fuel served this dual-purpose on the XB-70, and exotic coolant might not have been needed for <30 minutes at Mach 3 anyways.
