1/ @nosuchthing The fact about the SR-71 Blackbird in episode 315 was a bit wrong. It was designed to undergo thermal expansion due to shock heating to avoid structural damage from said heating. The structural elements most prone to the heating and thus thermal expansion were...

2/ ...designed to reach proper shape when flying at operational altitude and speed. Otherwise it would probably deform and suffer catastrophic failure during a test flight. @JamesHarkin @Schreiberland @andrewhunterm

3/ See the “Airframe, Canopy and Landing Gear” section of this Wikipedia article: https://en.wikipedia.org/wiki/Lockheed_SR-71_Blackbird?wprov=sfti1 (Retrieved 2020-04-06).

4/ Correction on tweet 1/ in this thread. The term should be “aerodynamic heating” not “shock heating”. See this Wikipedia article for details: https://en.wikipedia.org/wiki/Aerodynamic_heating?wprov=sfti1