[redgolum]

Expense of keeping the SR airborne.
The dang thing leaked until it hit cruising speed. All that heat also causes metal fatigue.

Years ago, they put one of the retired SR’s at the old Offut museum. It hadn’t been totally decommissioned yet. There was an old crewman talking about the work to keep the engines going.

I will never forget the feel of the skin of that bird. Like hard cardboard.

[tanknetter]

The SR-71 leaked fuel by design. Cracks were built in to allow the aircraft to
“stretch” by about a foot in flight due to the heat stresses.

However all that heat-treatment effect of Mach 3+ STRENGTHENED the titanium fuselage. The birds left service with stronger airframes than when they first flew.

[EternalVigilance]

Years ago, they put one of the retired SR’s at the old Offut museum.

I touched that bird myself.