[grogenaut]

hey at least they decided not to use hypergolic fuel in the sr-71 tho having a jet that was on fire all the time would be pretty bad ass looking. Titanium would probbably handle it and it'd eventually warm up the skin and close the gaps.

[dredmorbius]

Whilst the SR-71 didn't run on hypergolic fuel (because reasons -- including leaky tanks and supersonic skin-heating, so JP-7, which specifically has a high flash point was used for fuel), the ignition system for the aircraft, including its afterburner ignition system, used hypergolic fuel (triethylborane) to initiate combustion, with a limited number of ignition cycles aboard each mission.

Afterburner light-ups were limited by the availability of TEB aboard.

https://en.wikipedia.org/wiki/Triethylborane

[grogenaut]

I remember thinking from one of the books on the sr71 equating restarts to setting off a stick of Dynamite in the tailpipe... But I was younger then and didn't know about these fuels. Thanks for the details

[m4rtink]

IIRC, there are some issues with Red Fuming Nitric Acid & titanium, possibly resulting in sudden explosions under some circumstances.

Hydrazine + nitrous oxide could be fine though, but better check first before use. ;-)