3 ms·

So? The SR-71 has (had?) a bug that required both engines to restart in flight. Frequently.

by sliverstorm 11y ago

alayne 11y ago
Do you have a reference for this?
- beamatronic 11y ago
  How about this? http://www.airspacemag.com/military-aviation/how-things-work-supersonic-inlets-35428453/?no-ist http://www.airspacemag.com/military-aviation/how-things-work... "During some Blackbird flights, however, the harmonious working of the spike and the forward and aft bypass doors broke down, and all too quickly the inlet was filled with more air than it could handle. When the air pressure inside the inlet became too great, the normal shock wave was suddenly belched out of the inlet in an unstart, accompanied by an instantaneous loss of air flow to the engine, an enormous increase in drag, and a significant yaw to the side with the affected inlet. Unstarts occurred 'when you least expected them—all relaxed and taking in the magnificent view from 75,000 feet,' wrote Graham in SR-71 Revealed. If the crew’s attempts to restart the inlet’s supersonic flow failed, they would have to slow their aircraft to subsonic speeds."
- dogma1138 11y ago
  It wasn't really a "bug" but more that the computers could not keep up with changes in the flight conditions so if the engine spikes were not in the correct position for the speed and altitude it could cause a blow back which would extinguish the engines which will require the pilots to restart them. https://en.wikipedia.org/wiki/Lockheed_SR-71_Blackbird#Air_inlets https://en.wikipedia.org/wiki/Lockheed_SR-71_Blackbird#Air_i...
  - gherkin0 11y ago
    It also looks like they later mitigated it as technology improved: > Lockheed later installed an electronic control to detect unstart conditions and perform this reset action without pilot intervention. Beginning in 1980, the analog inlet control system was replaced by a digital system, which reduced unstart instances.
- deleted 11y ago
  [deleted]
kelvin0 11y ago
Yeah, for technology from 1966 its barely acceptable. F-35 is '21st' century technology, or so I thought. Can we really compare the two?
- SCHiM 11y ago
  If you assume that fighter planes were and are cutting edge, it's not really surprising.
  - smilekzs 11y ago
    Fighter jets are mechanical / propulsion / material science wonders, perhaps no less than space-faring rockets.
- reneherse 11y ago
  It was literally the cutting edge of 60's engine control technology, and an analog computer to boot. ;)
titzer 11y ago
The SR-71 flew faster than any plane in history and used cutting edge engine design whipped up by a very small team at Skunkworks in a short period of time. The F-35 doesn't outclass any fighter, is being developed with a huge budget by an enormous team, and they're using software tools and techniques that generally feel like regressions.

So? The SR-71 has (had?) a bug that required both engines to restart in flight. Frequently.

alayne 11y ago

Do you have a reference for this?

beamatronic 11y ago
How about this? http://www.airspacemag.com/military-aviation/how-things-work-supersonic-inlets-35428453/?no-ist http://www.airspacemag.com/military-aviation/how-things-work... "During some Blackbird flights, however, the harmonious working of the spike and the forward and aft bypass doors broke down, and all too quickly the inlet was filled with more air than it could handle. When the air pressure inside the inlet became too great, the normal shock wave was suddenly belched out of the inlet in an unstart, accompanied by an instantaneous loss of air flow to the engine, an enormous increase in drag, and a significant yaw to the side with the affected inlet. Unstarts occurred 'when you least expected them—all relaxed and taking in the magnificent view from 75,000 feet,' wrote Graham in SR-71 Revealed. If the crew’s attempts to restart the inlet’s supersonic flow failed, they would have to slow their aircraft to subsonic speeds."
dogma1138 11y ago
It wasn't really a "bug" but more that the computers could not keep up with changes in the flight conditions so if the engine spikes were not in the correct position for the speed and altitude it could cause a blow back which would extinguish the engines which will require the pilots to restart them. https://en.wikipedia.org/wiki/Lockheed_SR-71_Blackbird#Air_inlets https://en.wikipedia.org/wiki/Lockheed_SR-71_Blackbird#Air_i...
- gherkin0 11y ago
  It also looks like they later mitigated it as technology improved: > Lockheed later installed an electronic control to detect unstart conditions and perform this reset action without pilot intervention. Beginning in 1980, the analog inlet control system was replaced by a digital system, which reduced unstart instances.
deleted 11y ago
[deleted]

kelvin0 11y ago

Yeah, for technology from 1966 its barely acceptable. F-35 is '21st' century technology, or so I thought. Can we really compare the two?

SCHiM 11y ago
If you assume that fighter planes were and are cutting edge, it's not really surprising.
- smilekzs 11y ago
  Fighter jets are mechanical / propulsion / material science wonders, perhaps no less than space-faring rockets.
reneherse 11y ago
It was literally the cutting edge of 60's engine control technology, and an analog computer to boot. ;)

titzer 11y ago

The SR-71 flew faster than any plane in history and used cutting edge engine design whipped up by a very small team at Skunkworks in a short period of time. The F-35 doesn't outclass any fighter, is being developed with a huge budget by an enormous team, and they're using software tools and techniques that generally feel like regressions.