5 ms·

“unstart” - while a terrifying euphemism - is there is reason “stall”, or similar, is not used?

by eismcc 4y ago

corrral 4y ago
Looks like it's a technical term for a particular type of supersonic behavior: https://en.wikipedia.org/wiki/Unstart https://en.wikipedia.org/wiki/Unstart
- eismcc 4y ago
  The semantics is start/unstart are definitely more interesting in this context and seem less dramatic in the context of wind tunnel tests
sigstoat 4y ago
> “unstart” - while a terrifying euphemism - is there is reason “stall”, or similar, is not used? "stall" has a specific meaning, and it isn't what happened.
kurthr 4y ago
The supersonic shockwave-cone would enter the engine intake, which leads to an un-start. The weird cones that stick out the front of the engines can be manipulated to slow down the incoming air and keep it below supersonic at the intakes, which is normally done automatically with little analog computers that apparently failed somewhat regularly and in this case spectacularly during a banking turn.
- Wistar 4y ago
  In the course of helping an acquaintance do research for a book, I listened to hours of interviews with an 80 year old aerodynamics specialist who worked for Boeing for decades. It was fascinating stuff. One of his specialties was the design of the inlets for jet engines and, through the conversation, I learned that the inlet is the entire aerodynamic approach to the actual engine intake, starting before the air even encounters any of the structure of the aircraft. Turns out that certain designs cause turbulence out in front of the aircraft and all of that path to the intake must be taken into account. He referred to the SR-71 inlet design and called the potentially catastrophic disruption of the air an "inlet unstart."
Merad 4y ago
An unstart is a specific phenomenon where supersonic flow of air into the engine gets disrupted. It's very different from a compressor stall where the airflow _inside_ the engine is disrupted. Wikipedia has a pretty decent explanation: https://en.wikipedia.org/wiki/Unstart https://en.wikipedia.org/wiki/Unstart
hinkley 4y ago
In movies you see military folks with a very dry sense of humor. Doubly so for Airforce/Navy pilots, and then test pilots just bury the needle. Having worked with a few different veterans over the years (army, Intelligence, and submarine) I don't have anything in my small but diverse sample size that disagrees with that mythos. Golden Era NASA was mostly pilots and quite a few of them test pilots. "Houston, we have a problem" is iconic but as far as I can tell, not exceptional.
- marktangotango 4y ago
  > Houston, we have a problem A lot of people comment on this, but it succinctly relays the severity, in that the the pilot is alive, and the radio works.
- eismcc 4y ago
  I do wonder if the words should be further away from each other phonetically though - start … unstart seem close enough to be confused if the radio is noisy
  - jaywalk 4y ago
    Nobody is going to be talking about an unstart over the radio in an emergency situation. It took 2-3 seconds between the unstart and the aircraft disintegrating.
    - eismcc 4y ago
      I get that but it’s not my point. I’m wondering in general about word choice to minimize collisions
      - hinkley 4y ago
        I suspect the pilots and ground crew save their energy to fight about the things they are likely to say over a radio and let the engineers do whatever they want with the rest. Unstart is a lot less evocative than “flameout” as used in the Top Gun movie. Flameout sounds like the plane is on fire. Especially if garbled. Meanwhile, if your righter pilot sounds like he said engine start while flying? That’s only gonna happen if the engine already shut down. So that’s only ambiguous until the pilot keeps talking, in which case you know he was able to restart the engine before losing consciousness, versus the end of that conversation.
chiph 4y ago
Because "inlet fart", while descriptive of what happens, wasn't socially acceptable.

“unstart” - while a terrifying euphemism - is there is reason “stall”, or similar, is not used?

by eismcc 4y ago

“unstart” - while a terrifying euphemism - is there is reason “stall”, or similar, is not used?

Looks like it's a technical term for a particular type of supersonic behavior: https://en.wikipedia.org/wiki/Unstart https://en.wikipedia.org/wiki/Unstart

eismcc 4y ago
The semantics is start/unstart are definitely more interesting in this context and seem less dramatic in the context of wind tunnel tests

sigstoat 4y ago

> “unstart” - while a terrifying euphemism - is there is reason “stall”, or similar, is not used? "stall" has a specific meaning, and it isn't what happened.

kurthr 4y ago

The supersonic shockwave-cone would enter the engine intake, which leads to an un-start. The weird cones that stick out the front of the engines can be manipulated to slow down the incoming air and keep it below supersonic at the intakes, which is normally done automatically with little analog computers that apparently failed somewhat regularly and in this case spectacularly during a banking turn.

Wistar 4y ago
In the course of helping an acquaintance do research for a book, I listened to hours of interviews with an 80 year old aerodynamics specialist who worked for Boeing for decades. It was fascinating stuff. One of his specialties was the design of the inlets for jet engines and, through the conversation, I learned that the inlet is the entire aerodynamic approach to the actual engine intake, starting before the air even encounters any of the structure of the aircraft. Turns out that certain designs cause turbulence out in front of the aircraft and all of that path to the intake must be taken into account. He referred to the SR-71 inlet design and called the potentially catastrophic disruption of the air an "inlet unstart."

Merad 4y ago

An unstart is a specific phenomenon where supersonic flow of air into the engine gets disrupted. It's very different from a compressor stall where the airflow _inside_ the engine is disrupted. Wikipedia has a pretty decent explanation: https://en.wikipedia.org/wiki/Unstart https://en.wikipedia.org/wiki/Unstart

hinkley 4y ago

In movies you see military folks with a very dry sense of humor. Doubly so for Airforce/Navy pilots, and then test pilots just bury the needle. Having worked with a few different veterans over the years (army, Intelligence, and submarine) I don't have anything in my small but diverse sample size that disagrees with that mythos. Golden Era NASA was mostly pilots and quite a few of them test pilots. "Houston, we have a problem" is iconic but as far as I can tell, not exceptional.

marktangotango 4y ago
> Houston, we have a problem A lot of people comment on this, but it succinctly relays the severity, in that the the pilot is alive, and the radio works.
eismcc 4y ago
I do wonder if the words should be further away from each other phonetically though - start … unstart seem close enough to be confused if the radio is noisy
- jaywalk 4y ago
  Nobody is going to be talking about an unstart over the radio in an emergency situation. It took 2-3 seconds between the unstart and the aircraft disintegrating.
  - eismcc 4y ago
    I get that but it’s not my point. I’m wondering in general about word choice to minimize collisions
    - hinkley 4y ago
      I suspect the pilots and ground crew save their energy to fight about the things they are likely to say over a radio and let the engineers do whatever they want with the rest. Unstart is a lot less evocative than “flameout” as used in the Top Gun movie. Flameout sounds like the plane is on fire. Especially if garbled. Meanwhile, if your righter pilot sounds like he said engine start while flying? That’s only gonna happen if the engine already shut down. So that’s only ambiguous until the pilot keeps talking, in which case you know he was able to restart the engine before losing consciousness, versus the end of that conversation.

chiph 4y ago

Because "inlet fart", while descriptive of what happens, wasn't socially acceptable.