6 ms·

I'm also terrified by that wing aspect ratio. Fast it must have been, but it seems that they sacrificed a lot of common (flying) sense to get there.

Waterluvian 4y ago
I know so little about this but aren’t fighters much more ballistic in order to be nimble? My loose amateur sense is that a fighter pilot is always flirting with their plane no-longer behaving like a plane and more like a guided missile if they flew it just the slightest wrong (or right?) way.
- lmm 4y ago
  You're thinking of something different. Modern (computer-controlled) fighters are aerodynamically unstable because that makes them more manouverable, but that's about being able to turn or spin rather than flying balistically. For traditionally-shaped planes (delta wings work differently) there's a fairly straightforward tradeoff between big wings to increase lift at low speeds and small wings to reduce drag at high speed. Flaps help but there's a limit to how much you can change the shape of a wing in flight. So if you build a plane to go very fast, you tend to end up with a plane that has a high minimum speed as well, which makes take off and especially landing difficult.
  - Waterluvian 4y ago
    Thank you. To simplify, are you basically saying that with more unstable wing configurations, at slower speeds the plane simply wants to fall out of the sky rather than glide? Is that sensible to imagine for this topic?
    - lmm 4y ago
      It's not "unstable", it's low-lift, those are two orthogonal concerns.
    - WalterBright 4y ago
      It's more likely to stall at the lower speeds and then fall out of the sky.
    - mabcat 4y ago
      Stability is how the aircraft reacts to disturbances (control inputs, turbulence, ...). Stable aircraft resist disturbances and settle into going where they're pointed at a predictable speed, so you can let go of the controls and attend to other pilot things. Unstable aircraft, when disturbed, go more and more in the direction of the disturbance. (e.g. a turn gets tighter and tighter, nose oscillates up and down more and more, ...) You need to correct this with more control inputs, but these will also have unstable results. So they only let computers fly unstable aircraft. A car has good stability in turns: it wants to go straight, if there's a bump or you jerk the wheel a bit it still goes straight. If you apply a control input and get a turn, it will let you maintain the turn but it also wants to unwind and go straight. This is stability but not aerodynamic stability. The reason one might want a less-stable aircraft is that stability is the opposite of manoeuverability. Super-stable aircraft like training gliders really resist turning and can feel too much like hard work. As another commenter mentioned the wings don't contribute much to stability. The two big fins at the back (the stabilizers) are the main source. (disclaimer: I fly fixed-wing acft and gliders, barely, and am no physicist.)
lmm 4y ago
Yep. Killed so many pilots that the guy out of Hawkwind made a satircal concept album about it.
TylerE 4y ago
It makes a lot of sense in that lift grows linearly with area, and exponentially with speed.
- WalterBright 4y ago
  Yeah, but first you have to get off the ground and gain some altitude! Jet engines don't really start developing power until they're moving forward fast (forcing more oxygen into the intake). My dad said flying a jet out of Denver was always a challenge because the jet would just lumber along refusing to develop power. (Denver is at high altitude.) He'd always start the takeoff roll with the tail hanging over the edge of the runway start.
cycomanic 4y ago
And you would be right. The starfighter was widely deployed in Western Germany and had a terrible safety record (>100 pilots and >200 planes lost out of 900). I recall it widely being discussed in the media when I was young and the plane was called the widowmaker for that reason.
- hef19898 4y ago
  Iy was, a common joke was that if you wanted a Starfighter all you had to do was to buy an acre of land and wait for a while... Truth be told, the Starfighter was an interceptor, designed to carry air-to-air missiles fast towards approaching Soviet strategic bombers. That's it, nothing else. The German Airforce wanted a multi-role fighter, some creative Lockheed marketing assured the the Starfighter was bought in the F-104G variant. At that G-variant turned it into a brick to fly, stall speeds close to minimum take off speeds among other things. The starfighter's safety record with other operators was a lot better.
  - tokai 4y ago
    >creative Lockheed marketing assured It was bribery and corruption - not marketing. https://en.wikipedia.org/wiki/Lockheed_bribery_scandals https://en.wikipedia.org/wiki/Lockheed_bribery_scandals
    - hef19898 4y ago
      There is a reason Franz-Josef Strauss became as rich as he did being a "mere" minister and state prime minister. He never got caught so... In the end his insistence on a multirole fighter and the fighter being the F-104G (already almost oboslete at the time) killed a lot of pilots. Great example to show the cost of corruption.
      - rob74 4y ago
        Don't mention that in Bavaria though, or you risk being driven out of town. He's still a legend here, especially for the ruling party (CSU) of this virtual one-party state. The Munich airport is named after him, and AFAIK the current state prime minister still has a bust of him on his desk.

Waterluvian 4y ago

I know so little about this but aren’t fighters much more ballistic in order to be nimble? My loose amateur sense is that a fighter pilot is always flirting with their plane no-longer behaving like a plane and more like a guided missile if they flew it just the slightest wrong (or right?) way.

lmm 4y ago
You're thinking of something different. Modern (computer-controlled) fighters are aerodynamically unstable because that makes them more manouverable, but that's about being able to turn or spin rather than flying balistically. For traditionally-shaped planes (delta wings work differently) there's a fairly straightforward tradeoff between big wings to increase lift at low speeds and small wings to reduce drag at high speed. Flaps help but there's a limit to how much you can change the shape of a wing in flight. So if you build a plane to go very fast, you tend to end up with a plane that has a high minimum speed as well, which makes take off and especially landing difficult.
- Waterluvian 4y ago
  Thank you. To simplify, are you basically saying that with more unstable wing configurations, at slower speeds the plane simply wants to fall out of the sky rather than glide? Is that sensible to imagine for this topic?
  - lmm 4y ago
    It's not "unstable", it's low-lift, those are two orthogonal concerns.
  - WalterBright 4y ago
    It's more likely to stall at the lower speeds and then fall out of the sky.
  - mabcat 4y ago
    Stability is how the aircraft reacts to disturbances (control inputs, turbulence, ...). Stable aircraft resist disturbances and settle into going where they're pointed at a predictable speed, so you can let go of the controls and attend to other pilot things. Unstable aircraft, when disturbed, go more and more in the direction of the disturbance. (e.g. a turn gets tighter and tighter, nose oscillates up and down more and more, ...) You need to correct this with more control inputs, but these will also have unstable results. So they only let computers fly unstable aircraft. A car has good stability in turns: it wants to go straight, if there's a bump or you jerk the wheel a bit it still goes straight. If you apply a control input and get a turn, it will let you maintain the turn but it also wants to unwind and go straight. This is stability but not aerodynamic stability. The reason one might want a less-stable aircraft is that stability is the opposite of manoeuverability. Super-stable aircraft like training gliders really resist turning and can feel too much like hard work. As another commenter mentioned the wings don't contribute much to stability. The two big fins at the back (the stabilizers) are the main source. (disclaimer: I fly fixed-wing acft and gliders, barely, and am no physicist.)

lmm 4y ago

Yep. Killed so many pilots that the guy out of Hawkwind made a satircal concept album about it.

TylerE 4y ago

It makes a lot of sense in that lift grows linearly with area, and exponentially with speed.

WalterBright 4y ago
Yeah, but first you have to get off the ground and gain some altitude! Jet engines don't really start developing power until they're moving forward fast (forcing more oxygen into the intake). My dad said flying a jet out of Denver was always a challenge because the jet would just lumber along refusing to develop power. (Denver is at high altitude.) He'd always start the takeoff roll with the tail hanging over the edge of the runway start.

cycomanic 4y ago

And you would be right. The starfighter was widely deployed in Western Germany and had a terrible safety record (>100 pilots and >200 planes lost out of 900). I recall it widely being discussed in the media when I was young and the plane was called the widowmaker for that reason.

hef19898 4y ago
Iy was, a common joke was that if you wanted a Starfighter all you had to do was to buy an acre of land and wait for a while... Truth be told, the Starfighter was an interceptor, designed to carry air-to-air missiles fast towards approaching Soviet strategic bombers. That's it, nothing else. The German Airforce wanted a multi-role fighter, some creative Lockheed marketing assured the the Starfighter was bought in the F-104G variant. At that G-variant turned it into a brick to fly, stall speeds close to minimum take off speeds among other things. The starfighter's safety record with other operators was a lot better.
- tokai 4y ago
  >creative Lockheed marketing assured It was bribery and corruption - not marketing. https://en.wikipedia.org/wiki/Lockheed_bribery_scandals https://en.wikipedia.org/wiki/Lockheed_bribery_scandals
  - hef19898 4y ago
    There is a reason Franz-Josef Strauss became as rich as he did being a "mere" minister and state prime minister. He never got caught so... In the end his insistence on a multirole fighter and the fighter being the F-104G (already almost oboslete at the time) killed a lot of pilots. Great example to show the cost of corruption.
    - rob74 4y ago
      Don't mention that in Bavaria though, or you risk being driven out of town. He's still a legend here, especially for the ruling party (CSU) of this virtual one-party state. The Munich airport is named after him, and AFAIK the current state prime minister still has a bust of him on his desk.