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A pilot who stole a secret Soviet fighter jet

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Re: A pilot who stole a secret Soviet fighter jet

#71
post #9

Hard to believe the Soviets were using vacuum tubes instead of transistors In hindsight, the MiG 25, which the West had been so worried about, turned out to be a ‘paper tiger’. Its massive radar was years behind US models because instead of transistors it used antiquated vacuum tubes (a technology that did, however, make it impervious to electromagnetic pulses from nuclear blasts). The huge engines required so much f…

The factoid about resistance to EMP gets repeated endlessly online and in print, but it doesn't really make sense, and I doubt it's true. EMP damages electrical connections which are: a) long. b) thin. c) far from a ground plane. In more detail: the induced current depends directly on the length of the conductor; a thin is more easily overheated and damaged than a thick one; and conductors running near ground planes…

You're fundamentally wrong on this.

What you are talking about is true only for inductive coupling caused by fluctuating EM waves.

As someone who works in Embedded Electronics and Software for Aerosopace let me drop a little knowledge bomb.

The problem isn't with induction, all the units can be easily shielded from this and they are in EMC chambers every day. A simply faraday cage, some bypass and reservoir capacitors a choke here and there an opto-isolator on box boundaries and bobs your uncle.

The real problem with High Energy Particles (Neutrons, Gamma particles, Protons, etc) is that they displace atoms in your semiconductor lattice and change the doping densities and behaviours of your junctions. Causing your semiconductor to fail... HARD.

When we buy in components, we tend to buy rad-hard devices which have special considerations taken into account when designing the semiconductors because when you're in space, you're bombarded with LOADS of high energy particles all the time, and its not just enough to have memory TMR, you need RAD-HARDENED semiconductors.

Re: A pilot who stole a secret Soviet fighter jet

#72
post #70

Earlier quoted context omitted.

> Unlike similar American jets, you can find Mig-25's in private hands today being maintained and flying. It's hard to know where you came up with this. Starfighters Inc. came up in another thread recently: http://www.starfighters.net/fleet/ They fly F-104s, which I'd much rather be responsible for maintaining than something like a MiG-25. If you see a dearth of ownership of newer American jets, it's probably because…

F-104 doesn't look particularly similar to MiG-25. Things like take-off weight, maximum speed... At least Wikipedia https://en.wikipedia.org/wiki/Lockheed_F-104_Starfighter doesn't list MiG-25 as comparable to F-104.

I didn't mean to imply that they are similar aircraft. Interestingly, they have some similar strengths and a similar mission: relatively short-range and high-speed interception. They represent two very different, extreme engineering approaches.

They are both planes that set records for zoom climbing, a performance record associated with their interceptor mission, and some other speed and altitude records: https://en.wikipedia.org/wiki/Zoom_climb

Anecdotally, one of the more interesting things I've read over the years about their engineering is their failure modes. (who knows how much of this is really true, but it's interesting) Given the correct flight profile, the F-104 will keep accelerating towards Mach 3 right until the canopy material or some other relatively fragile thing starts to fail. The MiG-25 will fly up to the often-quoted Mach 3 number, the airframe is brutally strong, but the engines will be damaged by flying at that speed. But it's entirely possible the Russians upgraded those engines in the eighties. Upgrades to the F-104 over the years only brought the (reported) top speed from Mach 2 to Mach 2.2, but the thing's got razor-sharp wings...

Re: A pilot who stole a secret Soviet fighter jet

#73
post #9

Hard to believe the Soviets were using vacuum tubes instead of transistors In hindsight, the MiG 25, which the West had been so worried about, turned out to be a ‘paper tiger’. Its massive radar was years behind US models because instead of transistors it used antiquated vacuum tubes (a technology that did, however, make it impervious to electromagnetic pulses from nuclear blasts). The huge engines required so much f…

The factoid about resistance to EMP gets repeated endlessly online and in print, but it doesn't really make sense, and I doubt it's true. EMP damages electrical connections which are: a) long. b) thin. c) far from a ground plane. In more detail: the induced current depends directly on the length of the conductor; a thin is more easily overheated and damaged than a thick one; and conductors running near ground planes…

Vacuum tubes and transistors have different failure modes. If you apply high voltage to a vacuum tube, it will arc and warm up, but not sustain much damage. Do the same with a transistor and it will promptly turn into a resistor.

Source: burned plenty of transistors and vacuum tubes while studying electrical engineering.

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