Comments by "Lawrence D’Oliveiro" (@lawrencedoliveiro9104) on "Real Engineering" channel.

  1. Overly complicated, overly expensive, far too prone to problems (particularly software problems). They even had trouble with the laptops that were used to do diagnostics and software updates--it had to be this specific weird model of laptop, nothing else would do. And when they broke down, that was it.
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  2. The F-35 wasn’t even supposed to be the “high-end” fighter -- that role was reserved for the F-22. But as the cost kept going up and up, suddenly the F-35 wasn’t the cheap option any more.
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  3. Actually, the first transistors were germanium, not silicon. And other materials have been tried as well, e.g. gallium arsenide. Also note that the “doping” process uses such tiny traces of the additional elements to make such a big change to its electrical properties, the substrate would still for many purposes be considered “chemically pure”.
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  4. Then there is the problematic ALIS software that Lockheed-Martin offers to manage F-35 deployments: basically, you cannot buy an F-35 without also installing this software. That is supposed to do parts and maintenance management, which it manages to screw up in an endless variety of ways.
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  5. 4:43 A key thing happening here, as with the triode vacuum tube, is amplification : a small-amplitude signal can be used to control the amplitude of a much larger voltage or current, producing a stronger version of the same signal (barring well-known limitations like noise and distortion).
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  6. They even tried replacing ALIS with the new ODIN system, but that’s just ALIS under a new name, the product of the same old problematic process. For example, if a part is not properly entered into the system, it will neglect to inform you when it’s due for replacement. So it will suddenly and unexpectedly wear out, and suddenly your expensive aircraft cannot fly.
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  7. 2:43 There is a version of this need for unit conversion still relevant today. And that has to do with angles. Because most of us cope more intuitively with angles measured in degrees (or even fractions of a circle) than in radians, whereas most trigonometric calculations are most naturally done in radians. So it makes sense to store angles internally in radians, while letting the user see (and input) them in a choice of units.
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  8. Its everybody’s favourite Thunderbird. Even if the takeoff sequence from Tracy Island doesn’t make any sense.
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  9. It was called the “Bronze Age”.
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  10. What really baffles me, watching/hearing/reading records of the Apollo missions, is how they randomly switch between different units, such as mph versus knots versus miles per second. Couldn’t they at least forego the nautical miles and stick to statute miles?
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  11. 6:49 Actually, computers have unit-calculation apps available -- at least in all the self-respecting OSes -- that can cope with such common tasks. Such as this one https://www.gnu.org/software/units/ .
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  12. 8:41 There is a unit called the “poundal” for force/weight, distinct from “pound” for mass.
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  13.  @Appletank8  Except this aircraft is no longer “new”. That ALIS software was up to version 27 or more.
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  14. Remember, this aircraft has been in production for over a decade. And with all the hundreds of millions spent, you’d think they would have a decent quality software platform. But no: the interface computer they use for loading software updates and diagnostics is running ... Microsoft Internet Explorer! Yup, they are not only using a control platform based on a web browser, they are using a web browser whose own maker has given up trying to plug all the holes in it. And this is supposed to be a mil-spec system, able to withstand the rigours of hostile enemy attack.
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  15. Interesting that that Chinese “spy” balloon was just shot down by a missile from an F-22. Wonder why the F-35 couldn’t do the job?
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  16.  @Mortlupo  Spacecraft most certainly do not use knots. Remember, nearly all such missions are international nowadays, and it’s all metric out there. And there are places even within our atmosphere where aircraft are controlled using SI units.
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  17. So, instead of multiplying by 0.3937..., just divide by 2.54.
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  18. You can do measurements without errors? Or, just stick to rational arithmetic, then.
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  19.  @CaptainDangeax  Use exact rational arithmetic, if that’s what you want.
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  20. Quantum tunnelling is itself integral to how transistors (and vacuum tubes) work in the first place.
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  21. Fun question to contemplate: the transistor was an American invention; so why did the Japanese take it and run with it, to produce well-known transistorized appliances (transistor radios and the like) from the 1960s onwards? In the US there was already an established consumer-electronics industry, based on vacuum tubes. The reason was precisely those vacuum tubes. The US industry had a great deal invested in them over many prior decades, which it was reluctant to give up. The Japanese were starting from nothing, so they were free to adopt the new technology. This is an example of a “disruptive technology”, where the existing players will not adopt the new idea because they see it as a threat, either to themselves or their existing customers. And so it is left to new players to come in and take over the market.
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  22. 0:55 Countries that have landed on the Moon also include the USSR/Russia, and now China and India. So those using Imperial are already outnumbered there as well.
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  23. 3:01 Airflow separation is a turbulence phenomenon. The loss of lift would have nothing to do with Bernoulli’s Principle. Another term for it is “stalling”.
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  24. 3:55 No it doesn’t. The substance is still neutral, because the phosphorus nucleus still has that extra proton to counter the charge of the extra electron. The terms “n-type” and “p-type” just say that the “majority charge carriers” (quantum entities that flow to carry the current) are negatively-charged electrons in the one case, and positively-charged “holes” (actually, the absence of an electron) in the other case.
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  25. 18:00 The atomic number of beryllium is 4. Its atomic weight is more like 9.
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  26. 11:24 “Any future manned mission.”
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  27. 7:03 More penetrating kinds of radiation, really. Alpha particles are the largest, most massive and carry the greatest electrical charge, so are easiest to stop.
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  28. 18:59 Higher, not lower, frequencies (shorter, not longer, wavelengths).
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