Wikipedia:Reference desk/Archives/Science/2019 January 6

= January 6 =

All-weather fighters
What was the first American or Nato fighter jet to have true all-weather capability (take off, intercept and destroy the target in any weather, and then land in any weather from an ILS coupled and/or manual approach and/or a PAR approach)? Is it true that the F-102 was capable of this? What was the first Soviet fighter jet to have the same capability? 2601:646:8A00:A0B3:74C8:E1A4:A5D:7436 (talk) 07:49, 6 January 2019 (UTC)
 * PAR approach is the correct wikilink. DroneB (talk) 11:04, 6 January 2019 (UTC)
 * It should be noted that "all weather" really means "most weather". The procurement specifications for "all weather" aircraft don't include the ability to fly into category 3, 4 or 5 hurricanes, severe icing, or H5 and larger hail. --Guy Macon (talk) 15:40, 6 January 2019 (UTC)
 * Also see: Lockheed WP-3D Orion. --Guy Macon (talk) 15:44, 6 January 2019 (UTC)
 * Indeed, it's more useful to consider the gradual improvement in aircraft capability. One useful metric is the percentage of operations that had to be scrubbed (cancelled) due to weather: you can compare how that percentage varied with time across aircraft types.  Bear in mind that this analysis would be fraught with confounding variables, like the actual weather variability with time and geography of operations; and improvements to the infrastructure around the aircraft; and so on.
 * Personally, I consider the A-6 Intruder to be a significant milestone: its electronics and avionics look and feel very similar to modern aircraft. It even had computer screens in the flight deck!
 * Since the early days of aviation, pilots and engineers have been increasing the capability of the aircraft's control and navigation performance, marching toward operations in "all" weather. But even today, pilots use a healthy dose of Aeronautical Decision Making - that is, the scientific process of risk management (and specifically including quantitative analysis of the weather during the flight operation).  If the sum total of all risks, including weather risks, exceeds a reasonable threshold, the flight must be scrubbed!
 * Nimur (talk) 17:35, 6 January 2019 (UTC)


 * And while we're digging into winter all-weather history, this was the front-page story on the All Hands digital edition during November/December last year: story about a now-famous F-9F flight - a specific mission launched in 1952 over a geographic region that today is either Korea, China, and/or Russia - the Navy pilots flew through a blizzard-condition snowstorm because their orders came from the cryptography division known in 2019 as the National Security Agency. When there's a reason to go, they can fly Panthers into snow...
 * This was an aircraft that was not "designed" for an all-weather role; its on-board systems and its pilot training regimen probably meant that it was not fully-prepared for combat operations in blizzard white-out. But, as long as you have a working compass, a working altimeter, and at least one additional instrument such as a turn coordinator, it is possible for a skilled pilot to keep their head up ... even though we'd all surely prefer an attitude indicator.
 * Nimur (talk) 17:50, 6 January 2019 (UTC)


 * The F-15 and F-16 both got an update to allow full allweather operation. I only read for the F-15 that the "F-15E" was the first version that was allweather but i guess the F-16 got updated at the same time. Likely it was mainly software since both fighters already had very capable, modern computers. --Kharon (talk) 18:38, 6 January 2019 (UTC)


 * General Dynamics F-16 Fighting Falcon says this: "it evolved into a successful all-weather multirole aircraft" (note piped link) and later this: "The first C/D version was the Block 25 with improved cockpit avionics and radar which added all-weather capability with beyond-visual-range (BVR) AIM-7 and AIM-120 air-air missiles." Martinevans123 (talk) 18:48, 6 January 2019 (UTC)


 * Thanks Martinevans123. I also just read the F-16 was the first manufactured with an advanced Fly-by-wire-System. Quite a package if you compare all that in the F-16C/D for ~19 million $ compared to the new fighters which are somewhere beyond 100 million $ a piece. --Kharon (talk) 19:28, 6 January 2019 (UTC)
 * It's a widely-known fallacy to compare costs on a unit-basis for such extraordinarily large Government acquisitions that span multiple decades. Consider reading Metrics to Compare Aircraft Operating and Support Costs in the Department of Defense, an extensively-researched economics policy whitepaper published by RAND and ... made available to the general public at zero-cost.  Another relevant recent RAND Monograph, specifically as pertains to a total program cost comparison between F-16 and F-35, is MG-1225: Do Joint Fighter Programs Save Money?  And if you're really following the news closely, here's RAND Report 2063 from July, advising whether a 24-month block-buy is a net cost savings between now and 2021; put simply, if we buy the same number of airplanes in 2021 and pay for them in 2021, they cost quite a different amount than if we pay for them in 2019, or if we pay for them in 2023; and if we decide in 2020 that we want to buy a different number of airplanes, the cost per airplane will also change!  As you can surmise, this whole cost-per-airplane stuff is pretty heavily scrutinized by lots of experts!
 * Economics - it's a real thing with implications!
 * Of course, if you don't believe me, you can always hop on to Trade-a-Plane.com, where you, the discerning airplane-cost-expert, may purchase jets for discount prices, as long as you disregard the hidden costs of acquisition, transport, operation, training, airworthiness, maintenance, storage, fleet management, legal and regulatory items, taxes, tariffs, ... you know, the small details. I understand that as of January 2019, they even have MiG-29 listed on behalf of the owner.
 * Nimur (talk) 19:52, 6 January 2019 (UTC)


 * Some time before the F-102. Either the Gloster Meteor NF.11 (UK), the F-94 Starfire (US) or the CF-100 (Canadian). All of these first-gen jet fighters were of fairly limited performance compared to what came only a few years later, but they had the basics. and were really just intended as stop gaps before the Gloster Javelin, F-102 or CF-105 became available.
 * At this early time, there was little distinction between 'all-weather' and 'night fighter'. Both involved deploying on-board radar. The airframes were largely interchangeable, even if deployed aircraft might be long-term tasked to either one or the other.
 * The 'basics' here were to have radar, a second seat (as these early sets needed an operator who wasn't busy piloting) and two engines. This was mostly to lift the weight of a heavier radar-equipped, twin-seater aircraft with large fuel capacity (adequate endurance in the days before in-flight refuelling) – engines of this era were low thrust, so two were needed. A second engine was also needed for reliability in the real all-weather case. The F-94 was sngle-engined, but also had a lighter weight radar set than the others, of limited range. It used this radar for interception and gunnery, but search and acquisition was performed by ground radar (and the SAGE system).
 * ILS was still in its infancy at this time but was developing both rapidly and in gradual stages. It didn't 'suddenly appear' in one go. Andy Dingley (talk) 20:31, 6 January 2019 (UTC)
 * "All-weather" fighters was an outgrowth of night fighters. The Germans worked on night/all-weather version of their Me262, but since the OP ask about US and NATO jet aircrafts;
 * North American F-86D Sabre, first flight 1949 (developed as an all weather fighter)
 * Douglas F3D Skyknight, first flight 1948, entry into service 1951 (developed as a naval all weather fighter)
 * Avro Canada CF-100 Canuck, first flight 1950, entry into service 1952 (developed as a long range all weather fighter)
 * Gloster Meteor NF.11, first flight 1950, entry into service 1951 (modified from a "day fighter" as an interim night fighter)
 * de Havilland Vampire NF.10, first flight 1949 (modified from a "day fighter" as an interim night fighter)
 * Gloster Javelin, first flight 1951, entry into service 1956 (developed as an night & all weather fighter)
 * All of the above was capable of taking off, navigating, conducting combat and return to base (and land) in darkness and inclement weather. WegianWarrior (talk) 20:36, 6 January 2019 (UTC)
 * @Nimur So the F-16 from 1998 was US$18.8 million and the F-35B from 2018 is US$115.5 million. That is a 600% rise in just 20 years or a bit under 30% inflation per year. I dont need a lesson in economy and even less some made up science paper or study to see something went wrong there. Besides i remember even Mr. Trump had some talks about that with Lockheed Martin. Btw. the russian Sukhoi Su-57 aka T-50 will be US$50 million according our articles. Bet it has all the latest technology an F-35 has, so new technology is not the factor for these crazy (600%) developements, not is time. --Kharon (talk) 21:16, 6 January 2019 (UTC)
 * I wasn't following the whole discussion, but your math doesn't take into account that inflation per year is multiplicative (like compound interest). You want 6.00^(1/20) = 1.0937, or 9.4% increase per year.  Of course, this doesn't change the total amount the price has increased! Wnt (talk) 00:06, 7 January 2019 (UTC)
 * [un-indent] Thanks, all! So the conclusion (for the first question) is that by the end of 1950, the USA already had several interceptors with this capability.  Now for the other question: when did the Soviets acquire the same capability? 2601:646:8A00:A0B3:74C8:E1A4:A5D:7436 (talk) 04:07, 7 January 2019 (UTC)
 * For several reasons (language and security, to mention two) the information on early Soviet all weather capable interceptors are harder to come by, but the earliest I'm aware of is :
 * Yakovlev Yak-25, first flight 1952, entry into service 1955
 * Sukhoi Su-9, first flight 1956, entry into service 1959
 * It is commonly accepted - as far as I can tell - that the development of Soviet avionics and airborne radar lagged western development by several years. This - and different strategic and tactical considerations - explains why NATO forces fielded all weather jet fighters several years ahead of the Soviets. WegianWarrior (talk) 04:35, 7 January 2019 (UTC)
 * Thanks! So as far as the Soviets were concerned, this song (recorded 1951) was at the time just empty bragging and actually described the capabilities which would have been used against them, just as I thought?  :-) 2601:646:8A00:A0B3:940E:B215:E6AD:437C (talk) 03:31, 8 January 2019 (UTC)

Why are carbonate esters so obscure?
Carbonate esters have been promoted as "green solvents" (dimethyl carbonate), but aren't something I've heard much about. Probably this reflects a very limited role in biology, hence few sources of cheap bulk carbonate ester compounds -- even though there should be a carbonate analog for almost every ketone. I know that carbonic acid and bicarbonate are everywhere in the body, and I see a report about a catalytic antibody able to catalyze a relevant reaction and apparently their stability isn't all that different from esters. Artificially, people make polycarbonate plastics out of them. But I really see very little about them in the biological literature! What is the big obstacle that prevents biology from making free use of them? Wnt (talk) 18:42, 6 January 2019 (UTC)
 * The article Carbonate ester alludes to "the problem of high viscosity...". Abductive  (reasoning) 06:36, 8 January 2019 (UTC)
 * I will also quote from the article: "Many industrial production pathways for carbonates are not green because they rely on phosgene or propylene oxide." Phosgene is nasty stuff and extremely toxic, propylene oxide is a carcinogen and extremely flammable. shoy (reactions) 15:11, 10 January 2019 (UTC)
 * I was thinking that if a catalytic antibody could hydrolyze the ester, the reverse process might be wangled under sane biological conditions. To make an analogy, consider that oligonucleotide synthesis typically uses nucleoside phosphoramidites -- though to be sure, those are not so nasty as phosgene. Wnt (talk) 00:37, 13 January 2019 (UTC)

Source of medical opioids like Percocet, Percodan, and OxyContin.
Could the pill manufacturers rely absolutely on synthetic production means, or do they have to use the poppy (the plant) proper for producing their medicines? --Doroletho (talk) 23:54, 6 January 2019 (UTC)


 * According to "Synthetic opioids may be sub-divided into five chemical classes: phenanthrenes (including levorphanol and butorphanol), benzomorphans (including pentazocine and loperamide), phenylpiperidines (including fentanyl and its derivatives), diphenylheptanes (including methadone), phenylpropyl amines (including tramadol, tapentadol)."  Those are fully synthetic; the others are either natural, or (mostly) semi-synthetic (natural materials that are chemically modified, like modifying morphine with acetic anhydride).  Most of the semi-synthetic opioids still have a phenanthrene chemical structure.


 * I imagine that reference probably missed some more obscure classes from current research - it seems like somebody comes out of the woodwork with some yet more potent opium analog all the time nowadays. There are also cases like kratom where the classification is up for debate, and that too might be the case for obscure research chemicals. Wnt (talk) 02:09, 7 January 2019 (UTC)