Monocoque

Monocoque (pronounced mon-uh-kohk or mon-oh-kok (non-U))

(1) A type of boat, aircraft, or rocket construction in which the shell carries most of the stresses.

(2) A type of automotive construction in which the body is combined with the chassis as a single unit.

(3) A unit of this type.

1911: From the French monocoque (best translated as “single shell” or “single hull” depending on application), the construct being mono- + coque.  Mono was from the Ancient Greek μόνος (monos) (alone, only, sole, single), from the primitive Indo-European root men (small, isolated).  Coque was from the Old French coque (shell) & concha (conch, shell), from the Latin coccum (berry) and concha (conch, shell) from the Ancient Greek κόκκος (kókkos) (grain, seed, berry).  In the early twentieth century, it was the French who were most dominant in the development of aviation.  Words like “monocoque”, “aileron”, “fuselage” and “empennage” are of French origin and endure in English because it’s a vacuum-cleaner of a language which sucks in anything from anywhere which is handy and manageable.  Monocoque is a noun; the noun plural is monocoques.

Noted monocoques

Deperdussin Monocoque, 1912.

A monocoque (sometime referred to as structural skin) is a form of structural engineering where loads and stresses are distributed through an object's external skin rather than a frame; concept is most analogous with an egg shell. Early airplanes were built using wood or steel tubes covered with starched fabric, the fabric rendering contributing only a small part to rigidity.  A monocoque construction integrates skin and frame into a single load-bearing shell, reducing weight and adding strength.  Although examples flew as early as 1911, airframes built as aluminium-alloy monocoques would not become common until the mid 1930s.  In a pure design where only function matters, almost anything can be made a stressed component, even engine blocks and windscreens.

Lotus 25, 1962.

In automotive design, the word monocoque is often misused, treated as a descriptor for anything built without a separate chassis.  In fact, most road vehicles, apart from a handful of expensive exotics, are built either with a separate chassis (trucks and some SUVs) or are of unibody/unitary construction where box sections, bulkheads and tubes to provide most of the structural integrity, the outer-skin adding little or no strength or stiffness.  Monocoque construction was first seen in Formula one in 1962, rendered always in aluminium alloys until 1981 when McLaren adopted carbon-fibre.  A year later, the McLaren F1 followed the same principles, becoming the first road car built as a carbon-fibre monocoque.

BRM P83 (H16), 1966.

In 1966, there was nothing revolutionary about the BRM P83’s monocoque chassis.  Four years earlier, in the second season of the voiturette era, that revolution had been triggered by the Lotus 25, built with the first fully stressed monocoque chassis, an epoch still unfolding as materials engineering evolves; the carbon-fibre monocoques seen first in the 1981 McLaren MP4/1 becoming soon ubiquitous.  The P83 used a monocoque made from riveted Duralumin (the word a portmanteau of durable and aluminium), an orthodox construction for the time.  Additionally, although it had been done before and would soon become an orthodoxy, what was unusual was that the engine was a stressed part of the monocoque.

BRM Type 15 (V16), 1949.

The innovation was born of necessity.  Not discouraged by the glorious failure of the extraordinary V16 BRM had built (with much much fanfare and precious little success) shortly after the war, the decision was taken again to join together two V8s in one sixteen cylinder unit.  Whereas in 1949, the V8s had been coupled at the centre to create a V16, for 1966, the engines were re-cast as 180^o flat 8s with one mounted atop another in an H configuration, a two-crankshaft arrangement not seen since the big Napier-Sabre H24 aero-engines used in the last days of the war.  The design yielded the advantage that it was short, affording designers some flexibility in lineal placement, but little else.  It was heavy and tall, exacerbating further the high centre of gravity already created by the need to raise the engine location so the lower exhaust systems would clear the ground.  Just as significantly, it was wide, too wide to fit into a monocoque socket and thus was taken the decision to make the engine an integral, load-bearing element of the chassis.  There was no other choice.

BRM H16 engine and gearbox, 1966.

 

Structurally, it worked, the monocoque was strong and stable and despite the weight and height, the P83 might have worked if the H16 had delivered the promised horsepower but the numbers were never realised.  The early power output was higher than the opposition but it wasn’t enough to compensate for the drawbacks inherent in the design and, these being so fundamental they couldn’t be corrected, the only hope was even more power.  The path to power was followed and modest increases were gained but it was never enough and time ran out before the plan to go from 32 to 64 valves could come to fruition, an endeavour some suggested would merely have “compounded the existing error on an even grander scale.”  Additionally, with every increase in power and weight, the already high fuel consumption worsened.

The H16 did win one grand prix, albeit in a Lotus rather than a BRM monocoque, but that was a rare success; of the forty times it started a race, twenty-seven ended prematurely.  The irony of the tale is that in the two seasons BRM ran the 440 horsepower H16 with its sixteen cylinders, two crankshafts, eight camshafts and thirty-two valves, the championship in both years was won by the Repco-Brabham, its engine with 320 horsepower, eight cylinders, one crankshaft, two camshafts and sixteen valves.  Adding insult to the exquisitely bespoke H16’s injury, the Repco engine was based on an old Oldsmobile block which General Motors had abandoned.  After two seasons the H16 venture was retired, replaced by a conventional V12.

The Mercedes-Benz SLR McLaren

Mercedes-Benz McLaren SLR Coupé (left), Roadster (centre) and Speedster (right).

The monocoque Mercedes-Benz SLR McLaren (C199 / R199 / Z199) was a joint development with McLaren Automotive and was available as a coupé (2003-2010), roadster (2007-2009) & speedster (2009).  Visually, the car was something of an evocation of the 300 SLR gullwing coupé, two of which were built in 1955 for use in competition but never used, one of the consequences of the disaster that year during the Le Mans 24 hour endurance classic when a 300 SLR crashed into the crowd, killing 84 and injuring dozens of others.  Footage of that event is widely available and to a modern audience it will seem extraordinary the race was allowed to continue.

Lindsay Lohan, Britney Spears and Paris Hilton in Ms Hilton's Mercedes-Benz McLaren SLR, outside the Beverley Hills Hotel, Los Angeles.  This was the occasion which produced the photograph which appeared on the infamous “Bimbo Summit” front page of Rupert Murdoch’s (b 1931) New York Post, 29 November 2006.

The 300 SLR (Sport Leicht Rennsport (Sport Light Racing)) which crashed was an open version and the model name was a little opportunistic because it was essentially the W196R Formula One car with a 3.0 litre straight-8 (the F1 rules demanded a 2.5) so the SLR, built to contest the World Sports Car Championship, was technically the W196S; it became the 300 SLR to cross-associate it and the 300 SL gullwing (W198, 1954-1957).  Nine were built, two of which were converted to SLR gullwings and, although never raced, they came to be dubbed the “Uhlenhaut coupés” because they were co-opted by racing team manager Rudolf Uhlenhaut (1906–1989) as high-speed personal transport, tales of his rapid trips between German cities soon the stuff of legend and even if a few myths developed, the cars could exceed 290 km/h (180 mph) so some at least were probably true.  That what was essentially a Grand Prix race car with a body and headlights could be registered for road use is as illustrative as safety standards at Le Mans of how different was the world of the 1950s.  In 2022, one of the Uhlenhaut coupés was sold at auction to an unknown buyer (presumed to be Middle Eastern) for US$142 million, becoming by some margin the world’s most expensive used car.

As a footnote (one to be noted only by the subset of word nerds who delight in the details of nomenclature), for decades, it was said by many, even normally reliable sources, that SL stood for sports Sports Leicht (sports light) and the history of the Mercedes-Benz alphabet soup was such that it could have gone either way (the SSKL (1929) was the Super Sports Kurz (short) Leicht (light) and from the 1950s on, for the SL, even the factory variously used Sports Leicht and Super Leicht.  It was only in 2017 it published a 1952 paper (unearthed from the corporate archive) confirming the correct abbreviation is Super Leicht.  Sports Leicht Rennsport (Sport Light Racing) seems to be used for the the SLRs because they were built as pure race cars, the W198 and later SLs being road cars but there are references also to Super Leicht Rennsport.  By implication, that would suggest the original 300SL (the 1951 W194) should have been a Sport Leicht because it was built only for competition but given the relevant document dates from 1952, it must have been a reference to the W194 which is thus also a Sport Leicht.  Further to muddy the waters, in 1957 the factory prepared two lightweight cars based on the new 300 SL Roadster (1957-1963) for use in US road racing and these were (at the time) designated 300 SLS (Sports Leicht Sport), the occasional reference (in translation) as "Sports Light Special" not supported by any evidence.  The best quirk of the SLS tale however is the machine which inspired the model was a one-off race-car built by Californian coachbuilder ("body-man" in the vernacular of the West Coast hot rod community) Chuck Porter (1915-1982).  Porter's SLS was built on the space-fame of a wrecked 300 SL gullwing (purchased for a reputed US$500) and followed the lines of the 300 SLR roadsters as closely as the W198 frame (taller than that of the W196S) allowed.  Although it was never an "official" designation, Porter referred to his creation as SL-S, the appended "S" standing for "scrap".      

The SLR and its antecedents.

A Uhlenhaut coupé and a 300 SLR of course appeared for the photo sessions when in 2003 the factory staged the official release of the SLR McLaren and to may explicit the link with the past, the phrase “gullwing doors” appeared in the press kit documents no less than seven times.  Presumably, journalists got the message but they weren’t fooled and the doors have always, correctly, been called “butterflies”.  Unlike the machines of the 1950s which were built with an aluminium skin atop a space-frame, the twenty-first century SLRs were a monocoque (engineers say the sometimes heard “monocoque shell” is tautological) of reinforced carbon fibre.  Although the dynamic qualities were acknowledged and it was, by all but the measure of hyper-cars, very fast indeed, the reception it has enjoyed has always been strangely muted, testers seeming to find the thing rather “soulless”.  That seemed to imply a lack of “character” which really seems to suggest an absence of obvious flaws, the quirks and idiosyncrasies which can at once enrage and endear.

The nature of monocoque.

The monocoque construction offered one obvious advantage in that the inherent stiffness was such that the creation of the roadster version required few modifications, the integrity of the structure such that not even the absence of a roof compromised things.  Notably, the butterfly doors were able to be hinged along the windscreen (A) pillars, such was the rigidity offered by carbon fibre, a material for which the monocoque may have been invented.  McLaren would later use a variation of this idea when it released the McLaren MP4-12C (2011-2014), omitting the top hinge which allowed the use of frameless windows even on the roadster (spider) version.

The SLR Speedster (right) was named the Stirling Moss edition and was a homage to the 300 SLR (left) which in the hands of Sir Stirling Moss (1929–2020) and navigator Denis Jenkinson (1920–1996), won the 1955 Mille Miglia (an event run on public roads in Italy over a distance of 1597 km (992 miles)) at an average speed of 157.65 km/h (97.96 mph).

However, the minimalist (though very expensive) Speedster had never been envisaged when the monocoque was designed and to ensure structural integrity, changes had to be made to strengthen what would have become points of potential failure, the removal of the windscreen fame and assembly having previously contributed much to rigidity.  Door sills were raised (recalling the space frame which in 1951 had necessitated the adoption of the original gullwing doors on the first 300 SL (W194)) and cross-members were added across the cockpit, integrated with a pair of rollover protection bars.  Designed for speed, the Speedster eschewed niceties such as air-conditioning, an audio system, side windows and sound insulation; this was not a car for Paris Hilton.  All told, despite the additional bracing, the Speedster weighed 140 kg (310 lb) less than the coupé while the supercharged 5.5 litre V8 was carried over from the earlier 722 edition but the reduction in frontal area added a little to top speed, now claimed to be 350 km/h (217 mph) although the factory did caution that above 160 km/h (100 mph), the dainty wind deflectors would no longer contain the wind and a crash helmet would be required so even if the lack of air-conditioning might have been overlooked, that alone would have been enough for Paris Hilton to cross the Speedster off her list; she wouldn't want "helmet hair".  Only 75 were built, none apparently ever driven, all spending their time on display or the auction block, exchanged between collectors.

Flachkühler

Flachkühler (pronounced flak-koo-ler)

In German, (literally wide cooling device (radiator)), a name adopted by Daimler-Benz to describe the W111 Mercedes-Benz coupés and cabriolets built (1969-1971) with a lower, wider radiator grill than the earlier W111 (and W112) coupés and cabriolets (1961-1969).

Circa 1860s: The construct was Flach + kühler.  The adjective flach (the singular flacher, the comparative flacher and the superlative flachsten) (shallow (wide and not deep)) was from the Middle High German vlach, from the Old High German flah, from the Proto-Germanic flakaz of uncertain origin.  The construct of the noun Kühler ((1) cooler (anything device which cools) or (2) radiator (of an internal combustion engine) was kühlen +‎ -er.  Kühlen was from the Middle High German küelen, from the Old High German kuolōn & chuolen, from the Proto-Germanic kōlōną & kōlēną and related to kalaną (to be cold).  It was cognate with the Hunsrik kiele, the Luxembourgish killen, the Dutch koelen, the Saterland Frisian köile, the English cool (verb) and the Swedish kyla.  The German suffix -er (used to forms agent nouns etc from verbs (suffixed to the verb stem)) was from the Middle High German -ære & -er, from the Old High German -āri, from the Proto-West Germanic -ārī, from the Proto-Germanic -ārijaz, from the Latin -ārius.  When used as an adjective, kühler was a comparative degree of kühl ((1) cool (of temperature), (2) calm, restrained, passionless and (3) cool, frigid (particularly of the emotions)), from the Middle High German küele, from the Old High German kuoli, from the Proto-West Germanic kōl & kōlī, from the Proto-Germanic kōluz & kōlaz, from the primitive Indo-European gel-.  It was cognate with the Dutch koel and the English cool.  Flachkühler is a noun; the noun plural is Flachkühlers.

1965 Mercedes-Benz 300 SE Cabriolet (Hōchkühler)

The dimensions of the grill used on the Mercedes-Benz W111 coupé & cabriolet was dictated by the height of the 3.0 litre (183 cubic inch) straight six (M189; 1957-1967) engine used in the more exclusive W112 (300 SE) versions.  The M189 was one of several de-tuned variants of the M198 used in the 300SL Gullwing & roadster (W198; 1954-1963) which had started life as the M186 in the big 300 (W186 & W189, “Adenauer” 1950-1963) saloon before revealing its competition potential by gaining victories at the Nürburgring, the Carrera Panamericana in Mexico and, most famously, the 24 Hours of Le Mans.  In the sports cars, the long-stroke six had been installed at an angle of 50^o and fitted with a dry sump which permitted a low hood (bonnet) line but in the W111 & W112 the engine was in a conventional perpendicular arrangement and used a wet sump, further adding to the height, thus the relatively tall grill.  The smaller sixes used in the car (2.2 litre (M127); 2.5 (M129) & 2.8 (M130)) were of a more modern, short-stroke design and didn’t demand such a capacious engine bay but production line rationalization didn’t make viable two different sets of coachwork for what were low volume models.

1971 Mercedes-Benz 280 SE 3.5 Coupé (Flachkühler)

By the mid 1960s however, Mercedes-Benz realized their gusty, high-revving sixes were, in higher-priced segments, technologically bankrupt and for success in the vital US market, they needed a mass-market V8.  Their big-block 6.3 litre V8 (M100; 1963-1981), introduced in 1963 with the 600 Grosser (W100) wasn’t suitable for down-sizing so a physically smaller range was developed, the first of which was designated M116; released in 1969 and in displacements of 3.5, 3.8 & 4.2 litres, it would serve the line until 1991.  The 3.5 came first and in 1969 it was fitted to the W111 coupé & cabriolet.  By then, the old 3.0 litre six had been discontinued so the tall grill, which by then had come to look rather baroque, as no longer required and the factory took the opportunity to modernize things and the new, lower wider grill came to be known as the Flachkühler (literally “flat cooler” and best translated as “flat radiator grill”, the engineers deciding the earlier design should be referred to as the Hōchkühler (high radiator).  Hōch (high, tall; great; immense; grand; of great importance) was from the Middle High German hōch, from the Old High German hōh, from the Proto-West Germanic hauh, from the Proto-Germanic hauhaz, from the primitive Indo-European kewk-, a suffixed form of kew-; it may be compared to the Dutch hoog, the English high and the Swedish hög.

1968 Mercedes-Benz 280 SE Cabriolet (Hōchkühler, left) and 1970 Mercedes-Benz 280 SE 3.5 Cabriolet (Flachkühler, right).

Because of the first oil shock in 1973, the plans for mass-market (a relative term) Mercedes-Benz V8s were interrupted for a while (the W116 350 SE on-sale since 1972) but the 3.5 litre W111s had already reached the end of the line before the embargo began.  Produced only until 1971, they were always expensive with only 3,270 coupés and 1,232 cabriolets were built and, it being another age, they were available with a four-speed manual gearbox, an option a few actually choose.  The Mercedes-Benz manual gear-change was a rather clunky thing but such is rarity value, they have a cult following.  The whole ecosystem of 280 SE 3.5 coupés and cabriolets is actually a cult in itself, perfectly restored cabriolets commanding prices in excess of US$500,000 and some German tuning houses will charge even more for examples modernized with attributes like ABS, later V8 engines, transmissions and suspension.  Even now, although in essence the structure dates from the late 1950s and the mechanicals a decade later, the appeal remains because the things are remarkably usable in modern conditions and ascetically, nothing Mercedes-Benz has made since has anything like the elegance but then, nor have few others.  The time of the million US$ 280 SE 3.5 Cabriolet is close.

1953 Morgan Plus 4 ("flat radiator", top left), 1955 Morgan Plus 4 (top right), 1969 Morgan Plus 8 (bottom left) and 2024 Morgan Plus 6 (bottom right).  Thematically, not all that much has changed since 1954 although under the skin there is much is the modern Morgan which is "most modern".  

Strangely, the idea of the “flat radiator” had been around for a while in the vernacular of collector car circles but it referred to another aspect of geometry.  In 1952, Morgan of Malvern Link, Worcestershire, was (as it is now) a cottage industry manufacturing pre-war sports cars with more modern engines and they received advice from the manufacturer of their separate headlight assemblies that because MG’s new TF (due for release in 1953) would have its headlamps integrated into the bodywork, production of the housing was ending.  There being no alternative supplier, Morgan were compelled to follow MG’s lead restyle things so the headlamps were faired in.  Concurrent with this, the Morgan factory took the opportunity to do one of their rare styling changes, abandoning their long-establish upright radiator grill one mounted in a cowl that blended into the hood (bonnet).  It wasn’t exactly the onset of modernity but there presumably was some aerodynamic gain.  Just to assure buyers change wasn’t being made for the sake of change, disc brakes would have to wait another few years.  The change to the grill was made in 1953 although, because of the way Morgan operated, some of the older style cars were actually assembled later than the new.  The cars with the traditional Morgan look which features the upright grill are known among aficionados as the “flat radiator Morgans”.

Impromptu Flachkühler: In October 2005, Lindsay Lohan went for a drive in her Mercedes-Benz SL 65 AMG roadster.  It didn’t end well, a was a low-speed unpleasantness with a van resulting in her roadster suffering a Flachkühler.  Based on the R230 (2001-2011) platform, the SL 65 AMG was produced between 2004-2012, all versions rated in excess of 600 horsepower, something perhaps not a wise choice for someone with no background handling such machinery though it could have been worse, the factory building 400 (175 for the US market, 225 for the RoW (rest of the world)) of the even more powerful SL 65 Black Series, the third occasion an SL was offered without a soft-top and the second time one had been configured with a permanent fixed-roof.  A production number of 350 is sometimes quoted but those maintaining registers insist it was 400.

Frankfurt police officers examining Helga Matura's 220 SE cabriolet (Hōchkühler).  Note the jackboots.

The best-known owner of a Mercedes-Benz 190 SL (W121; 1955-1962) was Fraulein Rosemarie Nitribitt (1933-1957) who, by 1957, was Frankfurt’s most illustrious (and reputedly most expensive) prostitute, a profession to which she seems to have been drawn by necessity but at which she proved more than proficient and, as the reports of the time attest, there was nothing furtive in the way she practiced her trade.  Something of a celebrity in Frankfurt, the republic’s financial centre, her black roadster became so associated with her business model that the 190 SL was at the time often referred to as the “Nitribitt-Mercedes” (and, less charitably, the Hurentaxi (whore's cab), her car seen frequently, if briefly, parked in the forecourts of the city’s better hotels.  The lives of prostitutes, even the more highly priced, can descend to their conclusion along a Hobbesian path and in 1957, aged twenty-four, she was murdered in her smart apartment, strangled with a silk stocking, the body not found for several days.  Given Fraulein Nitribitt operated at the upper end of the market, her clients tended variously to be rich, famous & powerful and that attracted the raft of inevitable conspiracy theories there had been a cover-up to protect their interests, a rather botched police investigation encouraging such rumors.  The murder remains unsolved.  In a coincidence of circumstances, a decade later, Fraulein Helga Sofie Matura (1933-1966) was another high-end prostitute murdered in Frankfurt, the weapon this time a stiletto (the stylish shoe rather than the slender blade).  Never subject to the same rumors the Nitribtt case attracted, it too remains unsolved.  In another coincidence, Fraulein Matura’s car was a convertible Mercedes, a white (W111) 220 SE Cabriolet (Hōchkühler).  Despite the connection, the W111 never picked up any prurient nicknames and nor did its reputation suffer.

Metal

Metal (pronounced met-l)

(1) Any of a class of elementary substances, as gold, silver, or copper, all of which are crystalline when solid and many of which are characterized by opacity, ductility, conductivity, and a unique luster when freshly fractured.

(2) Such as substance in its pure state, as distinguished from alloys.

(3) An element yielding positively charged ions in aqueous solutions of its salts.

(4) An alloy or mixture composed wholly or partly of such substances such as steel or brass.

(5) An object made of metal.

(6) Formative material; stuff.

(7) In printing, as type metal, the stencils used to apply ink; the state of being set in type.

(8) The substance of glass in a molten state or as the finished product; molten glass in the pot or melting tank (mostly in technical use).

(9) As road metal, the crushed rock used in road construction; small stones or gravel, mixed with tar to form tarmac for the surfacing of roads.

(10) To furnish or cover with metal.

(11) In popular music, verbal shorthand for the genre heavy metal (but apparently usually not other variations (thrash; power; gothic; doom; twisted; black; molten; death)).

(12) In admiralty jargon, the total weight of projectiles that can be shot by a ship's guns at any one time; the total weight or number of a ship's guns.

(13) In heavy element astronomy, any atom except hydrogen and helium.

(14) In heraldry, a light tincture used in a coat of arms, specifically argent (white or silver) and or (gold).

(15) In rail construction, the rails of a railway (almost always plural).

(16) In mining, the ore from which a metal is derived (the use to describe the mine from which the ore is extracted is obsolete).

(17) Figuratively, the substance that constitutes something or someone; matter; hence, character or temper (now archaic and replaced by mettle).

(18) In the jargon of civil aviation, the actual airline operating a flight, rather than any of the code-share operators.

(19) In the jargon of drag-racing, a descriptor applied to the largest capacity (usually big-block) engines.

1250–1300: From the Middle English, from the Old French metal (metal; material, substance, stuff), from the Classical Latin metallum (quarry, mine, product of a mine, metal), from the Ancient Greek μέταλλον (métallon) (mine, quarry, ore).  The Greek work picked up the sense of “metal” only in post-classical texts, via the notion of "what is got by mining”; the original meaning was "mine, quarry-pit," probably a back-formation from metalleuein "to mine, to quarry," a word of unknown origin which may be related to metallan "to seek after" but there’s no evidence in support and it’s thought derived from a pre-Greek source because of the presence of -αλλο- (-allo-).  Metal is a noun, verb & adjective and metallic is a noun & adjective; the noun plural is metals.

In the West, what defined a metal was based on the metals known from antiquity: gold, silver, copper, iron, lead, and tin.  The adjectival form (or or covered with metal) emerged in the late fourteenth century reflecting the advances in metallurgy.  The term metalwork is attested from 1724 and has been used to describe both functional and decorative endeavours and is a common title in technical education (al la woodwork).

Iron Butterfly, In-A-Gadda-Da-Vida (1968).  An early heavy metal recording, their previous album was Heavy (1968).

The use to describe a variety of loud forms of popular music (heavy; thrash; power; gothic; doom; twisted; black; molten & death-metal (there may be others, it’s hard to tell)) began with heavy metal, the term coming into general use circa 1970 to describe a genre which had evolved since what came retrospectively to be called the proto-metal pieces of the 1950s such as Link Wray's Rumble.  As a shortened form, “metal” appears to be used properly to reference only heavy metal, presumably because it came first, the other forms almost always identified with the modifier.  The use in popular music seems to have been picked up from counterculture literature, William S Burroughs (1914-1997) using the phrase "heavy metal kid" in the 1962 novel The Soft Machine.  That was not a musical reference but in the subsequent Nova Express (1964), extended the use to a metaphor for drug use and from there, adoption in somewhere in popular culture was probably inevitable; it was the 1960s.

The lightness and heaviness of naturally occurring metals has been noted since pre-historic times, probably because of the interest in the malleability of materials which might be used to craft metal ornaments, tools and weapons and until the early nineteenth century, all known metals had relatively high densities, indeed that very quality of heaviness was thought a distinguishing characteristic which defined metals.  However, beginning in 1809, lighter metals such as sodium and potassium were isolated, their low densities demanding a definitional re-think and it was proposed they be categorised as “metalloids” but instead, that was reserved to later refer to a variety of non-metallic elements.

The term "heavy metal" seems first to have been used by German chemist Professor Leopold Gmelin (1788-1853) in an 1817 paper in which he divided the elements into non-metals, light metals, and heavy metals, based on relative density.  Later, “heavy metal” would be associated with elements with a high atomic weight or high atomic number and it is sometimes used interchangeably with the term “heavy element” although, two centuries on, there is criticism of the very usefulness of the now classical categories, the suggestion being they’ve become so diverse as to be meaningless.  Despite that, “heavy metal” in particular remains frequently used in both scientific and popular literature, the latter most often without any definitional rigor.  By comparison, presumably because their less associated with environmental pollution, “light metal” appears most often in association with metal trading, referring usually to aluminium, magnesium, beryllium, titanium and lithium.

The cosmological periodic table.  Chemists do at least agree on what metals are, heavy or otherwise.  Astronomers consider any element heavier than helium to be a metal, the distinction based on whether an element was created directly after the Big Bang (hydrogen and helium) or instead formed through subsequent nuclear reactions.  In the world of cosmology this is well understood but it can cause confusion among a general audience because it means elements such as carbon and oxygen are treated as metals, a most unfamiliar concept.

To astronomers, the production of metals is a consequence of stellar evolution.  Although metals lighter than iron are produced in the interiors of stars through nuclear fusion reactions, only a very small fraction escape (through stellar winds or thermal pulsations) to be incorporated into new stars.  For this reason, the majority of the metals found in the Universe are produced and expelled in the supernova explosions that mark the end for many stars.  This gradual processing of hydrogen and helium into heavier elements through successive generations of stars means that the metallicity of stars (the fraction of the mass of the star in the form of metals) varies.  Very old stars which formed from the almost pristine material of the Big Bang contain almost no metals, while later generations of stars can have up to 5% of their mass in the form of metals.  The percentage of metals in our star (the Sun) is around 2%, indicating it’s a later generation star.

When it comes to money, and not just with precious metals like gold, the choice of metal matters much; aluminum can become quite precious.

1950 Jaguar XK120 (chassis: 670165 (aluminum body))

Jaguar went to the 1948 London Motor Show thinking their big announcement would be the new XK engine, the twin-cam straight-six which faithfully would serve the line for the next forty-four years.  What instead stole the show was the test-bed, the roadster in which it was installed.  It was a sensation, the reaction convincing Jaguar's management to put it into production as the XK120.  However, tooling-up a production-line, even for a relatively low-volume sports car, takes time so the first 242 XK120s were hand-built with aluminum bodies affixed to an ash frame atop a steel chassis substantially shared with an existing model.  By 1950, the factory was ready for mass production and all subsequent XK120s were made with pressed-steel bodies although the doors, bonnet, and boot lid continued to use aluminum; the later cars weigh an additional 112 lb (51 kg).  All the aluminum-bodied cars were open two seaters (OTS (roadster)) and most were destined for the North American market, only fifty-eight being built with right-hand drive.  The most desirable of the XK120s, the record price for a road car at auction is US$396,000, realised in 2016.  Cars with a competition history have attracted more, a 1951 Roadster campaigned by the Scottish race team Ecurie Ecosse, sold for £707,100 in 2015 while the 1954 (steel) Competition Roadster that won its class at the Alpine Rally brought £365,500 in the same year.

1955 Mercedes-Benz 300SL (chassis: 550028 (aluminum body))

Intended for those planning to use the things in competition, the aluminum body for the 300SL gullwing was a regular production option, albeit a not inexpensive one although, given the processes required, it may have been a bargain.  Reducing weight by 215 lb (80 kg), the aluminum bodies were hand-crafted in the motorsports department in Untertürkheim and then mounted on the spaceframes sent from the Sindelfingen factory.  Of the 1400 gullwings, only 29 were built in aluminum, 26 of 855 in 1955 and 3 of 308 in 1956 so the option was taken-up only by two percent of customers.

Lindsay Lohan with metallic bags, London, 2014.

Adding to the desirability of the lightweights are the other modifications the factory made to improve competitiveness against the mostly British and Italian opposition.  Plexiglass windows, vented brake drums and stiffer springs were in the package, along with the Sonderteile (special parts (NSL)) engine with tweaked fuel-injection and a more aggressive camshaft, gaining fifteen horsepower.  Curiously, one option intended for use in motorsport actually added a little weight: the Rudge wheels, the seconds the knock-off hubs saved in the pits said to be worth the slight increase.  Available for any gullwing, the Rudge wheels are one of the desirable features, like the fitted luggage, tool kit and factory documents, the presence and condition of which attract a premium at sale.  For some years, the record price at auction for one of these was the US$4.62 million for a 1955 model, paid in 2012 for a car which in 1980 been bought by a German collector for US$57,000.  A new mark was set in 2022 at RM Sotheby's January auction at Scottsdale's Arizona Biltmore Resort when one crossed the block for US$6,825,000.

Toggle

Toggle (pronounced tog-uhl)

(1) A pin, bolt or rod placed transversely through a chain, an eye or loop in a rope etc, as to bind it temporarily to another chain or rope similarly treated.

(2) In various types of machinery, a toggle joint, or a device having one.

(3) An ornamental, rod-shaped button for inserting into a large buttonhole, loop or frog, used especially on sports clothes.

(4) In theatre, a wooden batten across the width of a flat, for strengthening the frame (Also called the toggle rail).

(5) In engineering and construction, a metal device for fastening a toggle rail to a frame (also called a toggle iron.); a horizontal piece of wood that is placed on a door, flat, or other wooden structure, but is not on one of the edges of the structure; an appliance for transmitting force at right angles to its direction.

(6) To furnish with a toggle or to bind or fasten with a toggle.

(7) In informal use, to turn, twist, or manipulate a toggle switch; dial or turn the switch of a device (often in the form “to toggle between” alternate states).

(8) A type of switch widely used in motor vehicles until outlawed by safety legislation in the 1960s.

(9) In admiralty jargon, a wooden or metal pin, short rod, crosspiece or similar, fixed transversely in the eye of a rope or chain to be secured to any other loop, ring, or bight.

In computer operating systems and applications, an expression indicating a switch of view, contest, feed, option et al.

(11) In sky-diving, a loop of webbing or a dowel affixed to the end of the steering & brake lines of a parachute providing a means of control.

(12) In whaling, as toggling harpoon, a pre-modern (believed to date from circa 5300 BC) harvesting tool used to impale a whale when thrown.

1769: In the sense of a "pin passed through the eye of a rope, strap, or bolt to hold it in place" it’s of unknown origin but etymologists agree it’s of nautical origin (though not necessarily from the Royal Navy) thus the speculation that it’s a frequentative form of “tug” or “to tug” (in the sense of “to pull”), the evolution influenced by regional (or class-defined) pronunciations similar to tog.  The wall fastener was first sold in 1934 although the toggle bolt had been in use since 1994.  The term “toggle switch” was first used in 1938 although such devices had long been in use in the electrical industry and they were widely used in motor vehicles until outlawed by safety legislation in the 1960s.  In computing, toggle was first documented in 1979 when it referred to a keyboard combination which alternates the function between on & off (in the sense of switching between functions or states as opposed to on & off in the conventional sense).  The verb toggle dated from 1836 in the sense of “make secure with a toggle” and was a direct development from the noun.  In computing, the toggle function (“to toggle back and forth between different actions") was first described in 1982 when documenting the embryonic implementations of multi-tasking (then TSRs (terminate & stay resident programs).  Toggle is a noun, verb & adjective, toggled & toggling are verbs, toggler, toggery and (the rare) togglability are nouns and togglable (the alternative spelling is toggleable) is an adjective; the noun plural is toggles.  Use of the mysterious togglability (the quality of being togglable) seems to be restricted to computer operating systems to distinguish between that which can be switched between and that which is a stand-alone function which must be loaded & terminated.

The Jaguar E-Type (XKE) and the toggle switches

1964 Jaguar E-Type roadster (Open Two Seater (OTS) as the factory at the time described the body-style).

Jaguar’s E-Type (sometimes informally called XK-E or XKE in the US), launched at the now defunct Geneva Motor Show in 1961, was one of the more seductive shapes ever rendered in metal.  Enzo Ferrari (1898-1988) was at the show and part of E-Type folklore is he called it “the most beautiful car in the world”.  Whether those words ever passed his lips isn’t certain because the sources vary slightly in detail and il Commendatore apparently never confirmed or denied the sentiment but it’s easy to believe and to this day many agree.  If just looking at the thing was something visceral then driving one was more than usually tactile and over sixty years on, the appeal remains, even if some aspects in the early models (such as the seats which looked welcoming but frankly were uncomfortable and the rather agricultural (no synchromesh on first gear) Moss gearbox) were a little too tactile.

1961 Jaguar E-Type OTS (Open Two Seater, now usually called a "roadster") with toggle switches.  Ergonomically, the layout was not wholly successful but was an ascetic delight and the toggle switches are thought more sexy than the later rockers.  There are two different patterns for the aluminium panel and the one used on the very early cars is much prized; it has never been available as a re-production.  In 1963, as a running change (the factory bulletin indicating it was done to reduce glare) the panel changed to use a black vinyl covering.

Another feature of the early (1961-1967) cars admired both for their appearance and pleasure of operation touch was the centrally-located array of toggle switches which controlled functions such as lighting and windscreen wipers.  Even by the slight standards of the 1960s, ergonomically the arrangement wasn’t ideal but, sitting under the gauges, it was an elegant and impressive look the factory would retain across the range for more than a decade, the E-type using the layout until production ended in 1974 (and it endured on the low-volume Daimler DS420 limousine until 1992).  However, while the layout survived, the toggle switches did not, the protruding sharpness judged dangerous by the NHSB (the National Highway Safety Bureau (which in 1970 became the National Highway Traffic Safety Administration (NHTSA)) under the newly established US DOT (Department of Transportation), established by an act of Congress on 15 October 1966 and beginning operation on 1 April 1967) which, since the publication of Ralph Nader’s (b 1934) book Unsafe at any Speed (1965) had begun to write legislation which stipulated standards for automobile safety, this in parallel with the growing body of law designed to reduce emissions.

1973 Jaguar E-Type roadster with rocker switches.  On the roadsters, the far-right switch was un-labeled because it was functional only on the coupés where it activated the rear-window demister.  On the XJ sedans (which used the same switch assembly), it swapped the flow between the twin fuel tanks.  When the S2 XJ was released in 1973, the whole dashboard was revised, greatly improving the ergonomics but lacking the visual appeal.  

In 1968, the new wave of legislation came mostly from the US DOT so applied almost exclusively to vehicles sold in the US but such was the importance of that market it made little sense for Jaguar to continue to produce a separate line with toggle switches for sale in the rest of the word (RoW) so the decision was taken to standardize on the flatter, more rounded rocker switches.  At much the same time, other changes were made to ensure the E-Type on sale in 1968 would conform also to other new rules, the most obvious being the banning of the lovely covered headlights which necessitated their replacement with higher-mounted units in a scalloped housing.  In view of the extent of the changes required, it was decided to designate the updated cars as the “Series 2” (S2).  Despite the perceptions of some, now fuelled by internet posts and re-posts, by 1967, Jaguar, while not a mass-production operation along the lines of a computerized Detroit assembly line, had long since ceased to be a cottage industry and as a change was made in a model’s specification, except for specified batches, that was applied to all production after a certain date.  Despite the factory’s records documenting this, urban myths continue to circulate, stimulated by “unicorns” such as the handful of 3.8 litre Mark 2 sedans built after 1967 when the line was rationalized (as the 240 & 340) and restricted to the 2.4 & 3.4 litre XK-Six; those 3.8s were documented  “special orders” and not ad-hoc aberrations.  However, nothing in the era has resulted in as much misinformation as the specification of what came (unofficially) to be called the S1.25 & 1.5 E-Types, the most common myth being that before S2 production proper began, some cars left the factory with a sometimes unpredictable mix of S1 & S2 parts, this haphazardness accounted for by the expedient of “using up stock”.  In the industry, (even in computerized Detroit) the practice was not unknown but there’s now no doubt it never applied to the 1967 E-Types.  What notably attracts speculation is the phenomenon of “overlap”: a Jaguar might be found to include some “later” or “earlier” features than the build date and VIN (vehicle identification number) sugget should be fitted.  It's part of the charm of the breed and is thought to be the result of the recorded “build date” reflecting when a car passed the final quality control checks so one with an earlier chassis number could be returned for rectification, thus picking up what appears to be an “out-of-sequence” date.  

The pure lines of the S1 E-Type (top) were diluted, front and rear, by the need to comply with US safety legislation, the later S2's head & taillights more clunky.  The collector market slang for the later headlight treatment is "sugar scoop".

The process by which S1 evolved into S2 was transitional which is why the designations S1.25 & 1.5 became accepted; not used by the factory, they’re said to have been “invented” by JCNA (Jaguar Clubs of North America), the S1.25 run beginning on 11 January 1967 after production resumed following the Christmas holiday while the first 1.5s were built that August.  Although much is made in the collector community of the defining differences between the “pure” S1 and the “transitional” S1.25 & S1.5, that “purity” is nuanced because like many others, the E-Type was subject to constant product development with changes appearing from time to time.  Early in the model run, there were some obvious changes such as (1) the modification to the “flat floors” to provide more leg-room, (2) the integration of the bonnet (hood) louvers into the pressing, (3) the external bonnet (really a “clamshell”) release being replaced by an internal mechanism, (4) internal trim changes including the dashboard materials, the console and seats, (5) the replacement of the Moss gearbox with an all-synchromesh unit and (6) the 4.2 litre engine replacing the original 3.8.  Beyond those well-known landmarks, between 1965 and early 1967 there was also a wealth of barely detectable (except to experts of which there are quite a few) cosmetic changes and mechanical updates including: (1) the glass windshield washer bottle replaced with plastic container (March 1965), (2) the addition of an alternator shield (October 1965), (3) an enclosed brake and clutch pedal box (October 1965), (4) a hazard waring (4-way) flasher added to US market cars (November 1965), (5) sun-visors added to roadsters (February 1966), (6) instrument lighting changed from blue to green (March 1966), (7) the rubber boot at the base of the gear lever being replaced by a black Ambla gaiter; there were also detail changes to the gearbox cover and prop shift tunnel finisher (October 1966), (8) the material used for the under-dash panels was changed from Rexine-skinned aluminum to fiberboard (October 1966) and (8) a Girling clutch master cylinder replaced the Dunlop unit (December 1966).

Jaguar E-Type: S1 with covered headlight light (left), S1.25 with early "sugar scoop" (centre) and S2 with later "sugar scoop" (right). 

After the headlight covers were legislated to extinction, the replacement apparatus on the E-Types came to be called “sugar scoops”, a term earlier used for the Volkswagens & Porsches sold in North America (NA) which had to be fitted with sealed-beam headlights because of protectionist rules designed for the benefit of US manufacturers.  The use of “sugar scoop” for the E-Type was appropriate because the visual link with the original utensil (which, in technical terms, is a "specialized spoon") was much more obvious than the more subtle hint seen on Volkswagens & Porsches.

A US market 1977 Porsche 911 (1964-1989), fitted with the front bumper assembly of a later 911 (964 (1989-1994)):  The original “sugar scoops” are seen on the left and the replacement Hella H4 lights are to the right (in RoW cars both H2 & H4 units were fitted).  The sugar scoop (centre) is Japanese, circa 1970s.  Sugar scoops are used to scoop sugar from a “sugar scuttle” whereas if one’s sugar is in a “sugar bowl”, a “sugar spoon” is used.  The difference between a “sugar spoon” and a “tea spoon” is the former has a deeper and usually more rounded bowl and most are supplied as part of a “tea set” or “tea service”, often with the same decorative elements.

Despite that myriad of modifications, all E-Types up to those informally dubbed 1.5 are S1s but the running changes can be of significance to restorers if the object is to emulate exactly the state in which a vehicle rolled off the production line; in events such as a concours d'elegance, judges can deduct points for even minor variations.  Things became more distinct when on 11 January 1967 the first E-Type destined for the US market was built without the covered headlights and this marked the beginning of the run of what would come to be known as the 1.25 although it wouldn’t be until June-July that year the open headlights became a universal fitting on all E-Types.  Unlike some cars where changes can be determined from the sequential VINs, the only way accurately to determine whether a 1967 E-Type built between January and July was fitted with covered or uncovered headlights is to authenticate the market for which it was built, those for NA using the uncovered fittings.  What this meant was an analysis of successive VINs will reveal on a given day there might have been a mix of cars with the the different headlight assemblies going down the production line.  Curiously, there were some 1968 E-Types built for Canada which included the triple SUs and while these included the interior changes mandated by US federal law, the Tex door mirror on the driver’s side wasn't fitted and the tail and side lights were a different specification.  From 1969, Canada aligned its regulations with those of the US so from that point on, the NA specification was standardized.

Between August-October 1967, the 1.5 began to evolve and that included the twin Zenith-Stromberg carburetors replacing the triple SUs (on NA cars), the substitution of ribbed camshaft covers, a higher mounting of the headlights (to meet minimum height requirements) and the adoption of rocker switches.  At this point, the teardrop tail lights remained, the most obvious external marker of the S2 being the chunky light below the rear bumper bar although, in the usual manner, updates continued, such as twin cooling fans (a good idea) and 1000-odd (the so-called "R2" run of cars, almost all of which are registered as 1971 models although some left the factory in 1970) E-Types gained a pair of "leaper" badges on the flanks, just behind the front wheel arches.  Unlike the centrally mounted steel leapers used on the saloons, the badge used on the flanks required two part numbers, one each for the left & right.  It seemed a pointless addition and just more clutter, as they were on the S1 (1968-1973) & S2 (1973-1979) XJs.

1971 S2 Jaguar E-Type (centre) from the "R2" run of 1000-odd with the leaper badges on the flanks.

So much did the clutter created by bigger bumpers, protuberant headlight assemblies, badges and side-marker lights detract from the lovely, sleek lines of the Series 1 cars, bolting a luggage rack to the boot (trunk) probably seemed no longer the disfigurement it would once have been.  The left-hand (left) and right-hand (right) badges, being directional, were different part numbers (BD35865 & BD35866 respectively) and those used on E-Types were silver on black.  There were also variants used on the XJs which were gold on black and some had the leaping feline at a slight slope, both matters of note for those wishing to restore to the challenging "factory original" standard.  

So it can be hard to follow without a flow chart but, because of some overlaps in the production process, the S1-to-S1.25-to-S1.5 transition wasn’t entirely lineal but none of this is mysterious because Jaguar’s Factory Service Bulletins (JFSB) have documented these “inconsistencies” (which were standard industrial practice).  For example, there were a certain 32 specific NA market vehicles fitted with the headlight covers which were built with serial numbers later than the first of the open headlight cars.  Not all E-Types built for NA in 1967 thus had the open headlights and a not insignificant number of those 1.25 spec vehicles have been retro-fitted with the covers.  Such is the appeal of the covered headlights that although the E-Type market is monitored by the originality police (the “matching numbers” crowd which have an extraordinary knowledge of things like “correct” hose clamps or screw heads), there seems to be much untypical forgiveness for “back-dating” headlights to the sleeker look and they're not unknown even on the later, and much different, S3 cars.

The lure of the headlight covers: 1973 E-Type with headlight covers subsequently added (left) and with the original "sugar scoops" (left).  These are US market cars with the additional "dagmars" appended to the bumperettes.  Even by 1973, thin whitewall tyres were still a popular option on US Jaguars and they remained available until the last were sold in 1975 but the wide whitewalls often supplied in the early 1960s had long fallen from favor.  Although the judges in the JCNA confederation are usually uncompromising members of the originality police, they make a rare exception in not deducting points from late-build E-Types (the so-called 1.25 & 1.5) which have been fitted with the headlight covers.  Although the covers never appeared on the S3 E-Types, their presence clearly doesn't dissuade buyers because the S3 pictured above (left), in February, 2021 sold at auction for US$230,000.  It was an exceptionally low-mileage example (8000-odd miles (13,000 km)) but even given that it represented an impressive premium. 

While the loss of the toggle switches, teardrop taillights and headlight covers was a cause of some lament, some other changes also induce pangs of regret.  The switch from three to two carburetors was necessitated by the emission control regulations; the claimed horsepower dropped from 265 to 246 and while not many took the original rating too seriously, there was a drop in performance, especially in the upper speed ranges.  One often less noticed change mandated by the DOT was the replacement of the “eared” knock-off hubs for the wire wheels (the E-Types only ever using a two-eared version although third-party items with three ears are available) with a more “pedestrian friendly” type which, bewilderingly, are now referred to as the “non-eared”, “curly”, “octagonal”, “smooth”, “federal” “safety” and “continental” knock offs.  Take your pick.  Buyers could also take their pick of whether their “improved” wire wheels (now incorporating a forged centre hub) were painted in matte silver or chromed although the JFSB did caution that because of the altered configuration of the spokes, the wheels were not interchangeable with the earlier type except as a complete set (ie five per car).  Available from 1 January 1968 (the effective date for many of DOT’s new rules), this was Jaguar’s last update of the wire wheels which, in a variety of forms, the company had been using since being founded in 1922 as the Swallow Sidecar Company.  Never offered on the biggest and heaviest of the post-war cars (the Mark VII, VIII, IX and X/420G) or the new XJ range, they were last used on the “overlap” Daimler saloons (250 & Sovereign) in 1969 although they remained an option for the E-Type until the last was built in 1974.  Although a handful of small-scale producers continued to offer wire wheels, their final appearance on the option lists of the UK industry’s volume models came in 1980 when the last MGB was built.

Norway’s Motorhistorisk Klubb Drammen (Historic Car Club of Drammen) from Buskerud county reported on an exhibition hosted on 2 July 2014 by the Norsk motorhistorisk museu (Norwegian Motor Historic Museum) in the village of Brund, the event honoring Lindsay Lohan’s (b 1986) 28^th birthday.  The S2 Jaguar E-Type was recently restored but it would require a detailed examination to determine the degree to which (note the triple carburetors) it remains in its original specification.  Given the location this may have been a RoW car but there’s a lively two-way trans-Atlantic trade in E-Types (many now restored in Poland) so it may originally have been sold in the US or Canada.

The “Shaguar” used in the three Austin Powers movies (1997, 1999 & 2002).

The Shaguar was a 1967 S1.5 E-Type which thus featured the combination of teardrop taillights, sugar scoop headlights and rocker switches and, being right-hand drive (RHD), it wasn't built for NA.  When the auction house published the photographs, the vibrant on-line Jaguar community did their analysis and concluded it was built in December 1967 as a 1968 model but was in far from original condition (beyond the obvious paint and Shaguar badge).  The dashboard included the earlier manual choke and the heater and vent controls appeared to be missing and while the side & turn lights were NA specification, the taillights were those used on RoW cars.  The tachometer was the one one fitted to S2 models and it was suspected this may have been swapped when the later, non-original engine with the twin Zenith-Stromberg carburetors was installed.  Over the decades, many E-Types have for one reason and another drifted far from their original build and usually this limits their appeal to collectors but at Mecum Auctions in January 2025, the Shaguar achieved US$880,000 (including 10% buyers premium), several times the typical sale price of a non-original S1.5 E-Type in the same condition, its history as a cinema prop clearly an attraction.