Desmodromic

Desmodromic (pronounced des-moh-drom-ick)

(1) In internal combustion engines, a valve drive-train in which poppet valves are positively closed by a cam and leverage system, rather than a conventional spring.

(2) By extension, in various mechanical devices, a component having different controls for its actuation in different directions.

1953:  A construct from the Ancient Greek δεσμός (desmós) (band, connection; fibrous connection, ligament; bond or knot) + δρόμος (drómos) (a course; travel; road).  The etymology is likely oblique to all but mechanical engineers but denotes the characteristic of valves continuously being "bound" to the camshaft.  The idea of desmo + dromic is thus often deconstructed as something like “running in unison” or “connected racing” but that’s because of the historic association with engines and speed and the desmo- prefix is also used in medicine and other biological sciences in the sense of “being or maintaining a connection”, a desmosome a filament-like substance with which cells adhere to each-other and desmoplakin" is the protein associated with this intercellular junction.  In zoology, the term most closely analogous to desmodromic valve trains is desmopelmous, a type of foot in birds in which the hind toe cannot be bent independently because planter tendons are united (ie they are connected and work in unison).

Conventional valve activation (left) versus desmodromic (right).

Probably as soon as there were poppet valves engineers began to ponder way of perfecting their opening and closing, the use of a spring for the latter effective but inexact and embryonic ideas would have been discussed but it was the German Daimler company which was first granted a patent for a desmodromic like valve-train system for a V-twin engine in 1889.  After that, designs, prototypes and even the odd racing car appeared so equipped and while there was some success on the track, no manufacturer attempted mass-production because of the high costs inherent in the intricate design and, more practically, the formidably frequency with which the system demanded adjustment to maintain perfect operation.  However, as the trophies won in competition had celebrated, the desmodromic arrangement uniquely permitted very high engine speeds and thus more power without the need to increase displacement and therefore bulk and weight.

A desmodromic valve schematic.

During World War II, there were great advances in metallurgy and the design of internal combustion engines and one manufacturer which had learned much was Daimler-Benz which had perfected the pressurized fuel-injection system which early in the conflict had given Luftwaffe pilots some real advantages over the allied opposition which continued to rely on primitive carburettors for fuel delivery, these adversely affected by gravity while the German aircraft were not.  However, the valve-train relied still on a spring to effect closing and this was a limitation which prevented the advantages of fuel-injection being fully explored.  The big aero-engines in the wartime Messerschmitts has been low-revving so the valve-springs weren’t challenged by physics but the company’s interest has returned to the race tracks and there, the systems limitations were exposed, “valve-float” intruding at high engine speeds.  The dreaded valve float is a phenomenon which occurs at high engine speeds when valve springs can’t return the valves to their seat with the cam follower still in contact with the cam.  This means the valves can be launched too high, even to the point where it can be still wide open when the piston arrives at the top dead centre (TDC), something which in the worst case can result in impact between the two, bending or even snapping the valve.  That will often be catastrophic, the debris perforating and possibly collapsing the hot aluminium piston head.  From that point on, the damage caused will be a matter only of extent, ranging from severe to complete destruction.

The Mercedes-Benz W196 Formula One Grand Prix (1954-1955) car used the desmodromic straight-eight in 2.5 litre form.  A 3.0 litre version was created for the W196S (300 SLR) used in sports car racing.  

That was something desirable to avoid in any engine but especially so in a racing car because, as the saying goes, “to finish first, first one must finish”.  Thus was designed Daimler-Benz’s surprisingly simple desmodromic system for the Mercedes-Benz W196 Formula One car for the 1954 season, ruin under the new 2.5 litre (152 cubic inch) displacement rule.  An amusing mix of new (fuel-injection and the desmodromics) and old (archaic swing axles and a straight-eight configuration), it succeeded, dominating the World Championship in 1954-1955 and in 3.0 litre form as the 300 SLR (technically the W196S), sports car racing too.  One thing which proved vital in all this was that the engineers had removed from the desmodromic hardware the small, final closing spring which had previously been thought necessary.  What the Daimler-Benz engineers discovered was that if a residual clearance of a mere 0.03 mm (0.001181099 inch) was machined, by simply leaving the return “desmo valve” in the closed position, the inertia of the valve and the gas pressure in the cylinder was sufficient to maintain the closure, a variation of the exploitation of the long-documented behaviour of fluid dynamics Chrysler would soon market (somewhat opportunistically) as Sonoramic.  The innovation was made possible by the development of metals stimulated by the demands of war; in the pre-war years, the desmodromic design adopted for the W196 simply wouldn’t have been possible.

Schematic of the Mercedes-Benz W196 straight-eight.

The desmodromic valve control system used an opening cam which directly controlled a shoe at the upper end of the cylindrical tappet rod while another (closing) cam used a deliberately out-of-alignment rocker arm which engaged in a hole drilled in the same tappet.  It was simple, precise and effective and reliably delivered such power that even Enzo Ferrari (1898-1988) considered matters desmodromic, discussing the matter with Dr Fabio Taglioni (1920-2001) who was working on the idea, his design first used by Ducati in 1954 on their 125 cm³ (7.6 cubic inch) racer and later adopted for many of their production and competition machines, used even to this day. 

Lindsay Lohan with Ducati Monster 600 (Desmodromic) in Freaky Friday (2003).

Not needing return springs, the valves being positively opened and closed by a cam and leverage system, desmodromic offered higher engine speed, more power and a variety of improvements to specific efficiencies.  Despite that, except for Ducati, it never became a system used by volume manufacturers (or indeed low-volume operations) because of the disadvantages which included complexity, cost, noise (especially as the cylinder count grew) and, critically, more frequent maintenance.  It was advances in high-speed photography and later computer analysis which rendered desmodromic an engineering cul-de-sac.  With a frame-by-frame view of how valves and valve springs behaved, designers were able to engineer solutions to the problems previously though inherent to conventional valve-trains and, by the 1980s, vastly more powerful computers permitted the virtual testing of every design permutation.  Eventually, the advantages offered by desmodromics became so small that few attempted to justify to additional cost and maintenance penalty.

2002 Ducati MH900e (desmodromic).

What the photography revealed was that valve float was caused mostly by resonance in the springs which generated oscillating compression waves among the coils and that at specific resonant speeds, the springs were no longer making contact at one or both ends, leaving the valve “floating” before crashing into the cam on closure.  The solutions were varied and some, such as Norton's “mousetrap” or “hairpin” spring were soon discarded because, although they worked well, the engineering challenges in integrating them with existing combustion chamber designs created as many problems as were solved.  A less elegant but more manageable approach was to install as many as three concentric valve springs, sometimes nested inside one other; not for more force (the inner ones having no significant spring constant), but to act as dampers, both absorbing and reduce oscillations in the outer spring (engineers delighting in calling the additional springs “snubbers”).  Again, the advances in metallurgy made possible what was once though unattainable.  Complex valve springs were engineered which did not resonate, being progressively wound with a varying pitch varying diameter and dubbed “beehive springs” because of the shape.  The number of active coils in these springs would vary during the stroke, the more closely wound coils located at the static end, becoming inactive as the spring compressed or (as in the beehive) where the small diameter coils at the top were stiffer.  Thus valve float was conquered with springs.

2023 Ducati Multistrada V4, the first Ducati in decades to use conventional valve activation.

But Ducati persists to this day, their raucous machines, once a cult known to a few now enjoying a wider audience which seems prepared to accept both the frequency of with which valve-train adjustments are required and the inherent clatter (which is admittedly quite spine-tingling if sampled at speed when wearing a crash helmet).  Tellingly, Ducati’s motor-cycles are almost all V-twins because the noise level does become intrusive as the cylinder count increases and their recent Multistrada V4 was the first in decades to not use desmodromic valves, the owner rewarded, inter alia, with recommended maintenance intervals of 60,000 km (37,500 miles), a considerable advance on the traditional 12-18,000 km (7500-11,200 miles).  Advances in engineering techniques have allowed the noise of the desmodromic arrangement to be reduced and there are now four-cylinder Ducatis using the system, appealing to those who lust for top end power.  Among collectors of US muscle cars, Ferraris, Jaguars and such there are those who can think of no more pleasurable way to spend a day than adjusting solid valve lifters or tinkering with an array of carburettors (the fascination of intricacy its own reward), the synchronization of which defy all but the chosen priesthood of such things so Ducati seems likely to offer the devoted their desmodromics as long as such things remain somewhere lawful.

Nail

Nail (pronounced neyl)

(1) A slender, typically rod-shaped rigid piece of metal, usually in many lengths and thicknesses, having (usually) one end pointed and the other (usually) enlarged or flattened, and used for hammering into or through wood, concrete or other materials; in the building trades the most common use is to fasten or join together separate pieces (of timber etc).

(2) In anatomy, a thin, horny plate, consisting of modified epidermis, growing on the upper side of the end of a finger or toe; the toughened protective protein-keratin (known as alpha-keratin, also found in hair) at the end of an animal digit, such as fingernail.

(3) In zoology, the basal thickened portion of the anterior wings of certain hemiptera; the basal thickened portion of the anterior wings of certain hemiptera; the terminal horny plate on the beak of ducks, and other allied birds; the claw of a mammal, bird, or reptile.

(4) Historically, in England, a round pedestal on which merchants once carried out their business.

(5) A measure for a length for cloth, equal to 2¼ inches (57 mm) or 1⁄20 of an ell; 1⁄16 of a yard (archaic); it’s assumed the origin lies in the use to mark that length on the end of a yardstick.

(6) To fasten with a nail or nails; to hemmer in a nail.

(7) To enclose or confine (something) by nailing (often followed by up or down).

(8) To make fast or keep firmly in one place or position (also used figuratively).

(8) Perfectly to accomplish something (usually as “nailed it”).

(9) In vulgar, slang, of a male, to engage in sexual intercourse with (as “I nailed her” or (according to Urban Dictionary “I nailed the bitch”).

(10) In law enforcement, to catch a suspect or find them in possession of contraband or engaged in some unlawful conduct (usually as “nailed them”).

(11) In Christianity, as “the nails”, the relics used in the crucifixion, nailing Christ to the cross at Golgotha.

(12) As a the nail (unit), an archaic multiplier equal to one sixteenth of a base unit

(13) In drug slang, a hypodermic needle, used for injecting drugs.

(14) To detect and expose (a lie, scandal, etc)

(15) In slang, to hit someone.

(16) In slang, intently to focus on someone or something.

(17) To stud with or as if with nails.

Pre 900: From the Middle English noun nail & nayl, from the Old English nægl and cognate with the Old Frisian neil, the Old Saxon & Old High German nagal, the Dutch nagel, the German Nagel, the Old Norse nagl (fingernail), all of which were from the unattested Germanic naglaz.  As a derivative, it was akin to the Lithuanian nãgas & nagà (hoof), the Old Prussian nage (foot), the Old Church Slavonic noga (leg, foot), (the Serbo-Croatian nòga, the Czech noha, the Polish noga and the Russian nogá, all of which were probably originally a jocular reference to the foot as “a hoof”), the Old Church Slavonic nogŭtĭ, the Tocharian A maku & Tocharian B mekwa (fingernail, claw), all from the unattested North European Indo-European ənogwh-.  It was further akin to the Old Irish ingen, the Welsh ewin and the Breton ivin, from the unattested Celtic gwhīnā, the Latin unguis (fingernail, claw), from the unattested Italo-Celtic əngwhi-;the Greek ónyx (stem onych-), the Sanskrit ághri- (foot), from the unattested ághli-; the Armenian ełungn from the unattested onogwh-;the Middle English verbs naile, nail & nayle, the Old English næglian and cognate with the Old Saxon neglian, the Old High German negilen, the Old Norse negla, from the unattested Germanic nagl-janan (the Gothic was ganagljan).  The ultimate source was the primitive Indo-European h₃nog- (nail) and the use to describe the metal fastener was from the Middle English naylen, from the Old English næġlan & nægl (fingernail (handnægl)) & negel (tapering metal pin), from the Proto-Germanic naglaz (source also of Old Norse nagl (fingernail) & nagli (metal nail).  Nail is a noun & verb, nailernailless & naillike are adjectives, renail is a verbs, nailing is a noun & vern and nailed is a verb & adjective; the noun plural is nails.

Nail is modified or used as a modifier in literally dozens of examples including finger-nail, toe-nail, nail-brush, nail-file, rusty-nail, garden-nail, nail-fungus, nail-gun & frost-nail.  In idiomatic use, a “nail in one's coffin” is a experience or event that tends to shorten life or hasten the end of something (applied retrospectively (ie post-mortem) it’s usually in the form “final nail in the coffin”.  To be “hard as nails” is either to be “in a robust physical state” or “lacking in human feelings or without sentiment”. To “nail one's colors to the mast” is to declare one’s position on something.  Something described as “better than a poke in the eye with a rusty nail” is a thing, which while not ideal, is not wholly undesirable or without charm.  In financial matters (of payments), to be “on the nail” is to “pay at once”, often in the form “pay on the nail”.  To “nail something down” is to finalize it. To have “nailed it” is “to perfectly have accomplished something” while “nailed her” indicates “having enjoyed sexual intercourse with her”.  The “right” in the phrase “hit the nail right on the head” is a more recent addition, all known instances of use prior to 1700 being “hit the nail on the head” and the elegant original is much preferred.  It’s used to mean “correctly identify something or exactly to arrive at the correct answer”.  Interestingly, the Oxford English Dictionary (OED) notes there is no documentary evidence that the phrase comes from “nail” in the sense of the ting hit by a hammer.

Double-headed nails are used for temporary structures like fencing.  When the shaft is hammered in to the point where the surface of the lower head is flat against the surface of that into which it's being hammered, it leaves the upper head standing proud with just enough of the shaft exposed to allow a claw-hammer to be used to extract nail.  There is a story that as part of an environmental protest against the building or demolition of some structure (the tales vary), activists early one morning went to the temporary fencing around the contested site and hammered in all the double-headed nails.  This is believed to be an urban myth.

The sense of “fingernail” appears to be the original which makes sense give there were fingernails before there were spikes (of metal or any other material) used to build stuff.  The verb nail was from the Old English næglian (to fix or fasten (something) onto (something else) with nails), from the Proto-Germanic ganaglijan (the source also of the Old Saxon neglian, the Old Norse negla, the Old High German negilen, the German nageln and the Gothic ganagljan (to nail), all developed from the root of the nouns.  The colloquial meaning “secure, succeed in catching or getting hold of (someone or something)” was in use by at least the 1760; hence (hence the law enforcement slang meaning “to effect an arrest”, noted since the 1930s.  The meaning “to succeed in hitting” dates from 1886 while the phrase “to nail down” (to fix in place with nails) was first recorded in the 1660s.

As a noun, “nail-biter” (worrisome or suspenseful event), perhaps surprisingly, seems not to have been in common use until 1999 an it’s applied to things from life-threatening situations to watching close sporting contests.  The idea of nail-biting as a sign of anxiety has been in various forms of literature since the 1570s, the noun nail-biting noted since 1805 and as a noun it was since the mid-nineteenth century applied to those individuals who “habitually or compulsively bit their fingernails” although this seems to have been purely literal rather than something figurative of a mental state.  Now, a “nail-biter” is one who is “habitually worried or apprehensive” and they’re often said to be “chewing the ends of their fingernails” and in political use, a “nail biter” is a criticism somewhat less cutting than “bed-wetter”.  The condition of compulsive nail-biting is the noun onychophagia, the construct being onycho- (a creation of the international scientific vocabulary), reflecting a New Latin combining form, from the Ancient Greek ὄνυξ (ónux) (claw, nail, hoof, talon) +‎ -phagia (eating, biting or swallowing), from the Ancient Greek -φαγία (-phagía).  A related form was -φαγος (-phagos) (eater), the suffix corresponding to φαγεῖν (phageîn) (to eat), the infinitive of ἔφαγον (éphagon) (I eat), which serves as aorist (essentially a compensator for sense-shifts) (for the defective verb ἐσθίω (esthíō) (I eat).  Bitter-tasting nail-polish is available for those who wish to cure themselves.  Nail-polish as a product dates from the 1880s and was originally literally a clear substance designed to give the finger or toe-nails a varnish like finish upon being buffed.  By 1884, it was being sold as “liquid nail varnish” including shads of black, pink and red although surviving depictions in art suggests men and women in various cultures have for thousands of years been coloring their nails.  Nail-files (small, flat, single-cut file for trimming the fingernails) seem first to have been sold in 1819 and nail-clippers (hand-tool used to trim the fingernails and toenails) in 1890.

Pope Francis (b 1936; pope since 2013) at the funeral of Cardinal George Pell (1941-2023), St Peter’s Basilica, the Vatican, January 2023.

The expression "nail down the lid" is a reference to the lid of a coffin (casket), the implication being one wants to make doubly certain anyone within can't possible "return from the dead".  The noun doornail (also door-nail) (large-headed nail used for studding batten doors for strength or ornament) emerged in the late fourteenth century and was often used of many large, thick nails with a large head, not necessarily those used only in doors.  The figurative expression “dead as a doornail” seems to be as old as the piece of hardware and use soon extended to “dumb as a doornail” and “deaf as a doornail).  The noun hangnail (also hang-nail) is a awful as it sounds and describes a “sore strip of partially detached flesh at the side of a nail of the finger or toe” and appears in seventeenth century texts although few etymologists appear to doubt it’s considerably older and probably a folk etymology and sense alteration of the Middle English agnail & angnail (corn on the foot), from the Old English agnail & angnail.  The origin is likely to have been literally the “painful spike” in the flesh when suffering the condition.  The first element was the Proto-Germanic ang- (compressed, hard, painful), from the primitive Indo-European root angh- (tight, painfully constricted, painful); the second the Old English nægl (spike), one of the influences on “nail”.  The noun hobnail was a “short, thick nail with a large head” which dates from the 1590s, the first element probably identical with hob (rounded peg or pin used as a mark or target in games (noted since the 1580s)) of unknown origin.  Because hobnails were hammered into the leather soles of heavy boots and shoes, “hobnail” came in the seventeenth century to be used of “a rustic person” though it was though less offensive than forms like “yokel”.

Colors: Lindsay Lohan with nails unadorned and painted.

The Buick Nailhead

In the 1930s, the straight-8 became a favorite for manufacturers of luxury cars, attracted by its ease of manufacture (components and assembly-line tooling able to be shared with those used to produce a straight-6), the mechanical smoothness inherent in the layout and the ease of maintenance afforded by the long, narrow configuration.  However, the limitations were the relatively slow engine speeds imposed by the need to restrict the “crankshaft flex” and the height of the units, a product of the long strokes used to gain the required displacement.  By the 1950s, it was clear the future lay in big-bore, overhead valve V8s although the Mercedes-Benz engineers, unable to forget the glory days of the 1930s when the straight-eight W125s built for the Grand Prix circuits generated power and speed Formula One wouldn’t again see until the 1980s, noted the relatively small 2.5 litre (153 cubic inch) displacement limit for 1954 and conjured up a final fling for the layout.  Used in both Formula One as the W196R and in sports car race as the W196S (better remembered as the 300 SLR) the new 2.5 & 3.0 litre (183 cubic inch) straight-8s, unlike their pre-war predecessors, solved the issue of crankshaft flex (the W196's redline was 9500 compared with the W125's 5800) by locating the power take-off at the centre, adding mechanical fuel-injection and a desmodromic valve train to make the things an exotic cocktail of ancient & modern (on smooth racetracks and in the hands of skilled drivers, the swing axles at the back not the liability they might sound).  Dominant during 1954-1955 in both Formula One & the Sports Car Championship, they were the last of the straight-8s.

Schematic of Buick “Nailhead” V8, 1953-1966.

Across the Atlantic, the US manufacturers also abandoned their straight-8s.  Buick introduced their overhead valve (OHV) V8 in 1953 but, being much wider than before, the new engine had to be slimmed somewhere to fit between the fenders; it would not be until later the platform was widened.  To achieve this, the engineers narrowed the cylinder heads, compelling both an conical (the so-called “pent-roof”) combustion chamber and an arrangement in which the sixteen valves pointed directly upwards on the intake side, something which not only demanded an unusual pushrod & rocker mechanism but also limited the size of the valves.  So, the valves had to be tall and narrow and, with some resemblance to nails, they picked up the nickname “nail valves”, morphing eventually to “nailhead” as a description of the whole engine.  The valve placement and angle certainly benefited the intake side but the geometry compromised the flow of exhaust gases which were compelled through their anyway small ports to make a turn of almost 180^o on their way to the tailpipe.

It wasn't the last time the head design of a Detroit V8 would be dictated by considerations of width.  When Chrysler in 1964 introduced the 273 cubic inch (4.5 litre) V8 as the first of its LA-Series (that would begat the later 318 (5.2), 340 (5.5) & 360 (5.9) as well as the V10 made famous in the Dodge Viper), the most obvious visual difference from the earlier A-Series V8s was the noticeably smaller cylinder heads.  The A engines used as skew-type valve arrangement in which the exhaust valve was parallel to the bore with the intake valve tipped toward the intake manifold (the classic polyspherical chamber).  For the LA, Chrysler rendered all the valves tipped to the intake manifold and in-line (as viewed from the front), the industry’s standard approach to a wedge combustion chamber.  The reason for the change was that the decision had been taken to offer the compact Valiant with a V8 but it was a car which had been designed to accommodate only a straight-six and the wide-shouldered polyspheric head A-Series V8s simply wouldn’t fit.  So, essentially, wedge-heads were bolted atop the old A-Series block but the “L” in LA stood for light and the engineers wanted something genuinely lighter for the compact (in contemporary US terms) Valiant.  Accordingly, in addition to the reduced size of the heads and intake manifold, a new casting process was developed for the block (the biggest, heaviest part of an engine) which made possible thinner walls.  Still, "light" is a relative term and the LA series was notably larger and heavier than Ford's "Windsor" V8 (1961-2000) which was the exemplar of the "thin-wall" technique.  This was confirmed in 1967 when, after taking control of Rootes Group, Chrysler had intended to continue production of the Sunbeam Tiger, by then powered by the Ford Windsor 289 (4.7 litre) but with Chrysler’s 273 LA V8 substituted.  Unfortunately, while 4.7 Ford litres filled it to the brim, 4.4 Chrysler litres overflowed; the Windsor truly was compact.  Allowing it to remain in production until the stock of already purchased Ford engines had been exhausted, Chrysler instead changed the advertising from emphasizing the “…mighty Ford V8 power plant” to the vaguely ambiguous “…an American V-8 power train”.

322 cubic inch Nailhead in 1953 Buick Skylark convertible (left) and 425 cubic inch Nailhead in 1966 Buick Riviera GS (with dual-quad MZ package) (right).  Note the “Wildcat 465” label on the air cleaner, a reference to the claimed torque rating, something most unusual, most manufacturers using the space to advertise horsepower or cubic inch displacement (cid).

The nailhead wasn’t ideal for producing ultimate power but it did lend itself to prodigious low-end torque, something much appreciated by Buicks previous generation of buyers who has enjoyed the low-speed responsiveness of the famously smooth straight-8.  However, like everybody else, Buick hadn’t anticipated that as the 1950s unfolded, the industry would engage in a “power race”, something to which the free-breathing Cadillac and Chrysler’s Hemis were well-suited.  The somewhat strangulated Buick Nailhead was not at all suited and to gain power the engineers were compelled to add high-lift, long-duration camshafts which enabled the then magic 300 horsepower number to be achieved but at the expense of smoothness and tales of Buick buyers returning to the dealer to fix the “rumpity-rump” idle became legion.  Still, the Nailhead was robust, relatively light and offered what was then a generous displacement and the ever inventive hot-rod community soon worked out the path to power was to use forced induction and reverse the valve use, the supercharger blowing the fuel-air mix through the exhaust ports and the exhaust gases through the larger intake ports.  Thus the for a while Nailhead enjoyed a career as a niche player although the arrival in the mid 1950s of the much more tuneable Chevrolet V8s ended the vogue for all but a few devotees who continued use well into the 1960s.  Buick acknowledged reality and, unusually, instead of following the industry trend and drawing attention to cubic inch displacement and horsepower, publicized their torque output, confusing some (though probably not Buick buyers who were a loyal crew).  The unique appearance of the old nail still retains some appeal for the modern hot-rod community and they do sometimes appear, a welcome change from the more typical small-block Fords or Chevrolets.

Lockheed SR-71 Blackbird (1964-1999).

Not confused was the United States Air Force (USAF) which was much interested in power for its aircraft but also had a special need for torque on the tarmac and that briefly meant another small niche for the Nailhead.  The Lockheed SR-71 Blackbird (1964-1979) was a long-range, high-altitude supersonic (Mach 3+) aircraft used by the (USAF) for reconnaissance between 1966-1998 and by the National Aeronautics & Space Administration (NASA) for observation missions as late as 1999.  Something of a high-water mark among the extraordinary advances made in aeronautics and materials construction during the 1950s & 1960s, the SR-71 used the Pratt & Whitney J58 turbojet engine which used an innovative, secondary air-injection system to the afterburner, permitting additional thrust at high speed.  The SR-71 still holds a number of altitude and speed records and Lockheed’s SR-72, a hypersonic unmanned aerial vehicle (UAV) is said to be in an “advanced stage” of design and construction although whether any test flights will be conducted before 2030 remains unclear, the challenges of sustaining in the atmosphere velocities as high as Mach 6+ onerous given the heat generated.

Drawing from user manual for AG330 starter cart (left) and AG330 starter cart with dual Buick Nailhead V8s.

At the time, the SR-71 was the most exotic aircraft on the planet but during testing and early in its career, to fly, it relied on a pair of even then technologically bankrupt Buick Nailhead V8s.  These were mounted in a towed cart and were effectively the turbojet’s starter motor, a concept developed in the 1930s as a work-around for the technology gap which emerged as aero-engines became too big to start by hand but no on-board electrical systems were available to trigger ignition.  The two Nailheads were connected by gears to a single, vertical drive shaft which ran the jet up to the critical speed at which ignition became self-sustaining.  The engineers chose the Nailheads after comparing them to other large displacement V8s, the aspect of the Buicks which most appealed being the torque generated at relatively low engine speeds, a characteristic ideal for driving an output shaft.  After the Nailhead was retired in 1966, later carts used Chevrolet big-block V8s but in 1969 a pneumatic start system was added to the infrastructure of the USAF bases from which the SR-71s most frequently operated, the sixteen-cylinder carts relegated to secondary bases the planes rarely used.

Cooper

Cooper (pronounced koo-per or koop-er)

(1) A person who makes or repairs casks, barrels, etc.

(2) A drink of half stout and half porter (obsolete).

1350–1400: From the Middle English couper (craftsman who makes barrels, tubs, and other vessels from wooden staves and metal hoops), which etymologists are convinced would have come from an Old English form but it has proved elusive.  Both the English words are almost certainly related to the Middle Low German kūper, the East Frisian kuperor and Middle Dutch cūper, from the Low German kupe (cask, tub, vat), from the Medieval Latin cūpārius, the construct being cūp(a) (cask or vat) + ārius. (from the The nominative neuter form -arium which, when appended to nouns, formed derivative nouns denoting a “place where things are kept”).

The meaning "craftsman who makes wooden vessels" was originally associated with the word couper, cooper a later construct of coop + er.  Coop is from the Middle English coupe & cupe, from the Old English cȳpe (basket; cask) or possibly the Middle Dutch cûpe (related to the modern Dutch kuip, Saterland Frisian kupe & Middle Low German kûpe), from the Old Saxon kûpa & côpa (cask), related to the Middle Low German kôpe, the Old High German chôfa & chuofa, the Middle High German kuofe, the modern German kufe (feminine form of cask), which most sources trace back to the Classical Latin cūpa & Medieval Latin cōpa (cask) although the OED has cast doubt on this etymology because of the mysterious umlaut in Old English cýpe.  The er agent (noun-formation) suffix is from the Middle English er & ere, from the Old English ere, from the Proto-Germanic ārijaz.  It’s thought a borrowing from the Latin ārius; cognate with the Dutch er and aar, the Low German er, the German er, the Swedish are, the Icelandic ari and the Gothic areis.  Related too are the Ancient Greek ήριος (ḗrios) and Old Church Slavonic арь (arĭ) and although synonymous, actually unrelated is the Old French or & eor (the Anglo-Norman variant is our) which is from the Latin (ā)tor, derived from the primitive Indo-European tōr.

As a surname, the name is attested from the late twelfth century, either from the unattested Old English or a Low German source akin to Middle Dutch cuper , East Frisian kuper, ultimate source the Low German kupe (which became kufe in German), cognate with the Medieval Latin cupa.  A now rare variation is hooper although it remains common as a surname.  Within the profession, a dry cooper makes casks to hold dry goods, a wet cooper those to contain liquids and a white cooper, pails, tubs, and the like for domestic or dairy use.  The surname Cowper is pronounced koo-per or koop-er everywhere except Australia which preserved the fifteenth century spelling but modified the pronunciation to cow-pah.  The Australian federal electorate of Cowper was created in 1900 as one of the original sixty-five divisions and is named after Sir Charles Cowper (1807–1875) who was on five occasions between 1856-1870 the premier of the colony of New South Wales (NSW), Australia.

The Maserati Formula 1 V12, 1956-1957 & 1966-1969

1954 Maserati 250F "short nose".

Remarkably, the three litre Maserati V12 used by Cooper to win Grand Prix races in 1966 & 1967 was an update (developed out of necessity) of a 2.5 litre engine used (once) in 1956.  Maserati’s new straight-six 250F had enjoyed a stunning start to its career, enjoying victories in the first two Grands Prix of the 1954 season but was soon eclipsed by the Lancia D50 and particularly the Mercedes-Benz W196, both with more powerful eight cylinder engines and advanced aerodynamics.

1955 Maserati 250F Streamliner.

Maserati responded and, taking note of the all-enveloping "streamliner" bodywork Mercedes-Benz used on the W196s used on the faster circuits, developed a quasi-enveloping shape, the emphasis wholly on reducing drag (downforce would attract the interest of a later generation).  For the slower tracks, there was also an aerodynamic refinement of the open-wheeler, the “long-nose” which proved such a success it would become the definitive 250F.  The more slippery shapes helped but the problem of the power deficit remained, the advanced Mercedes-Benz engine, built with the benefit of experience gained with the wartime aero engines, used fuel-injection and a desmodromic valve-train which permitted sustained high-speed operation.  Maserati’s engineers devoted time to devise a fuel injection system and borrowed an innovation from the roadsters built for the Indianapolis 500, an off-set installation of the engine in the chassis which permitted the driveshaft to be to run beside rather than beneath the driver, lowering the seat and thus improving both aerodynamics and weight-distribution.

1954 Maserati 250F "long nose".

Two grand prix wins in 1956 suggested progress was being made but, although Mercedes-Benz withdrew from racing after 1955, competition from other constructors was growing so Maserati turned its attention to both chassis and engine.  An all-new multi-tubular space-frame chassis was designed, lighter and stronger than its more conventional predecessor, it retained the double wishbone front and De Dion rear suspension and, perhaps surprisingly, the engineers resisted the more efficient and now well-proven disc brakes, the revised drums instead aided by enhanced cooling.  The new engine was not ready for 1956 so the straight-six was again fielded although the off-set layout was discarded.  The new chassis was called Tipo 2.

Maserati 250F Typo 2, Juan Manuel Fangio (1911–1995), German Grand Prix,  Nürburgring, 1957.

Developed specifically for the Tipo 2 was the V12, its twin camshafts driven by front-mounted gears with the novelty of the Weber carburetors being mounted between the camshafts.  Maintaining a Maserati tradition, a twin spark ignition system was fitted, the 24 spark-plugs fed by two sturdy magnetos, again gear-driven and linked by 24 individual coils.  In many ways the state of 1950s engineering art, the marvelously intricate 2.5 litre V12 produced 320 bhp at what was then a startling 12,000 rpm, an increase of 50 bhp over the 2.5 litre straight six.  With the V12 still being developed, the team started the 1957 season with the 250F Tipo 2 and the straight six.  The faithful six was reliable and proved powerful enough to prevail over the Ferraris and the cars which unexpectedly emerged as the most impressive competition: the British Vanwalls.  The season would be Maserati’s finest, Juan Manuel Fangio winning his fifth world championship (at the age of forty-five) and, had there been a constructors title (not awarded until 1958), Maserati would have taken that trophy too.  The season is remembered also for Fangio’s famous victory in the German Grand Prix at the Nürburgring, in which he broke the lap record ten times in twenty-two laps, the Tipo 2’s straight six clearly good enough.

1956 Maserati 250F Tipo 2 V12.

The success of the straight-six afforded the engineers a wealth of time thoroughly to develop the V12.  After early tests showed the power delivery, although impressive, was too brutal to deliver the flexibility needed in a racing car, attention was devoted to widening the torque curve.  Three Tipo 2 chassis were built for the V12 engine, one ready in time for the final Grand Prix of the year, the symbolically important home event, the Italian Grand Prix at Monza.  A redesigned gearbox housing again allowed an off-set mounting which, although improving weight distribution, made the body sit so low on the frame, two bulges had to be formed in the bonnet to clear the carburetor intakes.  It looked fast and it was.  However, in scenes reminiscent of the troubles suffered by the ferociously powerful Auto-Unions and Mercedes-Benz of the pre-war years, the V12 250F, although fast, suffered high tyre-wear, the rear tyres clearly not able long to endure the abrasive demands of 320 bhp.  Still, it had been an encouraging debut, even if a lubrication problem had prematurely ended the venture.

Lindsay Lohan in Mini Cooper, Mauritius, 2016.

Unfortunately, there would not for a decade be another chance to run the V12 in a Grand Prix.  Financially challenged, Maserati retired from international racing at the end of the 1957 season, the remaining 250Fs sold to privateers either with the straight six or as a rolling chassis.  How competitive a fully-developed Tipo 2 V12 might have been in 1958 will never be known but the credentials were there and, against the dominant Ferraris and Vanwalls, it would have been an interesting contest, the 1958 season the end of an era, the last year either the drivers’ or constructors’ championships would be won using front-engined cars.  On paper, the Maserati V12 was the most powerful engine fielded during Formula One’s 2.5 litre era.

Cooper-Maserati T81, Guy Ligier (1930–2015), Belgium Grand Prix, Spa-Francorchamps, 1967.

Although it did see some use in sports-car racing, the V12’s most (briefly) illustrious second life came when, in 1965, a doubling of engine displacement to three litres was announced for the next Formula One season, the 1.5 litre voiturettes used between 1961-1965 exquisitely engineered but lacking the noise, speed and spectacle with which others were attracting interest.   This created a scramble for competitive engines and with renewed interest in the mothballed V12, Maserati dusted-off the cobwebs.  Cooper adopted it and enjoyed early success with the advantage of being the first team running cars with a full three litres, the reliability of the old V12 adding another edge over others still shaking down their initially fragile new engines.

Cooper-Maserati T81b, Pedro Rodríguez (1940–1971),  German Grand Prix, Nürburgring, 1967.

Soon however, Cooper were running a decade-old design against much newer competition and the antiquity began to tell.  Although some updating had been done, early experiments with six and even a remarkable twelve carburettors quickly abandoned for the even by then de rigueur fuel injection, in that decade, several generations of engineering had passed and the V12 was looking pre-historic.  Unable to change anything fundamental, Maserati bolted on what it could, including 18-valve cylinder heads that added weight and complexity, but did little to narrow the widening gap.  Rumors of 24-valve heads and even three spark-plugs per cylinder never came to fruition but the latter did prompt some wry comments questioning the efficiency of Maserati's combustion chamber design if that many fires needed to be lit.  Maserati withdrew from Formula One during the 1968 season and Cooper soon followed.

Demand

Demand (pronounced dih-mand (U) or dee–mahnd (non-U))

(1) To ask for with proper authority; claim as a right.

(2) To ask for peremptorily or urgently.

(3) To call for or require as just, proper, or necessary.

(4) In law, to lay formal claim to.

(5) In law, to summon, as to court.

(6) An urgent or pressing requirement.

(7) In economics, the desire to purchase, coupled (hopefully) with the power to do so.

(8) In economics, the quantity of goods that buyers will take at a particular price.

(9) A requisition; a legal claim.

(10) A question or inquiry (archaic).

1250-1300: From Middle English demaunden and Anglo-French demaunder, derived from the Medieval Latin dēmandāre (to demand, later to entrust) equivalent to dē + mandāre (to commission, order).  The Old French was demander and, like the English, meant “to request” whereas "to ask for as a right" emerged in the early fifteenth century from Anglo-French legal use.  As used in economic theory and political economy (correlating to supply), first attested from 1776 in the writings of Adam Smith.  The word demand as used by economists is a neutral term which references only the conjunction of (1) a consumer's desire to purchase goods or services and (2) hopefully the power to do so.  However, in general use, to say that someone is "demanding" something does carry a connotation of anger, aggression or impatience.  For this reason, during the 1970s, the language of those advocating the rights of women to secure safe, lawful abortion services changed from "abortion on demand" (ie the word used as an economist might) to "pro choice".  Technical fields (notably economics) coin derived forms as they're required (counterdemand, overdemand, predemand etc).  Demand is a noun & verb, demanding is a verb & adjective, demandable is an adjective, demanded is a verb and demander is a noun; the noun plural is demands.

Video on Demand (VoD)

Directed by Tiago Mesquita with a screenplay by Mark Morgan, Among the Shadows is a thriller which straddles the genres, elements of horror and the supernatural spliced in as required.  Although in production since 2015, with the shooting in London and Rome not completed until the next year, it wasn’t until 2018 when, at the European Film Market, held in conjunction with the Internationale Filmfestspiele Berli (Berlin International Film Festival), that Tombstone Distribution listed it, the distribution rights acquired by VMI, Momentum and Entertainment One, and VMI Worldwide.  In 2019, it was released progressively on DVD and video on demand (VoD), firstly in European markets, the UK release delayed until mid-2020.  In some markets, for reasons unknown, it was released with the title The Shadow Within.

Video on Demand (VoD) and streaming services are similar concepts in video content distribution but there are differences.  VoD is a system which permits users to view content at any time, these days mostly through a device connected to the internet across IP (Internet Protocol), the selection made from a catalog or library of available titles and despite some occasionally ambiguous messaging in the advertising, the content is held on centralized servers and users can choose directly to stream or download.  The VoD services is now often a sub-set of what a platform offers which includes content which may be rented, purchased or accessed through a subscription.

Streaming is a method of delivering media content in a continuous flow over IP and is very much the product of the fast connections of the twenty-first century.  Packets are transmitted in real-time which enables users to start watching or listening without waiting for an entire file (or file set) to download, the attraction actually being it obviates the need for local storage.  There’s obviously definitional and functional overlap and while VoD can involve streaming, not all streaming services are technically VoD and streaming can also be used for live events, real-time broadcasts, or continuous playback of media without specific on-demand access. By contrast, the core purpose of VoD is to provide access at any time and streaming is a delivery mechanism, VoD a broad concept and streaming a specific method of real-time delivery as suited to live events as stored content.

The Mercedes-Benz SSKL and the Demand Supercharger

Modern rendition of Mercedes-Benz SSLK in schematic.  It's misleading because the four or five SSKLs built were all commissioned in 1931 (although it's possible one or more used a modified chassis which had been constructed in 1929).  All SSKs left the factory between 1928-1931. 

The Mercedes-Benz SSKL was one of the last of the road cars which could win top-line grand prix races.  An evolution of the earlier S, SS and SSK, the SSKL (Super Sports Kurz (short) Leicht (light)) was notable for the extensive drilling of its chassis frame to the point where it was compared to Swiss cheese; reducing weight with no loss of strength.  The SSKs and SSKLs were famous also for the banshee howl from the engine when the supercharger was running; nothing like it would be heard until the wail of the BRM V16s twenty years later.  It was called a demand supercharger because, unlike some constantly-engaged forms of forced-induction, it ran only on-demand, in the upper gears, high in the rev-range, when the throttle was pushed wide-open.  Although it could safely be used for barely a minute at a time, when running, engine power jumped from 240-odd horsepower (HP) to over 300.  The number of SSKLs built has been debated and the factory's records are incomplete because (1) the competition department, producing machines "for internal use" simply built "as required" and wasn't much concerned about documents and (2) many archives were lost as a result of bomb damage during World War II (1939-1945); most historians suggest there were four or five SSKLs, all completed (or modified from earlier builds) in 1931.  The SSK had enjoyed success in competition but even in its heyday was in some ways antiquated and although powerful, was very heavy, thus the expedient of the chassis-drilling intended to make it competitive for another season.  Lighter (which didn't solve but at least to a degree ameliorated the high tyre wear) and easier to handle than the SSK (although the higher speed brought its own problems, notably in braking), the SSKL enjoyed a long Indian summer and even on tighter circuits where its bulk meant it could be out-manoeuvred, sometimes it still prevailed by virtue of durability and sheer power.

Sometimes too it got lucky.  When the field assembled in 1931 for the Fünfter Großer Preis von Deutschland (fifth German Grand Prix) at the Nürburgring Nordschleife, even the factory acknowledged that at 1600 kg (3525 lb), the SSKLs, whatever their advantage in horsepower, stood little chance against the nimble Italian and French machines which weighed-in at some 200 KG (440 lb) less.  However, on the day there was heavy rain with most of race conducted on a soaked where the light-weight, twitchy Alfa Romeos, Maseratis and the especially skittery Bugattis proved less suited to the slippery surface than the truck-like but stable SSKL, the lead built up in the rain enough to secure victory even though the margin narrowed as the surface dried and a visible racing-line emerged.  Time and the competition had definitely caught up by 1932 however and it was no longer possible further to lighten the chassis or increase power so the factory had aerodynamics specialist Baron Reinhard von Koenig-Fachsenfeld (1899-1992) design a streamlined body, the lines influenced both by his World War I (1914-1918 and then usually called the "World War") aeronautical experience and the "streamlined" racing which had been seen in the previous two decades.  At the time, the country greatly was affected by economic depression which spread around the world after the 1929 Wall Street crash, compelling Mercedes-Benz to suspend the operations of its competitions department so the one-off "streamliner" was a private effort (though with some tacit factory assistance) financed by the driver (who reputedly borrowed some of the money from his mechanic).  This coaxed from the SSKL a victory in its final fling.  Crafted in aluminum by Vetter in Cannstatt, it was mounted on Manfred von Brauchitsch's (1905-2003) race-car and proved its worth at the at the Avusrennen (Avus race) in May 1932; with drag reduced by a quarter, the top speed increased by some 12 mph (20 km/h) and the SSKL won its last major trophy on the unique circuit which rewarded straight-line speed like no other.  It was the last of the breed.  Subsequent grand prix cars would be pure racing machines with none of the compromises demanded for road-use.

Evolution of the front-engined Mercedes-Benz grand prix car, 1928-1954

1928 Mercedes-Benz SS.

As road cars, the Mercedes-Benz W06  S (1927-1928) & SS (1928-1930) borrowed unchanged what had long been the the standard German approach in many fields (foreign policy, military strategy, diplomacy, philosophy etc): robust engineering and brute force; sometimes this combination worked well, sometimes not.  Eschewing refinements in chassis engineering or body construction as practiced by the Italians or French, what the S & SS did was achieved mostly with power and the reliability for which German machinery was already renowned.  Although in tighter conditions often out-manoeuvred, on the faster circuits both were competitive and the toughness of their construction meant, especially in the adverse environments then found on many road circuits, they would outlast the more more nimble but fragile opposition.

1929 Mercedes-Benz SSK.

By the late 1920s it was obvious an easier path to higher performance than increasing power was to reduce the SS's (Super Sport) size and weight.  The former easily was achieved by reducing the wheelbase, creating a two-seat sports car still suitable for road and track, tighter dimensions and less bulk also reducing fuel consumption and tyre wear, both of which had plagued the big, supercharged cars.  Some engine tuning and the use of lighter body components achieved the objectives and the SSK was in its era a trophy winner in sports car events and on the grand prix circuits.  Confusingly, the "K" element in the name stood for kurz (short) and not kompressor (supercharger) as was applied to some other models although all SSKs used a supercharged, 7.1 litre (433 cubic inch) straight-six. 

1931 Mercedes-Benz SSKL.

The French, British and Italian competition however also were improving their machinery and by late 1930, on the racetracks,  the SSK was becoming something of a relic although it remained most desirable as a road car, demand quelled only by a very high price in what suddenly was a challenging economic climate.  Without the funds to create anything new and with the big engine having reached the end of its development potential, physics made obvious to the engineers more speed could be attained only through a reduction in mass so not only were body components removed or lightened where possible but the chassis and sub-frames were drilled to the point where the whole apparatus was said to resemble "a Swiss cheese".  The process was time consuming but effective because, cutting the SSK's 1600 KG heft to the SSKL's more svelte 1445 (3185), combined with the 300-odd HP which could be enjoyed for about a minute with the supercharger engaged, produced a Grand Prix winner which was competitive for a season longer than any had expected and one also took victory in the 1931 Mille Miglia.  Although it appeared in the press as early a 1932, the "SSKL" designation is retrospective, the factory's extant records listing the machines either as "SSK" or "SSK, model 1931".  No more than five were built and none survive (rumors of a frame "somewhere in Argentina" apparently an urban myth) although some SSK's were at various times "drilled out" to emulate the look and the appeal remains, a replica cobbled together from real and fabricated parts sold in 2007 for over US$2 million at auction; this was when a million dollars was still a lot of money.  

1932 Mercedes-Benz SSKL, die Gurke.

The one-off bodywork (hand beaten from aircraft-grade sheet aluminum) was fabricated for the 1932 German Grand Prix held at Berlin's unique Automobil-Verkehrs- und Übungsstraße (Avus; the "Automobile traffic and training road") which featured two straights each some 6 miles (10 km) in length, thus the interest in increasing top speed and while never given an official designation by the factory, the crowds dubbed it die Gurke (the cucumber).  The streamlined SSKL won the race and was the first Mercedes-Benz grand prix car to be called a Silberpfeil (silver arrow), the name coined by radio commentator Paul Laven (1902-1979) who was broadcasting trackside for Südwestdeutsche Rundfunkdienst AG (Southwest German Broadcasting Service); he was struck by the unusual appearance although the designer had been inspired by an aircraft fuselage rather than arrows or the vegetable of popular imagination.  The moniker was more flattering than the nickname Weiße Elefanten applied to S & SS which was a reference to their bulk, the appearance exaggerated by the unrelieved expanses of white paint (Germany's designated racing color) although despite what is sometimes claimed, Ettore Bugatti’s (1881–1947) famous “fastest truck in the world” was his back-handed compliment to W. O. Bentley’s (1888–1971) eponymous racers which he judged brutish compared to his svelte machines.  Die Gurke ended up silver only because such had been the rush to complete the build in time for the race, there was time to apply the white paint so it raced in a raw aluminum skin.  Remarkably, in full-race configuration, die Gurke was driven to Avus on public roads, a practice which in many places was tolerated as late as the 1960s.  Its job at Avus done, die Gurke was re-purposed for high-speed tyre testing (its attributes (robust, heavy and fast) ideal for the purpose) before "disappearing" during World War II.  Whether it was broken up for parts or metal re-cycling, spirted away somewhere or destroyed in a bombing raid, nobody knows although it's not impossible conventional bodywork at some point replaced the streamlined panels.  In 2019, Mercedes-Benz unveiled what it described as an "exact replica" of die Gurke, built on an original (1931) chassis.    

1934 Mercedes-Benz W25.

After building the replica Gurke, Mercedes-Benz for the first time subjected it to a wind-tunnel test, finding (broadly in line with expectations) its c_d (coefficient of drag) improved by about a third, recording 0.616 against a standard SSK's 0.914.  By comparison, the purpose-built W25 from 1934 delivered a 0.614 showing how effective Baron Koenig-Fachsenfeld's design had been although by today's standards, the numbers are not of shapes truly "slippery".  Although "pure" racing cars had for years existed, the W25 (Werknummer (works number) 25) was the one which set many elements is what would for a quarter-century in competition be the default template for most grand prix cars and its basic shape and configuration remains recognizable in the last front-engined car to win a Word Championship grand prix in 1960.  The W25 was made possible by generous funding from the new Nazi Party, "prestige projects" always of interest to the propaganda-minded party.  With budgets which dwarfed the competition, immediately the Mercedes-Benz and Auto Unions enjoyed success and the W25 won the newly inaugurated 1935 European Championship.  Ironically, the W25's most famous race was the 1935 German Grand Prix at the Nürburgring, won by the inspired Italian Tazio Nuvolari (1892–1953) in an out-dated and under-powered Alfa-Romeo P3, von Brauchitsch's powerful W25 shredding a rear tyre on the final lap.  However, the Auto Union's chassis design fundamentally was more farsighted; outstanding though the engine was, the W25's platform was, in many ways, eine bessere Gurke (a better cucumber) and because its limitations were inherent, the factory "sat out" most of the 1936 season to develop the W125.

1937 Mercedes-Benz W125.

Along with the dramatic, mid-engined,  V16 Auto Union Type C, the W125 was the most charismatic race car of the "golden age" of 1930s European circuit racing.  When tuned for use on the fastest circuits, the 5.7 litre (346 cubic inch) straight-eight generated over 640 HP and in grand prix racing that number would not be exceeded until the turbocharged engines (first seen in 1977) of the 1980s.  The W125 used a developed version of the W25's 3.4 (205) & 4.3 (262) straight-eights and the factory had assumed this soon would be out-performed by Auto Union's V16s but so successful did the big-bore eight prove the the Mercedes-Benz V16 project was aborted, meaning resources didn't need to be devoted to the body and chassis engineering which would have been required to accommodate the bigger, wider and heavier unit (something which is subsequent decades would doom a Maserati V12 and Porsche's Flat-16.  The W125 was the classic machine of the pre-war "big horsepower" era and if a car travelling at 100 mph (160 km/h) passed a W125 at standstill, the latter could accelerate and pass that car within a mile (1.6 km).

A W125 on the banked Nordschleife (northern ribbon (curve)) at Avus, 1937.  At Avus, the streamlined bodywork was fitted because a track which is 20 km (12 miles) in length but has only four curves puts an untypical premium on top-speed.  The banked turn was demolished in 1967 because increased traffic volumes meant an intersection was needed under the Funkturm (radio tower), tower and today only fragments of the original circuit remain although the lovely art deco race control tower still exists and was for a time used as restaurant.  Atop now sits a Mercedes-Benz three-pointed star rather than the swastika which flew in 1937. 

1938 Mercedes-Benz W154.

On the fastest circuits the streamlined versions of the W125s were geared to attain 330 km/h (205 mph) and 306 km/h (190 mph) often was attained in racing trim.  With streamlined bodywork, there was also the Rekordwagen built for straight-line speed record attempts and one set a mark of 432.7 km/h (268.9 mph), a public-road world speed record that stood until 2017.  Noting the speeds and aware the cars were already too fast for circuits which had been designed for, at most, velocities sometimes 100 km/h (50 mph) less, the governing body changed the rules, limiting the displacement for supercharged machines to 3.0 litres (183 cubic inch), imagining that would slow the pace.  Fast though the rule-makers were, the engineers were quicker still and it wasn't long before the V12 W154 was posting lap-times on a par with the W125 although they did knock a few km/h off the top speeds.  The rule change proved as ineffective in limiting speed as the earlier 750 KG formula which had spawned the W25 & W125.

1939 Mercedes-Benz W165.

An exquisite one-off, the factory built three W165s for the single purpose of contesting the 1939 Tripoli Grand Prix.  Remarkable as it may now sound, there used to be grand prix events in Libya, then a part of Italy's colonial empire.  Anguished at having for years watched the once dominant Alfa Romeos enjoy only the odd (though famous) victory as the German steamroller flattened all competition (something of a harbinger of the Wehrmacht's military successes in 1939-1940), the Italian authorities waited until the last moment before publishing the event's rules, stipulating the use of a voiturette (small car) with a maximum displacement of 1.5 litres  (92 cubic inch).  The rules were designed to suit the Alfa Romeo 158 (Alfetta) and Rome was confident the Germans would have no time to assemble such a machine.  However, knowing Adolf Hitler (1889-1945; Führer (leader) and German head of government 1933-1945 & head of state 1934-1945), still resenting what happened at the Nürburgring in 1935 would not be best pleased were his Axis partner (and vassal) Benito Mussolini (1883-1945; Duce (leader) & Prime-Minister of Italy 1922-1943) to enjoy even this small victory, the factory scrambled and conjured up the V8-powered (a first for Mercedes-Benz) W165, the trio delivering a "trademark 1-2-3" finish in Tripoli.  As a consolation, with Mercedes-Benz busy building inverted V12s for the Luftwaffe's Messerschmitts, Heinkels and such, an Alfa Romeo won the 1940 Tripoli Grand Prix which would prove the city's last.      

 

1954 Mercedes Benz W196R Strómlinienwagen (literally "streamlined car" but translated usually as "Streamliner".

A curious mix of old (drum brakes, straight-eight engine and swing axles) and new (a desmodromic valve train, fuel injection and aerodynamics developed in a wind-tunnel with the help of engineers then banned from being involved in aviation), the intricacies beneath the skin variously bemused or delighted those who later would come to be called nerds but it was the sensuous curves which attracted most publicity.  Strange though it appeared, it was within the rules and clearly helped deliver stunning speed although the pace did expose some early frailty in road-holding (engineers have since concluded the thing was a generation ahead of tyre technology).  It was one of the prettiest grand prix cars of the post war years and the shape (sometimes called "type Monza", a reference to the Italian circuit with long straights so suited to it) would later much appeal to pop-artist Andy Warhol (1928–1987) who used it in a number of prints.

1954 Mercedes-Benz W196R.  In an indication of how progress accelerated after 1960, compare this W196R with (1) the W25 of 20 years earlier and (2) any grand prix car from 1974, 20 years later. 

However, although pleasing to the eye, the W196R Strómlinienwagen was challenging even for expert drivers and it really was a machine which deserved a de Dion rear suspension rather than the swing axles (on road cars the factory was still building a handful with these as late as 1981 and their fudge of semi-trailing rear arms (the "swing axle when you're not having a swing axle") lasted even longer).  Of more immediate concern to the drivers than any sudden transition to oversteer was that the aluminium skin meant they couldn't see the front wheels so, from their location in the cockpit, it was difficult to judge the position of the extremities, vital in a sport where margins can be fractions of a inch.  After the cars in 1954 returned to Stuttgart having clouted empty oil drums (those and bails of hay was how circuity safety was then done) during an unsuccessful outing to the British Grand Prix at Silverstone, a conventional body quickly was crafted and although visually unremarkable, the drivers found it easier to manage and henceforth, the Strómlinienwagen appeared only at Monza.  There was in 1954-1955 no constructor's championship but had there been the W196R would in both years have won and it delivered two successive world driver's championships for Juan Manuel Fangio (1911–1995).  Because of rule changes, the three victories by the W196R Strómlinienwagen remain the only ones in the Formula One World Championship (since 1950) by a car with enveloping bodywork.