Propeller

Propeller (pronounced pruh-pel-er)

(1) A person or thing that propels.

(2) A device with a hub to which are attached evenly spaced & shaped radiating blades, rotating on a shaft to pitch against air or water to propel an aircraft, ship etc.

(3) A wind-driven (usually three-bladed) device that provides mechanical energy, as for driving an electric alternator in wind plants (not a universal use).

(4) A steamboat thus propelled; a screw steamer (now rare).

(5) In fishing, a spinnerbait.

1780: The construct was propel + -er and the original sense was “one who or that which that propels”, an agent noun from the verb propel.  The verb propel was a mid-fifteenth century form from the Middle English propellen (to drive away, expel), from the Latin propellere (push forward, drive forward, drive forth; move, impel), the construct being pro- (the prefix here use in the sense of “forward direction, forward movement”) + pellere (to push, drive), from the primitive Indo-European root pel- (to thrust, strike, drive).  The meaning “to drive onward, cause to move forward” emerged in the 1650s.  The –er suffix was from the Middle English –er & -ere, from the Old English -ere, from the Proto-Germanic -ārijaz, thought most likely to have been borrowed from the Latin –ārius where, as a suffix, it was used to form adjectives from nouns or numerals.  In English, the –er suffix, when added to a verb, created an agent noun: the person or thing that doing the action indicated by the root verb.   The use in English was reinforced by the synonymous but unrelated Old French –or & -eor (the Anglo-Norman variant -our), from the Latin -ātor & -tor, from the primitive Indo-European -tōr.  When appended to a noun, it created the noun denoting an occupation or describing the person whose occupation is the noun.  The alternative spelling propellor dates from the early days of aviation in the first years of the twentieth century and is now extinct.  The standard abbreviation is “prop”, the use noted from military aviation since 1914.  Propeller is a noun; the noun plural is propellers.

Although the concept was used in antiquity and inventors and others (most famously Leonardo da Vinci (1452–1519))  had for centuries experimented, the use of the word in mechanical engineering dates from 1809 and was from nautical design describing the application of a “device for moving vessels on or under the water”.  In aircraft design the theory of the use of “propeller” appears in papers and drawings in the 1840s (in what were then described as “flying machines”) and models were built which demonstrated a “proof of concept” although it would be decades before lightweight engines of sufficient power existed to allow experiments in aerodynamics and construction to be powered.  The first known rendering of an aircraft propeller in a recognizably modern form dates from 1853.  The modern propeller uses two or (usually) more twisted, airfoil-shaped blades mounted around a shaft which are spun to provide propulsion of a vehicle through water or air, or to cause fluid flow, as in a pump.  The lift generated by the spinning blades provides the force that propels the vehicle or the fluid although this lift does not of necessity have to induce an actual upward force; its direction is simply parallel to the rotating shaft.

Lindsay Lohan getting off the propeller driven (technically a turbo-prop) NAPA Shuttle, The Parent Trap (1998).

The term “to disembark” was borrowed from nautical use and of late "to deplane" has entered English which seems unnecessary but the companion “to disemplane” seems more absurd still; real people continue to “get on” and “get off” aircraft.

The terms “impeller” & “propeller” both describe devices which use various implantations of the “rotating blade(s) design and are used in mechanical systems to take advantage of the properties of fluid dynamics to harness specific energy for some purpose.  A propeller is a type of rotating device with blades designed to propel or move a fluid (typically a gas or a liquid) by generating thrust; they are most associated with marine vessels, aircraft and some industrial applications.  In aircraft, propellers can be attached to wing-mounted engines or mounted just about anywhere on a fuselage although historically a location at the front has been most common.  In marine applications, propellers have on specialized vessels been located to the sides of the hull but they almost always emerge at or close to the stern.  An impeller is a rotating component with blades or vanes (almost always enclosed in a housing), typically used for fluid or air distribution, such as a pump or a compressor, the primary purpose being to increase flow or pressure.  The classic impellers those in centrifugal pumps where they spin, creating a flow of fluid (liquid or air) by imparting centrifugal force to the substance; in practice, impellers such accelerate liquids are more common.

So an impeller & propeller do much the same thing, using blades to propel some form of fluid.  The use of different terms is helpful because in practice they are very different devices and the distinction that one is external and the other located within a housing is handy and the origin of that seems to lie in the construct of impeller which came first, dating from circa 1680 (as an agent noun from the verb impel) in the sense of “someone or something which impels”.  What the design of an impeller does is use the energy from the rotation to increase the flow or pressure of the fluid and it that it’s the reverse of a turbine, the rotation of which extracts energy from, and reduces the pressure of the flow.  Engineers also have a number of highly technical rules about what is and is not defined as an impeller base on the whether the entry and exit of the fluids occur axially or radially but it seemed impossible to construct such definitions as absolutes so for most the simpler distinctions are more helpful.  In engineering, impellers have been recorded as a machine or component name since 1836.

News Corp website 22 January 2024.  To refer to a jet engine’s nacelle as a propeller could (almost) be defended on the basis it’s the jet engine which “propels” the aircraft but this is more likely an example of (1) the decline in the quality of journalists and (2) what happens when there are no sub-editors to correct the mistakes.  In time, artificial intelligence (AI) should improve things.    

The verb impel dates from the early fifteenth century and was from the Middle English impellen, from the Latin impellere (to push, strike against; set in motion, drive forward, urge on), the construct an assimilated form of in- (into, in, on, upon), from the primitive Indo-European root en- (in) + pellere (to push, drive), from the primitive Indo-European root pel- (to thrust, strike, drive).  The construct of the Latin impellō was in- +‎ pellō (push, drive), from the Proto-Italic pelnō or pelnaō, a nasal-infix present derived from the primitive Indo-European pelh- (to drive, strike, thrust).  The Latin prefix –in could be appended to create a negative (un-, non-, not etc) but here was used as an intensifier, another possible meaning (in, within, inside) coincidental to the mechanical devices being usually mounted within housings.

Propellers and impellers both use blades (although those of the latter are often in the form of a single piece wither cast, molded, or (occasionally) forged.  Turbines also use blade-like parts but these are called vanes and an industry which seems unable to decide on terminology is the burgeoning business of wind-power; the huge rotating assemblies on wind turbines are referred to variously as vanes, blades or rotors.  Rotor blades are familiar for the use in helicopters which is essentially an airframe where a large-scale propeller sits atop the structure, pointing upwards and rather than “propeller blades”, the accepted term is “rotor blades”, the design of which permits both lift and directional thrust although some exotic multi-engined machines have rotors in housings which, to maximize performance, can themselves be rotated to operate as conventional propellers.

Supermarine Seafang (1946) with contra-rotating propellers.  The Seafang was powered by the Rolls-Royce Griffon and was the final evolution of the Spitfire-derived Seafire and Spiteful, the trio all designed for use on Royal Navy aircraft carriers, the series enjoying success despite the basic design being hampered by the narrow undercarriage which made landings a challenge (something corrected on the Spiteful & Seafang).  Series production of the Seafang was contemplated but eventually only 18 were built because the jet-powered de Havilland Sea Vampire proved capable of carrier operations, surprising some at the Admiralty who doubted the jets could operate from anywhere but land.

The evolution of aircraft influenced propellers.  Once they had been fashioned from wood before the need for faster, more efficient shapes dictated the use of aluminium or other light metals.  By the time the first modern monoplane fighters appeared in the mid 1930s propellers were still two-bladed but as power increased over the years (something which accelerated during World War II (1939-1945)), three, four and five-bladed solutions were engineered.  The rising output however, although it permitted higher performance, created challenges for engineers, notably the “torque effect” which meant a tendency to cause the aircraft to roll in the direction of the propeller’s spin, a problem especially serious during take-offs.  In twin-engined aircraft the solution was to have the propellers rotate in opposite directions but in airframes with a single power-plant, sometimes used were contra-rotating propellers which, although introducing additional complexity and demanding additional maintenance, did offer advantages including: (1) harnessing more of an engine’s power, (2) increased thrust efficiency by a reduction in energy losses, (3) counteracting the torque effect, (4) improved low-speed manoeuvrability and ground-handling and (5) improved acceleration and climbing performance.

A flight of Republic P-47D Thunderbolts with under-wing drop-tanks.

The propeller also influenced other aspects of the aircraft.  When the prototype Republic P-47 Thunderbolt (1941-1945) first took to the air, it was the largest, heaviest single-seat piston-engined fighter ever produced (a distinction it still enjoys today).  Even the early versions used an engine rated at 2000 horsepower (later this would rise to 2800) and to harness this output demanded a large propeller.  The 12 foot (3.7 m) diameter of this four-bladed monster meant the landing-gear had to be extraordinarily long and the only way it could be accommodated was to have them retract inward, otherwise the heavy wing armament (8 x .50 inch (12.7 mm) M2 Browning machine guns (425 rounds per gun)) wouldn’t have fitted.

Chrysler XI-2220 V16.  The splined shaft is where the propeller attaches.

With things like the Thunderbolt, the Hawker Tempest and the later Supermarine Spitfires (and its derivatives), the piston-engined fighter achieved its final evolutionary form, the jet engine offering a path to performance unattainable while the physics of propellers imposed limits.  However, had the use of the A-Bombs not ended the war in 1945, development of the propeller aircraft would have continued because the early jets lacked thrust and reliability as well as suffering a rate of fuel consumption which rendered them unsuitable for long-distance operations.  With the war against Japan envisaged as lasting well into 1946, development of faster, more powerful piston engines continued although, given the parlous state of the Japanese military, it’s dubious at least there was much of a rationale for this but the military industrial complex is a creature of inertia and Chrysler’s research had perfected a new aero-engine for the Thunderbolt.  The XI-2220 was a 2,220 cubic inch (36.4 litre) V16 which was rated at a basic 2450 horsepower with some 4000 hp available when tuned for wartime use but with the end of the conflict, all such developments were cancelled and attention switched to the brave new world of jets and swept wings.  Thus ended the era of the big propeller-driven fighters, the V16 stillborn, as was the other extraordinary aero-engine on the drawing board: Britain's 32-cylinder Napier-Sabre H-32 which was a scaled-up version of their H24.

Skeg

Skeg (pronounced skeg)

(1) In shipbuilding, a fin-like projection supporting a rudder and protecting the propeller(s) at its lower end, located abaft a sternpost or rudderpost.

(2) In the design of smaller boats, an extension of the keel, designed to improve steering.

(3) In the slang of naval architects (in certain contexts), a stump or branch (the after-part of a ship's keel).

(4) In the slang of the General Motors (GM) stylists, a “lower fin”, matching the upper on the rear of 1961-1962 Cadillacs.

(5) The fin which acts as a stabilizer on a surfboard.  To suffer some injury after being hit by one of these fins is to be “skegged”.

(6) In Australian slang, a surfer; a person who leads the lifestyle of a surfer (used also derisively in the form “fake skeg” of those who adopt the style an appearance without actually surfing.

(7) A type of wild plum (obsolete).

(8) A kind of oat (obsolete).

(9) In Northern English dialectal use, a look or glance.

(10) In many cultures, a slang term applied to youth suggesting slovenliness, a predilection to petty crime and other anti-social behavior; also used widely in Scottish slang for a surprising variety of purposes including legs, trousers, dirt, scotch eggs, sex and women of loose virtue.

1590–1600: From a dialectal term for a stump, branch, or wooden peg, from the Dutch scheg (cutwater), of Scandinavian origin and related to the Swedish skog and the Old Norse & Icelandic skegg (projection on the stern of a boat).  In some Nordic languages, skegg means “beard” and was from the Old Norse skegg, from the Proto-Germanic skaggiją, from the primitive Indo-European skek, kek-, skeg & keg- (to jump, skip, move, hurry).  The name of the English coastal town of Skegness is though a construct of the Old Norse skegg (beard) + -nes (headland) and was thought a reference to the geography, the original settlement situated farther east at the mouth of The Wash (thus jutting out like a beard from a face).  A link with the Old Norse name Skeggi is thought unlikely.  The skegs of nautical architecture should not be confused with the homophone Sceggs, the acronym for students of Sydney Church of England Girls Grammar school (S.C.E.G.G.S.), seen also in the adjectival forms sceggesque & sceggish (one whose style suggests something similar to the stereotypical student of the school).  Skeg is a noun; the noun plural is skegs.

Lindsay Lohan in wet suit, with surfboard, Malibu, 2011.  The stabilizing skeg is the black protrusion at the back of the board.

On nautical vessels, skegs where they exist fulfill a significant function but they are not an essential part of hull design.  A skeg is an external structural feature, a vertical tapering projection permanently fixed at the aft, usually close to the centre-line.  Most are located in front of the rudder and structurally can often be considered a sternward extension of the keel (the internal, longitudinal members which lend much strength of the hull).  Although in military vessels there are additional functions, the moist significant contribution of a skeg is in hydrodynamics, a skeg designed to influence the flow patterns and thus affecting the dynamics of both the rudder (which is usually in line with the skeg) and propeller(s).  The design is thus a finely tuned equation because while a skeg inherently induces drag, the way it alters the flow pattern can reduces the drag and resistance suffered by the rudder and propeller(s), essentially by transforming the turbulent characteristics of the flow to laminar at the stern.  Historically, skegs were a vital component in maintaining a course and that’s still an important consideration in smaller vessels but in larger craft, improved rudder and advanced navigational as well as stabilization technologies like thrusters have meant skegs are no longer of the same significance in maintaining directionality.

An US Navy Iowa class battleship, showing the inner set of propeller shafts wholly enclosed in a pair of skegs.  On the big ships, the skegs were designed also as load-bearing supports while in dry-dock.

In the modern age, skegs became an unusual feature on warships, a relative few so equipped and the designs varied, some with only a few of their shafts inside skegs while others encased all.  While the traditional design imperatives were shared with other ships, for navies, they also offered the advantage of affording some degree of protection for rudders and propellers against torpedo attack.  Historically, another important attribute of skegs was what they add to a hull’s structural strength, making the (inherently weaker) stern resistant to outside forces and all the last of the US Navy’s dreadnoughts featured skegs.  Their hulls narrowed towards the stern and to save weight lacked the sternpost plates the British, German and Japanese navies always fitted to their battleships and the skegs compensated for this, offering a hull with similar rigidity.

The US Navy’s South Dakota class battleships were fitted with an unusual set of skegs, the design dictated by the relatively short hull, the large outboard skegs helping to reduce the adverse effects of fluid dynamics induced by the hull’s abrupt end.

However, advantages in engineering and metallurgy meant much of the functionality afforded by skegs could be achieved in other ways and skegs became unfashionable in naval architecture.  The modeling and simulations made possible by supercomputers meant hull designs could be rendered which mastered the turbulence caused by fluid dynamics so rudders and propellers were less affected so the skeg was in many cases a source of performance-sapping skin-friction drag with little compensating benefit.  Indeed, not only did this hamper performance, in some cases excessive vibration was caused, something which could only to a degree be ameliorated by changes to the propellers’ configurations.

Cadillac’s Skegs, 1961-1962

Cadillac Coupe DeVille, (1959, left & 1960 right).

The 1959 Cadillac’s tail-fins are the best remembered and most emblematic of the brief, extraordinary era during which the absurdly macropterous flourished.  They’re rightly known as “peak-fin” but it’s a myth they were the tallest because, measured from the ground, those on the 1961 Imperial are just under an inch (25 mm) more vertiginous.  The attractions of the style however were fading and in 1960, Cadillac and Chrysler (Ford never really got involved) began to tone them down.  Another cultural phenomenon is that because of the large number of pink 1959 Cadillacs which now exist, many assume they were a common sight when new, the things perhaps made memorable by the sight of the one owned by the admirable Jayne Mansfield (1933–1967).  However, the factory never made a pink 1959 Cadillac and in the era, it was only in 1956 such a color was on the option list and Ms Mansfield had one of those while her 1959 convertible received a custom re-paint.

Cadillac Coupe de Ville, (1961, left & 1962 right).

For the 1961 & 1962 range the fins became lower still but in compensation, the design staff added a lower fin and these, informally they called “skegs”.

1961 Cadillac Coupe de Ville, (left), one of the design proposals for 1961 (centre) & captured German V2 rocket (right).

While of course an extravagance, the skegs could have part of something even wilder because among the design proposals which emerged from the General Motors Advanced Design Studios was one which clearly was the ultimate expression of the motif of the 1950s which borrowed so much from the aerospace industry,  The proposed fins essentially were those of ballistic missiles which for decades were an evolution from the German Vergeltungswaffen zwei (V-2), developed first by the German military with the code name Aggregat 4 (A4).  Vergeltungswaffen is translated variously as "retaliatory weapons" or "reprisal weapons" but in English use is often written as “vengeance weapons”.  Aerodynamically, presumably the proposal has something to commend it and it proceeded far enough into the selection for an expensive, full-sized clay model to be rendered (one wonders what the rejected sketches looked like) but ultimately the longer though somehow more restrained skegs were preferred.

The 1961 Cadillac: The long (left) and slightly less long (right) of it.

One quirk of Cadillac’s brief embrace of the skeg was there were two iterations: skeg long and skeg short.  Whether in response to or in anticipation of some owners preferring their Cadillac in a more conveniently sized package, between 1961-1963 a “short-deck” option was made available on certain body styles.  Offered first on the six-window Sedan de Ville, an encouraging 3,756 were built so the option was in 1962 offered on the four-window Sixty Two Town Sedan but sales actually dropped to 2600, the decline in interest confirmed the next year when only 1575 of the four-window Park Avenue Sedan de Ville were sold.  Using the same 129.5 inch (3289 mm) wheelbase as the regular models but eight inches (200 mm) shorter in overall length (215 vs 223 inches (5461 vs 5664 mm)), space utilization was obviously a little better but the market had spoken.  With fewer than eight-thousand of the short-deck models sold across three seasons while the standard editions shipped in the tens of thousands, the flirtation with (slightly) more efficient packaging was abandoned for 1964; in the course of the following decade, Cadillacs would grow another seven inches (178 mm) and gain over 400 lb (181 kg).

For 1963, the short-deck models returned for another dismal season but the skegs were abandoned, never to return.  The fins however the design studio found harder to forsake, conscious perhaps it was on the 1948 Cadillac they’d first appeared.  Then, modestly sized, they’d been an allusion to the tail-planes used on the twin-boomed Lockheed P-38 Lightning (1939) but the fashion had passed and the fins had to go so, inch by inch, there was a retreat from the heights and exuberance of 1959 until in 1966 the fins were vestigial, a hint which for decades would be retained.

A gang of four Sceggs, Sydney, Australia.

Rat

Rat (pronounced ratt)

(1) In zoology, any of several long-tailed rodents of the family Muridae, of the genus Rattus and related genera, distinguished from the mouse by being larger.

(2) In (scientifically inaccurate) informal use, any of the numerous members of several rodent families (eg voles & mice) that resemble true rats in appearance, usually having a pointy snout, a long, bare tail, and body length greater than 5 inches (120 mm).

(3) In hairdressing, a wad of shed hair used as part of a hairstyle; a roll of material used to puff out the hair, which is turned over it.

(4) In the slang of certain groups in London, vulgar slang for the vagina.

(5) As “to rat on” or “to rat out”, to betray a person or party, especially by telling their secret to an authority or enemy; to turn someone in.

(6) One of a brace of rodent-based slang terms to differentiate between the small-block (mouse motor) and big-block (rat motor) Chevrolet V8s built mostly in the mid-late twentieth century but still available (as "crate" engines) from US manufacturers.

(7) As RAT, a small turbine that is connected to a hydraulic pump, or electrical generator, installed in an aircraft and used as a power source.

(8) Slang term for a scoundrel, especially men of dubious morality.

(9) In the criminal class and in law enforcement, slang for an informer.

(10) In politics, slang for a person who abandons or betrays his party or associates, especially in a time of trouble.

(11) Slang for a person who frequents a specified place (mall rat, gym rat etc).

(12) In hairdressing, a pad with tapered ends formerly used in women's hair styles to give the appearance of greater thickness.

(13) In the slang of blue-water sailors, a place in the sea with rapid currents and crags where a ship is prone to being broken apart in stormy weather.

(14) In zoology (in casual use), a clipping of muskrat.

Pre 1000: From the Middle English ratte, rat & rotte, from the Old English ræt & rætt, and the Latin rodere from the Proto-Germanic rattaz & rattō (related also to the West Frisian rôt, the German Ratz & Ratte and the Swedish råtta & the Dutch rat), of uncertain origin but perhaps from the primitive Indo-European rehed- (to scrape, scratch, gnaw).  Zoological anthropologists however point out it’s possible there were no populations of rats in the Northern Europe of antiquity, and the Proto-Germanic word may have referred to a different animal.  The attestation of this family of words dates from the twelfth century.  Some of the Germanic cognates show considerable consonant variation such as the Middle Low German ratte & radde and the Middle High German rate, ratte & ratze, the irregularity perhaps symptomatic of a late dispersal of the word, although some etymologists link it with the Proto-Germanic stem raþō (nom); ruttaz (gen), the variations arising from the re-modellings in the descendants.

Mall rats.  In North America and other developed markets, there is now less scope for habitués because changing consumer behavior has resulted in a dramatic reduction in the volume of transactions conducted in physical stores and some malls are being either abandoned or re-purposed (health hubs and educational facilities being a popular use).  

The human distaste for these large rodents has made rat a productive additive in English.  Since the twelfth century it’s been applied (usually to a surname) to persons either held to resemble rats or share with them some characteristic or perception of quality with them. The specific sense of "one who abandons his associates for personal advantage" is from the 1620s, based on the belief that rats leave a ship about to sink or a house about to fall, and this led to the meaning "traitor” or “informant" although, perhaps surprisingly, there no reference to rat in this sense prior to 1902 where as the modern-sounding sense of associative frequency (mall-rat, gym-rat etc) was noted as early as 1864, firstly as “dock-rat”.  Dr Johnson dates “to smell a rat”, based on the behaviour of cats, to the 1540s.  Sir Boyle Roche (1736-1807), was an Irish MP famous for mangled phrases and mixed metaphors, of the best remembered of which was “I smell a rat; I see him forming in the air and darkening the sky; but I'll nip him in the bud".  There’s the rat-terrier (1852), the rat-catcher (1590s), the rat-snake (1818), rat-poison, (1799), the rat trap (late 1400s), the rat-pack (1951) and rat-hole which in 1812, based on the holes gnawed in woodwork by rats meant “nasty, messy place”, the meaning extended in 1921 to a "bottomless hole" (especially one where money goes).  Ratfink (1963) was juvenile slang either coined or merely popularized by US custom car builder Ed "Big Daddy" Roth (1932-2001), who rendered a stylised rat on some of his creations, supposedly to lampoon Mickey Mouse.

Cricket's most infamous rat (mullygrubber), Melbourne Cricket Ground, 1981.  Brown & beige was then a fashionable color combination.

Rat has a specific meaning in the cricketing slang of the West Indies, referring to a ball which, after being delivered by the bowler, rather than bouncing off the pitch at some angle, instead runs along the ground, possibly hitting the stumps with sufficient force to dislodge the bails, dismissing the batsman, the idea being of a rat scurrying across the ground.  In Australian slang, the same delivery is called a mullygrubber which, although it sounds old-fashioned, is said to date only from the 1970s, the construct thought based on the dialectal rural term mully (dusty, powdery earth) + grub(ber) in the sense of the grubs which rush about in the dirt if disturbed in such an environment.  Such deliveries are wholly serendipitous (for the bowler) and just bad luck (for the batsman) because it's not possible for such as ball to be delivered on purpose; they happen only because of the ball striking some crack or imperfection in the pitch which radically alters it usual course to a flat trajectory.  If a batsman is dismissed as a result, it's often called a "freak ball" or "freak dismissal".  Of course if a ball is delivered underarm a rat is easy to effect but if a batsman knows one is coming, while it's hard to score from, it's very easy to defend against.  The most infamous mullygrubber was bowled at the Melbourne Cricket Ground (MCG) on 1 February 1981 when, with New Zealand needing to score six (by hitting the ball, on the full, over the boundary) of the final delivery of the match, the Australian bowler sent down an underarm delivery, the mullygrubber denying the batsman the opportunity to score and securing an Australian victory.  Although then permissible within the rules, it was hardly in the spirit of the game and consequently, the regulations were changed.

The Ram Air Turbine

Ram Air Turbine (RAT) diagram.

The Ram Air Turbine (RAT) is a small, propeller-driven turbine connected to a hydraulic pump, or electrical generator, installed in an aircraft to generate emergency power.  In an emergency, when electrical power is lost, the RAT drops from the fuselage or wing into the air-stream where it works as a mini wind-turbine, providing sufficient power for vital systems (flight controls, linked hydraulics and flight-critical instrumentation).

Vickers VC10.

Most modern commercial airliners are equipped with RATs, the first being installed on the Vickers VC10 in the early 1960s and the big Airbus A380 has the largest RAT propeller in current use at 64 inches (1.63 metres) but most are about half this size.  It’s expected as modern airliners begin increasingly to rely on electrical power, either propeller sizes will have to increase or additional RATs may be required, the latter sometimes the desirable choice because of the design limitations imposed by the height of landing gear.  A typical large RAT can produce from 5 to 70 kW but smaller, low airspeed models may generate as little as 400 watts.  Early free-fall nuclear weapons used rats to power radar altimeters and firing circuits; RATS being longer-lasting and more reliable than batteries

RAT in operation.

The airline manufacturers have been exploring whether on-board fuel-cell technology can be adapted to negate the need for RAT, at least in the smaller, single-aisle aircraft where the weight of such a unit might be equal to or less than the RAT equipment.  The attraction of housing a in an airliner's wing-body fairing is it would be a step towards the long-term goal of eliminating an airliner's liquid-fuelled auxiliary turbine power unit.  Additionally, if the size-weight equation could be achieved, there’s the operational advantage that a fuel-cell is easier to test than a RAT because, unlike the RAT, the fuel-cell can be tested without having to power-up most of the system.  The physics would also be attractive, the power from a fuel cell higher at lower altitudes where as the output of a RAT declines as airspeed decreases, a potentially critical matter given it’s during the relatively slow approach to a landing that power is needed to extend the trailing edge of the wing flaps.

If the weight and dimensions of the fuel cell is at least "comparable" to a RAT and the safety and durability testing is successful, at least on smaller aircrafts, fuel-cells might be an attractive option for new aircraft although, at this stage, the economics of retro-fitting are unlikely to be compelling.  Longer term research is also looking at a continuously running fuel cell producing oxygen-depleted exhaust gas for fuel-tank inerting, and water for passenger amenities, thereby meaning an aircraft could be operated on the on the ground without burning any kerosene, the fuel-cell providing power for air conditioning and electrical systems.

1944 Messerschmitt Me 163 Komet  (1944-1945).

The only rocket-powered fighter ever used in combat, the Messerschmitt Me 163 Komet had a small RAT in the nose to provide electrical power.  The early prototypes of the somewhat more successful (and much more influential) Messerschmitt Me 262 jet fighter also had a propeller in the nose for the first test flights but it wasn't a a RAT; it was attached to a piston engine which was there as an emergency backup because of the chronic unreliability of the early jet engines.  It proved a wise precaution, the jets failing on more than one occasion.

Small and big-block Chevrolet V8s compared, the small-block (mouse) to the left in each image, the big-block (rat) to the right.

Mouse and rat are informal terms used respectively to refer to the classic small (1955-2003) and big-block Chevrolet V8s (1958-2021).  The small-block was first named after a rodent although the origin is contested; either it was (1) an allusion to “mighty mouse” a popular cartoon character of the 1950s, the idea being the relatively small engine being able to out-perform many bigger units from other manufacturers or (2) an allusion to the big, heavy Chrysler Hemi V8s (the first generation 331 (5.4 litre), 354 (5.8) & 392 (6.4) cubic inch versions) being known as “the elephant”, the idea based on the widely held belief that elephants are scared of mice (which may actually be true although the reason appears not to be the long repeated myth it’s because they fear the little rodents might climb up their trunk).  Bee might have been a better choice; elephants definitely are scared of bees.  The mouse (small-block) and rat (big-block) distinction is simple to understand: the big block is externally larger although counterintuitively, the internal displacement of some mouse motors was greater than some rats.        

Parthian

Parthian (pronounced pahr-thee-un)

(1) A native or inhabitant of Parthia.

(2) An Iranian language of ancient and medieval Parthia.

(3) Of or relating to, or characteristic of Parthia, its inhabitants, or their language.

522: (Although use doubtless predates the first recorded use)  It refers to a native or inhabitant of Parthia (ancient kingdom northeast of Persia in western Asia) and was from the Old Persian Parthava (a dialectal variant of the stem Parsa and the source of "Persia" (the plural was Partienes).  In English, Parthian had been used by historians and geographers since the 1520s and the familiar adjectival form "Parthian shot" seems to date from the early nineteenth century but images of the act had existed for two millennia and had since the 1630s been referred to as the "Parthian fight".  William Shakespeare (1564–1616) liked the word: Or, like the Parthian, I shall flying fight (Cymbeline (circa 1610), Act I, Scene VII).  Parthian is a noun & adjective and if used in the sense of “of or relating to the historic Parthia or Parthians” it is with an initial capital; the noun plural is Parthians.

The Parthian shot and the parting shot

Journalists at Murdoch tabloid the New York Post can be relied upon to re-purpose a metaphor.

The Parthian shot was a military tactic, used by mounted cavalry and made famous by the Parthians, an ancient people of the Persian lands (the modern-day Islamic Republic of Iran since 1979).  While in real or feigned retreat on horseback, the Parthian archers would, in full gallop, turn their bodies backward to shoot at the pursuing enemy.  This demanded both fine equestrian skills (a soldier’ hands occupied by his bows & arrows) and great confidence in one's mount, something gained only by time spent between man & beast.  To make the achievement more admirable still, the Parthians used neither stirrups nor spurs, relying solely on pressure from their legs to guide and control their galloping mounts and, with varying degrees of success, the tactic was adopted by many mounted military formations of the era including the Scythians, Huns, Turks, Magyars, and Mongols.  The Parthian Empire existed between 247 BC–224 AD.

As a metaphor, “Parthian shot” describes a barbed insult or some sort of attack delivered while in the act of retreat.  There are aspiring pedants who like to point this out to those using the term “parting shot” in a similar vein and while they’re correct the latter is sometimes being used incorrectly, in many instances they’re right for the wrong reasons.  “Parthian shot” seems first to have appeared in a letter written by an army officer serving under the Raj, Captain Godfrey Mundy (1804-1860), ADC (aide-de-camp) to Field Marshal Stapleton Cotton (later Lord Combermere, 1773–1865; Commander-in-Chief, India 1825-1830) using it while speaking of a successful shot during one of the many hunting expeditions which so contributed to the slaughter of the sub-continent’s wildlife during the colonial era.  That was in 1832 and while there’s evidence of use in succeeding decades, it was after Sir Arthur Conan Doyle (1859–1930) published A Study in Scarlet (1886) which included the sentence: “With which Parthian shot he walked away, leaving the two rivals open-mouthed behind him” that the phrase began with some frequency to appear in English.

The battlefield tactic had for some time been known to historians and soldiers before it emerged as a metaphor and it’s thought Captain Mundy was being a little loose in his interpretation, everything suggesting the “Parthian shot” he mentioned was the firing his “Joe Manton” (a shotgun manufactured by the English gunsmith Joseph Manton (1766–1835)) backwards, over his shoulder, a trick with looks impressive in movies but which demands practice to avoid a self-inflicted injury.  Although it’s sometimes suggested “parting shot” was a folk etymology from “Parthian shot”, the former was in use by at least the late 1700s and etymologists can find no documentary evidence, however convincing the linkage may appear and it’s not impossible “parting shot” evolved (possibly even in more than one place) separately and among those who had never heard of the “Parthian shot”.  So, while the two terms are often used interchangeably and in general use “Parthian shot” is now rare, those who wish can achieve nuances of difference: (1) A “Parthian shot” is an attacking comment made while in retreat and (2) A “parting shot” is a “last word” delivered while breaking off from an oral engagement; it does not of necessity imply a retreat.

The Bolton-Paul Defiant (1939-1943)

The Royal Air Force (RAF) tried a variation of the Parthian shot with Bolton-Paul Defiant, a single-engined fighter and Battle of Britain contemporary of the better remembered Spitfire and Hurricane.  Uniquely, the Defiant had no forward-firing armaments, all its firepower being concentrated in four .303 machine guns in a turret behind the pilot.  The theory behind the design dates from the 1930s when the latest multi-engined monoplane bombers were much faster than contemporary single-engined biplane fighters then in service. The RAF considered its new generation of heavily-armed bombers would be able to penetrate enemy airspace and defend themselves without a fighter escort and this of course implied enemy bombers would similarly be able to penetrate British airspace with some degree of impunity.

By 1935, the concept of a turret-armed fighter emerged.  The RAF anticipated having to defend the British Isles against massed formations of unescorted enemy bombers and, in theory, turret-armed fighters would be able approach formations from below or from the side and coordinate their fire.  In design terms, it was a return to what often was done early in the First World War, though that had been technologically deterministic, it being then quite an engineering challenge to produce reliable and safe (in the sense of not damaging the craft's own propeller) forward-firing guns.  Deployed not as intended, but as a fighter used against escorted bombers, the Defiant enjoyed considerable early success, essentially because at attack-range, it appeared to be a Hurricane and the German fighter pilots were of course tempted attack from above and behind, the classic hunter's tactic.  They were course met by the the Defiant's formidable battery.  However, the Luftwaffe learned quickly, unlike the RAF which for too long persisted with their pre-war formations which were neat and precise but also excellent targets.  Soon the vulnerability of the Defiant resulted in losses so heavy its deployment was unsustainable and it was withdrawn from front-line combat.  It did though subsequently proved a useful stop-gap as a night-fighter and provided the RAF with an effective means of combating night bombing until aircraft designed for the purpose entered service.

Trends of Use

Because of the way Google harvests data for their ngrams, they’re not literally a tracking of the use of a word in society but can be usefully indicative of certain trends, (although one is never quite sure which trend(s)), especially over decades.  As a record of actual aggregate use, ngrams are not wholly reliable because: (1) the sub-set of texts Google uses is slanted towards the scientific & academic and (2) the technical limitations imposed by the use of OCR (optical character recognition) when handling older texts of sometime dubious legibility (a process AI should improve).  Where numbers bounce around, this may reflect either: (1) peaks and troughs in use for some reason or (2) some quirk in the data harvested.

Tsar

Tsar (pronounced zahr)

(1) An emperor or king.

(2) Title of the former emperors of Russia and several Slavonic states.

(3) Slang term for an autocratic ruler or leader.

(4) Slang term for a person exercising great authority or power in a particular field.

1545-1555: From the Old Russian tsĭsarĭ (emperor or king), akin to the Old Church Slavonic tsěsarĭ, the Gothic kaisar and the Greek kaîsar, all ultimately derived from the Latin Caesar (an emperor, a ruler, a dictator) while the Germanic form of the word was the source of the Finnish keisari and the Estonian keisar.  The prehistoric Slavic was tsesar, Tsar first adopted as an imperial title by Ivan IV (Ivan Vasilyevich, 1530–1584 and better remembered as Ivan the Terrible, Grand Prince of Moscow and all Russia 1533-1584 & Tsar of all Russia 1547-1584) in 1547.  There’s a curious history to spelling tsar as czar.  Spelled thus, it’s contrary to the usage of all Slavonic languages; the word was so spelt by the Carniolan diplomat & historian Baron Siegmund Freiherr von Herberstein (1486–1566) in his work (in Latin) Rerum Moscoviticarum Commentarii (Notes on Muscovite Affairs (1549)) which was such a seminal early source of knowledge of Russia in Western Europe that "czar" passed into the Western languages; despite that history, "tsar" definitely is the proper Latinization.  It still appears and some linguistic academics insist the lineage means it should be regarded as archaic use rather than a mistake and, as a fine technical point, that’s correct in that, for example, the female form czarina is from 1717 (from Italian czarina and German zarin).  In Russian, the female form is tsaritsa and a tsar’s son is a tsarevitch, his daughter a tsarevna.

Nicholas II (Nikolai II Alexandrovich Romanov, 1868–1918; last Tsar of Russia, 1894-1917).  He cut an imposing figure for the portraitists but his cousin Kaiser Wilhelm II (1859–1941; German Emperor & King of Prussia 1888-1918) reckoned the tsar's mental abilities rendered him most suitable to "a cottage in the country where he can grow turnips".  Wilhelm got much wrong in his life but historians seem generally to concur in this he was a fair judge of things.

Tsar and its variants were the official titles of (1) the First Bulgarian Empire 913–1018, (2) the Second Bulgarian Empire (1185–1396), (3) the Serbian Empire (1346–1371), (4) the Tsardom of Russia (1547–1721) (technically replaced in 1721 by imperator, but remaining in use outside Russia (also officially in relation to certain regions until 1917) and (5) the Tsardom of Bulgaria (1908–1946).  So, although most associated with Russia, the first ruler to adopt the title was Simeon I (usually written as Simeon the Great; circa 865-927, ruler of Bulgaria 893-927) and that was about halfway through his reign and nobody since Simeon II (Simeon Borisov Saxe-Coburg-Gotha, b 1937; (last) Tsar of the Kingdom of Bulgaria 1943-1946) has been a tsar.  The transferred sense of "person with dictatorial powers" seems first to have appeared in English in 1866 as an adoption in American English, initially as a disapproving reference to President Andrew Johnson (1808–1875; US President 1865-1869) but it has come to be applied neutrally (health tsar, transport tsar) and use does sometimes demand deconstruction: drug tsar has been applied both to organised crime figures associated with the distribution of narcotics and government appointees responsible for policing the trade.  In some countries, some overlap between the two roles has been noted.

Comrade Stalin agitprop.

Volgograd, the southern Russian city was between 1925-1961 named Stalingrad (Stalin + -grad).  Grad (град in Cyrillic) was from the Old Slavic and translates variously as "town, city, castle or fortified settlement"; it once existed in many languages as gord and can be found still as grad, gradić, horod or gorod in many place-names.  Before it was renamed in honour of comrade Stalin (1878-1953, leader of the USSR 1924-1953), between 1589-1925, the city, at the confluence of the Tsaritsa and Volga rivers was known as Tsaritsyn, the name from the Turkic-related Tatar dialect word sarisin meaning "yellow water" or "yellow river" but because of the similarity in sound and spelling, came in Russia to be associated with Tsar.  Stalingrad is remembered as the scene of the epic and savage battle which culminated in the destruction in February 1943 of the German Sixth Army, something which, along with the strategic failure of the Wehrmacht in the offensive (Unternehmen Zitadelle (Operation Citadel) in the Kursk salient five months later, marked what many military historians record as the decisive moment on the Eastern Front.  It has become common to refer to comrade Stalin as the "Red Tsar" whereas casual comparisons of Mr Putin (Vladimir Vladimirovich Putin; b 1952; president or prime minister of Russia since 1999) don't often reach to Russia's imperial past; they seem to stop with Stalin.

Caesar (an emperor, a ruler, a dictator) was from the late fourteenth century cesar (from Cæsar) and was originally a surname of the Julian gens in Rome, elevated to a title after Caius Julius Caesar (100-44 BC) became dictator and it was used as a title of emperors down to Hadrian (76–138; Roman emperor 117-138).  The name ultimately is of uncertain origin, Pliny the Elder (23–79) suggested it came from the Latin caesaries (head of hair) because the future dictator was born with a lush growth while others have linked it to the Latin caesius (bluish-gray), an allusion to eye color.  The "probity of Caesar's" wife (the phrase first recorded in English in the 1570s) as the figure of a person who should be above suspicion comes from the biography of Julius Caesar written by the Greek Middle Platonist priest-philosopher & historian Plutarch (circa 46–circa 123).  Plutarch related the story of how Julius Caesar divorced his wife Pompeia because of rumors of infidelity, not because he believed the tales of her adultery but because, as a political position, “the wife of Caesar must not even be under suspicion”.  That’s the origin of the phrase “the probity of Caesar’s wife, a phrase which first appeared in English in the 1570s.

In late nineteenth century US slang, a sheriff was "the great seizer" an allusion to the office's role in seizing property pursuant to court order.  The use of Caesar to illustrate the distinction between a subject’s obligations to matters temporal and spiritual is from the New Testament: Matthew 22:21.

They say unto him, Caesar's. Then saith he unto them, Render therefore unto Caesar the things which are Caesar's; and unto God the things that are God's.

Christ had been answering a question posed by the Pharisees to trap Him: Is it lawful to pay taxes to Caesar (Matthew 22:15–20)?  To answer, Jesus held up a denarius, the coin with which pay the tax and noted that on it was the head of Caesar, by then Caesar had become a title, meaning emperor of Rome and its empire.  It was a clever answer; in saying "render unto Caesar that which is Caesar's and render unto God that which is God's", Jesus dismisses the notion of believers being conflicted by the demands of the secular state as a false dilemma because, one can fulfil the requirements of the sate by a mere payment of coin without any implication of accepting its doctrines or legitimacy.  Over the years much has been made of what is or should be "rendered unto Caesar", but more interesting is inference which must be drawn: if we owe Caesar that which bears his image, what then do we owe God?  It can only be that we owe God that which bears the image of God, an impressive inventory listed in the book of Genesis and now interpreted by some Christians as "the whole universe".  To Caesar we can only ever owe money; to God we owe ourselves.

In the Old English the spelling was casere, which would under the expected etymological process have evolved into coser, but instead, circa 1200, it was replaced in the Middle English by keiser, from the Norse or Low German, and later by the French or Latin form of the name.  Cæsar also is the root of German Kaiser, the Russian tsar and is linked with the Modern Persian shah.  Despite the common assumption, "caesar" wasn’t an influence on the English "king".  King was from the Middle English king & kyng, from the Old English cyng & cyning (king), from the Proto-West Germanic kuning, from the Proto-Germanic kuningaz & unungaz (king), kin being the root.  It was cognate with the Scots keeng (king), the North Frisian köning (king), the West Frisian kening (king), the Dutch koning (king), the Low German Koning & Köning (king), the German König (king), the Danish konge (king), the Norwegian konge (king), the Swedish konung & kung (king), the Icelandic konungur & kóngur (king), the Finnish kuningas (king) and the Russian князь (knjaz) (prince) & княги́ня (knjagínja) (princess).  It eclipsed the non-native Middle English roy (king) and the Early Modern English roy, borrowed from Old French roi, rei & rai (king).

The Persian Shah was from the Old Persian xšāyaθiya (king), once thought a borrowing from the Median as it was compared to the Avestan xšaϑra- (power; command), corresponding to the Sanskrit (the Old Indic) kṣatra- (power; command), source of kṣatriya (warrior).  However, recent etymological research has confirmed xšāyaθiya was a genuine, inherited Persian formation meaning “pertaining to reigning, ruling”.  The word, with the origin suffix -iya was from a deverbal abstract noun xšāy-aθa- (rule, ruling) (Herrschaft), from the Old Persian verb xšāy- (to rule, reign).  In the Old Persian, the full title of the Achaemenid rulers of the First Empire was Xšāyaθiya Xšāyaθiyānām (or in Modern Persian, Šāhe Šāhān (King of Kings)), best as "Emperor", a title with ancient, Near Eastern and Mesopotamian precedents.  The earliest known instance of such a title dates from the Middle Assyrian period as šar šarrāni, used by the Assyrian ruler Tukulti-Ninurta I (1243–1207 BC).

Tsar Bomba: the Tsar bomb

Tupolev Tu-95 in flight (left) and a depiction of the October 1961 test detonation of the Tsar Bomb.

Царь-бомба (Tsar Bomba (Tsar-bomb)) was the Western nickname for the Soviet RDS-220 hydrogen bomb (Project code: AN602; code name Ivan or Vanya), the most powerful nuclear weapon ever detonated.  The test on 30 October 1961 remains the biggest man-made explosion in history and was rated with a yield of 50-51 megatons although the design was technically able to produce maximum yield in excess of 100.  For a long time the US estimated the yield at 54 megatons and the Russians at 58 but after the fall of the Soviet Union in 1991, it was confirmed the true yield was 50-51 megatons.  Only one was ever built and it was detonated on an island off the Russian arctic coast.  The decision to limit the size blast was related to the need to ensure (1) a reduced nuclear fall-out and (2) the aircraft dropping the thing would be able to travel a safe distance from the blast radius (the Kremlin's attitude to the lives of military personnel had changed since comrade Stalin's time).  No nuclear power has since expressed any interest in building weapons even as large as the Tsar Bomb and for decades the trend in strategic arsenals has been more and smaller weapons, a decision taken on the pragmatic military grounds that it's pointless to destroy things many times over.  It's true that higher yield nuclear weapons would produce "smaller rubble" but to the practical military mind such a result represents just "wasted effort".

Progress 1945-1961.

The Tupolev Tu-95 (NATO reporting name: Bear) which dropped the Tsar Bomb was a curious fork in aviation history, noted also for its longevity.  A four-engined turboprop-powered strategic bomber and missile platform, it entered service in 1956 and is expected still to be in operational use in 2040, an expectation the United States Air Force (USAF) share for their big strategic bomber, the Boeing B-52 which first flew in 1952, the first squadrons formed three years later.  Both airframes have proven remarkably durable and amenable to upgrades; as heavy lift devices and delivery systems they could be improved upon with a clean-sheet design but the relatively small advantages gained would not justify the immense cost, thus the ongoing upgrade programmes.  The TU-95's design was, inter-alia, notable for being one of the few propeller-driven aircraft with swept wings and is the only one ever to enter large-scale production.  It's also very loud, the tips of those counter-rotating propellers sometimes passing through the sound barrier.

Footage of the Tsar Bomb test de-classified and released after the dissolution of the Soviet Union (1922-1991).

The Tsar Bomb was in a sense the “ultimate” evolution of the centuries long history of the bomb although it wasn’t the end of innovation, designers seemingly never running out of ideas to refine the concept of the device, the purpose of which is to (1) blow stuff up and (2) kill people.  Bomb was from the French bombe, from the Italian bomba, from the Latin bombus (a booming sound), from the Ancient Greek βόμβος (bómbos) (booming, humming, buzzing), the explosive imitative of the sound itself.  Bomb was used originally of “projectiles; mortar shells etc”, the more familiar “explosive device placed by hand or dropped from airplane” said by many sources to date from 1908 although the word was in the former sense used when describing the anarchist terrorism of the late nineteenth century.  As a footnote, the nickname of Hugh Trenchard (1873-1956), the first Marshal of the Royal Air Force (RAF) was “boom” but this was related to his tone of voice rather than an acknowledgement of him being one of the earliest advocates of strategic bombing.

The figurative uses were wide, ranging from “a dilapidated car” (often as “old bomb”, the use based presumably on the perception such vehicles are often loud).  The bombshell was originally literally a piece of military equipment but it was later co-opted (most memorably as “blonde bombshell) to describe a particularly fetching young women.  So, used figuratively, “bomb” could mean either “very bad” or “very good” and in his weekly Letter from American (broadcast by the BBC World Service 1946-2004), Alistair Cooke (1908–2004) noted a curious trans-Atlantic dichotomy.  In the world of showbiz, Cooke observed, “bomb” was used in both the US & UK to describe the reaction to a play, movie or whatever but in the US, if called “a bomb”, the production was a flop, a failure whereas in the UK, if something was called “quite a bomb”, it meant it was a great success.

I Know Who Killed Me (2007)

I Know Who Killed Me bombed (in the traditional US sense) but in the way these things sometimes happen, the film has since enjoyed a second life with a cult-following and screenings on the specialized festival circuit.  Additionally, DVD & Blu-Ray sales (it's said to be a popular, if sometimes ironic, gift) meant eventually it generated a profit although it has never exactly become a "bomb" (in the UK sense).  However, while it now enjoys a following among a small sub-set of the public, the professional critics have never softened their view.