©2004-2023 F. Dörenberg, unless stated otherwise. All rights reserved worldwide. No part of this publication may be used without permission from the author.

Latest page updates: May 2023 (completed this page)

Previous updates: June 2022 (made into separate page; added ref. 230R8, 245B-245D); January 2022 (inserted section on bombing); December 2021 (added ref. 230Q5, 230Q6, 230R13); 28 May 2021 (note: now about 800 literature references provided on the WW2 Rad Nav pages, almost all downloadable!); April 2020 (started complete overhaul & expansion of this page).

red-blue line


"For once you have tasted flight, you will walk the earth with your eyes turned skyward,
for there you have been and there you long to return."

John H. Secondari, 1965 (Italian-born writer, producer & narrator of the 1963-1969 American ABC TV series "The Saga of Western Man". The quote is from the episode "I, Leonardo da Vinci"; minute 39 of 51), but is persistently & errononeously attributed to Leonardo da Vinci himself!

"Home, to an airman, is wherever there are hangars, planes to fly, and a field to fly them from."

C. Nordhoff, J.N. Hall, 1929

Catapults, for hurling projectiles at enemies, date back to 4th century China. Man-carrying kites were used extensively in 6th century China. In the 19th century, they were briefly considered for throwing projectiles, rather than for the original reconnaissance purposes. The words "bombardment", "bomb", and "bombing" trace back to the word "bombard": a ca. 14th century type of wide-muzzled canon or mortar. They were used for shooting large round stone projectiles at walls of enemy fortifications. The non-entertainment use of rockets dates back a lot further: the Wujing Zongyao, a Chinese military compendium written around 1040 AD (during the Song dynasty), includes the earliest known written chemical formulas for gunpowder, and details on various gunpowder weapons such as fire arrows, incendiary bombs and projectiles, grenades and smoke bombs. The early 15th century Middle English word "canon" comes from the 8th century Mesopotamian word "gina" for "reed", via ancient Greek and Latin, and the Italian word "cannone" (reed or tube).

In 1670, Francesco Lana (born in Brescia/Italy, later working as a professor in Terzi) published his "Prodromo" introductory treatise, in which he presents his concept of building "a boat that, suspended in the air, moves by oars and sails, and proves to be able to succeed in practice". Ref. 280D19 (title of Chapter 6 = p. 52). Lift was to be provided by several large vacuum spheres, made of very thin copper foil. See Fig. 1. The idea being that a volume of vacuum would be lighter than air, hence, provide lift. Lana's lighter-than-air vessel represents the earliest concept of flight based on aerostatic principles! For this, and his scientific work on the mechanics of flight in general, he is sometimes referred to as the "father of aeronautics". On page 61 of the "Prodromo", he warns that, with such a "flying boat"...

"... no city would be safe from surprises, since it would be possible at any time, to take such ship right over the square of a city, land it, and let men off; the same thing could happen in the courtyard of private homes; and onto ships that sail the sea; in fact, by merely descending the ship from high up in the air, down to the sails of a seagoing ship, its ropes could be cut; and even without descending, they could thrown down irons from the ship, which could upset ships and kill men, and set fire to ships with fireworks, cannon balls, and bombs; not only to ships, but to houses, castles, and cities, with the assurance that those who would drop them from an immense height, would not be harmed themselves."

Translation ©2023 by Frank Dörenberg

Francesco Lana airship

Fig. 1: Francesco Lana's concept of a lighter-than-air "nave volante" (lit. "flying boat), pubished 1670 (left) and 1684 (right)

(source: adapted from ref. 280D19 and ref. 280D20)

This is the earliest recorded description of aerial bombing: manually or mechanically dropping (= passively releasing or actively ejecting), a "bomb" from an aircraft! It is elaborated in his 1684 dissertation "La nave volante" ("The flying boat"). Ref. 280D20. A "bomb" is generally understood to be a container that is filled with explosive, incendiary, or other chemical material, designed to explode on impact or when detonated by a timer, proximity detector, or remote-control. Note: all airplanes are aircraft, but not all aircraft are airplanes! Only airplanes, as the name clearly suggests, have wings. See Fig. 2:

aircraft helicopter kite glider balloon airship dirigible notar gyrodyne autogyro gyrocopter gyroplane variable wing sweep swing camber

Fig. 2: Simplified taxonomy of aircraft categories, based on the primary means of generating lift

(i.e., not of aircraft types/models, usage/purpose, weight classes, approach classes, land/sea, number & type of engines, etc.)

It took another century (!) for the first tethered and untethered hot air balloons to be demonstrated by the Montgolfier bros. at Versailles/Paris in 1783. Nearly 30 years later, during the 1812 French invasion of Russia (the seventh - and final - Napoleonic War), the Russians constructed a large balloon at Moscow. It was to hover over the French army and "rain forth shells and explosives", but the balloon "refused to move off the ground". The French soldiers found the ballon at Vorotsov Manor near Moscow, "bearing many thousand pounds of gunpowder, which were to have been launched upon them". Ref. 280D14, p. 176. Another 36 years later, early June of 1848, Henry Tracey Coxwell took up the "Sylph" hot air balloon near Brussels/Belgium, in order to...

"... show, on a miniature scale, how practicable it was to discharge aërial shells from a balloon, supposing they were needed in warfare, when it was not possible to bombard in the usual way, owing to intervention of hills, water, or other impediments.... A Belgian pyrotechnist having made the explosive shells, in strict accordance with my instructions, and in exact imitation of a model to scale... I would then pass down a rope ladder, and by communicating with a fuse at a safe distance from the gas, the shells would be ignited... a bluish outburst of smoke, followed by a sharp sound, announced that the first aërial shell had burst in mid air... the rest following at stated intervals, and with remarkable precision."

In the following months, Coxwell made several other ascents: at the Bourse of Antwerp/Belgium, at Wuppertal-Elberfeld in Prussia/Germany, and at military practice grounds outside Berlin. He used firework shells to demonstrate a "miniature bombardment, illustrative of the applicability of aërial shells to military purposes". Ref.280D14 (pp. 85-86, 103).

The first crossing of the English Channel with an aircraft took place in January of 1785: Jean-Pierre Blanchard and John Jeffries flew from Dover to Guînes (just south of Calais/France) with a hydrogen gas balloon. It did not take long for balloons to become considered for military troop transport:

invasion of England

Fig. 3: Balloons, ships, and the Channel Tunnel (!) - ways for France to invade England (1803 French caricature)

(source: adapted from ref. 280D16; also used in ref. 280D18)

The Republic of Venice lost its independence when Napoleon Bonaparte conquered Venice in May of 1797. Venice became Austrian territory with the signing of the Treaty of Campo Formio in October of that same year, and the Austrians took control of the city in January of 1798. The Napoleonic Wars started in 1799. Austria was defeated at the battle of Marengo in 1800. Venice was taken from Austria by the Treaty of Pressburg (renamed Bratislava after World War I) in 1805 and became part of Napoleon's Kingdom of Italy. After Napoleon's defeat in 1814, Austria expanded its territory, and gained control of northern Italy. The Republic of Venice became part of the Austrian-controlled Kingdom of Lombardy-Venetia. The Napoleonic Wars ended in June of 1815, with the battle of Waterloo/Belgium. In 1848, the "risorgimento" insurrection briefly re-established the Republic of Venice. Austria besieged Venice in 1849.

The lagoon city was out of reach of the 5000 paces range of the Austrian artillery. Needed solution. The first recorded of bomb dropped from aircraft / balloon during military conflict.

Ref. 280D21-280D22.

Uchatius Venice

Fig. 4: The Uchatius "balloon bomb"

(source of bomb images: adapted from ref. 280D20)

The Uchatius bomb and its balloon delivery system had a fuze (with "z") as well as a fuse (with "s"):

  • A fuse is cord/rope or tube for the transmission of flame or explosion usually consisting of cord or rope with gunpowder or high explosive spun into it. = time delay, with a fairly constant time per unit of length.
  • A fuze (with "z") is a device with explosive components designed to ignite the main explosive charge (here: gunpowder).

The Uchatius balloon bomb has its fuze threaded into the bottom ( = base ) of the shell. So it was a base fuze. It comprised a bolt-shaped percussion head, three percussion pins (a.k.a. strikers, pistons), several stacked detonator caps (a.k.a. primers, percussion caps), and a threaded insert - with 3 channels - to guide the hot detonator gasses into the main explosive charge and ignite it. The caps ignite on impact, when the head is injected into the shell. Hence, it was also a contact fuze (a.k.a. percussion fuze).

Fuse + explosive charge: a package of "raketentreibsatz" rocket fuel, a slow (= long) burning gunpowder pixture, to burn through the rope from which the bomb was suspended, and let it drop. The Kaiserliches & Königliches Heeresgeschichtliches Museum (Imperial & Royal Army History Museum) in Vienna/Austria has several in its collection.

Uchatius Venice

Fig. 5: (left) "The bombing of Venice in August of 1849", hand-colored lithography after drawing by M. Fontana; (right) "Venice bombed by the Austrians", 1876 wood engraving after drawing by Albert Tissandier

(source: adapted from ref. 280D24 (left image) and 280D25)

Clément Ader was a French aviation pioneer and inventor (incl. improved Bell telephone, stereo telephone, 8-cylinder V-engine, train-track lifting machine, bicycle wheel with hard-rubber track, train with self-laying track - precursor to caterpillar track vehicles, navy "flat top" aircraft carrier,...). The first autonomous takeoff in a motorized airplane is attributed to him. On 9 October of 1890, he used his bat-like airplane, the "Éole" ("Wind"), for a brief "flight" at the grounds of Chateau d'Armainvilliers, about 20 km southeast of the center of Paris. He actually made several hops off the ca. 200 m long prepared terrain. All hops were very close to the ground (definitely less than the 1 m hight of the bushes, probably only about 20 cm), the longest one over a distance of about 50 m. The plane had a wingspan of 14 m, an Ader steam engine, but no directional control (like a rudder or asymmetrical wing-warping). The prop blades, made of strips of bamboo and paper, resembled a bird's quill feathers - resulting in a kind of automatic variable prop pitch, very much avant la lettre. Ader claims to have doubled this distance with the same Éole in August of 1891, at the military grounds of Camp de Satory (just south of Versailles, about 12 km southwest of the center of Paris). In February of 1892, some 20 years after the Franco-Prussian War (and the associated cession of the Alsace-Lorraine region to Germany in 1871), Ader signed a contract with the French "Ministère de la Guerre" (War Ministry), for developing "a machine capable of bombing the German enemy". The aircraft had to be fully dirigible, be able to carry a pilot plus a passenger or explosives, and fly for six hours at a speed of about 55 km/h (≈ 30 kts) at an altitude of "several 100 meters". This contract came with a substantial grant. Five years later, towards the end of 1897, his efforts had (only) progressed to a hop of 250-300 m in his "Avion Nr. 3" airplane, again at Satory. It had a wingspan of 16 m, fully foldable wings, two Ader-made 20 horsepower steam engines, and a rudder for directional control. Even though his airplanes were underpowered, Ader's engines had a power-to-weight ratio that remained unequalled until the advent of gasoline (UK: petrol) engines. Early 1898, his "Avion Nr. 4" was ready to go, but - frustrated and broke - Ader abandoned his pursuit of flight... Whereas Ader's attempts do qualify as "powered take-off from a level surface with a heavier-than-air aircraft", they do not qualify as "sustained and controlled" flight. His airplanes never had the power to climb out of the so-called "ground effect". Close to the ground (less than about half of the tip-to-tip wingspan), a cushion of air is formed underneath the wings, which significantly increases lift and reduces drag. This supporting cushion disappears when climbing out of the effect zone, requiring more lift (= speed = power). Note that the contractually required 6 hours cruise endurance was not achieved routinely during military conflict until about 25 years later (!), i.e., the latter part of World War I - combat endurance being about half of that. Ader's "Avion", derived from the latin noun "avis" = "bird", has remained the common French word for "airplane" ever since. It is predated by the word "aviation", which was coined in 1863 by the Frenchman Gabriel de La Landelle, as the combination of the latin words "avis" ( = "bird") and "actio" ( = "action"), to signify "imitating bird flight". Ref. 280D1, 280D13, 280D23, 280D26.

Bombing history

Fig. 6: Clément Ader’s "Avion No. 3" twin-engine twin-prop monoplane - 1890

(source: adapted from "Clément Ader, 9 octobre 1890", 15 min video documentary, Albert Bayard, Bibliothèque de France, accessed January 2022; No. 3 is on permanent display at the Musée des Arts et Métiers in Paris. no photos of his Éole / Avion No. 1 appear to have been made and survived - it had a single, centered prop)

The 19th century was a very bellicose century: worldwide about 600 wars and significant armed conflicts. Source: wikipedia.org. That is more than three times the number recorded for the 18th century! At the turn of the 20th century, this horrible record led to the first international treaties that addressed the conduct of warfare. They were negotiated at the 1899 and 1907 Peace Conferences, held at The Hague in The Netherlands. However, many of the important states, such as France, Germany, Italy, Japan and Russia, did not sign or ratify the final Declaration and all of its Articles. Austria-Hungary signed, but did not ratify it. Of the Great Powers, only Great Britain and the United States ratified it. The 1899 Peace Conference predates the advent of powered airplanes (powered and steerable airships date back to Henri Giffard's dirigible of 1852). However, a Conference "discussion of the question of throwing projectiles from balloons" already foresees that "... the use of more perfect balloons may soon become a practical and lawful means of waging war". This led to the following Declaration (ref. 280E1):

"The contracting Powers agree to prohibit for a term of five years, the discharge of projectiles and explosives from balloons or by other new methods of a similar nature".

I.e., no bombing from any type of aircraft. The Declaration had the following "members only" limitation:

"The present declaration is only binding on the contracting Powers in case of war between two or more of them. It shall cease to be binding from the time when, in a war between contracting Powers, one of the belligerents is joined by a non-contracting Power".

The above declaration had already expired several years before it was extensively discussed during the second Peace Conference, in 1907. It was neither renewed nor made permanent. However, a permanent Declaration of the 1899 Conference did already cover aspects of "bombardments", including (Article 25):

"It is forbidden to attack or bombard towns, villages, dwellings or buildings that are not defended."

This was considered by some Conference parties to already adequately cover aerial bombardments (i.e., not only conventional bombardments by surface-based and naval guns and canons), as such bombardments were not explicitly excluded from that general 1899 Article.

None of the 1923 Hague "Rules concerning the Control of Wireless Telegraphy in Time of War and Air Warfare" were ever adopted in a legally binding form. Ref. 230E3. The "Bombardment" section of these Rules comprises articles nr. 22-26. E.g., Article 24 states:

"The bombardment of cities, towns, villages, dwellings or buildings not in the immediate neighbourhood of the operations of land forces is prohibited. In cases where [military objectives] are so situated, that they cannot be bombarded without the indiscriminate bombardment of the civilian population, the aircraft must abstain from bombardment."

Ever since, the topic and definitions are revisited internationally once every couple of years. Ref. 230E2. To this day, some countries (or rather: regimes) continue to apply a rather flexible definition of "valid military target" when attacking and waging war on neigboring countries (or domestic opposition), and remain unpunished...

Louis Blériot crossed the Channel by airplane in July of 1909, from Les Barraques (renamed Blériot-Plage in 1936; just west of the port of Calais) to a meadow near Dover Castle. This revived the Napoleonic-era fear of the Britons that the French might plot again to invade England: "As might have been expected, Mr. Blériot's flight across the Channel has resulted in a revival of those invasion scares that were so prevalent recently in connection with dirigibles, and there seems to be a good many people who cannot sleep o' nights for fear that the enemies, skimming into England like a flight of all devouring locusts, drop bombs outside their doors" (ref. 280D17):

invasion of England

Fig. 7: "Hush! Hush! Hush! Here comes the bogey bird: The Scare-Oh-Plane!"

(source: adapted from ref. 280D17 (England, 1909))

The first recorded experiments with dropping bombs from an airplane took place in California in 1910 and 1911 – but not as part of an armed conflict. Lieutenant Paul W. Beck, in a Farman III biplane flown by the French aviator Louis Paulhan, conducted a rudimentary dummy-bomb dropping demonstration during the January 1910 Los Angeles Air Meet at Dominguez Field. A year later, at the 1911 Air Meet at the Tarforan Park horse racing track in San Bruno (just south of San Francisco), Lieutenant Myron S. Crissey (U.S. Army Air Corps), dropped the first "live" ( = explosive) bombs from a Wright airplane. The bombs were of his own design and had stabilizing fins. The plane was piloted by Phillip Parmalee, member of the Wright Bros. Exhibition Team.

Bombing history

Fig. 8: Lt. Crissey holding a dummy bomb, ready to go aloft in a Wright plane at the 1911 Air Meet near San Francisco/California, with pilot Phillip Parmalee

(source: US Air Force Historical Research Agency)

In France, during August of 1911, the Michelin brothers (André and Édouard), sponsored an aerial bomb-aiming competition, the "Aéro-Cible Michelin” ["Aero Target Michelin"]. They considered the competition indispensable for improving national defense. The monetary prizes were equivalent to appr. 80 and 160 thousand euros in Jan-2022 (≈90 & 180 thousand US$), ref. 280A9, 280A12. By the way: in 1916, the Michelin brothers built the world's first hard-surface runway & taxiway at their airplane factory's Aulnat aerodrome. In December of 1911, André Michelin proclaimed the need for a French air force with 5000 airplanes, and the same number of pilots - France being the only country able to do so, because, well,... the French are "special" in that only they have the required "brightness of mind and precision of gestures" (ref. 280D5, 1911). A persistent misconception, despite France indeed being the world leader in aviation at that time...

Bombing history

Fig. 9: 1912 promotional postcards of the Michelin company (artwork by Georges Hautot)

(source: unknown; Bibendum (the “Michelin Tire Man” mascot) refers to the bombs as “Bibendum turds”; the 1898 mascot was inspired by a stack of tires and the quote "Nunc est bibendum!" "Now it's time to drink!" or "Cheers!" for short, which is a fragment of a verse from the year 37 BC by the latin poet Horace [Horatius], which was actually a translation of a nearly 300 years older verse by the Greek poet Alcaeus [Alkaois] of Mytilene.)

The actual Michelin competition took place in 1912 at the artillery field of the military Camp de Châlons (a.k.a. Camp de Mourmelon-le-Grand), ca. 160 km (≈100 miles) northeast of down-town Paris. It was spread out over five stages, from February through August. Ref. 280A1-280A12. There were five competing teams - one civil and four military. They had to use round dummy projectiles with a diameter of 16 cm (≈6.3 inch) and a weight of 7.1 kg (≈16 lbs). During the initial stages, the ground target was round with a diameter of 20 m (≈66 ft). A minimum altitude of 200 m (≈650 ft) had to be maintained. During several rounds, one of the bomb aimers/releasers was the American USN Lieutenant Riley E. Scott. He used a version of his patented bomb-release device. See ref. 280A3, 280A8, and his 1910 US Patent 991378 "Means for dropping projectiles from aerial crafts". The final rounds of the competition used a target with the size of an airship hangar (120x40 m, ≈400x130 ft) and a minimum altitude of 800 m (≈2600 ft). Despite the pilots and airplanes being French, the results of the first round were "negative" and "not exactly brilliant" (ref. 280A2, 280A4): 15 bombs per airplane, but none hit the target.

Bombing history

Fig. 10: A competition dummy bomb suspended from Lt. Mailfert's airplane (left) and a Riley Scott bomb release device

(source: ref. 280A6 (left) and 280A3)

Also in August of 1912, there was a competition in Gotha/Germany that included bombing trials: the "Aeroplane Turnier" ["Airplane tournament"]. It was organized by the Deutscher Fliegerbund - the German federation of flying clubs, founded 1910 - and the Reichsflugverein (frmr. Verein Deutscher Flugtechniker, Association of German Aeronautical Engineers). Only military participants were allowed. They used the same type of dummy bombs as the Michelin competition, but ground targets of 100x100 m (≈330x330 ft), 150x150, and 200x200 m. The minimum altitudes were 200, 400, and 800 m, respectively. A moving target was also used: a tethered sausage-balloon (30 m long, 3 m diameter, 4 m above ground). It was to be bombed from a minimum altitude of 50 m. Ref. 280A13; also see ref. 280D3, 280D6. The British War Office did announce its first Military Aeroplane Trials in 1911. They were not held until early August of 1912, at Larkhill on Salisbury Plain. However, the event was focused entirely on airplane performance under various conditions, construction, engine technology, etc. No bombing trials were held. Ref. 280D11 (p. 235ff.). The August-September 1912 military competitions at St. Petersburg/Russia did include dropping of bombs. Actually, starting in 1910, throughout 1912, dropping dummy bombs was a popular highlight during many public exhibition flying events and aviation meetings in Europe and the USA. In all fairness, mediocre results at bombing trials - despite perfect visibility - were caused by lack of training and proficiency, some pilots also having to simultaneously act as bomb aimer/releaser, etc. (ref. 280D10), as well as general lack of awareness and understanding of many other factors listed below.

During 1996-2000, I was member of a large flying club at Boeing/King County Field just outside Seattle/WA/USA. This is where I got my "blind flying" Instrument Rating in 1998. One of the highlights in the flying club was the annual fly-in at Copalis Beach State Airport on the Pacific coast, 95 miles (150 km) southwest of Seattle. It is the only beach "airport" in the USA. As the name suggests, the "runway" is the sand of the narrow beach. Landings and take-offs have to be timed well with the tides. Standard soft-field landing & take-off techniques must be used and always keep the carburator heat on! The damp medium-dark sand at low tide is surprisingly hard. You do not want to get into the soft dry sand! I have made several landings and take-offs on this beach in a Cessna 172 (4-seater) and a 152 (2-seater) airplane. During the August 1997 fly-in, I participated in a friendly bombing competition with flour-filled paper bags. I piloted a Cessna 172, with my dear friend R. Büse as bombardier. Flying low-and-slow, we hit the small target beautifully... but got disqualified for flying well below 50 ft during our bombing run. It was jolly good fun nonetheless!

Copalis Beach runway

Fig. 11: August 1997 - myself on the runway of Copalis Beach/WA

(source aerial photo: Washington State Dept. of Transportation (WSDOT) 2019 Airport Guide)

The world's first bombing attack by airplane took place during the Italo-Turkish War. This war was fought from September 1911 to October 1912 in Ottoman Libya, by the Kingdom of Italy and forces loyal to the Ottoman Empire. On 1 November of 1911, Lieutenant Giulio Gavotti of the Royal Italian Army Air Service, took off in an early-version Etrich "Taube" (En: "Dove") monoplane. He proceeded to drop four bombs over Turkish-Arab encampments at Tagiur (Tajoura) and Ain Zara, two small oases southeast of Tripoli/Libia, about 10 km from the mediterranean coast. Contrary to a rather euphoric Italian newspaper article the next day (ref. 280D4, with translation), little damage was done, and there were no casualties.

Bombing history

Fig. 12: A 1913/14 model “Taube”, built by the Rumpler factory under license from the Austrian designer Ignaz "Igo" Etrich

(source: adapted from German Bundesarchiv image nr. 146-1972-003-64)

Those bombs were actually hand grenades, originally developed by Giuseppe Cipelli at the Silurificio di San Bartolomeo (San Bartolomeo Torpedo Works) in La Spezia/Italy in 1907/08. They were filled with picric acid - which is in the same chemical family as trinitrotoluene (TNT, the explosive ingredient of "dynamite"), and had mercury fulminate (= ignite when struck) as detonator. The grenades weighed about 1½ kg (≈ 3 lbs) each. Subsequent bombing runs used model A2 bombs from the Danish company Det Aasenske Granatkompani, named after its Norwegian owner and developer Nils Waltersen Aasen. Those bombs were about twice as heavy as the Cipelli grenades, and had a small parachute at the tail. Cipelli was killed in 1908 by accidental explosion, when he was loading one of his creations near Viareggio. On 6 March of 1912, the Italians dropped the first bombs from airships: on a Turkish-Arab camp at Zanzur, west of Tripoli. Those bombs were significantly heavier. Ref. 280D7, 280D8, 280D9.

Bombing history

Fig. 13: A Cipelli hand grenade – used as a bomb by Gavotti in 1911

(source: adapted from "L'aeronautica", T. Brinati, U. Fischetti, S. Stefanutti, Vol. II of "L'uomo e l'aria", Dr. F. Vallardi (publ.), 1939, 623 pp.)

A hand "grenade" is called that, because its shape clearly resembles that of the many-seeded apple, also known as a pomegranate fruit (latin name punica granatum), and also explodes into many small fragments. Some pomegranates even have a built-in peace sign - see the photo above! Fragments of exploding bombs, mines, and artillery shells are generally referred to as "shrapnel". It is named after Henry Shrapnel (1761-1842). In 1784, while a lieutenant in the British Royal Artillery, he invented a "spherical case ammunition" - basically a hollow cannonball, filled with lead pellets. It would explode mid-air, and shred the enemy (or their animals) with the pellets and splinters of the shell.

About half way through World War I, using airships for bombing of land targets had become obsolete and came to an end. They had become an easy prey for increasing anti-aircraft defenses on ground, as well as fighter aircraft. They were also rather ineffective, as far as damage inflicted and casualties caused. So, they were replaced with much smaller fighter and bomber airplanes. Those were a lot less expensive to build and maintain, required a much smaller crew and ground support, and could fly increasingly faster and higher. Note: during 1910-1912, the world airplane altitude record increased from ca. 300 to over 3000 m (≈1000-10000 ft). However, due to their flight range and endurance, airships were retained in service somewhat longer, for naval reconnaissance and bombing of ships.

Bombing history

Fig. 14: An RNAS lieutenant about to drop a bomb from the rear cockpit of the gondola of a Sea Scout Zero airship, ca. 1916

(source: Imperial War Museums (IWM) Photograph Archive Collection, catalog nr. Q 67698; used in accordance with IWM NCL)

Bombing history

Fig. 15: The tandem-cockpit control car (gondola) of Sea Scout Zero airship SSZ 8 - with a bomb rack behind the rear cockpit

(Royal Navy SSZ: length 143.5 ft (≈44 m), diameter 27.9 ft (≈8.5 m), height 43.9 ft (≈13.4 m), speed 50 mph (≈80 km/h), engine: 1 x 75 hp)

Passive projectiles were also used. In particular relatively small steel darts of various shapes. They were intended to pierce helmets and "a man's body from head to feet". They are also referred to as "flêchettes", French for "small darts". Contrary to popular belief (esp. in France), they were invented in Italy. The French practiced with them on natives in Morocco in 1912. Millions were strewn over enemy trenches during WWI in France, by both sides of the conflict.

Bombing history

Fig. 16: Small bomb and cradle on outside of the fuselage, and a box with flêchettes, for strewing over enemy trenches

(source news paper segment: adapted from "Navy and Army Illustrated" weekly magazine, 23 January 1915, pp. 16, 17)

invasion of England

Fig. 17A: March 1918, somewhere in Belgium - Gotha G.V heavy bomber of the German Air Force, with selection of bombs

(source: wikipedia.org)


Fig. 17B: Two "munitionette" workers with examples of shells produced at National Shell Filling Factory No.6 at Chillwell, Nottinghamshire , ca. 1917

(source: wikipedia.org)

Bombing as popular entertainment - the grand finale of the annual British RAF Pageant starting 1920 (1925 etc as the RAF Display), at RAF Hendon aerodrome on the northwest side of London; bombng of a mock German village, mock Arab village, or mock Arab oil field.

Bombing history

Fig. 18: Poster for 1922 RAF Pageant & 1927 RAF Display at Hendon Aerodrome, attack on immitation German village (1921)

(sources: 1922 poster: wikimedia.org; photo: Flight International, 7 July 1921; 1927 poster: posterazzi.com - retrieved May 2023 )

under construction

"Bombing brought to being a number of crude devices in the first year of the War. Allied pilots of the very early days carried up bombs packed in a small box and threw them over by hand, while, a little later, the bombs were strung like apples on wings and undercarriage, so that the pilot who did not get rid of his load before landing risked an explosion. Then came a properly designed carrying apparatus, crude but fairly efficient, and with 1916 development had proceeded as far as the proper bomb-racks with releasing gear." Ref. 280D11, p.252ff.

Ref. 280D12: "strategic bombing" = destroy or disrupt an enemy's war-making potential and to break or weaking his will to resist; to deter war or defeat an enemy Def. of Tactical Bombardment? More truthfully: bomb built-up areas of cities to destroy the emorale of enemy civilian popuation, in particlar industrial workers. I.e., effectivly destroying entire cities and civilian infrastructure with large numbers of civilian casualties, but no (or limited) impact on military capability. Also referred to as "carpet bombing" / "saturation bombing" - doctrine - hitting target area with a large number of bombs, irrespective of collateral damage, or hit target and on purpose cause collateral damage), indiscriminate [ = without making distinction] bombing to destroy a wide area. Of course, though denied by most perpetrators (by calling it, e.g., "precision bombing of a city"), because indiscriminate bombing is a direct violation of Article 51 of the Geneva Protocol I (1924 League of Nations Protocol for the Pacific Settlement of International Disputes) which prohibits considering multiple separated and distinct military targets as a single target.

Technique: Dive bombing, toss-bombing, ...

Method: tactical/strategic, carpet-, area-,

Strategic bombing causes [intentionally, unintentionally, "don't care"] collateral damage: the killing, wounding, and dstruction of civilllians and their property.

Tactical bombing: = close air support to ground forces.

See bombing.notes.txt. Ref. 280D15.

Actual bombing. AGARD Ref. 280C3,§ C1-C4.


under construction

Accuracy, spread, consistency/repeatability. Quality (precision bombing, pin-point bombing) vs. quantity (area bombing, strategic bombing, saturation bombing, carpet bombing)

There are many forces and moments that act upon a released bomb. Conventional free-falling "dumb" bombs are unguided and passive: they have no movable surfaces for trajectory corrections - whether by an on-board control system or via remote control, nor propulsion. Note: wired and wireless remotely controlled bombs (and aircraft) were developed during the 1930s and WW2 (some even with a video camera in the nose, such as the German "Tonne" system for standoff bombs ("Gleitbombe")), ref. 230Q29, pp. 376-380).

Predicting the real point-mass trajectory of a released bomb is very far from trivial. The following are primary factors that affect this trajectory, and the resulting "target miss distance" (a.k.a. "stores delivery accuracy"):

  • The earth's gravity acceleration "g". This is location and altitude dependent.
  • No, the earth is not flat! But is not a a perfect sphere either. Its shape is closer to an oblate spheroid: it is slightly flattened at the poles, resulting in a polar diameter that is about 43 km smaller than the equatorial diameter. It is neither smooth, nor homogeneous: mass is distributed unevenly within the planet, and this unevenness moves around, due to plate tectonics and other dynamic effects. At sea level, gravity at the earth's poles is about 0.5% larger than at the equator. Gravity at, e.g., 20 thousand feet (6 km) Above Sea Level (ASL) is about 1% smaller than at Sea Level.

  • Aerodynamic drag:
  • Drag induced force is proportional to the product of the bomb's drag coefficient, the local density of the air, and the square of the speed with respect to the air (not speed over ground!). Both air density and air speed change continuously during the entire fall of the bomb.
  • xxxxxxxx other xxxxxxx

airplane aerodynamic drag curves

Fig. 19: Simplified break-down of aerodynamic drag components

  • Bomb release altitude: clearly impacts the fall time to the local terrain hight at the point of impact.
  • Considerations. Aircraft without supplemental oxygen: German bombers 6000 ft? Modern-day civil aviation rules require pilots to use supplemental oxygen when flying at cabin pressure altitudes at or above 14 thousand feet (≈4.3 km), and for any portion of a flight at 12½ to 14 thousand feet that exceeds 30 minutes. Above 15 thousand feet (≈4.5 km), all occupants must use oxygen.
  • Desire to fly above the reach of anti-aircraft guns.

  • Aircraft conditions in terms of position (altitude error) and motion at the time of bomb release (pitch, roll, and yaw attitude angle, rate of change and acceleration of that angle, airspeed error).
  • Before the moment of release, the bomb follows all movements of the airplane. These movements (speed vector, rotation) continue after the release. This is due to the Law of Conservation of Momentum.
  • The best pilots, and even modern-day automatic pilots, cannot keep an airplane flying perfectly "straight and level", with a constant altitude, constant speed, and without any pitch, roll, and yaw motion ( = rotation about the three aircraft axes of motion). Closed loop control systems are inherently based on generating corrective control inputs that are based on detecting a certain non-zero deviation from the desired state ( = the setpoint). I.e., even with such a control system, the aircraft will always meander around the desired state.
  • Advanced modern bombing computers can compensate for movements of the aircraft, whether pilot induced, or caused by weather conditions or shock waves from exploding anti-aircraft projectiles. However, they can not compensate if those movements are relatively abrupt.
  • Basic straigh-and-level, dive bomb, maneuvres during bombing.

  • Bomb release method:
  • Passive release ( = helped only by gravity) by hand, while holding the bomb in the air flow. This is highly unrepeatable, and also adds movements.
  • Passive release from a free-fall external rack mounting (wing or fuselage mounted).
  • Passive release from a free-fall rack in the bomb bay, inside the fuselage. The bomb bay may be semi or fully recessed, and the bomb rack may be horizontal or vertical (with the bombs head-down or tail-down).
  • Active ejection, by firing a cartridge-actuated device (compressed air or pyrotechnic impulse). This method induces forces and moments. It is used with high speed fighter-bomber or attack aircraft: at high speeeds, the low air pressure condition under the aircraft fuselage tends to keep the bomb near the aircraft. Ejection is also used to avoid separation effects from causing the bomb to hit the aircraft.

  • Separation effects: the bomb falls through the aircraft's flow-field ( = the air flow around the aircraft). This is significantly different from the free-stream air farther away from the aircraft, which is not disturbed by the aircraft passing through. The flow-field causes sidewash and upwash. In turn, this causes pitching and yawing forces on the bomb. This is a major miss-distance factor.
  • Temporary influence on the motion of a released bomb by interaction of the bomb and the non-uniform airflow between aircraft and bomb.
  • This depends on aircraft configuration, bomb rack physical & aerodynamic characteristics (esp. for external racks), manufacturing tolerances, and installation tolerances.
  • Also depends on the individual position of a bomb within/on a mult-bomb rack, and the release squence.
  • When releasing multiple bombs in rapid sequence, separation effects may cause bomb-to-bomb collisions. This alters the bombs' trajectories. It can also result in detonation of one or more bombs and damage to the aircraft.
  • Tumbling, "out of round" precession (wobble, "coning" effect), and spinning movements significantly impact the aerodynamic behavior of the bomb. Bombs are typically designed so as to minimize these movements and expedite their stabilization after release.

He-111 bomb release

Fig. 20: Bombs tumbling from a Heinkel He-111 (1940)

  • Bombing angle:
  • Level bombing: the aircraft drops its bomb load while it is in "level flight", i.e., while flying "horizontally" at a constant altitude. Normally, it is not only "level" but "straight-and-level" with a constant speed, so as to avoid (minimize to the extent practicable) all aircraft movement.
  • Dive bombing: the aircraft makes a steep, high-speed dive toward the target, while keeping that target in its unsophisticated cross-hair bombsight. Basically, the airplane is used to aim the bomb, and the point of the bomb's impact is just slightly ahead of where the nose of the bomber is pointing. The bomb is released at an altitude from which the pilot can still recover the dive. A distinction is made between "light" dive bombing (pitch angle 20-40° down), and heavy (60-90° nose down).
  • Toss bombing (a.k.a. loft bombing): the aircraft pulls the nose up when releasing the bomb load. This "tosses" the bomb upward: the ballistic path of the bomb is upward before its starts to drop. This extends the time-of-flight and down-range distance of the bomb. This allows the bomber to avoid having to overfly the - ususally defended - target area.

  • Physical and geometric characteristics of the bomb:
  • Aerodynamic (free-stream drag coefficient, cross-sectional area, ...).
  • Weight, the center of gravity (CoG), and the inertia about each of the three axes of the bombs motion.
  • Some bombs have stabilizing fins that unfold upon release.
  • Manufacturing tolerances. This affects weight, CoG, intertia about all axes, and aerodynamic behavior.

  • Non-standard atmospheric conditions, in terms of temperature, absolute pressure, density, dynamic viscosity.
  • Bombsights and look-up tables typically assume a predefined "standard atmosphere" (molecular weight, purity, at sea-level: specific humidity, relative amounts at sea level of the seven principal gasses that make up "air", pressure, temperature, density, gravity, the gas constant; their variation vs. altitude).
  • Actual weather and atmospheric conditions are typically non-standard, and vary with location, season, time of day, altitude, ...

  • Variation in wind velocity and direction (gradual and turbulent).
  • At altitude: causes aircraft movement --> bomb release movement: vs altitude causes trajectory change.
  • direction and strength/speed of winds aloft vs near/on the ground.
  • Due to coriolis force: direction close to ground (i.e., in the friction layer / surface boundary layer) is ALWAYS different from that at altitude.
  • Example: in the atmosphere (away from ground friction), air flows from a high pressure zone to a low pressure zone. The Coriolis force causes the air flow to rotate counterclockwise around a low pressure weather systems, when looked at from above. Conversely, clockwise around a high pressure area.
  • The earth's surface causes resistance to air that flows across it --> wind strengthen with height/altitude. As a result, air close to the ground flows (more) directly from a high to a low pressure zone, without rotating around those zones. So, in general, the direction of wind aloft always changes with altitude.
  • Perfect headwind along the runway centerline on ground --> during descent / approach to the runway for landing: contniuously correct for cross-wind from right (Northern hemisphere).
  • High altitude currents (e.g., jetstream, mid/upper latitudes)
  • https://geography.name/how-does-the-coriolis-effect-influence-wind-direction-at-different-heights/

  • Coriolis force (a.k.a. Euler force, centrifugal force), resulting from rotation of the earth.
  • "The key to the Coriolis effect lies in earth’s rotation. Specifically, Earth rotates faster at the Equator than it does at the poles [not angular speed!!!!!!]. Earth is wider at the Equator, so to make a rotation in one 24-hour period, equatorial regions race nearly 1,600 [1670] kilometers (≈ 1,000 miles) per hour [40 thousand km / 24 hrs]. Near the poles [not the Magnetic Poles, but the Geographic Poles, where the Earth's axis of rotation meets its surface] Earth rotates at a sluggish 0.00008 kilometers (0.00005 miles) per hour. [why not zero: precession, our planet wobbles around its axis of rotation!] Equator (latitude = 0° : groundspeed = 465 m/s, vs 0 m/s at poles. Trade fuel for payload (and tank weight/size!). Note: currently, the siderial rotational period of the earth is not 24.0 hrs but 23h56'4" = 23.934 hrs.Note: the word "sidereal" is not pronounced "side real"; all four sillables are pronounced separately: si-de-re-al. This adjective is derived from the from the latin word "sidus" (genitive: sideris), meaning "pertaining to a star, group of stars, or a constellation. In other words: with respect to distant stars and constellations, not with respect to the star, Earth or other planets of our solar system.
  • All points on/in the earth have the same rotational speed: 360!° per day.
  • Difference between earth's LINEAR speed at equator vs poles is also the reason why space rockets are preferable launched from a site near the equator: a rocket that can lift a particluar payload and accelerate it to the earth's gravitational escape velocity (about 40 thousand km/hr ≈ 24x earth's equatorial speed !), cannot do so when launched at the poles. For LEO low earth orbit: abt 28 thousand km/h. Required rocket speed increase [ = fuel weight] = orbital or escape velocity minus ground speed.
  • This force is zero at the equator and increases towards the poles.
  • It acts to the right (with respect to the direction of movement) in the Northern Hemisphere.
  • 2D example: grammophone record, move straight [wrt universe] from center to edge --> curved path on wrt surface.
  • The significance of this effect on the bomb trajectory depends on the fall time of the bomb. Only significant for high-altitude, with a path that has a southerly or northerly component.

Target motion. Non-stationary target: requires visual or radar contact.

Trajectory models were (and still are !) primarily determined by flight tests, and to some extent by wind-tunnel tests. Simplied, idealized: the trajectory of a bomb is the downward branch of a balistic trajectory. Also, not unlike archery, that, of course, predates canons.

The impressive Greek philosopher and systematic universal scientist Aristotle (384 - 322 BC), concluded that all objects have a natural tendency to fall towards the center of the Universe, i.e., of the Earth. Hence, all objects tend to fall towards the Earth's surface. Moreover, the speed of falling objects is proportional to their weight, and is inversely proportional to the resistance of the medium that the object falls through. Note that this pre-dates - by over two thousand years (!) - Newton's 1666 famous observations about falling apples, and subsequent conclusions and accurate equations about mutual attraction between all objects, forces and motion.

ballistic trajectory

Fig. 21: Leonardo da Vinci's postulated parabolic projectile trajectories - 1493

Ref. 280D26: Clément Ader, 1909/1911, incl: Newtonian formulas ,"resistance" drag, wind. but parabolic. diagrams

(source: ref. 280C5; note: the original document was written and drawn "mirror-image" !)

bomb trajectory

Fig. 22: The trajectory of a bomb dropped from an airplane is equivalent to the downward branch of a ballistic trajectory

bomb trajectory

Fig. 23: Simplified trajectory of a released bomb

(3D graph neglects separation effects, Coriolis effect, wind direction vs. altitude, gravity variation vs. altitude, etc.)

Also diagrams in ref. 230F5, 280A7 & 280A3 (1912).


under construction

Define "blind": no visual contact with the target - due to weather, dark night + blackout, flying in or above the clouds, ...

black outs

Fig. 24: WW2 posters reminding the population to blackout so as to make it more difficult for enemy night bombers to find their target in the dark

So: need to navigate on instruments - not to a runway but to a predefined bomb release point, with aircraft (typ. a "bomber" airplane). This point must somehow be calculated (least complicated when assuming aircraft flying at a specific altitude, speed, and course ["straight-and-level" level=altitude + constant speed]; fall time and trajectory characterestics of the bomb type used, taking into acount best-estimate of wind conditions in the target area), and then navigated to - with radio nav aids. --> calculate "right to left" from the target position.

bomb fall time

Fig. 25: Fall time of US American bombs with average ballistic characteristics - based on data up to 1943

(source: adapted from ref. 280B2; fall time tables & graphs are also used for bomb sight correction)


Obviously, during "blind" bombing, visual contact with the target is not possible, and a bombsight is useless. Refs. historic summary from crude pointers / cross-hair to motion-compensated gyro-based.

stabilized visual bombsight, bomb aiming device

my photos of AOB vorsatzgerät.

Use of a bombsight, and the sophistication and inherent & installation errors thereof, and accuracy of the operator. Ref. XXXX. For articles on bombsights and associated myths (primarily the usual Allied propaganda): see ref. 280B1-280B4.

Use of "pathfinders" / lead aircraft with high accuracy "blind" navigation to "illuminate" (mark) the target with incendiary bombs, long-lasting colored flares, ... I.e., not necessarily all bombers equipped for high accuracy nav to bomb release point.

Hence the need for radio navigation (no accurate inertial nav until YYYY).

List and link subpages: (precision) blind bombing target guidance / targeting systems. Ground-mapping airborne radars were also used to identify target locations. See the radar navigation page.

Refs: 280A1-280A13, 280B1-280B4, 280C1-280C4, 280D1-280D12, 280E.

GAF USAF RAF airfields WW2

Fig. 26: Location of airfields used by WW2 Allied & German forces and German defence lines

(source of airfield & air defence data: ref. 132A-132H; the Luftwaffe used 1000-1500 airfields within the Reich & occupied countries, ref. 255)

ADD BaMa RL 8-88 NJ map though not bombing???


Note 1: due to copyright reasons, this file is in a password-protected directory. Contact me if you need access for research or personal study purposes.

red-blue line