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Arthur Constantin Krebs (16 November 1850 in Vesoul (Haute-Saône), France – 22 March 1935 in Quimperlé (Finistère), France) was a French officer and industrialist, pioneer in aeronautics, electric motors, underwater navigation, fire services, motorboats and automotive engineering.

Origin and youth
"My dear cousin, you ask me, in your kind letter of May 25 [1924], to explain how, as a simple infantry officer, I was led to fulfil the roles and to carry out work bearing little relation to the career I had entered.

''This obliges me to recall my memories and remind myself that from the age I started to enjoy mechanical toys, my biggest hobby was fixing and restoring whatever came into my hands.

1861 - Later my reading always focused on books describing mechanics, so that at 11 years old, Ganot's Physics having fallen to my hands, I studied it with the greatest interest, initiating myself into all the mysteries of the steam engine and its applications."

"As a child, young Krebs had made a steam engine that ran a whole mechanical sawmill installed in an old sewing machine."

Military engineer
1873 - "After the war and the time spent in St-Cyr, I came to garrison in Brest. As an officer, the arsenal was open to me. I took advantage of it to deepen my knowledge of mechanics and continue my technical studies."

Brest maps
1873 - "During my stay in Brest, I made plans of this city and its surroundings, and I had the authorization to manufacture, with the help of workers of the regiment, a press with which I was able to print a few thousand copies of the map I had drawn up, which was used for many years."

Hull design
1875 - "My future father-in-law [Antoine de Fréminville]'', my father's childhood friend, had given me books on Marine Steam Machines and the construction of ships he taught at the École du Génie Maritime in Brest.

I profited from this and later, in garrison in Nantes, in 1875, I drew up the plans for a ship which was built by an industrialist whom I had met."

"A difficulty having arisen one day in the construction of a new model, it was Lieutenant Krebs who undertook to solve it. He alone made the plans for the ship, and his proposals were implemented point by point."

The Chalais-Meudon Aerostatic Research Park with Charles RENARD

 * History of aerostation
 * 1884-10-01 - airships

1876 - "''At the end of 1876 my battalion came to Paris. Put in touch with  Captain Renard by a mutual friend,, I contacted him and he informed me of the work he had undertaken at the Air Communications Commission and asked for my collaboration.

''Colonel Laussedat, who chaired this commission, had me appointed by the minister, and I was seconded to the Engineering Department, on which the Chalais-Meudon Workshops depended. My dearest wishes were thus fulfilled, but to inspire confidence and obtain credit, you had to succeed and only promise what you were sure you could achieve.

''Renard had already built a captive balloon, but the mechanical part allowing ascents to be carried out was only embryonic. I undertook to remedy this, and thanks to the Exhibition of 1878, I quickly assembled all the elements necessary to establish a steam winch which functioned to our great satisfaction from the month of August.''"

Captive balloon train
History of the tethered balloon

"''The experiments and demonstrations followed one another brilliantly in complete safety and allowed us to interest members of the Budget Committee, because it was necessary to obtain the funds to continue the studies and carry out the projects covered by the Committee of Air Communications.

Gambetta, then Clémenceau, came in turn to attend the experiments and promised their support.

''Two goals were to be pursued:

''1 / Design and construction of a captive balloon equipment transportable in the field;

''2 / Design and construction of an airship.

''The first seemed easy to me. It basically involved the construction of a steam winch on wheels for balloon manoeuvres, and that of two other cars to transportat the tackle and accessories of the steam engine (water and coal) and an apparatus, also on wheels, for the production of hydrogen gas. Renard took care of this last requirement and I took the first.''"

Hydrogen generator

 * Hydrogen production history

1879-1880 - C. RENARD designs stationary and mobile hydrogen generators and A. C. KREBS designs the steam engines that power them.

"To carry out this work quickly and successfully, we had to establish a laboratory and set up a mechanical workshop, both provided with the necessary tools and tools workshop. We had engineering Sappers from the Regiment of Versailles as workers".

1906 - "All the mechanical work has been the subject of special study by me, and to accomplish this I constructed and organized a shop located in the park of Chalais-Meudon, which shop is still in existence".

1879-1880 - "The following year (June 1879), a first station was created and made it possible to experiment with balloon transport and ascents on the plateau which dominates Meudon to the south. Following these tests, the minister decided that this park would attend the Grandes Manoeuvres which were to take place around Silliers-le-Guillaume (22 and 23 September 1880). During these manoeuvres, the information on the progress of operations by the staff officer deputised to the ballon station Arthur_Constantin_Krebs was so convincing that it was decided to build 4 similar stations whose construction was entrusted to us."

"The funds allocated allowed us to expand the workshops, improve the tools and establish a manufacturing operation which served as a model for the 25 captive balloon stations in the various Army Corps and strongholds in 1914."

Marriage
1881 - A. C. KREBS married Marie de Fréminville, sister of Charles de Fréminville.

"La France" airship with Charles RENARD and Henri DUPUY-de-LÔME
Collaborating with Charles Renard, he piloted the first fully controlled free-flight made in the French Army airship La France, which was designed in 1884. The flight covered 8 km in 23 minutes. It was with a landing at the starting point. On five of its seven flights La France returned to its starting point.

"In the meantime, studies and experiments continued for the construction of the airship. Its realization was for us the height of our aspirations and was the object of our deepest meditations. The shape of the balloon, the arrangement of the nacelle and the determination of the kind of energy to be employed as the motive force for its propulsion, were the subject of a long examination and in-depth discussions."

Search for a light engine: steam, hydrogen, electricity
1878 - "Before the 1878 Exhibition while at the aeronautic station I bought and accepted, at the shops of Panhard & Levassor, a two horse power [city gas] Otto four cycle engine for installation at the balloon sewing shop."

1881 - "''At that time, the electrical industry was developing. The International Electricity Congress of 1881 had just determined the units of measurement necessary for the study and applications of this new branch of energy. The gasoline engines, so widespread now, were not yet known, we decided the use of electricity for the motive force of the balloon."

"Renard devoted himself to the search for a very lightweight electrical source capable of developing the energy necessary for operating about 2 hours of a 10 HP motor. I took care of setting up the engine and all the mechanical parts that operate the propeller. This is how I was led to study electricity when this science was developing industrially."

1882 - "In 1882, for the purpose of driving a dirigible balloon, which was then being investigated by the Ministry of War, I undertook the development of an internal combustion engine which was to use as a fuel the hydrogen which inflated the balloon. It was on this occasion that for the first time I thoroughly tackled a complete study of internal combustion engines."

1884 - "It is thus in about 1884 I followed with great interest the construction of the small petrol motors of Mr Daimler."

Aerodynamic research: the Balloon shape

 * Categories: Fluid dynamics, Aircraft wake turbulence

1883 - "M. Krebs had wooden models of various shapes made, which were successively tested in the pond of Chalais; these tests proved that in order to ensure consistent operation, it is necessary to give the mobile an asymmetrical shape. Thus the ovoid shape, proposed by Captain Krebs, was definitively adopted for the Chalais airship."

1884 - "''The evaluation of the energy required to maintain to the balloon a given speed was made in two ways:

"''1° Starting from the data put forward by M. Dupuy de Lôme and appreciably verified by the experience of February 1872;

"2° By applying the formula accepted in the navy for passing from a known ship to another of very little different shapes and by admitting that, in the case of the balloon, the work is in the ratio of the densities of the two fluids."

A. C. KREBS piloted the first fully controlled free-flights
1884 - "The first ascent of the balloon "La France", which took place on August 9, 1884, and in which an aerostat described for the first time by its own means a closed curve while returning to its starting point, was the crowning of our work. We could not then claim to obtain an operating time exceeding 2 hours because of the weight of the engines. It was therefore only an interesting experience but without a future.

In fact, 15 years had to elapse before, thanks to the improvements brought by the automobile to gasoline engines, we could provide a balloon similar to "La France" with an engine light enough for Lebaudy balloons to remain in the air for 10 hours."

"Gymnote" submarine with Gustave ZEDE
1884 - "The airship experience was over without leaving any hope of being able to do better in the short term. It was then that General Zédé, brother of Mr. Zédé, director of Naval Constructions, whom I had met through my father-in-law, suggested that I leave the Military Engineering Department, where I had no future, and to appoint myself to the Firefighters Regiment in Paris, whose capabilities were to be modified and improved to bring them up to the level of what existed abroad."

1885 - "Mr. Gustave Zédé, former Director of Naval Constructions and Administrator at the Société des Forges et Chantiers, had undertaken the study of a submarine on behalf of the Navy in 1885. This ship was to be propelled by an electric motor powered by accumulators, all of which had to be designed and built. He told me about his project and asked me to collaborate with him."

"The hull was built by the Arsenal at Toulon, and all the mechanical and electrical part had to be carried out in the shops of the Forges et Chantiers in Le Havre."

The A. C. KREBS electric motor for the Gymnote submarine
"I accepted the offer with pleasure, although the conditions of construction of an electric machine of 50 hp at 200 rpm [required by Zédé] presented serious difficulties. In fact, completely new arrangements had to be made in order to accomodate the machine, accumulators and operating devices in a very limited space. At the request of the Minister of the Navy, I was authorized by the Minister of War to lend my assistance to the Navy while retaining my functions in the Regiment of Firefighters."

Electric motor launch
1887 - "A first experiment, consisting in propelling a Navy boat by means of a dynamo and accumulators, had first to be prepared to convince the Minister of the Navy of the possibility of the operation. This first experiment (1887) took place in Le Havre and was fully successful. Work for the submarine could then be undertaken."

The first fully functional submarine
"Years 1887 and 1888 were used for their execution. The assembly of the machines, tested beforehand in Le Havre where they gave complete satisfaction, took place in Toulon under the direction of Mr. Romazzotti, marine engineer in charge of the construction of the submarine "Le Gymnote"."

"''In December 1888, I was sent to Toulon to attend the tests. The year 1889 was used to equip the submarine with special features to improve vision, and with an electric gyroscope, of which I am supplying the plans, to replace the compass which is indifferent when it is inside an iron shell."

"In December 1889 I witnessed new trials, quite conclusive, following which a larger ship was started, studied and built directly by the Naval Constructions."

Transportable electric motor
1885-1890 - "It was during this period that I studied a portable electric motor to power the drills used on ships under construction to drill holes in sheets which must then be riveted together. Likewise, electric motors operating the fans circulating the air in all parts of the ships etc."

Paris Universal Exposition of 1889
1889 - For the Universal Exposition, A. C. KREBS:


 * Is appointed member of the "Technical Committee of Machines".


 * Organize fire safety throughout the Exhibition and took this opportunity to test the new fire alarm.


 * Is appointed member of the organizing committee of the International Congress of Fire Officers and Non-Commissioned Officers.


 * Design the DURENNE & KREBS Compound steam engine and the A. C. KREBS electric dynamo built by the Société des Forges et Chantiers of which Gustave Zédé is an administrator, produced the lighting for the central dome of the Galerie des Machines at the Universal Exposition at Paris in 1889, which inaugurates the Gustave EIFFEL's Tower.

"Ville de Paris" fire service reorganization
1884-1897 - "It would take too long to dwell on the work carried out during the 12 years (1885-1897) that I spent in this corps. After several study trips to the United States of America [1885 and 1895] and Europe [1884, 1885 and 1891], I was led to make proposals: but this time the task was not the same."

"The proposals were discussed in committees, and before they came to execution, they had to be made to triumph. I managed to get them accepted and the result was to completely transform the organization of the Fire Department as well as its equipment."

Study trips to Europe and America
1885-11-26 - New York Times: "Among the passengers of the French steamship Normandie, which sailed yesterday for Havre, were Rear-Admiral Baldwin, of the United States Navy ; A. Bartholdi, the sculptor ; Baron Hulot, Capt. Krebs, the Abbé Gaudin, Capt. Garcin, Martin Clerc, Ch. de Fréminville."

1895-09-10 - New York Times: "Three Frenchmen Who Will Study Methods Used in This Country: Three Frenchmen, Col. Varigault, Commandant Krebs, and Capt. Cordier, officers of the Paris Fire Department, arrived in this city on La Touraine Saturday last to begin a tour of the principal cities of the United States for the purpose of investigating the methods adopted in various Fire Departments."

1895-11-06- Quebec Morning Chronicle: "Chief Varigault, Commandant Krebs and Captain Cordier, of the Paris Fire Department, returned to New York yesterday after a two months’ tour of the United States and Canada for the purpose of inspecting the fire departments in the larger cities. Chief Varigault was seen this morning. He said:— “We have visited New York, Boston, Montreal, Cleveland, Chicago, St. Louis, New Orleans, Cincinnati, Pittsburg and Washington. We have been received everywhere with the greatest kindness and our trip has been a complete success. The New York Department is far ahead of any other we have seen in this country, both in equipment and discipline. Next I should name Boston, although Montreal is not far behind. Chicago and San Francisco are also good. But I can’t see how the Chicago Fire Department could fight a fire in one of her high buildings."

Other Fire Apparatus
Photos du matériel d'incendie à l'EXPOSITION de 1900 : https://gallica.bnf.fr/ark:/12148/bpt6k6584731t/f367.image.r=krebs

Fire intervention areas reorganization
1889 - Improvement committee for Paris firefighters: "The areas of the perimeters each defended by a fire post are proportional to the square of the speeds with which these fire posts staff can be transported, and as an immediate and very important consequence, the number of fire post to be placed is inversely proportional to the square of these same displacement speeds. Thus, a transport system that could go twice as fast as another will require four times fewer fire posts to arrive at the same time."

1896-05-20 - Accident at the Opera - A 625 kg counterweight from the deflector of the broke off in the middle of the show, fell 12m while crossing several levels and killed one person: "The version of Major Krebs, of the fire brigade, however, seems most likely: under the action of a contact current, the wires supporting the counterweight of the ventilation device heated up, became elastic and, each thread, having no more than the consistency of cooked macaroni, broke under the weight which it was charged to support. The wires of the cable have not been heated to fusion, but they are stretched and the sections are unevenly placed."  "By a bizarre coincidence, M. Garnier, the architect of the Opera, returned to Paris this morning. He attended the committee's deliberations."

KREBS system car and Émile LEVASSOR
1894 - the Paris-Rouen race: "I was present on the 18th of July, 1894, in the morning, at the starting of the automobile vehicles entered in the race of Le Petit Journal. The starting took place at La Porte Maillot. At least 20 vehicles reported to start."

1896 - "Around 1894 appeared the first motor cars powered by gasoline engines. Automobile locomotion having already struck my imagination from the point of view of its application to the Fire Department, I got a small engine from the Panhard & Levassor company to study it thorowghly and built in the fire department workshop a small experimental car whose speed changes were obtained by magnetic clutches [patented in 1896]. I had conseived of this arrangement to avoid the brutal shocks that the gears undergo when changing gear, a solution that seemed barbaric to me."

The 1896 Krebs car system introduced in car design (FR256344, GB189619774A, BE124538):


 * The general three point suspension system (engine and chassis):

"Since we know that 3 points suffice to determine a plane."

"To these sides [of the frame of the car] I fix or suspend at three points provided with pivoted joints, the motor mechanism which is thereby placed out of the influence of the deformations to which the frame of the car is liable to be subjected during the motion."


 * The electromagnetic constant mesh gear box:

"I had imagined this arrangement to avoid the brutal shocks that the gears undergo when changing gear, a solution that seemed barbaric to me."


 * The speed shifting at the steering device:

"For the purpose of operating the electro-magnetic clutch, I employ a commutator arranged preferably under the handle bar and adapted to be operated in such a manner as to establish, according to five different positions, the electrical connections that correspond respectively to: rest ; forward movement at low speed ; forward movement at medium speed ; forward movement at high speed ; and movement in the rearward direction."


 * The damped steering and the rack and pinion steering gear:

"Upon the turntable of the fore-carriage is fixed a toothed sector in which engages a pinion mounted on the upper turntable and whose axle carries a toothed wheel situated in a box connected by two tubes to the box of the car. A second toothed wheel mounted on the steering spindle is connected to the first one by means of a chain passing through thses two tubes. Elastic rods, consisting for example of coiled springs, are substituted for the links of the chain in the straightportions of the said tuges. By this means the chain is always taut and the springs neutralize the vibrations transmitted to the chain by the jolting of the fore-carriage and so prevent the said vibrations from being transmitted to the steering spindle."


 * The forward (positive) caster angle on the steering axis:

"To ensure the stability of direction by the means of a special arrangement of the fore-carriage, that is to say, to re-establish automatically the parallélism of the two axles of the vehicle when there is no tendancy to keep them in any other direction, or after a temporary effort has caused them to diverge from said parallélism ; [...] The axle of the fore-carriage is situated behind the projection of the axis of the pivot pin in order to ensure the stability of direction above referred to [of a quantity which can vary from 1/7 to 1/8 of the distance which separates the points of contact of the two front wheels with the ground (FR256344)]." (GB189619774A)


 * The French artillery wheel with metallic wheel hub system: see above.
 * 1896 - Émile LEVASSOR to A. C KREBS: "You would kindly give us permission to use your wheel hub system for which, since you say it is very good, it might be worth patenting." (see above)


 * 1900 - The controversy over ball bearings: "Panhard and Levassor, the celebrated French automobile constructors, made elaborate experiments with ball bearings under working conditions and arrived at the conclusion that ball bearings gave no gain [...] Undoubtedly the experiments of Panhard and Levassor were made with faulty forms of ball bearings". 1900 - Congrès International d'automobilisme: "M. le commandant Krebs prétend qu’il a fait monter en course 5 voitures dont deux étaient munies d’essieux patents et trois d’essieux à billes et qu’il n’a trouvé aucune espèce de différence. Les essieux à billes ne présenteraient d’avantages que dans les petites vitesses, ce qui est original". 1900 - Automobile Magazine: "Panhard and Levassor, the celebrated French automobile constructors, made elaborate experiments with ball bearings under working conditions and arrived at the conclusion that ball bearings gave no gain at low speeds, and also announced in general terms that the frictional resistance of the wagon bearings formed only a very small part of the total resistance to wagon propulsion and ball bearings for wagon, motor and transmission parts are almost universally regarded as unsuitable for all wagon use, except in vehicles of the very lightest description. Certainly no rider would use a bicycle without ball bearings, and our light American steam-driven wagons which may be regarded as having more nearly reached a standard form than any other mechanically driven vehicle made, use ball bearings in the road wheels, for the balance gear, for the crank-shaft and for the crank ends of the connecting rods. Undoubtedly the experiments of Panhard and Levassor were made with faulty forms of bearings". 1909 - OMNIA - "[...] Or l'on s'accorde à juger que l'amélioration d'une friction par les billes est de 10 pour 100. Par conséquent le bénéfice procuré par les billes dans ce cas ne pouvait s'appliquer qu'à 500 grammes sur 15000, c'est-à-dire faire descendre l'effort de 15 kilogrammes à 14.950 [?!?]. Le résultat est donc assez pitoyable. Mais la bille ne vaut pas seulement par cette amélioration illusoire du rendement. Son mérite principal consiste dans la commodité de son emploi ; elle rend le roulement pratique. Non seulement elle permet le raccourcissement de la fusée, diminue par conséquent l'encombrement et les chances d'accrochage, mais elle n'exige plus (dans la forme "annulaire" tout au moins) aucun réglage ni pour l'ouvrier qui monte le roulement, ni pour le client qui l'emploie. Son entretien est à peu près nul puisque, si la fusée patent demande une nouvelle charge d'huile tous les 150 à 200 kilomètres environ, une fusée à billes roule parfaitement 2 à 3000 kilomètres sans qu'on ait à se soucier d'elle."

1896-09-03 - Emile LEVASSOR buys the license of the automobile car patent (FR256344, GB189619774A, BE124538) from A. C. KREBS with an electromagnetic gearbox, three-point suspension, caster angle and other inventions.

1896-12-22 - Emile Levassor to Gottlieb Daimler: "For the car with electric gear changes [...] by seeing this car alone you can be sure that you will see much more than what you have seen in England in your various trips."

Three point suspension system
1888 - Steam fire pump from the city of Paris (1888 model) by MM. Durenne & Krebs: "The mechanism is connected to the chassis by three points with the interposition of an elastic material allowing the deformation of the chassis without distorting the parts of the assembly. The boiler is also fixed at three points only."

1896 - The three point suspension system generalized (engine and chassis) on the Krebs system car (see above).

1898 - The Voiture Clément Panhard (VCP): see below.

1901 - Patent of the gearbox suspended by three points (see below).

Vehicle's Steering-Systems
In 1898 Krebs replaced the tiller with an inclined steering wheel for the Panhard et Levassor car he designed for the Paris-Amsterdam race which ran from the 7 to 13 July 1898. Fernand Charron won that race on a four cylinders Panhard et Levassor.

In this car he also introduced the irreversible steering in the automotive btechnology.

Electric Fire Van
1899 - French Electric Fire Department Wagon: "Paris firemen have also lately been out making successful experiments with the automotor constructed especially for the fire service, after the plans of Colonel Krebs".

Automotive engineering at Panhard & Levassor
Krebs succeeded Levassor as Panhard et Levassor's general manager from 1897 to 1916. He transformed the Panhard et Levassor company into one of the largest and most profitable automobile manufacturers before World War I.

"At the beginning of 1897 [in fact the 1896/09/03]  I showed my completed working car to Mr. Levassor. He was greatly struck by it and asked me to allow him to put several into production in his workshops and to kindly supervise their manufacture. Two months later, Mr. Levassor died suddenly. His partner, Mr. Panhard, transformed his association into a limited company and asked me to take charge of it."

Emile Levassor acquired the license of this electromagnetic gearbox in 1896 and Panhard & Levassor built it at least until 1903.

"The automotive industry was in its infancy, its future was not in doubt and the Panhard & Levassor company held the lead. Encouraged by the success of my previous work and my personal tastes, I did not hesitate to accept and abandon the military career to enter the industry."

"I have known Mr. Daimler in 1897, when I went to visit him at Cannstadt, Germany, in October. In the house he lived in he showed me the laboratory and shop where he had studied and first built his little engine, then the first vehicle on which he made his first trials."

Racing cars
"The eraly days were not without difficulty. It was first necessary to enlist the support of a very tight technical team possessive of their experience. A few improvements which I immediately introduced to certain mechanical components leading to the success of the company's 4 cars in the "Paris-Amsterdam" race (arriving first at every stage), the following year earned me the confidence of the staff."

"''During my 18 years in charge, I can only praise the devoted support of all my colleagues, I have always found willing to assist me to carry out changes or new provisions introduced in the mechanical organs of cars.

''It is unnecessary to recall them here in detail. Those that I am happy to point out because they have given me great personal satisfaction are:


 * Engine balancing;


 * ''the automatic carburetor making it possible to vary the speed of the engine and to give it a flexibility that the all-or-nothing adjustment did not allow;


 * Dynamometer brake for testing high-speed engines, measuring the work on the shaft according to the Prony formula, recovering approximately 90% of the energy produced in electrical form, etc."

"Krebs carburetor"
The Krebs carburetor can be said the first automatic carburetor (1902 patent) and the first diaphragm carburetor (1908 patent).

1906 - "At the present time we are not sufficiently in possession of the factors that would enable us to fully understand the reasons why it is possible to transform into work only a very small part of the heat developed in the combustion from which we are trying to realize work."

1903 - The automobile: "''The object gained is a constant degree of carburation at all speeds, each active piston stroke developing the same amount of power, and the total power of the motor consequently is directly proportional to its speed. Also, carburation can be kept at its lowest possible limits, and it is perfectly automatic and independent of variations in the atmospheric temperature. The carburation is always good. The usual dash-board adjustment for additional air and a special hot-air feed are not needed: the warming of the mixing chamber with the motor jacket water maintains a constant temperature. The motor can be run at a very low speed without lowering its efficiency. For instance, as the Automotor Journal states the case, if the change-speed lever is put on the third speed, which ordinarily might give a speed of 50 km. (31 miles) per hour, and it is desired to run at only onetifth of that speed, the speed of the motor is reduced to one-fifth, say from 1,000 to 200 revolutions per minute; of course, the total output is diminished, but the power of each stroke remains the same. The new Krebs carburetter, then, goes far to supplying one of the chief needs of the petrol motor — flexibility.''"

1913/05/26 - Panhard & Levassor Management Committee: " The United States is asking to purchase our 1903 carburetor patent, which is still valid for 5 years. We send 2 proposals: 1° Sale of the patent for $ 10,000, 2nd License for cash $ 2000, plus $ 1 per carburetor."

1919 - "In the early days of the 20th century, Krebs, a French engineer, invented what may be termed the first automatic carbureter in which the mixture was regulated automatically by the speed of the engine ; flexibility being thus obtained to an extent hitherto undreamed of. This invention paved the way for, and inspired, a vast number of others of greater or less merit [...] The Krebs type can today be considered the simplest form of carbureter which operates satisfactorily and there are several different models now manufactured based on the principle of the auxiliary air valve only. In these the problem is worked out in different ways. [...] While they all differ in the details of working out the design they are, nevertheless, based on the basic principle of the auxiliary air valve as originally worked out by Krebs."

See below: [[Arthur_Constantin_Krebs#Carburators A. C. KREBS carburetors patents].

Dynamometric brake
1905-11-13 - To the French Académie des sciences: "On a dynamometric brake intended for the measurement of the power of motors, which allows the use, in electrical form, of most of the work developed".

"Voiture Clément-Panhard (VCP)" and Adolphe CLEMENT
1900 - La voiturette Krebs (Panhard & Levassor)

Automobile handling
"The question of steering is one that I have taken up towards the end of 1897, as soon as I had acquired a sufficient knowledge of the operation and of the organization of the Panhard & Levassor business. This new P&L steering device was not anything else but an adaptation of means already known and used since a very long time for the same object."

As for automobile handling A. C. KREBS promote:
 * 1900 - The exterior Ackermann quadrilateral of Panhard & Levassor
 * 1900 - The irreversible steering
 * 1898 - A. C. KREBS implements his solutions in racing cars: Paris-Amsterdam-Paris race.

Paris Universal Exposition of 1900
During the 1900 Exposition A.C. KREBS is:
 * Member of the Scientific Aerostation commission (Classe 34, Groupe VI)
 * Member of the Committee for the Study of Fire Safety Measures
 * Member of the Physical Exercises Commission: Automotive (Section VII)
 * Member of the Commission for International Automobile Competitions
 * Secretary of the General mechanical materials and processes commission jury (Classe 20, group IV): Panhard & Levassor standout
 * Member of the motorboat competition jury
 * licenses the Lohner-Porsche petroleum-electric car patent.
 * Member of the International Automobile Congress of 1900 and 1903
 * Appointed officer of the Legion of Honor.

Metallurgical research with Ch. de FREMINVILLE
"In 1898, I took with me, to assist me, my brother-in-law Mr. Charles de Fréminville, engineer of Arts and Manufactures, who took care more specifically of the administrative part of the workshops, the organization of work, the selection and treatment of metals used in manufacturing, etc."

"He had to make his selection among metals which were then new and the qualities and defects of which were little known and often misunderstood. The construction and operation of the automobile brought about, a new conception of the resistance of materials."

1904 - The brittleness of steel (H. Le Chatelier): "Mr. De Fréminville discovered this peculiarity that, after being subjected to a certain heat treatment, certain special steels required to be broken transversally by impact, an amount of energy much greater than that required in the ordinary tensile tests."

1913-04-04 - '''Ch. de Fréminville to his wife: "I realized the project I had made to mold the hole made by a bullet in the bay window of General Healey's building [in New York]. General Healey pointed out to me that it had the same on almost all the bay windows in his building. There's a lot to choose from. Yesterday I went to stock up on plaster from an Italian. What a neighborhood! It's just a stone's throw from the upscale neighborhood and it's not a badly-reputed neighborhood. My molding was admirably successful. I thought there was going to be a considerable crowd behind the bay window while I operated in shirt sleeves - like a good American. And all these people didn't know what they were looking at and would never have looked at a fracture'''. Luckily two steam [fire] pumps passed in quick succession. All these admirers abandoned me."

1915 -

Chevalier légion d'honneur


 * 1899: Laboratoire de mécanique et laboratoire de chimie


 * 1900: Essais de résistance des aciers durs aux chocs


 * 1901-06-03 - L'acier au nickel


 * 1902: cylindres en acier forgé


 * L'acier au vanadium


 * L'acier au cobalt (stellite)

Motorboats & Racing boats with Alphonse TELLIER
1895 - A. C. KREBS has been the main promoter of motorboating in Europe as soon as 1895.

1903-12 - Automobile Magazine: "Where speed wins out: As an excellent example of the new type of water racer take the Lutece".

1904-02-27_10_The-Automobile='Auto Boats at the Sportsmen’s Show.':

The Panhard boat furnishes the same tune in its engines as in automobiles. When running, the four-cylinder motor throbs with that rythmic sound so soothing to the motorist.

1902 - The variable pitch propeller system A. C. KREBS:

Hybrid motorcar with Ferdinand PORSCHE
1900/07/07 - A. C. KREBS file the patent FR301991: "Electromagnetic regulator for admission-valves of hydrocarbon-motors" (US691638, GB190016291).

1900/10 - At the Paris Exposition Universelle A. C. KREBS remarks the Lohner-Porsche "Semper vivus" hybrid car and acquire for Panhard & Levassor the wheel hub electric motor patent  (GB190018099) license for France, Great-Britain and Italy.

1903/01/24 Scientific-american - The Panhard et Levassor Lohner-Porsche system: "... the most novel of all, being a Lohner-Porsche, 28 horse power, gasoline-electric tonneau car, with electric motors in the hubs of the front wheels, which also steer the machine. A gasoline motor direct-connected with a dynamo furnishes power for generating electricity to run the car, any superfluous current being sent into a storage battery, which supplies extra power as it is needed. The car is said to have 14 different speeds, the maximum of which is 48 miles per hour. This system has been so successful that the Panhard Company has purchased the patents and is making machines".

Engine
In 1900, A. C. KREBS designed the Centaure engine with the aim of freeing itself from the royalties owed to Mme Levassor on the Daimler engine.

In 1909, he became interested in the Knight patent (sleeve valve engine) and was first in France to build that type of engine which Panhard et Levassor would produce during the thirty years leading up to World War II.

Carburetors
See above: The [[Arthur_Constantin_Krebs#The_Krebs_carburetor Krebs carburetor].

1900 - Automobile Magazine: Alcohol in Automobile Practice: "In December, at the instance of the Society for the Industrial Utilization of Alcohol, M. Krebs, of the Panhard et Levassor Company, experimented with a three horse-power Phoenix auto mobile, the only alteration being the widening of the opening to the carbureter. With the Dusart alcohol 4.2 horse-power was developed, and with ordinary 95 per cent. alcohol 3.6 horse- power; with benzine at full speed, 4.4 horse-power. According to Araschaquene it would be sufficient to abolish the tax on alcohol in order to cause it to replace benzine".

1916 – Panhard & Levassor catalog: "We have adopted on all our engines a carburetor based on an entirely new principle of automaticity, which rigorously doses the mixture at all speeds and offers the advantage of no longer having any intake additional air, no moving parts. The rubber membrane of our old models is thereby eliminated. In our 20 HP and 35 HP engines, the carburetor is double and controlled by two accelerator pedals. The ordinary accelerator pedal ensures walking in town and at medium speeds, while the second pedal, actuated with the left foot, brings into play the second carburetor which is added to the first to provide very high speeds, and at this time to provide additional lubrication."

Ignition
1903 - "Panhard & Levassor firm has a new method of distributing or directing the current successively to the induction coils of a multicylinder motor."

Gearbox and transmission
The Panhard Type of Gearbox is enhanced by A. C. KREBS.

Flexible couplings
First A. C. KREBS research on flexible couplings:

The single disc coupling
1909 - The single disc coupling: "The device in question is substantially as follows: The ends of the shafts to be joined, facing each other, are provided with circular or cylindrical extended portions to which is secured alternately a membrane of suitable shape, of strong and flexible material such as leather, flexible fiber, suitably woven and prepared canvas or any other similar material. The dimensions of the said widened portions and the number of the points at which the material used for effecting the connection indicated is secured to them are in proportion to the strain to be transmitted."

The Tire elastomeric coupling
1911 - The FLECTOR joint: "In our models 10, 12 and 16 HP Tourism, the universal joint is constituted by the elastic device which we call "Flector" and which, formed of canvas and rubber, allows the relative displacement of the shafts without friction, without wear and without noise. Its adoption gives the car equipped with it a very smooth drive, and it does not require any maintenance."

Aviation
1910 - Aircraft: "On June 14th. among the visitors to the Farman School at Buc, was Commandant Krebs, the director of the Panhard-Levassor firm. He was taken for a lenthy trip by Mr. Maurice Farman, who afterwards carried M. Defly, an engineer of the Panhard firm."

The 1909 engine of Tellier's monoplane

 * Alphonse Tellier (constructeur aéronautique)

Aircraft engines
1902 - Wilbur Wright to Octave Chanute: "I also enclose a letter from France which I take to be from Capt. Krebs, though my acquaintance with foreign customs of signing names leaves me in some doubt as to who it is from. Can you enlighten me?" O. Chanute to W. Wright: "I return the French letter, which is from Commandant Krebs, formerly associated with Colonel  Renard."

Helicopters with Gustave PLAISANT
1912 - Gustave PLAISANT: "During fixed-point tensile tests that I recently carried out on a cycloidal thruster at the Laboratoire des Etablissements Panhard et Levassor with the gracious authorization of Commander Krebs, I was led to study different combinations of propellers [...]."

The SELDEN Trial with Henry FORD
In 1906 A. C. KREBS traveled to the United States to testify in the Selden case in which Panhard & Levassor was associated with Henry FORD as an opposing party. He probably met Henry FORD during the presentation of evidence for the Selden patent (US549160) on October 29-30, 1906 in a New York garage.

It should be noted the many similarities in principle between the Clément-Panhard car of 1898 and the Ford model T of 1908 (See above).

Work organization: Scientific Management with Ch. de Fréminville
1904 - Ways to combat or prevent dust: Commandant Krebs requests the tarring of the street of the establishments on Avenue d'Ivry..

Innovations with Pr Arsène d'ARSONVAL
A. C. KREBS and the physician, physicist and academician Pr Arsène d'ARSONVAL were longtime friends.

1891: Pr s'Arsonval helps Levassor for his patent FR215695 dated 1891-08-21 for "Improvement in gas engines".

1894 - Société Française de Physique: Pr d'Arsonval demonstrates that the Panhard & Levassor petroleum engine is "the real engine applicable to road traction".

1901-1905 - A. d'ARSONVAL having proved that benzole presented no risk of explosion in a confined environment, the French navy ordered benzole engines from A. C. KREBS for its NAÏADE-class submarines (See below).

1902 - A. d'ARSONVAL lends his laboratory at the Collège de France to A. C. KREBS for his preliminary experiments on his automatic carburetor.

1905 - A. d'ARSONVAL presents to the Academy of Sciences the note of A. C. KREBS on his electric dynamometric brake (see above) allowing to precisely measure the power of petroleum engines.

1905 - A. C. KREBS participated in scientific spiritualism sessions organized by academician A. d'ARSONVAL within the framework of the General Psychological Institute.

A. C. KREBS and Ettore BUGATTI
1913-01-24: Panhard & Levassor board - "Mr. Director [A. C. KREBS] reports on the visit he made to Mr. Bugatti in his factory in Molsheim [Alsace] where he was able to test the cars built by Mr. Bugatti and engines on dynamometric break. Mr. Director noticed different very interesting construction processes; However, he thinks that Mr. Bugatti, to achieve this result, makes the material work at its greatest limit of resistance, which is contrary to the ways of proceeding in our company which always tend to keep a fairly large margin in the resistance of the metal".

Military vehicles
Krebs utilized his former military membership to supply the French Army with engines and vehicles including the 1904 Genty Armored car, the 1911 Chatillon-Panhard 4x4 truck, the 1916 St Chamond tank, and others.

Automobiles in Madagascar for General Galliéni
1899 - General Gallieni, governor of Madagascar, brought three Panhard & Levassor cars from Paris, two 12hp cars and one 6hp car.

Lebaudy & Astra airship engines
A. C. KREBS built all the engines for Lebaudy military airships.

Benzol engines for submarines
A. C. KREBS built all the engines for the Naïade class submarines.

1901-1905 - A. d'ARSONVAL having proved that benzole presented no risk of explosion in a confined environment, the French navy ordered benzole engines from A. C. KREBS for its NAÏADE-class submarines.

Genty armored car in Morocco for General Lyautey
A. C. KREBS built Genty armored cars.

1913 - Panhard-Genty Machine Gun Car: "Modification of 1912 on the Panhard 24 HP Model 1907."

A Panhard 24 HP was acquired by the French Ministry of War in 1904, to experiment with the military capabilities of automobiles and particularly for reconnaissance. Following the military maneuvers of September 1905, Captain Genty was authorized to install machine gun mounts on the Panhard 24 HP, of which he was the pilot. After transformation in 1906, the Panhard-Genty 24 HP was sent in December 1907 to Morocco and put into service on the borders of Algeria and Morocco. General Maurice Bailloud of the 19th army corps of Algeria calls for new machines. Clément-Bayard cars were shipped in 1908 and 1910 and proved to be unsuitable. Three Panhard 24 HP were then delivered again in 1912.

In 1903, Captain Genty proposed, jointly with A. C. KREBS, modifying a Panhard & Levassor chassis to make it an operational armored car.

It raises the ground clearance of the chassis by 32cm using springs of 0.90m at the front and 1.30m at the rear. The gasoline is distributed in 2 solid independent cylindrical tanks of 45 liters forming seats, with a range of 400 km on good roads and 250 km on bad roads.

The engine is a 35 HP allowing the vehicle to reach 65 km/h at “high speed”. It has a Krebs automatic carburetor and dual ignition (batteries and magneto), automatic lubrication, cooling by pump and radiator with insulated tank, free exhaust "at will", a leather cone clutch, gear change by sliding train and chain transmission.

The steering is irreversible, turning at 25°. The brakes are shoe brakes on the differential shaft and ribbon brakes on the rear wheels. The wheels are equipped with removable rims, Michelin system, allowing tire replacement in 4 minutes maximum. The risk of punctures is reduced thanks to the choice of 920 x 120 tires, of the “iron sole” type, resistant to both stones and thorns. Two spare tires are attached to the right of the car.

The car's armament included 2 Hotchkiss machine guns: one on its mount and a spare on its stirrups, to the right of the car. The machine gun used could be placed on one of the two legs located at the rear and in the middle part of the vehicle. The ammunition was divided into 9 boxes with a total capacity of 20,000 cartridges, including 3,600 in the trunks of the car.

Chatillon-Panhard artillery tractor
In 1911 A. C. KREBS designed, jointly with the Chatillon Co, an all-terrain vehicle with four wheel drive and four wheel steering "fully adherent", using only one differential. This truck was meant for military and civil purposes and was used during World War I as artillery tractor.

Saint-Chamond tank
A. C. KREBS builds the valveless engines for the Saint-Chamond tanks.

Gasoline tethered balloon winches
1916 - A. C. Krebs transposes his hippomobile car steam winch of 1882 on his military trucks Panhard & Levassor, by adding an engine and a workstation dedicated to the balloon maneuvers so as to allow the device to remain operational along the way.

Large projects manager (1876-1916)
See also: Panhard & Levassor (Deutsch), list of types.

1888-04-17 - A. C. KREBS: "Success in such a matter largely depends on the relationships that exist between all the dimensions and sizes of the elements that are brought together."

1902-02 - Automobile Magazine: "Indeed the attitude of the British maker has been well described as sitting on Panhard's doorstep, a good place also for the American maker.

1902-04 - Automobile Magazine: "The French automobile is the result of long experimenting and thought devoted to each and every part, from the pin and lock bolt and washer, to the cylinder casting and piston rings".

Papers presented to the French Académie des sciences

 * 18 August 1884 – A. C. KREBS and C. RENARD: "On an airship". About the "La France" airship.


 * 1884-08-25 - M. Dupuy de LÖME: "Note sur les aérostats dirigeables".


 * 1884-08-31 - M. A. LAUSSEDAT: "Sur les tentatives effectuées à diverses époques pour la direction des aérostats".


 * 1884-11-10 - M. Hervé MANGON: "Note sur l'aérostat dirigeable de MM. Renard et Krebs".


 * 1886- PONTI PRIZE: "for the progress made in air navigation."


 * 1886-04-05 - M. ZEDE: "Sur les navires sous-marins".


 * 1888-07-30 – A. C. KREBS: "On a telephone with a closed magnetic field, with a plate of equal concentric cylindrical sections".


 * 1888-03-26 – A. C. KREBS: "Electric Engine Trials for a Submarine Boat".


 * 1890-09-15 – MM. Dumoulin-Froment and Dubois: "First electric gyrocompass for the Gymnote submarine designed by A. C. KREBS".


 * 1902-11-24 – A. C. KREBS: "On an automatic carburettor for internal combustion engines".


 * 1905-11-13 – A. C. KREBS: "On a dynamometric brake intended for the measurement of the power of motors, which allows the use, in electrical form, of the major part of the work developed".


 * 1906-01-15 – A. C. KREBS: "Conditions for establishing and applying a progressive shock absorber to the suspension of vehicles on the road".


 * 1907-04-08 – A. C. KREBS: "Apparatus for measuring the flow of liquids: The Krebs volume meters".


 * 1931-12-07 - M. Jean Rey: "The invention of the periscope, about the periscope ordered by A. C. KREBS for the Gymnote submarine".

Retirement
"''In 1916, when I reached the age when the need for rest began to be felt and where one could no longer develop the same physical activity, I resigned my functions as Director while retaining those of consulting engineer.

The previous year M. de Fréminville had to leave the Maison Panhard & Levassor to enter Le Creusot."

A. C. KREBS and André CITROËN
At the request of the banks, A. C. KREBS made a report on the car project built on an assembly line by André Citroën after the WWI. A. C. KREBS made a favorable report and André Citroën was able to start manufacturing the Type A.

Administrator of Savary & Rivière Co.
In the 1920s, A. C. Krebs was administrator of the Savary and Rivière company, of which he was a shareholder, and who is a manufacturer of agricultural machinery in Quimperlé where he retired.

Under his direction, the company diversifies its activities towards the manufacture of school furniture, railway equipment, military engineering, posts and telegraphs.

The commemoration of the 50 years of the airship "La France"
1934 - At the age of 83, A. C. KREBS traveled from Quimperlé (Brittany) to Paris to attend the commemoration of the fiftieth anniversary of the airship La France in 1884. He is the only survivor of this historic technological epic.

1935 - Several months before A. C. KREBS's death, he was made a Commandeur of the Legion of Honor for his work in Aeronautics and for his contributions to the automotive industry.

The Krebs Glacier
1960 - The United Kingdom Antarctic Place-Names Committee (UK-APC) named "Krebs Glacier" a glacier flowing west into the head of Charlotte Bay on the west coast of Graham Land in the Antarctic continent, after the name of Arthur C. Krebs who constructed and flew, with Charles Renard, the first dirigible airship capable of steady flight under control, in 1884.

Nicolas Krebs (1786-1839)
Nicolas KREBS is a grandfather of A. C. KREBS. Born in Boppard on the left bank of the Rhine in 1786, he enlisted in Napoleon's army and took part in his campaigns. Wounded at Wilna in 1812, he was taken in by the Grand Duke Constantin of Russia, and became his chidren's tutor for 2 years in Saint-Petersburg. Back in France in 1814 he married Elisa Marie Dureau de la Buffardière. He was decorated with the Legion d'honneur on 1809-06-05.

Commander Léonce Krebs (1849-1822)

 * 1878 - Officer at the general staff
 * 1895 - Campagnes dans les Alpes pendant la Révolution.


 * 1898 - Archivist of the city of Nice


 * 1909 - Commander of the Légion d'honneur.

Jean Krebs & Georges GUYNEMER
1918 - Henry Bordeaux: “Jean Krebs crystallized Georges Guynemer's vocation. He developed and specialized his taste for mechanics, separating it from vague abstractions and guiding it towards material realities and the wider experiences these procure. He deserves to be mentioned in any biography of Guynemer, and before passing on, it is proper that his premature loss should be cited and deplored. Highly esteemed as an aviator during the war, he made the best use of his substantial and reliable faculties in the work of observation. Airplane chasing did not attract him, but he knew how to use his eyes. He was killed in a landing accident at a time almost coincident with the disappearance of Guynemer. One of his escadrille mates described him thus: "With remarkable intelligence, and a perfectly even disposition, his chiefs valued him for his sang-froid, his quick eye, his exact knowledge of the services he was able to perform. Every time a mission was entrusted to him, everybody was sure that he would accomplish it, no matter what conditions he had to meet. He often had to face enemy airplanes better armed than his own, and in the course of a flight had been wounded in the thigh by an exploding shell. Nevertheless, he had continued to fly, only returning considerably later when his task was done. His death has left a great void in this escadrille. Men like him are difficult to replace..."

Louis Krebs shipyard
1911 - Louis krebs presents a law thesis for which he was advised by his uncle, Charles de Fréminville, entitled "Work performance in the arsenals".

In 1933, Louis Krebs bought the Le Roy Frères shipyard in Concarneau, which he named "Chantier Krebs".

We owe him in 1931 with the refrigeration specialist Henri Alliot, the idea and the design of the cold room on tuna boats, as well as the creation of the concept of trawlers-tuna boats, these "mixed boats" which practice trawl fishing during the winter and tuna fishing in the summer.

He will be elected mayor of Lanriec (1943-1945).

Marie Krebs-Chamming's, his daughter, will describe her years in the service of the French Resistance during the 2nd World War in her book "I chose the storm" which will receive the Truth Prize in 1964.

Marguerite Paulet, born Krebs (1900-1979): the remarkable works

 * Youth, until 1920
 * Port de Bouc, under the Mediterranean sun, 1920/1922
 * Quimperlé (and a little Nantes), 1923/1930
 * Douarnenez mainly, the beautiful boats, 1930/1940
 * Post-war 1940/1955
 * Flowers and trees... 1956/1979

Other categories
Births_in_Vesoul Deaths_in_Quimperlé Alumni_of_the_Special_military_school_of_Saint-Cyr  Henri Dupuy de Lôme Gustave zédé Charles_Renard_(aviation_pioneer) La France (airship)

Forges_et_Chantiers_de_la_Méditerranée Société_Nouvelle_des_Forges_et_Chantiers_de_la_Méditerranée Canet_artillery Gymnote_(submarine,_1888)

Brigade_de_sapeurs-pompiers_de_Paris_people Brigade_de_sapeurs-pompiers_de_Paris_equipment Steam_engine_inventors Jean-François_Durenne

Automobile_industry_entrepreneurs People_associated_with_the_automotive_industry Designers_of_automobiles People_associated_with_automobile_racing Émile_Levassor Monument à Émile Levassor René_Panhard Hippolyte Panhard Émile Mayade Panhard_&_Levassor History of automobiles Panhard_&_Levassor_automobiles Anciennes usines Panhard et Levassor Panhard_&_Levassor_vehicles Clément-Panhard_vehicles Panhard_&_Levassor_automobile_engines Panhard_&_Levassor_racing_automobiles 1898 Paris-Amsterdam-Paris race 1898 racing automobiles Panhard & Levassor Type U3 Auto shows in Paris Charles de Fréminville Adolphe Clément-Bayard George Baldwin Selden

La République (airship) Saint Chamond tank

Georges Guynemer Arsène d'Arsonval Ettore Bugatti André Citroën Georges Guynemer Maurice Farman Henri Farman George Heath (racing driver) Henri Cissac Robert de Vogüé (1870-1936) Antarctica

Steering_wheels Sleeve valve engines Gyrocompasses Differentials Worm gears Couplings Rag joints Giubo Rotating shaft couplers Transmissions Final drives Automobile axles Mechanisms (engineering) Glaciers Hydrogen technologies Vélizy-Villacoublay Alberto Santos-Dumont Santos Dumont Collection Early aircraft Historical gas balloons Internal combustion engines Combustion engine inventors Chalais-Meudon Type ou modèle de dirigeable Dirigeable national d'études et de recherches aérospatiales in Meudon