Reaction-Propelled Manned Aircraft Concepts of the 1890s by Frank H. Winter and Wolfgang Both

From The Space Library

Reaction-Propelled Manned Aircraft Concepts of the 1890s---Some German Patents: Glimpses into the History of Early Rocket Plane Developments

by Frank H. Winter and Wolfgang Both

I. Introduction and Background:

The rocket-propelled airplane is usually thought of as a strictly “modern” invention of the 20th century. Yet, the foregoing article clearly shows that nothing could be further from the truth. Indeed, we are now presenting brief descriptions of some 15 recently discovered late 19th century German patents of concepts of propulsion systems towards what were then more quaintly termed “reaction-propelled flying machines,” or other comparable names. Call them what you will, they were ideas for the motors for what today we would call “rocket planes.”

(By the way, long before the birth of true aviation in 1903 upon the first manned controlled flights with heavier-than-air machines by the Wright brothers, the basic terminology ¬ including the words we take for granted, “aircraft,” “airplane,” or simply “plane” ¬ had yet to be invented themselves and then fully accepted into various languages of the world; hence, the appearance of terms like “flying machines.” We will explain more on the historical context of the terms “reaction-propelled, “or“reaction propulsion” below, as well as how we came to discover the 15 patents.)

But before continuing further, we must briefly sketch the background of the patent finds as well as the overall subject of the history of the earliest “reaction-propelled flying machines.”

Back in 2013 and 2015, the principal author (Winter) presented a two-part survey history paper titled “New Observations on Reaction-Propelled Manned Aircraft Concepts, ca. 1670-1900” at the 64th and 66th International Astronautical Congresses (IAC), held in Beijing, People's Republic of China, and at Jerusalem, respectively. Part 1 covered the period of 1670 to 1869, while Part 2 completed the survey, covering the period 1870 to 1900.1

Normally, history papers presented at IAC congresses are devoted to different aspects of the history of rocketry, especially as applied to its earliest adaptations for spaceflight. However, the unusual topic of the earliest known concepts of reaction-propulsion (i.e., rocket propulsion) for manned “flying machines” was chosen since it is a largely overlooked although very important area of the history of the rocket---in this case, part of the history of an application of rocket power. In fact, it goes back far earlier than is generally believed (back to at least 1670) and the more the principal author studied them the more diverse and surprisingly widespread they turned out to be; in addition, while some of these early ideas were very primitive by our standards, other concepts were complex and ingenious for their day.

Yet, it was also realized even during the preliminary collecting of material on these kinds of concepts that a two-part survey would still not result in a genuinely “definitive” study. Why was this so? There were two basic reasons, both of which were stated in the abstract and introduction of the survey.

The first is because it was not possible to make a completely thorough examination of all relevant patents on a truly international scale. After all, the patents used in the survey were largely limited to those that had been issued in Great Britain, America, and France; a far smallernumber came from Germany and other countries though even here, complete patents were unavailable and at that time the author had little recourse but to rely upon “second hand” mentions of such patents and with only the scarcest of descriptions. More often than not, the original patent numbers and exact dates of the issues of those patents were totally lacking in standard histories of rocketry and the like; as may be expected, some of the interpretations of the mentioned patents were also questionable---in short, unreliable.

The second reason why the survey could hardly be definitive is because patents were hardly the only sources for early manifestations of such ideas; in fact, only a handful of patents were used. Indeed, the compilation of material that had taken several years to carry out and eventually led to the survey came from a wide variety of other sources. Many items, for instance, were discovered in several 19th century popular science journals when those types of journals first emerged in the wake of the Industrial Revolution and naturally also aroused enormous new and highly popular interest in the progress and greater promise of man's attempts to solve the great question of achieving manned flight.

Albeit, those kinds of sources were beset with their own problems in the research. For one, not all of those journals of the pre-1900 period came with indexes and early proposals on “reaction propulsion” were consequently often frustratingly difficult to find in these journals. The lack of terminology in the relatively new field of “aeronautics,” also hindered the searches. Still other sources were promotional pamphlets and the like authored by some of the “inventors” of this or that approach to reaction propulsion for manned flying machines, although these are quite rare and are often extraordinarily difficult to locate, much less study.

Nevertheless, despite all these problems the author continued to find this topic fascinating and worthy of continued exploration. Searches for other examples of reaction-propulsion concepts for manned flying machines was therefore further pursued, as well as efforts to answer questions on several of the examples already cited in the two-part survey.

Eventually, with many thanks to the co-author of this article, Dr. Wolfgang Both, the retired German engineer and fellow historian of rocketry and whom the principal author had the opportunity to finally meet at the IAC Congress held in Bremen, Germany in 2018, it became possible to obtain complete copies of some 16 hitherto unexamined German patents on these topics. At the same time, it was also quite interesting that these particular patents all dated to the narrow time frame of 1893 to 1897. So in this respect, we are also offered a kind of a rare “glimpse” backward in time into an already rich period of the appearances of these kinds of concepts as covered in the two-part survey, although now on the German side that we previously knew very little about.

Hence, both authors of this article hope that it might be both interesting and perhaps instructive in several ways to review all these new-found patents as a discrete group, one by one. But before we get to the patents per se, there is a “bigger picture” that also needs to be conveyed.

II. The “Bigger Picture”

To begin with, we must explain “Why the term reaction-propulsion rather than rocket-propulsion or rocket-propelled? The reason is an historical one that is not always easily understood.

Nowadays, it is common knowledge and taken for granted---especially among readers of literature on both aeronautics and astronautics---that the rocket moves because it is acting in accordance to Isaac Newton's classic Third Law of Motion, first expressed in 1687 in his Principia (his Philosophiae Naturalis Principia Mathematica, or Mathematical Principles of Natural Philosophy, but usually just referred to as the Principia) which states: “For every action there is an equal and opposite reaction.”

Ironically, Newton himself did not bring up the rocket as an example or illustration of his Third Law. To further complicate matters, Principia was a complex work of physics that most people –-fellow scientists among them---did not fully comprehend. Consequently, throughout all those centuries following Newton's Principia the real meaning of his Third Law as explaining rocket motion was largely missed. Rather, the most commonly-held belief---or theory---as to why the rocket moved fitted into what we may call the “air pushing school.” This theory held---erroneously---that the rocket ascended or flew horizontally on its own after ignition simply because its exhaust gases pushed against the atmosphere. This seemed very logical. That is, it was presumed the exhaust gases pushed the rocket away from the atmosphere.

It is another irony that not only scientists but most professional pyrotechnists (firework-makers) who made skyrockets for lavish firework displays, and artillerists, who often also used signal rockets during the courses of battles, fit squarely into the camp of the “air pushing school”.

Yet, a minority of scientists and others did grasp the correct explanation and either expressed it in accordance with the Third Law, or slight modifications of it, to realize that the rocket did not need air to push against [our emphasis] in order to move; the movement, as also seen in the recoil of a gun that is fired, was really an opposite reaction. But as fundamental as this premise is at present, the “air-pushing school” lingered from Newton's day up to as late as the 1920s or later, in the popular literature.

On a completely different and more profound level, proponents of the air-pushing school were hindrances to the earliest advocates of the potential use of the rocket as a mode of reaching and continued propulsion in the vacuum of space---since the Third Law can work in a vacuum and also helps explain the movements of some bodies in space. We need not go into the finer details here of that controversy that surfaced when the founders of astronautics like Konstantin E. Tsiolkovsky of Russia, Robert H. Goddard of America, Hermann Oberth of then, Austro-Hungary (and later of Rumania), and Robert Esnault-Pelterie of France were laying the groundwork from the late 19th to early 20th centuries before World War I, of the then new scientific field of spaceflight that afterwards (from 1927) became known as “astronautics.”

Suffice it to say that even many of the originators as well of early concepts of “reaction-propulsion” prior to 1900, say, did not also fully comprehend the basic scientific principle as to why a rocket---or any other object propelled by reaction motion---really “flew.” This is important to state because not only were their designs carried out with this flawed thinking but it also explains why they did not always apply the word “rocket,” or qualifying terms like “rocket-like” or “like a rocket” in their patents or other writings on their concepts. Rather, they used more commonly preferred terms like “reactive flight” and occasionally, “reaction propulsion,” to explain their chosen mode of propulsion. (In these instances though, they probably likened their mode of propulsion to the reaction or recoil or backward jerking motion of a gun when it fired its round---although this recoil, unbeknown to them was, as mentioned, another example of Newton's Third Law of Motion.)

By the same token in closely examining some of the early patents such as those covered in this article, it is still common to see these types of patents under the sub-classification of “reaction motion” or “reaction propulsion” as modes of propulsion for “flying machines.” (Still another popular general term for these machines was “aerial locomotion” while their respective propulsion was referred to as “propulsion of aerial locomotion,” or “methods of aerial locomotion.”)

Now another very important factor to keep in mind while examining these early reaction-propelled flying machines is, in a nutshell, the almost stagnant state-of-the-art of the rocket prior to roughly 1900. In short, the basic rocket appears to have originated in the eastern half of China during the Sung Dynasty (960-1127 A.D.) and throughout that millennia and into the early 20th century, without almost no exceptions, gunpowder (also known as “black powder”) remained the basic propellant both in the East and in the West for “operational rockets.” That is, the applications of the rocket were then largely confined to “skyrockets,” or firework types; signal rockets; and occasionally as small caliber war rockets. However, during the 19th century during the so-called Congreve and Hale eras named after the British inventors Sir William Congreve and William Hale, iron-cased gunpowder rockets with incendiary or explosive warheads witnessed a very widespread vogue in many countries. But by around the turn of the century, they had become outmoded due to the concurrent evolution of more superior conventional artillery in terms of accuracy, range, and reliability. Apart from these, there were a few other applications that were developed during that century, such as lifesaving rockets and whaling rocket harpoons.

Hence, during that pre-1900 period rockets were not that powerful and even Congreve type war rockets of were generally of “medium” down to smaller calibers of 32-pounders or 24-pounders and under, like 12-pounders; Hale rockets widely used during the latter half of the century were generally of smaller calibers, including 9-pounders. (Other countries besides England had comparable war rockets during this time, with comparable calibers and performances.) In sum, with very few exceptions, even the supposed most powerful rockets of the day were far too feeble and of extremely short firing durations of just a few seconds and were understandably rarely taken seriously as prospective modes for producing “motive power” –- another 19th century term (particularly as intended for sustained power or performance) –- for propelling manned aircraft to any reasonable distances.

To these downsides of the rocket during that period, we should add that they were hardly known for being “reliable”. In truth, they were notoriously unreliable as to be expected from being largely hand-produced, including how the gunpowder propellant was rammed into their bodies. These combined explanations regarding the “state-of-the-art” of rocket technology of the 19th century goes very far in pinpointing why the rocket was then not the most favored of the means of reaction propulsion for reaction-powered aircraft as compared to say, compressed gaseous systems that then seemed to be not only more reliable but potentially more powerful, more controllable, and certainly of longer durations.

As for the development of aviation itself, this of course started with the first unmanned balloon flights in 1783 undertaken by the Montgolfier brothers of France and were very quickly followed by manned balloon flights. Yet, although these were lighter-than-air efforts, they did open up a huge impetus for inventive men around the world to seek the answer to one day create heavier-than-air machines capable of fully controlled flights rather than to trust only the vagaries of the winds and weather for successfully accomplishing their ascents with balloons.

(Incidentally, the word “aeronautics” meaning the study of the science of flight, originated in 1784, just a year after the Montgolfiers' first successful achievements, the word deriving from the Greek “aero,” meaning “air,” and “nautica” “or “nautics,” pertaining to “sailing” or “sailing through”. Initially, the word was largely applied to flight in hot air balloons while the travelers in these balloons were known as “aeronauts”. Yet “aeronautics” was also loosely adapted to encompass the design and construction of other modes of flying into the air, that is, an airplane or other flying machine.

But the words “aviation” and “'airplane'” arrived much later. “Aviation” came first. It was coined by the French writer and former naval officer Gabriel La Landelle in 1863. He derived it from the verb avier, then a relatively new French verb for "to fly,” with roots from the Latin “avis” or "bird,” plus the suffix “ation,” denoting some kind of action. Then, a decade later in 1873, the term “airplane” came into use into the English language, from “air” plus the stem of the French word, “planer” or "to soar".)

Most writers and speakers on the subject throughout much of the 19th century thus came to use the term “flying machine”---which is another reason why it is cited throughout the present article as it was in the two-part survey.

Ballooning, of course, continued and was steadily improved following the Montgolfiers, albeit balloons were never fully controlled. But at the same time progress in early aviation in general from the late 18th to 19th centuries was an especially rich period of ideas and actual projects---many of them wholly impractical. Others were more ingenious and detailed their respective modes of propulsion for those machines. The choices for propulsion varied widely. The majority incorporated propeller systems, or “screws,” as they were more commonly called, although the search for an extremely light weight yet powerful and efficient energy source was by far the most difficult of the technological challenges faced by these early inventors.

Human muscle power was not overlooked although this method was obviously found wanting, weak, and wholly inefficient, and had no chance of success. Perhaps inevitably, several techniques of using “reaction propulsion” were also among the early proposals considered to achieve sufficient motive power for manned flight although for a number of reasons, a few of which we have already seen, reaction propulsion itself was then not the most favored approach; in fact, this form of motive power was among the least favored and is thus far rarer to find in the early aeronautical and related literature compared with other modes of propulsion like screws.

Now, when we say there were “several techniques” of using reaction propulsion, from our two-part survey we can further divide these types into specific categories, or sub-categories if you will, although the following are not necessarily in the order of their predominance or “preference”; we also note some of their characteristics:

a) Solid-propellant rockets (gunpowder, or in a very few cases, guncotton): typically of very short durations, uncontrollable, and of feeble power.

b) Compressed gas (air or an inert gas, usually: generally of short durations if a compressed gas, otherwise needs a pump or compressor, although probably of longer durations than rockets; some examples of inflammable gas also suggested; interestingly, of the approximately 70 examples of reaction-propulsion concepts covered in the two-part survey, the majority of them, or about 30, were of the compressed gas type.

c) Steam as a separate category, when suggested or used for strictly its reactive force: but still needs a boiler to heat the water; duration also short and power feeble.

d) Air breathing reaction engine: meant of course, for atmospheric flights only; complicated internal construction; in fact, only one example is known of a 19th century theoretician who patented and eventually experimented with this form of motive power for propulsion, the French civil engineer Charles de Louvrié during ca. 1863-1866 who also employed electrical sparks to ignite incoming compressed air with hydrocarbons as well as valves to regulate the airflow; his work is thus considered the precursor to the jet engine, although it was more like a pulse-jet.

e) Liquid-propellant rocket: several (late) 19th century designs are known, although these are more scarce in the early aeronautical literature and unfortunately, none are found among these particular German patents; yet, these early systems cannot not be entirely equated with modern (20th-21st century) liquid propellant systems in using, for example, bi-propellants (a liquid oxidizer, like liquid oxygen, or other substance containing oxygen atoms needed by the liquid fuel to burn, although some 19th century designs did suggest monopropellants that are similarly used today); de Laval nozzles are absent from 19th century designs although there were cruder nozzles and other efforts to channel the exhaust gases and to speed their flow by funnel and similar type arrangements; pumps for forcing in the fuel into the combustion chamber were also included in several 19th century concepts; and other elements of modern liquid-propellant rockets are also not found in 19th century designs, like high heat resistant materials and, of course, high speed aerodynamic and control considerations).

There were other pre-1900 variants or sub-categories of reaction propulsion systems though these are the main ones.

Nevertheless, apart from the above we may also delineate the most serious overall drawbacks of some of these early proposals: (1), often underestimations by their inventors as to the required level and/or actual output of power (which today, we may call “thrust” and/or specific impulse) from their suggested propulsion systems and/or propellants to lift given or assumed weights of their machines; (2), insufficiently designed modes of control of their reaction propulsion systems; (3), insufficient or lack of concerns of the safety in using certain propellants; (4), uses of unsuitable construction materials [related to No. 3 above]; (5), insufficient, or lack of data or considerations on the durations of operation of their propulsion systems required for these flying machines to travel to any appreciable distance, or to make return flights for that matter; (6), insufficient aerodynamic stabilization of their flying machines (that was not, of course, related to their proposed propulsion systems); and (7), insufficient or lacking designs of suitable landing means and re-use of their machines; et. al. From both of the above lists we may be able to better detect some of the weaknesses in the proposed reaction propulsion systems of the 15 German patents presented in this article.

It must additionally be born in mind---as is evident in the patents presented here---that we know of no communications between any of the inventors who were granted the patents, nor if their ideas were disseminated between any of them. By the same token, it would be inaccurate and misleading to infer that each idea followed each other in succession as “follow-ups” or a linear evolution in the continued development of the reaction-propulsion principle as applied to manned flying machines. Thus, each of the patents should be judged on its own merits, or lack thereof, as the case may be.

Now as to how we came to learn of the 15 German patents covered here, these were discovered in the two-volume 723-page comprehensive book by Dr. Bruno Alexander-Katz (1862 – 1927), Die deutschen Patente über Flugapparate; vollständige Sammlung deutscher Patente vom Jahre 1879 bis Ende Juni 1911, systematisch bearb. von Patentanwalt Dr. B. Alexander-Katz (German Patents on Flying Machines; Complete Collection of German Patents from 1879 to the End of June 1911, Systematically Revised. by Patent Attorney Dr. B. Alexander-Katz) and published in Berlin in 1912. Moreover, the patents are located in a dedicated chapter headed “Reaktionsflieger” (“Reaction Flyers”). Hence, Dr. Alexander-Katz, a professional German patent attorney at that time, was the one who interpreted them---in one fashion or another---to constitute the application of what we presently call “reaction motion”, to these inventions.

Mind you, this book only contained what are called “abridgments”, or summations of the said patents, although lengthy ones to be sure. It is most interesting that the author of that work, Dr. Alexander-Katz, also presented a short description of how he interpreted this class known as “Reaktionsflieger” among German aviation patents covering the specific period of 1879 to 1911 as follows:

“This group of aircraft includes those in which a pressurized gaseous propellant is made to escape and the resulting reaction shock is used to propel the aircraft with the aid of wings, turbine wheels or the like.” (Evidently, however, during that period Dr. Alexander-Katz had not encountered, or had possibly overlooked, strictly solid-propellant reaction-propulsion techniques---and certainly those that may have suggested the incorporation of liquid-propellants as well. This statement is thus perhaps also telling in that a more complete range of types of reaction propulsion was either also overlooked---even to a professional patent attorney at the time---or was not regarded very highly nor well known.)2

At any rate, these patent discoveries were subsequently brought to the attention of Dr. Both who had recently completed writing a book on a completely different aspect of the early history of rocketry, namely a history of the Verein für Raumschiffahrt (the [German] Society of Spaceship Travel, or VfR), formed in 1927 and lasting up until 1934 as the most well known and active of the rocket and spaceflight advocate groups of the international space and rocket “fad” of the 1920s-30s. Nevertheless, Dr. Both who had used German patents as one of his sources, as stated at the outset, most graciously provided the lead author with complete copies of all the relevant patents as well as his considerable guidance.

Lastly, we feel it is fascinating to observe that according to the German patent system of the time, all these patents then curiously fitted into the category of “Sport” (or what we would translate as “Sports”). This was evidently because the field of “flying machines” was still considered little more than a “pastime” or a “hobby” or a “recreation,” even as late as the 1890s. That is, the field of aviation had yet to be considered a bonafide (established) area of technology in that country. Put another way, aviation itself, along with its various modes of proposed propulsion such as reaction propulsion, were still very much highly experimental. We do not know of a similar patent category or sub-category in other countries during this same period, keeping in mind that each country had its own patent system.

We will now proceed in describing and depicting the 15 patents in chronological order, using the date that each patent was granted.

III. The German Patents:

(1) 1893 --- Interestingly, the first cited patent by Alexander-Katz in the “Reaktionsflieger” sub-category in his compilation of German aviation patents for the said period was one issued to the Frenchman E. Lavarenne of Paris!

We can now more properly identify this individual as Joseph Emile Lavrarenne (who often went by the name of Emile Lavarenne, or more simply, “E. Lavarenne.”) Moreover, he had been earlier granted French patent No. 215,756 for a "Nouveau système de navigation aérienne par moteurs à réaction" (“New System of Aerial Navigation by Reaction Motors”). However, according to several mentions of his concept in the French journal L'Aėronaute (The Aeronaut) (Paris) for 1893, the same invention was examined by a “commission” that did not find the idea viable. Notably, in the issue for July 1893 it is said that a “Report on the Memoire of Mr. E. Lavarenne relative to a system of air navigation, [a] heavier-than-air [machine] by means of perfected motors of reaction [propulsion]” concluded that due to “the enormity of the [actual] amount of force” that would be necessary to carry out a flight based on the system of Lavarenne, this project was not practical and his plan had not been subject to careful calculations”.

This did not deter the inventor because on 3 June 1893 Lavarenne was granted German patent No. 68783 in “Class 77 (or “Sport”) for the same invention though now titled “Eine die Reaktion eines aus einem Rohrsystem austretenden Treibmittels (Druckluft, Dampf, Gas) ausnutzende Autriebsvorrichtung für Luftschiffe” (“A Propulsion Device for Airships that Utilizes the Reaction of a Drive [Compressed Air, Steam, Gas] Emerging from a Pipe System”). Lavarenne had filed the German version of the patent on 1 March 1892.

In the introduction to the German version (that does not appear in his original French patent), Lavarenne stated: “The invention relates to a new propulsion device, which is intended in particular for airship travel, but can also be used to move other vehicles on and under the water or on land.” But from here on, the text is a convoluted description of a complex system involving tubes upon tubes. We therefore do not need to trouble the reader with this and will just jump to the beginning of his “Patent Claims” as follows: “A propulsion device for airships which exits the reaction of a propellant (compressed air, steam, gas) emerging from a pipe system, characterized by the fact that inside the rearward and the downward directed pipe[s]...one each with propeller blades (occupied [the] shafts...[are] arranged to regulate the outflow of the propellant.”

To put this more simply, the exhaust gases were to exit from two main “flared tubes,” or funnels, one aimed downward (for lift); the other (for driving the ship forward) and opening at the wider end of this funnel was at the rear end of the “square or cylindrical” apparatus. Then, within each of rear and lower flared tubes were mounted a series of the propellers for the respective regulation of the exiting gases. (In the accompanying patent drawing one can count as many as six of these propellers in the cutaway of the rear-mounted tube.) To further complicate matters, a shorter flared tube was mounted opposite the longer one at the rear and was evidently meant for propelling the vessel backwards if required.

Hence, overall this was an extremely cumbersome and wholly unworkable idea yet more amazingly the inventor had practically nothing to say about how the propelling gases were to be generated, nor the power for the so-called regulating propellers. Rynin merely explained in passing that: “In this machine a special engine forces compressed air, steam, or gas[,] through [a] chamber into two [main] nozzles.” Thus, although this was an airship using reaction-propulsion, it did not involve combustion, only super-compressed air, steam, or gas generated by an undefined means.

We can only add that among other features, the inventor included the carrying of four medium-sized parachutes “intended in case of an accident,” plus a “balloon, necessary only in the case of engine failure.” It was thus naive of him, to say the least, to express his own uncertainty that his invention would ever work although still trying to promote it. 3

(2) 1893 – On 23 June of this year “Nicolay” (or Nikolai) (Ley calls him Nicholas) Petersen, residing in Guadalajara Mexico, was granted German patent No. 69348, Class 77 (also in the “Sport” category), for a unique cigar or torpedo-shaped “rocket-propelled airship” for carrying passengers or “loads” in which the rocket bodies, or cylinders, were automatically fed into a large “revolver cylinder” and fired successively by an electric igniter, then was removed for the next rocket. Ley likened this arrangement to that of the Colt revolver except that the cartridges were rocket tubes.

The gases escaped from a truncated cone, or nozzle, at the stern of the ship. Petersen called this part a “funnel-shaped guide tube.”

The rockets were in “a number of chambers concentrically around an axis of rotation mounted in a universal joint to accommodate the rockets and a guide tube for the outflowing combustion gases, adjustable in vertical and horizontal planes...” Petersen thereby also claimed his airship was “steerable...[by means of the universal joint] whether in the horizontal or vertical path corresponding to the respective setting.” (The accompanying drawing for this patent depicts four clusters, or “rocket groups,” of equidistant rocket tubes for a total of 20 rocket tubes for the ship.)

Many years later, Rynin correctly judged the invention “hardly suitable in practice” since the impulses of the rockets would have endangered the structure of the ship, the replacement of the rockets was “manual and...unreliable” (and therefore added to its lack of safety), and that Petersen had provided “no computation of the quantity and power of the rockets.” (This meant the thrust or impulse and duration of each rocket, nor how many rockets were needed for any given distance of travel of the airship, and other necessary operating and performance data; nor do we learn anything of the construction of each rocket.) Besides all this, there was no safety device “against explosions”. In sum, Peterson's concept was wholly unworkable---apart from being judged completely unsafe.

Ley had also mentioned that Petersen was of Mexico City that may have been an error while Miller (who obtained his information from Ley) assumed that he was an “engineer working in Mexico City” but Guadalajara is clearly cited in the patent. According to the German Patent Office's Patentblatt: Herausgegeben von der Kaiser. Patentamt for 1893, Petersen had two representatives in Germany at the time, Alexander Specht and J.D. Petersen, both of Hamburg, perhaps indicating the true roots of the inventor. Peterson is not known to have taken out any other patents in Germany, as well as in Austria, France, England, and the U.S.4

(3) 1893 – On 3 July of this year August Klumpp of Munich and Conrad Haussner of Ingolstadt, which is about 70 km (40 mi) directly north of Munich, were granted German Patent No. 69520 for their concept of a reaction-powered flying machine although it is curiously titled a “Method of Floating a Body in the Air.” Moreover, it is not explained anywhere in this short patent the purpose for keeping the “Body” (a flying machine, presumably a manned one) suspended in the air although it is assumed it was meant for military reconnaissance or for other observations from a high altitude.

According to Ley, the aircraft was to be “kept suspended by diverting and commutating [the regulating] or reversing [of] the direction of air currents.” The inventors explain in their patent that the apparatus utilized an air turbine operated by a pump in which the “the medium is water and the pump intended was an ordinary piston put water flowing through the impeller per second with increasing speed” for forcing the air through the system, and the air eventually expelled from a nozzle for propulsion using the recoil principle. Some of the air was also removed to supply it to the operating motor.

In other words, the onboard turbine and pump were theoretically to “deflect” a quantity of air from its original direction and utilize this force of work to increase the power of the pump as well as provide propulsion. The patent for this overly complicated apparatus includes mathematical formulas for calculating the amount of work obtained from the pump. Thus, overall the machine was to be kept aloft, and presumably moved into place and later set down for a controlled landing, by the recoil principle, or reaction motion. The concept of Klumpp and Haussner was therefore also wholly unworkable and impractical.5

(4) 1894 – On 5 January of this year the priest Richard Czygan of the town of Hermeskeil in the Trier-Saarburg district in Rhineland-Palatinate, Germany, was granted German patent No. 77895 for “Rotary propellers for airships”. Overall, this was a type of propeller arrangement fitted with two semicircular metal strips to which a flat or curved or sail was attached. When the propeller was rotated, “air is forced from all sides towards the axis, with counter pressure acting on the sheet or sail...” Czygan was thus suggesting that this type of propeller could move an airship by reaction propulsion, although his patent is short and very simple and does not adequately explain this nor go into any details of his balloon type airship at all.6

(5) 1894 – On 15 January of this year, the German firm of Hüttner, Walter & Co., “merchants,” of Hamburg obtained German Patent No. 72902 for “An Airship to be Moved by a Stream of Air Drawn in...and Expelled to the Rear.” The airship in the shape of a cigar that operated “by the reaction of air” (or “recoil principle” as Brandau terms it) in which air was sucked at high speed through a hollow cylinder by means of a screw propeller in the body of the airship and discharged also at high velocity at the rear through a cone-shape shell. By means of perforations or “apertures” around the hollow cylinder on different sides of the airship, and that could be opened as necessary, this was to interrupt the flow of air and in this way the airship could be diverted (i.e., steered or deflected) from the prevailing wind direction. “This distraction [of air],” the patent says, “may occur arbitrarily down and up, right and left, or in two of these directions simultaneously.” The patent further provided that instead of one screw propeller, a number could also be used and concentrically arranged around the central axis.

As in other patents of this type, there is an “airship crew and engine room.” Additional patents regarding this invention are: No. 82,257, 82,904, and 86,738. This patent is also cited in the German aviation journal Zeitschrift für Luftschiffahrt und Physik der Atmosphäre (Berlin), Jg. 13 (1894), p. 135 - 7

(6) 1894 – Gustav Koch (b. 1843) of Munich, Germany, was one of the few in the early history of reaction propulsion concepts who regarded himself as a professional “aeronaut” and called himself as such as well as a “flight engineer.” (The latter designation was Koch's own term but today he would be known as an “aeronautical engineer.”)

Koch certainly had a prolific career in this field and wrote in his 72-page brochure, Die Lösung des Flugproblems in Physikalischer und Maschinentechnischer Hinsicht (The Solution of the Flight Problem in Terms of Physical and Mechanical Aspects) (Munich, 1896), that he had become deeply involved in aviation from about 1881 or 1882. He additionally remarked that: “Almost 15 years [ago, also from 1881], as theoretically and practically the solution of the problem steerable airship came closer, I was following my [own] experience on the side of flight technology after the announcement of the flying machine project of Hiram Maxim…” (Hiram Maxim, 1840-1916, the American-born English pioneer of aeronautics was then carrying out his first experiments toward building his first flying machine.)

From then on, Koch similarly studied all facets of the possibility of achieving manned flight besides undertaking his own extensive experiments in his own country and authoring a number of technical brochures on the subject and taking out a series of patents. One of the latter was his American patent No. 282,647 of 1 August 1883 for “An Airship.” This was his most favored design which he continually improved upon and was an elongated cigar-shaped hydrogen-filled balloon propelled by two horizontal paddle wheels each driving a screw, or propeller.

By 1885 he had completed a model of 140 cubic meters capacity and exhibited these in Munich as well as in Stuttgart and elsewhere in Germany. This working model had two screws with four wings. For a rudder a small triangular sail was employed at the back of the balloon and was guided by “cords” from the “boat” part of the airship. Yet despite its relatively small size, Koch was able to successfully obtain a speed of a meter per second and the rudder also “behaved very satisfactorily in the experiments,” according to May. For a larger version, by May, Koch reported that he hoped to use electricity as the driving force, “or a gas engine, the gas taken from the balloon.”

In his classic work, Progress in Flying Machines, the French-born aviation pioneer Octave Chanute reported further progress by Koch. In 1891, Chanute wrote, Koch had published his other brochure Der freie menschliche Flug als Vorbedingung dynamischer Luftschiffahrt (Free Human Flying as the Preliminary Condition of Dynamic Aeronautics) in which he presented his plan and description of an apparatus to imitate the soaring of birds and also gave an account of other experiments he had tried with models. Chanute added that Koch had succeeded in obtaining a small grant of 1,600 Marks (then about $ 400, but today the equivalent of about $2,770) from the Bavarian Ministers of the Interior and Education to carry out the experiments with his assistant over Lake Constance near Lindau. This “aeroplane,” as Chanute called it, had a pair of rigid wings shaped like those of a dragonfly, each about 27 feet long and a triangular tail about 7 feet long. This was to carry a man although the first trials were to be made with a dummy. (The “aeroplane” was to be carried up to about 3,000 ft then dropped.) In short, it was to be a kind of glider.

Yet, it turned out that his compatriot Otto Lilienthal (1848-1896) became the first person to make well-documented repeated successful flights in his own glider, although he perished on 10 August 1896 in his last glider attempt. Evidently Koch was not able to carry out his own manned flights although was close to that achievement.

Among his patents, Koch was granted German patent No. 73 603 granted on 10 March 1894 for a “Flying Machine with Wings and Paddle Wheels” and used his considerable knowledge and experience in the design, making, and flying of “flying machines” that interestingly did not included a proposal for a reaction propulsion method. However, the patent is lengthy and does offer a detailed explanation of how “reaction force,” as he called it, often manifested itself in the flight behavior of flying machines such as in his paddle wheel design, as well as during the operations of this machine's standard engine. On the latter, for instance, he observed that occasional recoil of the engine was “the `reaction force of the engine,' whose most important effect and use seems to be overlooked by all flight technicians today.”

“This reaction force, or the recoil of the motor in the current case” [of his paddle wheel design], he continued, “endeavors to turn around the apparatus [the airship itself] backwards around the axis of the paddle wheels by lifting the front of the vehicle and depressing the rear part. However, the air present under the wings and the tail pushes against it, since it is compressed by the air masses thrown backwards by the paddle wheels.” In other words, Koch recognized that the “aeronaut” had to be fully cognizant of the principle of reaction force in several aspects in the dynamics of flying machines to better design and control them. Koch also cited the importance of the knowledge of the crucial design factor of “Reaktionskraft” ("Reaction force") in his brochure Die Lösung des Flugproblems and it probably appears as well in his other works.

Hence, of all the patents presented here, Koch is the only one of the 15 who openly at at length described reaction motion [our emphasis] plus the need for other designers of flying machines to be aware of it; yet, ironically, he did not propose such a machine himself.

Among Koch's other brochures are: Das Luftschiff: Ein Beitrag zur Bedürfniss & Nützlichkeitsfrage der praktischen Luftschiffahrt (The Airship: A Contribution to the Needs & Practical Questions of Air Navigation) (1883); Beschreibung und Motivirung der Construction des Koch'schen Luft-Schiffes (lenkbarer luft-ballon) (Description and Motivation for the Construction of the Koch Airship [Steerable Air Balloon]) (1884); Populäre Abhandlung über die Möglichkeit dynamischen Fluges (Popular Essay about the Possibility of Dynamic Flight) (1886); Der Weg zur Lösung des Flugproblems (The Way to Solve Flight Problems) (1887); Neue Bahnen: Eine Denkschrift für Jedermann (New Railways: A Memorandum for Everyman) (Munich, 1891); Die Lösung des Flugproblems und das Luftschiff der Zukunft (The Solution of the Flight Problem and the Airship of the Future) (1893); and Das Flugschiff (The Airship) (Munich, 1901).

In addition to the above published works, the Special Collections Research Center of the University of Chicago Library holds the Crerar Ms 174 which is a collection of handwritten facsimiles of three essays by Koch, with annotations, concerning the principles of mechanical flight. These are illustrated with diagrams, drawings, and photographs. The essays are: (I), Introduction of Air Navigation by the Paddle Wheel-Flying-Machine, n.d.; (II), The Physical Base of the Phenomenon of Flight and the Solution of the Problem of Flight, 1894; and (III), Principle of Flight and Flying Machine, 1897. Part IV of this collection is authored by “various experts and titled Opinions on Herrn Gustav Koch's System of Dynamical Flight.” (An attached note to this material interestingly indicates that it had been “assembled [organized or arranged and copied?]” by Octave Chanute.)8

(7) 1895 – On 11 February of this year, the firm of F. Gaebert of Berlin (later, F. Gaebert GmbH, Berlin), was granted German patent Nr. 79446 for a “Method and Device for Lifting Loads etc. to Fly into the Air.” Interestingly, (Friedrich) Gaebert, a gas and water valve manufacturer and developer, was one of the financiers of the famous Count Ferdinand von Zeppelin, the inventor of rigid airships after his name. It is additionally important to note that upon closer examination, the German patent is identical down to the same accompanying plates in the earlier British patent No. 7919 granted on 25 May 1894 to Joseph Hofmann for “Improvements in the Art of Aërostation [sic.], and Apparatus employed therefor[sic.]” Furthermore, since Hofmann is identified in this British patent as a “Counsellor [i.e., lawyer] of the [German] Government,” he evidently served in this case of the British patent as Gaebert's patent agent even if this is not stated as such.

Following the British version of Gaebert's patent, it is said at the outset that: “Dynamical Aërostation [an awkward and now archaic term for flight by man-made devices], if motive power supplied by animals is not considered, hitherto has been obtained only by two kinds of mechanical means or machinery, namely, by rockets, as employed in fire-works [sic.], and by toys with screw-propellor-wheel.” In the former case, he continues, flying is “only obtained by re-action (the pressure of gases discharging into the surrounding air in an opposite direction of the motion of the rocket)...”(Hence, Hoffmann, or rather, the firm of F. Gaebert in Berlin, were assuredly of the “air-pushing school”.)

The latter mode, the “screw-propellor-wheel,” the inventor(s) believed, “is practically impossible to carry the weight of its source of motive power,” while in the rocket the “driving power” is “too rapidly spent.” Flapping wings (ornithopters) were also entirely impractical they felt, as well as arrangements with steam boilers or explosive engines suffered from “considerable weight”. Gaebert thus believed “sailing flight” as employed by birds was more practical and could be used to fly in “almost line to considerable differences, by cautiously using gravity.”

Yet the inventor or inventors, brushed “sailing flight” in the manner of birds as well and settled on a steam boiler after all though in which the steam was “blown off through pipes carrying nozzles...” Gaebert also recommended the mixture of “atmospheric air, steam and products of combustion” while another of the inventor or inventor's concepts, but also not an original one, was a turbine “by which interrupting blades” would cause a “jet...to operate to its utmost power of reaction.” In sum, Gaebert had dismissed the rocket as a means of propelling aircraft, albeit the inventor was simply referring to ordinary gunpowder-propelled skyrockets yet opted for other means that would also have not been practical.

It also turns out that this patent was the first of five taken out by the firm of F. Gaebert between 1894 and 1898 that incorporated reaction propulsion though the other patents were either improvements to the original patent or extensions of ideas as to the application of the invention. The other four patents in this series are: [2], No. 82257 issued 27 July 1895; [3], No. 82904 issued 19 September 1895; [4], No. 86738 issued 2 May 1896; and [5], No. 100379 issued 8 December 1898.

The firm of F. Gaebert was very prolific and took out yet more patents on flying machines although only those that utilized reaction propulsion are covered here.9

(8) 1895 – On 27 July of this year, the firm of F. Gaebert of Berlin was granted German patent No. 82257 for a “Device for Lifting Loads into the Air” although this is really the first addendum to Gaebert's original patent utilizing reaction propulsion, No. 79446 issued on 11 February 1895.

According to the opening description in the patent of 27 July 1895: “When steam is spoken of in the main patent with respect to the flying machine described therein, steam is primarily meant. However, it can also be carbon dioxide vapor or explosive gas mixtures (hydrocarbons, ethers, and the like) can [also] be used for this operation.” The patent goes on to describe in detail how the carbon dioxide from a container enters a heating coil and the resulting expanded gases conveyed to nozzles. The nozzles are controlled by means of a spring valve and piston arrangement.10

(9) 1895 – On 19 September of this year, the firm of F. Gaebert of Berlin was granted German patent No. 82904 that embodied further improvements in their original reaction-propelled flying machine patented as German patent No. 79446 on 11 February1895 especially since it was realized that it contained certain technical flaws. Among these, it was found that the original concept only “partially sucked” in air and that the utilization of heat was insufficient. Therefore, among other changes, this patent contains a different shape of the guide vanes for sucking in the air and the vanes are additionally made automatically moveable, or adjustable. It is unknown whether these machines, or working models, were built although there is no evidence that they were.11

(10) 1896 – August Boehm of Breslau (now Wrocław, Poland) was granted German Patent No. 85903 on 10 March 1896 for an “airship” in which the screws (propellers) were supposed to drive air downward and therefore, according to the inventor, the machine was propelled forward by “forward reaction.” Obviously, this was not strictly a reaction-propelled machine and the concept was not well thought out. Steering controls are interconnected by lines to a rotatable wheel that were used to steer the ship. However, the description in this patent is very short and vague. 12

(11) 1896 – According to Rynin, [the firm of] F. [Friedrich] Gaebert of Berlin was granted German Patent No. 86738 of 2 May 1896 for a flying machine lifted and propelled horizontally “by the reaction created by gas ejected from a rotating wing. The reaction was to be increased by a system of pipes...similar to injectors...”

In actuality, this patent, simply titled “Flying Machine,” embodied yet more corrections and refinements to Gaebert's original patent No. 79446 issued on 11 February 1895 (See). In fact, under the above title are the words: “Third addition to Patent Nr. 79446...”

In one correction in the opening paragraph of this specification of 2 May 1896 it is stated that the “main” (i.e., original) patent of 11 February 1895 did “not allow enough time for the sucked-in air to remove the still available heat from the hot gases and the steam.” “In order to avoid these disadvantages,” the new patent continued, “a [newly designed] wind chamber...should be switched on between the suction nozzle and the pressure nozzle apparatus.”

Other new features were that the “wind boiler is bellows-shaped or when executed in hose form, [it] can be folded...” Also, the wings of the machine could spread automatically “in the running position of the machine.” Overall, according to the first patent claim of this patent, this is a “better utilization of the heat of the hot gases or steam...” But again, there is no evidence that this flying machine, or variations of it, were ever built.13

(12) 1897 – Carl Reiter of Munich was issued German Patent No. 89 890 of 2 January of this year for a reaction motor for a flying machine that the inventor believed would have been capable of flight in both vertical and horizontal directions. Atmospheric air was “assumed” to be the working gas. The apparatus consisted of two main parts or sections: the motor that generated the reaction; the other section was the remainder of the machine, or supporting apparatus.

The motor was a truncated cone-shaped hollow body open at the top. This cone was divided by radial walls into several chambers. The cone was rotated about its axis by means of a shaft and belt pulley, “or otherwise suitably by a suitable [conventional] motor” (i.e., the type of motor is not specified in the patent). Air was thus to be sucked in downward by centrifugal force created by the motor through the cone and then ejected through holes around the lower circumference via several radially directed blades thereby causing a steady reaction pressure. At the same time, according to handwritten notes by Ley, “new air is sucked in from above, which is also caught by the vortex and blows out through the lower openings. This process is intended to produce a steady upward reaction thrust... [and] keep a wingless aircraft in suspension.”

Much of the rest of the patent is devoted to details of the air flow through a complicated system and based upon the assumed power of the unspecified motor as well as the assumed efficiency of centrifugal force in this system.

Ley also commented elsewhere that this arrangement was “supposed to keep up an airplane...up in the air,” or as the inventor put it, the forced-in air was to move “upwardly [so that a] directed progressive movement is achieved.” In short, the inventor assumed far too much and overall the machine probably would have been over-heavy and greatly underpowered to have ever worked. 14

(13) 1897 – On 19 February of this year, Ch. [sic.] Steinau of Braunschweig, Germany, was granted German patent No. 90 695, Class 77 (as before, “Sport”), for “Fabric Surfaces for Air and Water Vehicles” that was actually a patent for a flying machine.

Despite the title of the patent, Steinau mainly focussed upon the propulsive nature of his proposed flying machine that was a cigar-shaped balloon vehicle with an elongated under-carriage that included the motor. This motor, that he also called the “flat blast wheel” or “flat impeller,” consisted of “two parts, the housing and the impeller.” “The housing, he went on, “has the shape of a truncated cone.” The impeller itself was a type of turbine in which were radially-mounted “shovel-like” curved surfaces. Steinau then explained that “air currents” or “natural airflow” entered into “the centrifugal wheel [the impeller or turbine, and] are generated by means of motor force,” so as to compress this airflow, although he did not describe the “motor force” that was to drive the impeller, but that a “steady countercurrent takes place.” Thus, despite his sometimes difficult description, it does appear this flying machine was to move by reaction propulsion.

He says the “blast wheel” (or impeller) also served “for the steering” of the vehicle. Though here too, he does not explain how this was effected and neglected to explain how his invention could have also been used to propel vehicles over the water. In sum, Steinau instinctively recognized the value of reaction propulsion for the movement of his “vehicles” through the air (and water), though omitted several key elements for the operation of his system and did not fully comprehend nor adequately explain the principle of reaction propulsion as applied to a manned flying machine.15

(14) 1897 – Armin Beckmann of Charlottenburg (later, a borough of Berlin), Germany, was granted German patent Class 77, Nr. 93692 on 1 October of this year for an “Elongated Balloon.” According to the patent, if two metal openings of his airship were evacuated with an air pump to create a vacuum and air was suddenly admitted into the interior of the vessel through a previously air-tight other opening, the air would penetrate “with violence.” But if a circle-shaped sheet were placed in the way of the incoming air, the airship would be “propelled [by reaction propulsion] in any direction” depending on the position of the air intake opening. A system of adjusting cocks and “regulating piston” could control the flow of air, as a sudden or continuous flow. Also, sheet metal strips placed at certain angles could be used to steer the airship.

Needless to say, this invention as well was highly impractical and ill thought out, such as the need for an air pump to initiate the operation of the airship. Additionally, there is no mention in the summary of the patent by Alexander-Katz of how air was suddenly admitted into the vessel. This patent is also briefly described in the Illustrierte Aëronautische Mittheilungen (Strassburg, 1898).16

(15) 1898 – On 8 December of this year the firm of F. [Friedrich] Gaebert of Berlin was granted German patent No. 100399 for a reaction-propelled “aeroplane” designed for “a short vertical or oblique dive or lift [jump] movement”, like “the bounce of a bird from a high nest...to the ground.”

Therefore, this was not a high-performance craft that was mainly to be operated by a steam boiler expelling steam from “nozzles” as its primary form of propulsion, although capable of a quick boost from the method embodied in the patent. In fact, the title of the patent is “[A] Method and Device for Taking Off in an Airplane,” while the opening statement of the patent says: “The difficulty that an airplane on take-off claims a [need for a] much greater force than the actual flight...” This invention was to therefore counter this problem by being able to furnish “a short...lifting movement.” In other words, the firm of Gaebert was really suggesting a take-off device for quick take-offs that appears to have been one of the earliest known concepts for a kind of JATO (Jet-Assisted-Takeoff) method---and was invented six years before the Wright brothers undertook the first controlled manned flight in an aircraft on 17 December 1903. (Yet, we cannot say this was the first patent for a JATO. See the discussion given below in footnote 17 about British patent No, 11,158 of 9 September 1885 of the German August Winkler that had been granted 13 year earlier for the same application.) Like the prior Gaebert aircraft design, this one also included an undercarriage with four wheels (i.e., to assist in the take-off and landing of the craft.)

It is also significant that the last line of the patent specification adds the following: “...it is also possible to use a plurality of steam cylinders...or spring-powered motors or cylinders for explosive mixtures (gas engines, [gun] powder engines, for instance with simultaneous ignition) and the like.” Hence, this patent likewise came close to suggesting the possible use of a solid-propellant motor for affecting take-offs or for very short flights.

This was also the last of Gaebert's five patents utilizing reaction-propulsion, started with patent No. 79446 issued on 11 February 1895 and the last that we know of taken out in Germany during the 19th century.17

Thus concludes the last of these late 19th century German patents. Most, as we have seen, were of the compressed gas type as described above and only one, by Petersen, theoretically operated by a type of solid-propellant rocket. These patents also add to our knowledge that the idea of “rocket planes” did indeed surprisingly witness numerous early precursors. Far more than these basic facts, however, we have gained some historical insights as to why such proposed concepts did not succeed beyond the patent stage in the 19th century. Notably, we have additionally seen the drawbacks of several forms of these early propulsion proposals---particularly the low state-of-the-art of rocket technology of the time---besides weaknesses within the patent proposals themselves.

Yet, there is one other factor and that seems to appear in almost all of these patents that perhaps best explains why these kinds of proposals did not advance as they might have. That is, these early patents appear to underscore our assertion, with almost no exception, these inventors themselves failed to recognize Newton's Third Law of Motion that precisely explains “reaction propulsion”---in its many forms---and why it works. Who knows what other early reaction propulsion concept might have been possible and could have perhaps been far more sophisticated than those presented here if the Third Law of Motion was recognized and a well engineered design built on this basis?

We must lastly note that since some of the technical language in these patents is not easy to interpret and also contains some archaic legalese and translated from the German, the authors welcome any comments or other interpretations that may be directed to: fhwinter@gmail.com

Sources

These papers were subsequently published in the history proceedings of those congresses, in Andrew S. Erickson, Editor, History of Rocketry and Astronautics, AAS History Series, Volume 45 (Univelt, Inc.: San Diego, 2015), pp. 95-12, and Tal Inbar, Editor, History of Rocketry and Astronautics, AAS History Series, Volume 47 (Univelt, Inc.: San Diego, 2017), pp. 105-132, respectively.
B. Alexander-Katz, Die deutschen Patente über Flugapparate; vollständige Sammlung deutscher Patente vom Jahre 1879 bis Ende Juni 1911, systematisch bearb. von Patentanwalt Dr. B. Alexander-Katz (M. Krayn: Berlin, 1912), p. 365.
Willy Ley, “The Chronological History of the Rocket,” Part 2, Astronautics (American Interplanetary Society, New York), No. 23, October 1932, Part 2, p. 5; N.A. Rynin, Interplanetary Flight and Communication [Translated from the Russian, as NASA TT-643] (Israel Program for Scientific Translations: Jerusalem, 1971), Vol. 4, p. 50 and Vol. 9, p, 189; Lavarenne, E., French Patent No. 215756 of 27 August 1891; Lavarenne, E., German Patent No. 68783 of 3 June 1893; L'Aéronaute (Paris), 26 Année, issues of May, June, July, and December 1893, pp. 118, 139, 165, and 287, respectively.
Nicolay Petersen, German Patent No. 69348 of 23 June 1893; Rynin, Vol. IV, p. 53; Willy Ley, Rockets, Missiles (The Viking Press: New York, 1958), pp. 88-89; Ron Miller, The Dream Machines---An Illustrated History of the Spaceship in Art, Science and Literature (Krieger Publishing Co.: Malabar, Florida, 1993), p. 74; (Germany, Patent Office), Patentblatt: Herausgegeben von der Kaiser. Patentamt (Carl Heymanns Verlag: Berlin, 1893), Vol. 17, p. 5.
Klumpp, August and Conrad Haussner, German patent No. 69520 of 3 July 1893; Willy Ley, “The Chronological History of the Rocket,” op. cit; Alexander-Katz, pp. 367-369; Daniel Brandau, “Cultivating the Cosmos: Spaceflight Thought in Imperial Germany,” History and Technology, Vol. 28, September 2012, p. 24.
B. Alexander-Katz, 12), pp. 453-454; Czygan, Rich. [sic.], German Patent No. 77895 of 5 January 1894; (Germany, Patent Office), Patentblatt und Auszüg aus den Patenschriften (Berlin), Nr. 24, 27 May 1894, p. 336.
Hüttner, Walter & Co., German Patent No. 75,902 of 15 January 1894; Ley, “Chronological,” Part 2, p. 5l; Alexander-Katz, pp. 369-370; Brandau, op.cit.; Ley, Willy, untitled handwritten notes on early German patents for reaction propelled flying machines, Willy Ley Collection, NASM, box and file number unknown.
Alexander-Katz, pp. 24-33; Koch, Gustav, German Patent No. 73603 of 10 March 1894; Gustav Koch, Die Lösung des Flugproblems in Physikalischer und Maschinentechnischer Hinsicht (The Solution of the Flight Problem in Terms of Physical and Mechanical Aspects) (Verlag Hermann Likashick: Munich, 1896), pp. 8, 56; Koch, Gustav, U.S. patent No. 282,647 of 1 August 1883 for “An Airship”; Gustav May, Ballooning: A Concise Sketch of its History and Principles (Symons & Co.: London, 1885), pp. 89, 91; Octave, Chanute, Progress in Flying Machines (The American Engineer and Railroad Journal: New York, 1894, and other editions), pp. 216-217.
Gaebert, F., German patent No. 79446 of 11 February 1895; Hoffmann, Joseph, British patent No. 7910 of 25 May 1894; K. Hackenstetter and Ferdinand Graf von Zeppelin, Die Luftschiffahrt: Dem heutigen Stande der Wissenschaft… (Franckh Verlagshandlung: Stuttgart, [1908], p. 153.
Alexander-Katz, pp. 378-380; Gaebert, F., German patent No. 82257 of 27 July 1895, also available online.
Alexander-Katz, pp. 380-383; Gaebert, F., German patent No. 82904 of 19 September 1895.
Boehm, August, German patent, 10 March 1896; Alexander-Katz, pp. 154-156.
Rynin, Vol. IV, p. 51; Alexander-Katz, pp. 383-386; Gaebert, F., German patent No. 86738 of 2 May 1896, also available online.
Reiter, Carl, German Patent No. 89890 of 2 January 1897; Ley, “The Chronological,” Part 2, p. 6; Rynin, Vol. 4, p. 51; Alexander-Katz, pp. 156-159; Willy Ley, untitled handwritten notes on early German patents for reaction propelled flying machines, Willy Ley Collection, NASM, box and file number unknown.
Alexander-Katz, pp. 610-613; Steinau, Ch., German Patent No. 99,695 of 19 February 1897; original patent also available on-line.
Alexander-Katz, pp. 403-406; Armin Beckmann, German Patent No. 93692 of 1 October 1897; Illustrierte Aëronautische Mittheilungen (Strassburg), 2 Jahrg. (1898), p. 58.
Alexander-Katz, pp. 579-58; Gaebert, F., German patent No. 100399 of 8 December 1898.

We cannot assume, however, that this was actually the last of the German patents on the topic of reaction propulsion during the 19th century. For one, German citizens sometimes also took out patents in other countries (just as the Frenchman Lavarenne had taken out a patent in Germany, as seen above). For example, August Winkler a merchant of Breslau (then, a city in “the Empire of Germany” and as mentioned, now known as Wrocław, Poland), was granted British patent No. 11,158 on 19 September 1885 for “Improvements in Steering and Propelling Apparatus to Floating Bodies.” In this specification, “jets of steam or other compressed gases...[were] so arranged at an acute angle...[and] could be applied for the propulsion and steering of steam ships as well as balloon, and is not intended for use under ordinary circumstances, but in exceptional cases, as for instance, at times of collisions, extra maneuvers...” This patent was therefore clearly for a JATO application and was only meant to be used during emergencies. By the same token, we must underscore that the JATO application was an altogether a distinctive and different application of reaction propulsion (or “rocket power,” in modern parlance) than when it was applied as the primary source of propulsion. That is, we have to differentiate the difference between rocket power a primary source of power vs. a usually one-term use of it in the cases or emergencies or other short-term purposes. Moreover, JATO concepts have their own unique, if little studied early history. Notably, for instance, apart from Winkler's 1885 British patent, one Haden Herbert Bales of British Columbia, Canada, was granted U.S. patent No. 1,003,411 of 19 September 1911 for a “Pyrotechnical Auxiliary Propelling Mechanism,” that utilized a gunpowder rocket adapted to a plane for this purpose, while on 20 June 1925, Dr. Friedrich Wenk of Tübingen, Württemburg was granted German patent No. 415161 for (as translated into English), a “Method and Device for Starting Enginless or Low[powered]-engine Aircraft.” Dr. Wenk, a well-known gliding plane designer and builder of the period, was really conceiving the use of a small gunpowder rocket mounted “in the vicinity of the aircraft's [say, a glider's] center of gravity” for strictly boosts. Interestingly, in his patent claims he also suggested that this rocket contained “a fuel of such a type that initially [produced] low propulsive force and only gradually [produced] the full propulsive force...(i.e. a fuel that burns more slowly in its first part than in the main part...”). We should also note that in all cases, all three of these patents considerably pre-dated the earliest known commercial development and production of JATOs in Germany, during the mid-1930s to 1940s (during World War II) by the firm of Hellmuth Walter; and in the U.S. from the early 1940s by then, Aerojet Engineering Company, formed in Pasadena, California, U.SA., in 1942.