The main object of this book is to direct discussion of rocket flight into serious channels and .to free it from Its former fantastic notions, which have, understandably but technically undesirably, prevented sober consideration by engineers busy with many other matters.

The principles of rocket flight considered together here in part reflect known facts, but ones which are widely scattered in the literature and whose relation to rocket flight is often scarcely apparent at first sight.

One of the major and essential purposes of this book is to collect as far as possible the material on hand for the designer. The sources that have been employed are conscientiously quoted. Where such references are not given, it is to be assumed that we have lines of thought which either are of general technical validity or have been developed by the author himself.

Rocket flight is above all a technical problem, and the book is directed primarily to the engineer and his -ways of thinking. All studies are presented from the technical point of view rather than from the physical one. Important facts whose mathematical demonstration is to be found in the specialist literature, but which are evident to the engineer as such without fundamental proof, are merely mentioned as such where appropriate.

If the specialist finds that some special topic or other has been too superficially treated in one of the innumerable specialized sections, it is to be hoped that it will be excused on the ground that a complete treatment of every discipline Involved in rocket technology would demand an altogether exceptionally many-sided technical knowledge, which could be acquired only as a result of many years' acquaintance with the material.

For this reason, and in accordance with the scope of the, book, only the major relationships in rocket technology can be discussed, out of the vast amount of material. It might be possible in a later edition to deal with some especially Important particular topics, such as the effects of gas dissociation on the behavior of rocket motors, temperature relations of motor walls, control and stability of rocket vehicles, various flight paths, heating consequent on air friction and compression, possible uses of high-pressure rocket motors, and so on; this might make possible description of the research leading to each result.

Structural details, of course, are not discussed for the present although there is no opposition to this. The author wishes to record his thanks to various sources for interest in the writing and publication of this hook.

First of all there is my respected head of division. Professor P. Rinagl of the Technical Research Institute at Vienna Technical University, for the greatest assistance in this work. The author also wishes to thank him as an active and tireless investigator of all problems, even those far from commonplace, for this most valuable advice and support.

By rocket flight is meant here the motion of such a vehicle within the general air space, the propulsive force being provided by a rocket motor.

Rocket flight in the narrow sense is taken to be motion in the upper levels of the stratosphere with a speed such that inertial forces arising from the curvature of the path have a marked effect on the lift.

This type of rocket flight is the next major development from tropospheric flight, which has been the product of the last thirty years; it is also the forerunner of space travel, the greatest technical problem of the present time.

This forerunner and the installation of a space station are the noblest tasks of rocketry, but for the present they are still not realizable.

There are also several directly practical purposes to be served. Rocket flight should especially:

1. Provide rapid intercontinental travel around the globe with the highest possible terrestrial speeds.

2. Advance scientific research in certain fields, especially geophysics and astrophysics.

3. If necessary provide a war weapon of exceptional power.

These three purposes can now be reckoned as In part technically feasible. The present book is concerned with the technical basis of the realization of this first stage of rocket flight.

Any travel technique generally, and hence rocketry in particular, must be concerned with all three basic demands on a means of travel, namely performance, economy, and reliability.


Rocketry is in the very earliest stage of development. For the present, economy and reliability must take second place to performance in our demands on it.

For this reason I consider mainly the principles of performance in rocket flight, which are primary at present and in respect of the ultimate purpose, namely the emplacement in orbit of a space station.

Aspects of rocket flight that should become very much more Important than in ordinary propeller aircraft are flight speed, ceiling height, and range.

The mechanical basis for flight performance is provided by the forces exerted on the vehicle.

The external forces occurring in rocket flight are as for ordinary propeller aircraft, namely drive, air, weight, and inertial forces.

The quantitative relationships between these are considerably altered, of course.

This is especially so for drive and air forces, so these are considered in particular detail in two of the three main sections of this book.

There is little new to be said about the gravitational attraction of the Earth, and the inertial forces are a consequence of the other forces; these will be dealt with in the treatment of flight performance' in the third section.

This third section deals further with the calculation of response of the rocket vehicle to the forces and with the result in the form of the flight path.

These discussions of performance show, amongst other things, that:

Rocket vehicles for the first experiments can be built on the basis of the theoretical knowledge and available techniques, extension to ranges of up to about five thousand kilometers between stops being feasible. These long-range flights take the rocket vehicle to a path at a height of about fifty kilometers in the stratosphere. Further, the rocket vehicle would attain in these long-range flights a maximum flight speed of about 4000 m/sec and an average cruising speed of up to about 1000 m/sec.

These values represent upper limits and may be subject to modification, on account of the uncertainty of many assumptions made in the calculation.

Other and technically equally possible assumptions would allow perhaps of even higher ceilings at the expense of range.

Considerably longer ranges or higher flight speeds appear hardly conceivable except in the light of essentially new discoveries, especially as regards propellants, or as a result of expenditures scarcely to be considered as economic.

Especially it would seem that attainment of orbital velocities in the upper levels of the atmosphere (and hence the escape to altitudes for space stations is not for certain possible with techniques presently known.

The discovery of appropriate techniques is a problem for future development.

Performance presently attainable leads us to expect that rocket vehicles excel ordinary propeller aircraft by about a factor twenty as regards maximum speed and cruising speed, and by about a factor five as regards ceiling height.

The ranges between landings meanwhile remain comparable.

Constructional details are most conveniently Ignored in all discussions, although any calculation of flight performance must naturally be based on a certain design of the rocket vehicle.

For this purpose we assume the form of currently standard aircraft.

The following performance calculations are then concerned with a rocket aircraft having a spindle-shaped fuselage bearing rigid free wings and the usual land or water undercarriage and controls. The single rocket nozzle Is assumed to be at the rear of the fuselage.

The process of flight by a rocket aircraft is externally exactly the same as that of an ordinary aircraft.

To sum up, we may say that the difficulties to be overcome in rocket flight are not fundamental but rather merely ones of construction.

Constructional difficulties are nothing uncommon to the modem engineer, though.

The main theoretical design principles are dealt with in the following publications.