Dipl.-Ing Robert Lusser

© Copyright (as translator) For the entire text below, rests with Calum E. Douglas, no part of this may be reproduced by any means without my permission.

On the 15th of January 1942, a letter was drafted to the German Secretary of State for Air, Erhard Milch. In the letter, one of Germany`s most renowned freelance aeronautical engineers, launches a tirade against the policies employed in Germany in aircraft design, procurement, and most seriously, in production planning. Whilst perhaps due to his own work on the aircraft, Lussers views on the He177 are not wholly objective, as a whole it is an astonishingly blunt and interesting window into various very profound and fundamental aircraft programme errors made in Germany going right back to 1936.

If Lusser was indeed correct, it shows that it was not just in engines that Germany exhibited very poor upper-level management, but also in aircraft themselves. The Allies were of course not immune from such problems, but they seem to have done a “less-worse” job of procurement and planning than did Germany under the Nazis.

Covering Letter to Milch

Field Marshal
Erhard Milch
In the Reich Aviation Ministry
Berlin W8
Leipziger Strasse 7

Secret !

Dear Field Marshal,

During the interview on December 23, 1941, for which I would like to thank you once again, you expressed the wish that I should remain active in the aviation industry after I left EHF. I can see this as recognition of my previous work in aircraft development, which I was particularly pleased about.

Stimulated by the conversation, I have laid down my thoughts on the development and development planning in the enclosed memorandum. I believe that the memorandum may be useful in light of today’s pressing issues, and I therefore ask for your kind attention.
The principles presented in the memorandum have been advocated by me for years. I refer to Director Hayn, EHF. as well as my longtime employee and successor as head of the design office at Messerschmitt, Dipl.Ing. W Voigt.

Precisely because I advocated strong rationalization and determination in development, I sometimes got into disagreements with Professor Heinkel and probably also with some gentlemen in your ministry.

Far be it from me to attack anyone personally. My only concern is to use my own many years of experience to help ensure that in the future, more than in the past, the way for a planned and successful aircraft development will be found.
Heil Hitler

Your very devoted

Robert Lusser

Memorandum on development and development planning in the German air armament.

1. Introduction:

The causes of the current difficulties in air armament are sought primarily in the field of production.

This memorandum proves that the difficulties of large-scale production are largely due to errors in development and development planning and that their causes must therefore largely also be sought and combated in the field of development.

Successful aircraft development 1933-1936

In the years from about 1933 to 1936, a number of aircraft types were developed by the RLM and others, which were released by the German aircraft industry with a punctuality far superior to similar programmes in other countries at the time, for example the Me 109, 110.- He 111.- Ju 52, 87.- Thu 17.- Fw 200.E

In the present war, i.e. 4 – 8 years after the start of development, these types have proved to be almost the only aircraft types of the German Air Force which have proven to be consistently valuable. The superiority of the German Air Force to date is mainly due to them!

These prototypes were not only healthy in terms of the planning, the drawing and the construction, but they were freed from their teething troubles in 3 to 5 years of strenuous construction work and testing and thus made ready for large-scale production. At that time, the development took place in the following 5 stages shown schematically below:

<GRAPH “Construction and Development of Aircraft in 1936”>

2. Rapid development since 1936.

In the understandable endeavour to increase the pace of development of new models, the RLM has been demanding more and more since about 1936 that the stages “ready for series production” and “pilot series” each be brought forward by 1 year. So one hoped with the preparation for series production [CD: “Serienreifmachung”] and with that being able to start construction of the pilot series [CD: “Null-Serie”] before the results of the normal tests [CD: “Erprobung”] were completed would therefore enable us to emerge with the first mass produced [CD: “Gross-Serie”] aircraft after about 2 years instead of after 3 years, for example.

<GRAPH “Construction and Development of Aircraft 2nd Revision, Compressed Timeline”>

This belief has turned out to be little more than an illusion! It is seen as one of the main reasons for any “delay-delays” and serious disappointments in German aircraft production. In reality, the process actually achieved was as follows below:

<GRAPH “Construction and construction of the model aircraft 3rd version, the real results of attempting to employ a compressed timeline”>

As a result of the lack of test results, the aircraft were often mass-produced in a completely immature condition, which inevitably led to increased expenditure of time and effort for changes of all kinds and to a blockage of the factory facilities. This in turn increased the nervousness and the friction between design, operation and RLM considerably and finally the first usable large-scale mass production came out not after 2 years, but again after 3 years or even later. Examples: Ju 86, Ju 88, He 177, Fw 190.

3.) Scheduling without considering the increasing technical complexity of the aircraft.

As is well known, the military requirements force aircraft to be developed are made more complicated from year to year, for example with dive brakes, pressurized cabins, remote-controlled weapons and so on. It can therefore be said that the development effort for aircraft of roughly the same size (e.g. Ju 52 and He177) has increased 5 to 10 times in the last 10 years.
This additional work as a result of the increased technical effort was not or not sufficiently taken into account when drawing up resourcing and schedule plans. In many cases, the deceptive hope of being able to shorten the development times compared to the past has been enthusiastically entertained!
The result of this totally incorrect planning was often a harmful and over-hasty period of panicked re-development, which affected series production through serious technical setbacks and incessant missed deadlines.

4.) Deadlines that are too short for reasons of competition.
It was often due to competitive factors that prompted the companies to give too short estimates for the release of the model aircraft, the pre-production series and the mass production series. Example: Ju 88.

5.) Overestimation of the possible acceleration of the delivery date.
The goal and the success of the development was seen by some places in the shortest possible development time until the aircraft type could be flown. In doing so, it was often recognized that an apparent gain in time by over-hasty development usually has to be paid for by a multiple of time lost in large-scale mass-production, and that the creation of a combat-capable air force is far less dependent on the earliest possible flight of the model aircraft than on the possible early release of the 500 or 1000 operational mass-produced machines. Examples of this are the types:

Ju 86, Ju 88, Ju 288, Ar 340, Ar 240, Fw 191, Me 209, Me 210, He 100, He 119.

After 1936, numerous aircraft types were created that had to be cancelled or mothballed before the first flight (or soon after) because of numerous serious defects in the first production batches. Other types, such as the Ju 88, only got rid of these “birth defects” years later, leading to serious setbacks both in production, and at the front.
The millions of development hours spent on these misguided developments were often wasted and missed other important areas and tasks, such as the development of engines, propellers, weapons, and other devices.

6.) Overburdening development through optimistic planning.
When drawing up schedules, it was often not recognized that the engineering hours required for preparation for series production and further development are many times greater than the effort required for the new development up to the first flight. This fact can be easily seen from the statistical charts of the hours expended on any successful large-scale mass-produced model. Examples: Me 109, He 111.

The consequence of this was a far too optimistic development plan and thus an often incorrect use of already very scarce engineering capacity.

Regarding graph a [CD below-left]: Here it is assumed that once a certain level has been reached in the design costs for a sample, the number of design engineers required will soon fall again. This is a dangerous mistake!

Regarding graph b [CD below-right]: In fact, after the new design has been completed, a successful series aircraft often requires a growing number of designers (for the following work items listed below) for many years:

1.) Elimination of defects due to flight testing.
2.) Preparation for series production for the purpose of large-scale production.
3.) Constant adaptation of military equipment to the latest state of war technology.
4.) Further development with more powerful engines and for other purposes and so on
Examples: Me 109, He 111, Ju. 88 and Ju 88b.

[CD, Graphs vertical axis is the number of Engineers/Designers, the text on the upslope reads “Increasing Capacity”, and the horizontal text at the top with an arrow pointing left reads “Increasing Engineer Shortage” – what this is trying to show, starting on the left (a) is that people “hoped” that you could have (just as an example here) seven aircraft types developed and produced between 1933 and 1941, because the number of engineers/designers needed would tail off rapidly after each type was put into early testing, thus leaving lots of capacity free to start on the next project, never needing more than 400 engineers/designers. The reality was actually like (b), each type needed a LOT of continual effort years after it had already been designed and the prototypes built, thus, you could not really achieve more than 3 or at most 4 new types over the same 8 year period.]

7.) Fragmentation jeopardizes the preparation for the production and maturing of mass produced types. The often far too low estimate of these four workloads [above] meant that some companies, under the false assumption that they would soon have enough free capacity again, constantly commissioned unwisely large numbers of brand new developments, which led to a fragmentation of the resources and then to inevitably stalling of the development and finally led to chronically late achievement of deadlines.

A worrying side effect of this fragmentation is that the new developments took up so much of the interest and energy of both the managerial and the individual designers that the less interesting but often more important supervision of the large-scale projects were neglected.

We apparently recognized these dangers of fragmentation too late. This can be seen, among other things, from the fact that the RLM did not begin to set up a development planning system until the fall of 1940. Although this system is now in order, it has only been able to provide the statistical documents necessary for advance planning and to give a full overview of the elasticity possibilities of the individual development companies since the summer of 1941.

The development at Heinkel from 1933 to early 1939 offers a significant example of the fragmentation and its consequences. The successful large-scale aircraft production of the He 111, is nevertheless opposed by no less than 10 poor or unsuccessful developments, namely the 10 models:

He 74; 112, 114, 115, 116, 118, 119, 176, 178, 100.

Of these 10 models, with the exception of the He 115 (240 units), all the others were only built in very few test-prototype batches or very small pilot series. None of the models justified the sometimes-enormous development and construction costs in military use.

Although of course it cannot be demanded that every new development be a large-scale success, such as the Me 109 or the He 111, and even if the experience from failed developments may represent a certain value, the ratio of 1:10 in aviation programme success for our air-force is unacceptable and a sure proof of the misdirection of a considerable part of the engineering capacity, which is limited by the lack of engineers.

Immediately after joining Heinkel on June 1, 1939, I emphatically fought this dangerous fragmentation and used the engineering capacity entrusted to me primarily for the only available wartime aircraft the He 111 and for future-oriented new developments, just the He 177. As the plan shows, I retained this deployment of an average of 350 engineers even when the He 177 was almost completely killed in the summer of 1940 (reduction of the program from 55 units per month to 5 units). For the same reasons I also resisted the inclusion of the “Bomber B” and the “Tactical Transporter” because, as can be clearly seen from the plan, the necessary engineering capacity for such large-scale developments was simply not available, or, at least only at the expense of the He 177 project.

My fight against the acceptance of the “Bomber B”, the He 219a and the “Tactical Transporter” was interpreted as an obstacle to development in misjudgement of my true intentions, although it ultimately turned out to be completely correct and meritorious and despite the success of the He 177, for the benefit of which I have fought division of resources – the results of which exceeded the expectations of all concerned.

Those who thought they could accuse me of this [CD: opposition to advancing new designs] have obviously overlooked the following:

1.) That I took over the He 177 at a very early stage, half a year before the first flight, and that the scope of work for a large 4-engine bomber is 4-6 times greater than for a fighter or destroyer (see also Flow chart of the Heinkel development).

2.) That I developed the Strahljaeger [CD: Jet Fighter] He 280 with numerous technical innovations, such as the nose wheel, in a short time and brought it to a recognized technical success. The He 280 would perhaps start in large series today if the engines had matured in time.

3.) That I have also completely designed a fighter with nose wheel and DB 603, which would have been flying for a long time today and might have been up to date if it had not been rejected by the RLM.

4.) That I finally designed the He 219b almost wholly as a long-range reconnaissance aircraft.

I ask you not to consider it immodest if I list the aircraft types in whose successful overall development or project planning I was significantly involved during my 16 years of work in the aviation industry in order to invalidate the accusation of development inhibition, which is shameful for a head of development:

K1 25, Ki 26, Ki 32, He 71, Me 108, Me 109, Me 110, Me 209, Me 210, Me 261, He 177, He 280.

Of these 12 models, only 3 did not go into series production:

1.) The He 71, a one-seater exercise aircraft, with which a 20,000 km flight around Africa was completed in 1933
2.) The Me 261, a civilian long-haul aircraft
3.) The Me 209, which holds the world speed record.

All these specimens are distinguished by the rapidity of their development. As an example, the big bomber He 177 should be mentioned, which was released 3 years after the start of construction at the license company Arado, despite serious setbacks, and the jet fighter He 280, which was finished 13 months after the first draft sketch and apart from the engines no setbacks so far made themselves known.

The goal of rapid development for mass production, which is crucial for air armament, can be achieved much more reliably through careful assignment of tasks, development and planning while avoiding fragmentation [CD dividing resources] than through nervous haste.

8.) Example France.

A cautionary tale of fragmentation and its consequences is the French Air Force.

According to the RLM report from autumn 1940, about 70 new aircraft types were developed and flown in France in the years from about 1934 to 1940. Nevertheless, when the war broke out, France had hardly a single modern large-scale mass produced aircraft such as the Ju 52, Ju 87, Me 109, Me 110 or He 111.

In transporters, too, there are about 10 actually load-carrying aircraft types with a very large number of more or less major failures, which must be evident from the official documents. Only a small part of these unsuccessful developments are entitled as parallel or experimental developments.

I believe that we must see a great danger for our air forces in this disproportionately poor success ratio. I am convinced that the Americans have correctly recognized this danger today and are already putting all their energy into the mass production of relatively few but really mature [CD i.e designs which have had the bugs worked out] types.

9.) Wrong tasks by overestimating the real “state of the art” available to us.

The reason for some of the erroneous developments lay in poorly defined tasks, which in turn were due to an often considerable overestimation of the benefits available from the current state of the art. In many cases it was believed to be possible to make performance calculations using weights and flight performance estimates that later turned out to be just utopian:

Examples: Ju 88, Ju 288, Fw 190, Arado 240, Arado 340.

The result of this incorrect performance data was that in several cases healthy aircraft types running in mass-production were actually curtailed because it was believed that a new, significantly more powerful model would soon be coming to the front.

Examples: Ju 88b against Ju 288, Me 109 against Fw 190.

Unfortunately, the RLM did not have enough professionals with sufficient skills in checking the proposals of bidding firms and associated technical verification. Only in 1941, at my suggestion, were the first specialists in the industry asked to recalculate the weights and performance of competing models. Several serious non-compliance issues with the aircraft performance (supposedly guaranteed by the firms) were immediately uncovered.

Examples: Ju 288, Arado 240.

10.) Incorrect assignment of tasks due to the lack of procedural design documents.

During the consultations on tasks between the General Staff, RLM and industry, irreconcilable, protracted differences of opinion often arose as a result that systematic standardised design guidelines were missing or not used. Their purpose is to determine the dependency of the flight performance on the other military requirements and to present them so clearly that all the necessary inter-dependencies can be seen at a glance.

Examples of this are the studies on the fighter problem of the Messerschmitt company from 1938 (author Dipl. Ing. Voigt) and the “Studies on the Bomber B” of the Heinkel company from the spring. With the latter I proved that the required flight performance was impossible to achieve with the required military loads and that the weight of the “Bomber B” had to be many tonnes heavier than was hoped for and required by the client.

I recommend having such basic issues worked out for any future projects. This is the only way to avoid eternal differences of opinion and subsequent disappointments.

11.) Neglect of on-board weapon development.

The need for strong defensive armament, for the bomber and reconnaissance aircraft, has been unrecognized for years. Until the outbreak of the war, the position, which could easily be proved to be wrong, was adopted that our German bombers were so fast that they were very difficult to catch and attack by enemy fighters. The Heinkel company in particular represented this point of view. You only need to stick out a “broomstick” or a “tranquilizer” to drive away the opponent!

Since 1936, on the occasion of the armament of the Me 110, I have repeatedly drawn attention to the fact that our bombers with the drum-fed MG 15 guns have a very weak defence and finally in January 1939 I proved in an investigation submitted to the RLM that a normal fighter ( Me 109) was superior to the normal bomber (He111) not by a factor of 7, as was believed, but by a factor of more than 500 in aerial combat. This investigation remained unnoticed for 4 months and was only retrieved from the files after my personal inquiry. No consequences were drawn from this.

It was only when our bombers were shot down by the English fighters in frightening numbers that it became apparent that our defensive armament had been seriously neglected.

At the beginning of the war, the English had equipped their bombers (Wellington) with very modern power-controlled twin and later quadruple machine guns with belt feeds, which gave our fighters a hard time.


In order to come as close as possible to the goal of optimal large-scale production of high-quality military aircraft, the following requirements must be made of the development.

1.) A healthy large-scale production of mature types must be considered the main goal of development, especially in wars. False inventor ambition and company interests, on the other hand, take a back seat. You can’t wage war with prototype aircraft! (See France).

2.) In order to avoid the dangerous fragmentation, especially of the leading contractors, and to achieve the highest quality while reliably meeting the series deadlines, no company should construct or develop more than 3 to 6 types at the same time – depending on the size of the project. Large aircraft, such as the He 177, are weighted in this respect, several times more than small aircraft, such as fighters or destroyers.

3.) Preparation for series production and further development before new development, especially during war.

4.) Rushing when defining the project, design and construction certainly leads to technical setbacks and often to profound mistakes in development. Therefore, the apparent gain in time achieved is usually lost many times over when mass-production is delayed.

5.) Illusionism in task definition, design and construction represents one of the most serious dangers for aircraft weaponry, because it often commits considerable energies uselessly and takes them away from other tasks. The designers must therefore be educated to the highest degree of conscientiousness and self-criticism.

6.) Development planning has to be done on the basis of real circumstances and on the basis of experience with previous models. Here, too, any illusionism is dangerous and must therefore be fought.

Final note:

There is, of course, no recipe for avoiding disasters with certainty. The subject matter is far too complicated for that and, moreover, even the best plan and the best solution can at any time be overtaken by war-related or strategic developments.

The severe necessities of war force us all the more to recognize and eliminate all intellectual, material and organizational dangers to air armament earlier than our opponents.

The present work aims to serve this goal.


15 January 1942