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00:26:37
00:37:21
00:26:37

Transcription: [00:26:37]
{SPEAKER name="MICHAEL NEUFELD"}
Now, so you, so... I know that Dr. Hölzer -- as he later became Dr. Hölzer anyway -- was working on the 'guide beam', or Leitstrahl, in early '40--Was he, at that point, or was he at that point doing this also, as well, on the side, or is this after he finished with the guide beam work, I think?

[00:27:01]
{SPEAKER name="WALTER HAEUSSERMANN"}
At that time, you had [[ ? ]] also the name of Dr. Steuding. Dr. Steuding was the one who, mathematically, was involved in the dynamics of attitude control and guide beam stability.

[00:27:24]
And so, we developed, at that time also in the labratory, another system, or another analogue simulator that showed you how the missile moved back into the guide beam when it was -- through a disturbance like from wind or so -- put outside the center of the beam, and this was another equipment which I had designed at that time.

[00:27:51]
And when Dr. Hölzer who looked into how the beam could be generated, how the signal could be received for guidance, he gave us this information and we then simulated the behavior of the missile with respect to the guide beam.

[00:28:13]
{SPEAKER name="MICHAEL NEUFELD"}
And this is a simulation carried out completely in electronic form, right, as opposed—? Oh was it? --

{SPEAKER name="WALTER HAEUSSERMANN"}
—It was almost mechanical again—
It had again a second order differential equation which you use to move a mass -- in this case on the guide beam it was a rotating mass -- and that simulator then... it was constrained and controlled by a motor.

[00:28:38]
{SPEAKER name="MICHAEL NEUFELD"}
So you had the rotating mass as a simulation—

{SPEAKER name="WALTER HAEUSSERMANN"}
Yes.

{SPEAKER name="MICHAEL NEUFELD"}
—of umm... I'm trying to imagine this, because I guess my technical training is not up to it. The rotating mass simulated the—

[00:28:52]
{SPEAKER name="WALTER HAEUSSERMANN"}
—The mass of the system, of course in a translation of the motion towards the center of the beam. But the mathematical equations are basically the same. You have a second order equation, and whether you simulated this by rotating or by actual transverse motion, that doesn't matter. A transverse motion was almost impossible to be used in this case, and so we used the rotating.

[00:29:24]
{SPEAKER name="MICHAEL NEUFELD"}
And the correction, the equivalent of the correction for lateral dispersion was the rate of rotation?

{SPEAKER name="WALTER HAEUSSERMANN"}
The distance from the center of the beam.

[00:29:40]
{SPEAKER name="MICHAEL NEUFELD"}
OK. Now—

{SPEAKER name="WALTER HAEUSSERMANN"}
—and of course you had to have some damping effect, again, by generating a derivative of the system.

[00:29:55]
{SPEAKER name="MICHAEL NEUFELD"}
Now, so you... So did the simulation of... which you developed of attitude control... you know, in one axis, evolve from that simulation of lateral deviation from the guide beam?

{SPEAKER name="WALTER HAEUSSERMANN"}
We kept these two, as two separate analogue systems-- one for attitude control, and one for beam control.

[00:30:27]
{SPEAKER name="MICHAEL NEUFELD"}
What I meant by evolved, did the equipment evolve from the simulator for lateral dispersion, or was it parallel development?

{SPEAKER name="WALTER HAEUSSERMANN"}
No.

[00:30:40]
We choosed the equipment by checking it on the analogue computer, and improved both at the same time. We refined the analogue computers, and then we could give better specifications again for the equipment that had to be used in actual flight.

[00:31:01]
{SPEAKER name="MICHAEL NEUFELD"}
Now what I'm saying is, is -- well, I'm sure they evolved simultaneously to some extent -- Did one come first? Did the guide beam simulation come first, or did you sort of do these two things more or less in parallel?

{SPEAKER name="WALTER HAEUSSERMANN"}
Well, we had first the idea how to do it.

[00:31:17]
We had an idea how to build the equipment. Then immediately you asked yourself how can I test it? And of course, in case of the guide beam, you had first made some airplane flights -- to measure the signal when the airplane deviated from the center of the beam.

[00:31:37]
And this gave us first, the signal strength with which, then we derived, from which we derived mathematically the equations, and then we determined mathematically what the missile should do, what the gain factors would be, and then we tested it on the analogue equipment.

[00:31:57]
{SPEAKER name="MICHAEL NEUFELD"}
So that you had something to go on.

{SPEAKER name="WALTER HAEUSSERMANN"}
Right — I should put one additional point in. All these simulations, like attitude control and control with respect to the flight path, of course were only time-frozen simulations, not considering the varying coefficients of the equations.

[00:32:21]
See, when you have a higher speed, when you are constrained, aerodynamically constrained, it's different-- your mass is different because you have used up fuel and all this, this changes your gain factors and for the control system. So you had to consider all these viewpoints, and you could do it only step by step, by making a test for instance at take-off, shortly after take-off, on the simulation equipment-- the tenth, and the twentieth, and the fiftieth second and so on.

[00:32:57]
{SPEAKER name="MICHAEL NEUFELD"}
By a series of steps — that you could get an approximation.

{SPEAKER name="WALTER HAEUSSERMANN"}
Right — You could not continuously change the coefficient at that time.

[00:33:05]
{SPEAKER name="MICHAEL NEUFELD"}
This might get me out of chronologic order, but did you solve that problem later with the development of the simulators and of Hölzer's analogue computer?

[00:33:19]
{SPEAKER name="WALTER HAEUSSERMANN"}
It was never used, what the equipment could have done in Peenemünde-- we made these changes then later here in the States. But we, I had then, later in Darmstadt -- I continued to work in Darmstadt for Peenemünde beginning first of May '42 -- and there I developed an analogue computer for attitude control which would have permitted this contiuous change. But by that time the specifications were frozen already for the V-2s so nobody wanted to use it anymore. [[laughs]]

[00:34:00]
{SPEAKER name="MICHAEL NEUFELD"}
Everyone was too busy running around trying to get the thing — into production.

{SPEAKER name="WALTER HAEUSSERMANN"}
Yeah — I had, by the way, described all this in a report... I don't know whether you had seen this?

[00:34:10]
{SPEAKER name="MICHAEL NEUFELD"}
I don't know if I have... Which one is it? Is that the report in one of these [[?]] ... Or --?

{SPEAKER name="WALTER HAEUSSERMANN"}
I have a copy here...

[00:34:22]
{SPEAKER name="MICHAEL NEUFELD"}
OK. So, can you remember approximately when in 1940 or '41 you finished the... Was it in 1940 that you finished the simulators and started using the simulators for attitude control — in one axis ?

{SPEAKER name="WALTER HAEUSSERMANN"}
—There was a continuous development and improvement.

[00:34:45]
They were conceived in '40, but the development continued practically throughout the time. For instance, for Wasserfall, another pendulum type, purely mechanical, had to be developed, which I developed also in Darmstadt, and this one had the features to avoid time constants which were still permissive in the V-2 control system, or in the V-2 analogue computer.

[00:35:20]
{SPEAKER name="MICHAEL NEUFELD"}
So, from '40 to '42, while you were still physically located at Peenemünde, that was your main task — was it?

{SPEAKER name="WALTER HAEUSSERMANN"}
—Quite, quite.

{SPEAKER name="MICHAEL NEUFELD"}
—And was involved in simulating the performance of the competing gyro systems?

{SPEAKER name="WALTER HAEUSSERMANN"}
—Yes.

{SPEAKER name="MICHAEL NEUFELD"}
And...

[00:35:44]
{SPEAKER name="WALTER HAEUSSERMANN"}
Improving simulators, as well as the... Mainly it was the problem, how to reduce the time constants in the control system.

[00:35:54]
{SPEAKER name="MICHAEL NEUFELD"}
OK, by reducing... Let me see if I can translate that into, into a more non-technical language. You mean reduce the — response time--

{SPEAKER name="WALTER HAEUSSERMANN"}
—have a faster response—

{SPEAKER name="MICHAEL NEUFELD"}
—faster response time, so, within the system.

[00:36:09]
So you were constantly striving to improve the time constants for A-4 systems, both the Siemen system and Kreiselgeräte...

{SPEAKER name="WALTER HAEUSSERMANN"}
Yes.

{SPEAKER name="MICHAEL NEUFELD"}
And I know that -- also some time in there, and I'm not exactly sure when right now -- the Askania/Möller system came into play, and then I know even less about Anschütz...

[00:36:36]
{SPEAKER name="WALTER HAEUSSERMANN"}
Yes, I got familiar somewhat when I started in Peenemünde. But very soon these schemes were abandoned-- I think it was already in 1940 they were put aside, because the other two systems were more promising.

[00:36:54]
{SPEAKER name="MICHAEL NEUFELD"}
So, when you returned to Peenemünde in March 1940, Anschütz and Askania were already possibilities that were being investigated, that is they were already... —contract—?

{SPEAKER name="WALTER HAEUSSERMANN"}
—At that time, Askania was... only Siemens-Halske was at that time involved, and Askania was practically—


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