TA152 and FW190-Series Aircraft Stabilisation and Engine Management Systems.......

[xylstra]

Forum contributor "MIflyer" recently posted a TA152 Pilots Manual (which see). This immediately piqued my interest and I eagerly scanned the pages using my mediocre grasp of technical German in search of details that would describe the Automatic Flight Stabilising system with which the TA152 was equipped and any additional mention of the throttle/propeller-pitch/engine-boost automatic controller as was used with the FW90 radial-engined marks.
Damn! Couldn't find any useful descriptions.... disappointing, to put it mildly!
Knowing the considerable interest such specialised points of tecnical innovation - and especially when associated with these iconic Focke-Wulf fighters - then I am sure I am not alone in wanting some drill-down, blow-by-blow technical descriptions of these 'gerat'.
Indeed, in the majority of reference books printed on these subject aircraft the majority omit any mention of them. On the rare occasion that they are mentioned this usually consists of one sentence at best and bereft of any detail at that.
Kurt Tank was a qualified Electrical Engineer and his first foray into the nascent beginnings of electric 'fly-by-wire'for aircraft was the prototype FW191 in which heavy dependance was placed on the innovative use of electrically remote controlled and directed gun barbettes. It was a fiasco! The concept was a winner but the implementation was sabotaged by poor quality and low reliability of the electical components employed. It was never fixed and the idea shelved.
When it came to the FW190 he was mildly obsessed with wanting to reduce the pilot's workload in the midst of combat by the elimination of distractions arising from the need for 'control-juggling' to obtain optimal coordination of propeller-pitch and throttle/boost settings so that the pilot could keep both hands on the stick and concentrate on achieving the kill. So to this end he equipped the radial-engined FW190's with what was effectively an early form of electro-mechanical engine management system. Not sure whether this was carried over to the 'Dora' (can anyone confirm?).
Evolving the 'Dora' into the TA152 he went further and added an automatic flight stabiliser, which I believe was made by SIEMENS. The rationale was simply that in order to produce the 'knock-out punch' by keeping his fighter design ahead of the opposing and ever-improving allied fighters faced by the Luftwaffe he essentially had to build a 'Hot-Rod': cram an over-powerful engine into small airframe weighed down with multiple large-calibre cannon and just add NOx boost and you're good to go! Trouble was the resulting aircraft had become almost unflyable: far too much torque available far too quickly by just breathing on the throttle and all under the hand of ever younger and inexperienced pilots. A recipe for disaster!
He was adamant that his oversight control solution would keep his fighter designs on the leading-edge of the technology curve. In the case of the TA152 he was so convinced of it's utility he was prepared to suffer the weight-penalty of armouring the battery box - an indication of how important he regarded it.
All these complex systems weren't plucked out of thin air. They must have been developed over a long period and would have been a monumental research effort. This story has never been told and I for one, am curious to know more about how this was undertaken.
Can anyone full in the details?
More broadly, can anyone provide as much information (i.e. schematics, pictures, blueprints, technical and development narratives, etc) on the various systems, and their auxiliaries I have referred to?
Interestingly, Tank and Sydney Camm met aftet war, the latter taking an instant dislike to Tank whom he regarded as arrogant (probably true). Camm eschewed the very notion of automated flight control systems but only likely because he couldn't see past his bloated ego. History of course, was to prove Tank correct. His primitive systems having evolved into the complex fly-by-wire autonomous aircraft control systems we take for granted today and for which no modern aircraft is designed without. Testifies to Tank's future-focussed vision.
Before I forget: the TA152 was also equipped with the Askania EZ.42 lead-computing gyro-gunsight although many of these installations were of a permanently experimental nature as it had been placed into production before it had been fully developed whilst in the meantime Askania continued to hone and fettle the design so it is uncertain which version of sight went into the last TA152 before production ceased ( Does anyone know?). A most interesting post-war B.I.O.S. report has emerged fully describing these and other German weapons developments:- BIOS-67.pdf

On a separate note but may as well deal with while I'm at it: German WW2 flare identification systems. If you study closely some of the period TA152 photographs you'll just be able to pick out a verical column of 5 black dots in the rear fuselage.
Curious?
........ I'll put you out of your misery. They're the barrel ends of flare projectors. The German airfield flak crews had become 'trigger-happy' due to frequent strafing sweeps by allied fighters that they frequently shot down their own! There was insufficient time to relay an urgent message to them via the control tower so German aircraft came to be equipped with installed flare signal dispensers as standard equipment.
Can anyone provide further details?

 

[Crimea_River]

There is a pretty good basic description of the Kommandogerãt for the BMW 801 in Classic Wings Issue 80 covering the FW190A-5 restoration for the Flying Heritage Collection. It's a start, but does not answer your larger question as to what extent this, or similar system, was used on the Ta152 or FW190D.

"The command computer (Kommandogerãt) was the most difficult part of the engine to both understand and to get to function. The computer takes input from the pilot to operate a power-lever that goes from 0 degrees to 90 degrees for the power application and back to -20 degrees to idle cut-off for stopping the engine. The computer operates the throttle valves with the boost regulator to give the engine a given boost for each degree of movement of the power lever. When the boost reaches one atmosphere of pressure the mixture is changed from lean to rich and the boost is reduced slightly. As the lever is advanced the boost continues to rise. If the engine is not able to achieve the boost needed due to higher altitude, the computer shifts the supercharger into the higher speed for more boost. The computer also adjusts the RPM for each position of the lever. Another regulator that senses the pressure and temperature of the compressed air coming out of the supercharger adjusts the fuel mixture. The magneto timing is coordinated with the mixture regulator and starts retarded, then advances to 36 degrees and at higher power reduces to 22 degrees. The computer has its own oil pump, filter and regulator to supply oil at pressure to operate all the servos and power assists for the various regulators. The system operates much like our power assist steering in our cars. The regulators make a small low energy movement and the servo multiplies it to a large high-energy movement to operate the various controls of the engine."

 

[Tom Fey]

The Kommandogerat is a fabulously complex machine. Image from the National Archives and Records Administration via the Aircraft Engine Historical Society (www. enginehistory.org).

 

[MiTasol]

Damn that is complex. Are you sure it is not English?

 

[tomo pauk]

...
Kurt Tank was a qualified Electrical Engineer and his first foray into the nascent beginnings of electric 'fly-by-wire'for aircraft was the prototype FW191 in which heavy dependance was placed on the innovative use of electrically remote controlled and directed gun barbettes. It was a fiasco! The concept was a winner but the implementation was sabotaged by poor quality and low reliability of the electical components employed. It was never fixed and the idea shelved.
When it came to the FW190 he was mildly obsessed with wanting to reduce the pilot's workload in the midst of combat by the elimination of distractions arising from the need for 'control-juggling' to obtain optimal coordination of propeller-pitch and throttle/boost settings so that the pilot could keep both hands on the stick and concentrate on achieving the kill. So to this end he equipped the radial-engined FW190's with what was effectively an early form of electro-mechanical engine management system. Not sure whether this was carried over to the 'Dora' (can anyone confirm?).

The '1-lever engine control' was not a fruit of Kurt Tank's fertile mind, but it came from BMW, and has been in development by Bramo before BMW bought Bramo. Jumo 213 have had it's own control mechanism, obviously dveloped by Jumo.
Calling the flight controls of the Fw 191 as 'fly by wire' is over the top. I'm afraid that without computers to analyze input and calculate output hundreds and thousands time in second, there is no fly-by-wire.

 

[xylstra]

The '1-lever engine control' was not a fruit of Kurt Tank's fertile mind, but it came from BMW, and has been in development by Bramo before BMW bought Bramo. Jumo 213 have had it's own control mechanism, obviously dveloped by Jumo.
Calling the flight controls of the Fw 191 as 'fly by wire' is over the top. I'm afraid that without computers to analyze input and calculate output hundreds and thousands time in second, there is no fly-by-wire.

Hi Tomo,
Re-read my post: I did NOT say that the FW 191 had fly-by-wire controls. I referred specifically to the remote-controlled gun barbettes. The same electrical-control principles used to control these are little different than would apply if the barbette was substituted for say, an elevator. These very concepts ARE indeed the nascent beginnings of modern 'fly-by-wire' principles (look-up the meaning of 'nascent'). Computers are merely a further development and enhancement of 'fly-by-wire', i.e. 'intelligent fly-by-wire'. Back-up flight controls have been developed for modern supersonic jet fighters that employ intelligent fluidic controls that require no electronics whatsoever in order to make them invulnerable to nuclear EMP.

 

[xylstra]

There is a pretty good basic description of the Kommandogerãt for the BMW 801 in Classic Wings Issue 80 covering the FW190A-5 restoration for the Flying Heritage Collection. It's a start, but does not answer your larger question as to what extent this, or similar system, was used on the Ta152 or FW190D.

"The command computer (Kommandogerãt) was the most difficult part of the engine to both understand and to get to function. The computer takes input from the pilot to operate a power-lever that goes from 0 degrees to 90 degrees for the power application and back to -20 degrees to idle cut-off for stopping the engine. The computer operates the throttle valves with the boost regulator to give the engine a given boost for each degree of movement of the power lever. When the boost reaches one atmosphere of pressure the mixture is changed from lean to rich and the boost is reduced slightly. As the lever is advanced the boost continues to rise. If the engine is not able to achieve the boost needed due to higher altitude, the computer shifts the supercharger into the higher speed for more boost. The computer also adjusts the RPM for each position of the lever. Another regulator that senses the pressure and temperature of the compressed air coming out of the supercharger adjusts the fuel mixture. The magneto timing is coordinated with the mixture regulator and starts retarded, then advances to 36 degrees and at higher power reduces to 22 degrees. The computer has its own oil pump, filter and regulator to supply oil at pressure to operate all the servos and power assists for the various regulators. The system operates much like our power assist steering in our cars. The regulators make a small low energy movement and the servo multiplies it to a large high-energy movement to operate the various controls of the engine."

Thanks "Crimea_River". Read that many years ago but kept no copy. Great way to kick-off the response trail - hopefully will pull some more info out of the wood-work.
Thanks again.

 

[Joe Broady]

When it came to the FW190 he was mildly obsessed with wanting to reduce the pilot's workload in the midst of combat by the elimination of distractions arising from the need for 'control-juggling' to obtain optimal coordination of propeller-pitch and throttle/boost settings so that the pilot could keep both hands on the stick and concentrate on achieving the kill. So to this end he equipped the radial-engined FW190's with what was effectively an early form of electro-mechanical engine management system.

That triggered an old memory from a book I had not pulled off the shelf in years. Here's a German wartime test pilot's view of the device. I have made quite a few cuts in his engine management discussion to stay close to the thread topic. "At this point, I could also consider the question of to what extent foreign air forces pamper their crews and in particular their pilots. For example the B-24D Liberator which I flew in the first instance still had a manual propeller rev control instead of the more comfortable automatic device. Also, the engine fuel mixture still had to be set manually at 'rich' or 'weak' according to the load, and the oil and engine cylinder temperatures also had to be regulated by hand...

"The exhaust-driven turbo-superchargers on the American bombers and fighters also had to be controlled manually, depending on altitude and the air speed indicator... Nevertheless, although the control of the superchargers and the high-altitude engines by a second crew member may be regarded as reasonable in a bomber, to my mind the supervision of all these devices by a fighter pilot was too much to expect... Of course one must take into account that German engines were much more sensitive to correct temperatures, pressures, revolutions pre minute, and so on. In this connection I should like to mention the Kommando-Gerat (automatic engine control device) for the BMW 801 double-row radial engine. This control device was designed to adjust the boost pressure and engine revs according to the different performances required under throttled back, normal, combat, take-off and emergency power conditions by means of a single lever. Naturally such desirable engine control simplifications demanded great effort and more important, much valuable development time. And so it took literally years before the urgently needed BMW 801 - which had caused certain difficulties only at the outset with insufficiently cooled rear lower cylinders - was finally performing perfectly with its automatic control device. Generally speaking, I believe the Allies expected much more of their aircrews in this respect, while God knows we really had no money, time or effort to spare for such automatic devices.

"Meanwhile, we had heard that an almost undamaged Liberator had made a forced landing in a maize field near Ploesti during an attack on the oil wells. I don't remember exactly what was wrong with it; possibly it was also a matter of a damaged nose-wheel. The repairs had already been completed and the Liberator stood ready to fly on the same maize field. It was November 1943. At that time I had had the most experience with this type of aircraft and was prepared to fly the B-24 out of the field for the Rumanians."

That last paragraph was a "tease" that I will post some of his opinions on the Allied aircraft he tested. But this thread is not the place.

Hans-Werner Lerche, "Luftwaffe Test Pilot: Flying Captured Allied Aircraft of World War 2," 1977 (English translation 1980)

 

[eagledad]

Would this link be of use?
Characteristics of the BMW 801D2 automatic engine control as determined from bench tests
http://naca.central.cranfield.ac.uk/reports/1945/naca-wr-e-192.pdf

Eagledad

 

[xylstra]

Would this link be of use?
Characteristics of the BMW 801D2 automatic engine control as determined from bench tests
http://naca.central.cranfield.ac.uk/reports/1945/naca-wr-e-192.pdf

Eagledad

Bravo 'Eagledad'!! It doesn't get more thorough than that! Fantastic report and provides an excellent technical appraisal and descrition of the 'Kommando Gerat' - it'll keep me busy for hours................. Thanks again. Cheers, Xylstra.

 

[eagledad]

You are welcome.

Eagledad

 

[xylstra]

That triggered an old memory from a book I had not pulled off the shelf in years. Here's a German wartime test pilot's view of the device. I have made quite a few cuts in his engine management discussion to stay close to the thread topic. "At this point, I could also consider the question of to what extent foreign air forces pamper their crews and in particular their pilots. For example the B-24D Liberator which I flew in the first instance still had a manual propeller rev control instead of the more comfortable automatic device. Also, the engine fuel mixture still had to be set manually at 'rich' or 'weak' according to the load, and the oil and engine cylinder temperatures also had to be regulated by hand...

"The exhaust-driven turbo-superchargers on the American bombers and fighters also had to be controlled manually, depending on altitude and the air speed indicator... Nevertheless, although the control of the superchargers and the high-altitude engines by a second crew member may be regarded as reasonable in a bomber, to my mind the supervision of all these devices by a fighter pilot was too much to expect... Of course one must take into account that German engines were much more sensitive to correct temperatures, pressures, revolutions pre minute, and so on. In this connection I should like to mention the Kommando-Gerat (automatic engine control device) for the BMW 801 double-row radial engine. This control device was designed to adjust the boost pressure and engine revs according to the different performances required under throttled back, normal, combat, take-off and emergency power conditions by means of a single lever. Naturally such desirable engine control simplifications demanded great effort and more important, much valuable development time. And so it took literally years before the urgently needed BMW 801 - which had caused certain difficulties only at the outset with insufficiently cooled rear lower cylinders - was finally performing perfectly with its automatic control device. Generally speaking, I believe the Allies expected much more of their aircrews in this respect, while God knows we really had no money, time or effort to spare for such automatic devices.

"Meanwhile, we had heard that an almost undamaged Liberator had made a forced landing in a maize field near Ploesti during an attack on the oil wells. I don't remember exactly what was wrong with it; possibly it was also a matter of a damaged nose-wheel. The repairs had already been completed and the Liberator stood ready to fly on the same maize field. It was November 1943. At that time I had had the most experience with this type of aircraft and was prepared to fly the B-24 out of the field for the Rumanians."

That last paragraph was a "tease" that I will post some of his opinions on the Allied aircraft he tested. But this thread is not the place.

Hans-Werner Lerche, "Luftwaffe Test Pilot: Flying Captured Allied Aircraft of World War 2," 1977 (English translation 1980)

Hi Joe, thanks for that - always interesting to hear commentary from the 'other side' (adds balance). Eagledad's latest post was brilliant and has substantially wrapped up the BMW 'Kommando Gerat' system. Would like to get back to the flight stabilisation systems so am still hopeful that more on these will still emerge into the light. Cheers.

 

[xylstra]

Back to the primary query of my original post:
The flight-stabilisation component of the "under-the-skin" control avionics of the TA-152 derives from the LGW Siemens K-23 autopilot. Kurt Kracheel published some schematics and a description in his book, see:
.9783763761050: Flugführungssysteme. Blindfluginstrumente, Autopiloten, Flugsteuerungen - AbeBooks: 3763761055
Other than this there are some US intelligence reports as they captured a number of units, completed them and test flew them after the war. The K23 was a further development of the K22 with the LRM12 servo replaced by a simple electric servo controlled by a so called "ITA-regler". In the K23 all the main components (Dämfungskreisel, Normalkraftmesser, Mischgerät and ITA-regler) were all united into a single control unit. There is some information published on the k22 and K23 - start reading from about page 540:- http://cdn.rochesteravionicarchives.co.uk/img/catalog/ZZ_1395660705_DDBR0264+(O&A-1b).pdf
More pictures would be welcome............... anyone??

 

[Vintageaeroengines]

The quote on the operation of the kommando gerat was from me. I have gotten two of these to function now. I also have a translation of the operation of the unit with the curves for each part. If you want to send me your email I'll get a scan done and send it to you. Or I could just post it if that works.
I have restored to flying the DB 601, DB 605, BMW 801, Argus V8, Ash 82, Jumo 211, and working on a Jumo 213. That is all after the Merlin, Allison, Griffon V-12's. Also the R1820, R3350, R1830 Radials.
On the German engines I have translated over 30 manuals for those engines. The overview of the Jumo 211 has been printed with all the color pages also translated. If interested I will sell copyrighted copies for $20 plus postage. If there is a market for these manuals I can come up with some prices for copies. No digital copies as it is too easy to duplicate and I have a lot of time and money doing them.
MIKE NIXON

 

[Snautzer01]

The quote on the operation of the kommando gerat was from me. I have gotten two of these to function now. I also have a translation of the operation of the unit with the curves for each part. If you want to send me your email I'll get a scan done and send it to you. Or I could just post it if that works.
I have restored to flying the DB 601, DB 605, BMW 801, Argus V8, Ash 82, Jumo 211, and working on a Jumo 213. That is all after the Merlin, Allison, Griffon V-12's. Also the R1820, R3350, R1830 Radials.
On the German engines I have translated over 30 manuals for those engines. The overview of the Jumo 211 has been printed with all the color pages also translated. If interested I will sell copyrighted copies for $20 plus postage. If there is a market for these manuals I can come up with some prices for copies. No digital copies as it is too easy to duplicate and I have a lot of time and money doing them.
MIKE NIXON

Nice collection. Any pictures? I do love the big pistons.

Edit found your site. Take a look guys !

Vintage V12s - Company History

 

[Crimea_River]

Thanks Mike. You guys do great work.