Question about TA-152H MBG cutoff system

[rocaf2003]

Hi,There,I have a question of the MBG emergency handle of TA152H.By the end of the war, were all TA-152H fighters actually equipped with the MBG (Motorbediengerät) cut-off system? In other words, was that red MBG emergency handle actually functional on every TA-152H?

 

[Wurger]

The Motorbediengerät was an integral accessory of the Jumo 213 engine and couldn't be removed or replaced neither entirely nor partially. So the red Notzug handle being a part of the device was still there. However, the reality of whether pilots could freely use it in combat was a completely different matter.
Towards the end of the war, the quality of metal alloys used in engine construction deteriorated drastically due to a shortage of raw materials. Forcing the Jumo 213E engine to operate without the precise assistance of the MBG system created an immediate risk of engine damaging. Consequently, mechanics in units frequently installed wire seals on the Notzug control. Pilots were permitted to break this seal only in situations of extreme mortal danger. What is more , it seems that using of the dedicated MW 50 system was more safer. This injection cooled the combustion chambers, allowing engine power to be increased without risking structural failure. This rendered the use of the mechanical Notzug override completely pointless in a functional aircraft. IMHO E Engineman may add much more.

 

[rocaf2003]

 

[rocaf2003]

The Motorbediengerät was an integral accessory of the Jumo 213 engine and couldn't be removed or replaced neither entirely nor partially. So the red Notzug handle being a part of the device was still there. However, the reality of whether pilots could freely use it in combat was a completely different matter.
Towards the end of the war, the quality of metal alloys used in engine construction deteriorated drastically due to a shortage of raw materials. Forcing the Jumo 213E engine to operate without the precise assistance of the MBG system created an immediate risk of engine damaging. Consequently, mechanics in units frequently installed wire seals on the Notzug control. Pilots were permitted to break this seal only in situations of extreme mortal danger. What is more , it seems that using of the dedicated MW 50 system was more safer. This injection cooled the combustion chambers, allowing engine power to be increased without risking structural failure. This rendered the use of the mechanical Notzug override completely pointless in a functional aircraft. IMHO E Engineman may add much more.

Appreciate for your help,Sir!You mentioned that the mechanics installed wire seals on the "Notzug" control device, which is quite useful to me. It is said that once the "Notzug" handle is pulled out, the MBG will no longer control the engine; instead, a separate backup control system will take over. Given the supply shortages in Germany at the end of the war, was this backup control system actually installed on every single TA 152 H?

 

[Wurger]

Actually the Notzug option wasn't the cut-off switch. It was a kind of engine boost. Using of the handle allowed to get a temporary exceeding of standard boost pressure limits and the attainment of maximum power. Under the normal conditions, the MBG automatically managed the engine parameters with just a single throttle lever only. I'm not sure but it seems the MBG didn't have backup control system in the sense that there were two devices. There was the mechanical emergency override system called Notsteuerung allowing to mechanical override of the MBG automatic control system. It was used in the case the MBG failed or if there was an oil pressure failure or a jam in the control system's hydraulics. So the pilot could take control of the engine using direct linkages and pushrods. However it should be kept in mind that the manual control over the Jumo 213 engine wasn't the easy thing. But the lack of the Notsteuerung system would mean the immediate engine shotdown and the loss of the aircraft. For the reason the system was a standard and mandatory technical solution for the Jumo 213 engine.

 

[rocaf2003]

Actually the Notzug option wasn't the cut-off switch. It was a kind of engine boost. Using of the handle allowed to get a temporary exceeding of standard boost pressure limits and the attainment of maximum power. Under the normal conditions, the MBG automatically managed the engine parameters with just a single throttle lever only. I'm not sure but it seems the MBG didn't have backup control system in the sense that there were two devices. There was the mechanical emergency override system called Notsteuerung allowing to mechanical override of the MBG automatic control system. It was used in the case the MBG failed or if there was an oil pressure failure or a jam in the control system's hydraulics. So the pilot could take control of the engine using direct linkages and pushrods. However it should be kept in mind that the manual control over the Jumo 213 engine wasn't the easy thing. But the lack of the Notsteuerung system would mean the immediate engine shotdown and the loss of the aircraft. For the reason the system was a standard and mandatory technical solution for the Jumo 213 engine.

Ah, yes, please forgive my clumsy wording, which stems from a lack of expertise,Sir... What I mean by the so-called "second system" is actually the Notsteuerung system. I would like to ask whether, due to supply issues at the end of the war, Germany was able to install it on every single TA 152 H without exception.

 

[Wurger]

Ah, yes, please forgive my clumsy wording, which stems from a lack of expertise,Sir... What I mean by the so-called "second system" is actually the Notsteuerung system. I would like to ask whether, due to supply issues at the end of the war, Germany was able to install it on every single TA 152 H without exception.

It is all fine with your wording. So take it easy.

And to answer your question. Yes it was mounted on all Ta 152H with the Jumo 213 engine. Both the MBG and the mechanical Notsteuerung system had to be there because it was an emergency system. Without of the system it would be impossible to keep the control over the engine if the MBG failed, and in a result, loosing the plane over the flight. IMHO the lack of the Notsteuerung system would cause the Ta 152H being "disposable". Could you imagine what would happen when the MBG would fail while taking off? Or the MBG would be hit during a dogfight etc ...

 

[rocaf2003]

The Motorbediengerät was an integral accessory of the Jumo 213 engine and couldn't be removed or replaced neither entirely nor partially. So the red Notzug handle being a part of the device was still there. However, the reality of whether pilots could freely use it in combat was a completely different matter.
Towards the end of the war, the quality of metal alloys used in engine construction deteriorated drastically due to a shortage of raw materials. Forcing the Jumo 213E engine to operate without the precise assistance of the MBG system created an immediate risk of engine damaging. Consequently, mechanics in units frequently installed wire seals on the Notzug control. Pilots were permitted to break this seal only in situations of extreme mortal danger. What is more , it seems that using of the dedicated MW 50 system was more safer. This injection cooled the combustion chambers, allowing engine power to be increased without risking structural failure. This rendered the use of the mechanical Notzug override completely pointless in a functional aircraft. IMHO E Engineman may add much more.

Dear Sir,

You mentioned yesterday that "Towards the end of the war, the quality of metal alloys used in engine construction deteriorated drastically due to a shortage of raw materials. Forcing the Jumo 213E engine to operate without the precise assistance of the MBG system created an immediate risk of engine damaging. Consequently, mechanics in units frequently installed wire seals on the Notzug control. Pilots were permitted to break this seal only in situations of extreme mortal danger." However, I have since come across a statement in an operating manual suggesting that during cold-start procedures at low temperatures, pulling out the Notzug lever actually facilitates starting. This leaves me puzzled: since the device appears to be secured by a wire seal in actual practice and is not to be used lightly, would the seal be broken and the Notzug lever pulled out as recommended for cold-starting at low temperatures? I would be most honoured if I could once again receive your expert and patient assistance.

 

[Wurger]

In fact, using the Notzug could make a cold engine start easier. To the best of my knowledge, starting the engine with the Notzug lever pulled out was prohibited. The mechanical linkage had to be coupled with the MBG hydraulic automatic unit to ensure the engine did not receive an excessively rich or lean mixture and to prevent a sudden surge in RPM the moment the cylinders fired. For a proper start, the pilot would set the main throttle lever to a specific notch or position marked Anlassen (Start/Idle), the MBG unit would then precisely meter the fuel injected into the cold engine. Certainly the the maintenance teams could have their own tips and tricks but these might not follow the official procedures. Secondly if there was was the wire seals installed on the Notzug lever they just didn't use it rather. What is more, using the metal alloys of the worse quality and the breaking of blockade didn't mean the engine had to be damaged. It seems that the wire seal was more the warning than the blockade. And again it should be highlight that the manual control over the engine without the MBG wasn't the easiest thing and required some of experience at using the proper settings manually. Additionally the Ta 152H is a kite introduced into service in January 1945, So its "life" as a fighter machine wasn't too long. Contrary to this the Fw 190D-9 entered the service in summer 1944. Using the same system for the Jumo engine had them made of the better quality materials than the Ta 152H.

 

[rocaf2003]

In fact, using the Notzug could make a cold engine start easier. To the best of my knowledge, starting the engine with the Notzug lever pulled out was prohibited. The mechanical linkage had to be coupled with the MBG hydraulic automatic unit to ensure the engine did not receive an excessively rich or lean mixture and to prevent a sudden surge in RPM the moment the cylinders fired. For a proper start, the pilot would set the main throttle lever to a specific notch or position marked Anlassen (Start/Idle), the MBG unit would then precisely meter the fuel injected into the cold engine. Certainly the the maintenance teams could have their own tips and tricks but these might not follow the official procedures. Secondly if there was was the wire seals installed on the Notzug lever they just didn't use it rather. What is more, using the metal alloys of the worse quality and the breaking of blockade didn't mean the engine had to be damaged. It seems that the wire seal was more the warning than the blockade. And again it should be highlight that the manual control over the engine without the MBG wasn't the easiest thing and required some of experience at using the proper settings manually. Additionally the Ta 152H is a kite introduced into service in January 1945, So its "life" as a fighter machine wasn't too long. Contrary to this the Fw 190D-9 entered the service in summer 1944. Using the same system for the Jumo engine had them made of the better quality materials than the Ta 152H.

Understood,Sir. That is to say, for an intact aircraft, there is often a wire seal on the Notzug handle. When the aircraft is intact and there are no issues, people do not break it. Only if the MBG fails and the aircraft is no longer intact would they break the wire seal to try to get the aircraft to return or make an emergency landing (at which point the aircraft is no longer intact). May I ask if my understanding is correct,Sir?

 

[Wurger]

Understood,Sir. That is to say, for an intact aircraft, there is often a wire seal on the Notzug handle. When the aircraft is intact and there are no issues, people do not break it. Only if the MBG fails and the aircraft is no longer intact would they break the wire seal to try to get the aircraft to return or make an emergency landing (at which point the aircraft is no longer intact). May I ask if my understanding is correct,Sir?

Yes you understood it correct. But a note though. The wire seal on the Notzug lever could be or not. It seems that the installation wasn't the fabric requrement. Just the maintence team could attach it there or not. No matter if the plane was airworthy. The pilot was the one who should remember when the Notzug handle should be used.

 

[rocaf2003]

Yes you understood it correct. But a note though. The wire seal on the Notzug lever could be or not. It seems that the installation wasn't the fabric requrement. Just the maintence team could attach it there or not. No matter if the plane was airworthy. The pilot was the one who should remember when the Notzug handle should be used.

Thank you for your professional and patient assistance, sir. With this, I can confirm that the Notzug handles in the cockpits of all intact aircraft parked on the ground are not in the pulled‑out position. That is sufficient for me.

All my lengthy questions essentially boil down to one point: the Notzug handle will not be pulled out in the cockpit of an intact aircraft. Your help has provided crucial evidence: in some airframes these handles are even secured with wire, let alone being pulled out on an intact aircraft.

 

[Wurger]

Glad I could help. And you are rght. The Notzug/Notsterung lever couldn't be in the pulled-out position. If it would be it meant that the Motorbediengerät was disconnected.