The German proximity fuse.

[Eunometic]

The German proximity fuse.

The development of the US proximity fuse by the US in WW Two is
regarded as a unique allied triumph.

Little known however is that the Germans independently developed and
successfully test fired almost 1000 rounds of a similar proximity fuse
near the wars end that if introduced into service would have had a
dramatic effect. The allies estimated that the availability of the
proximity fuse would force them to abandon use of the B-24 Liberator
due to its lower flying altitude compared to the B-17.

The Allied Proximity fuse was used on both Anti-Aircraft Artillery and
anti-personnel howitzers where they were set to explode approximately
50 feet above the ground. At that height they would produce a lethal
zone over a terrifyingly wide area. When used against aircraft it
seemed to increase effectiveness of a round by 3-7 or more.

The proximity fuse was fielded as an AA weapon from ships in the
Pacific from June 1943 where it was reasoned that secrecy could not be
compromised as dud rounds would fall into the sea. (I have no
knowledge of its use against the Japanese Troops on islands). It on
one occasion apparently helped shoot down 90 of 120 attacking Japanese
planes.

It was first supplied to Britain to help overcome the V1 cruise missile
fired at London where it in combination with radar and computer
directed guns reduced the mean number of rounds expended to destroy a
V1 from 4000 to 180.

Finally there are records of it used against German troops during the
Ardennes Offensive (Battle of Bulge). It was reasoned that the
Germans would not be able to reconstruct the fuses in time to make use
of them. In fact the 'folklore' on the Internet is that they
captured some 20,000 but did not recognize them and also that they
recovered duds and reasoned that they were triggered by the Earth's
magnetic Field. (Note the magnet field theory probably came from the
troops themselves before being analysed by more technical branches of
the German forces)

The allied fuse workings.

Technically the Allied fuse was not radar: it did not send out a pulse
and listen for an echo. It had 4 tubes. One tube was part of the
oscillator. When a 'target' that was about a =BD wavelength in size
came within a few wavelengths it would load the amplifier and the anode
current would increase. Two additional amplifiers would detect this
change and then triggered the 4th valve (a gas filled thyraton) to set
of the detonator. Contrary to other reports it apparently did not
trigger on Doppler shift either or on frequency change. There were
many shock hardening techniques including planar electrodes and packing
the components in wax and oil to equalize the stresses.

The German fuse workings.

The fuse was based on electrostatic principles.

The circuitry of the German fuse is not precisely known to me as I do
not have the schematics however the details are in allied files refred
to I do not have a circuit layout drawing. It is known that the nose
of the shell was electrically insulated and isolated from the rest of
the shell. It was built by the company Rheinmetall. The program was
halted in 1940 then restarted in early 1944 and then terminated again
due to being over run by the allies at the point that it was ready for
production.

Initial fuse testing demonstrated a sensitivity of 1-2 meters and a
reliability of 80% when fired against a metal cable target. A circuit
adjustment yielded an increase to 3-4 meters and a reliability of close
to 95%.

Further work showed a 10-15 meter sensitivity. This was with 88mm
canon shells. The shell to all intents and purposes ready for
production.

References are "Truth About the Wunderwaffen" by Igor Witowski who
cites "Proximity Fuse Development - Rheinmettal Borsig A.G.
Mullhausen. CIOS report ITEM nos 3 file nos XXVI -1 (1945)

Capacitance based fuses became highly developed after the second world
war due to their high resistance against jamming techniques.

It is unlikely that the shell could have been easily degraded by
jamming or chaff. (unlike the Allied shell).

I can speculate as to several ways that this might work. It is
referred to as a "influenz zunder" based in electrostatic
principles.

Method 1: Bridge Cicuit. The shells external capacitance is made
part of a bridge circuite with an internal reference capacitor in the
other arm. Any disturbance caused by an large object such as an
aircraft would cause a current to flow across the bridge that would be
amplified.

Method 2: QT or charge transfer methods. A high speed vibrating
contact charges the shell and then discharges it into a known
capacitance which is then measured.

Method 3: making the shell body part of a resonant circuit and
detecting frequency changes.

I can not find the precise reason for the abandonment of the work in
1940 however it probably relates to the 'fuhrer befehle' or fuhrer
directive that with few exceptions all work that could not be put into
production within 6 months were to be terminated to increase resources
for those that could (in order to support operation Barborosa). It
was at this time that the Germans also abandoned their magnetron and
microwave development teams and programs. Many programs suffered
severely due to this; something that was to have far reaching
consequences for the German war effort.

What would have happened if the proximity fuse was not abandoned in
1940 but development continued such that it entered service in 1943?

[Robert Kolker]

Eunometic wrote:

> consequences for the German war effort.
>
> What would have happened if the proximity fuse was not abandoned in
> 1940 but development continued such that it entered service in 1943?

The Allies would have need bombers to fly at higher altitudes than the
B-17 mormally did and would have required some kind of "smart bomb"
technology. Maybe bombs guided by narrow beam radio signals. Lasers
would not have been ready on time.

Bob Kolker

>

[Eunometic]

As far as I can see the only aircraft the allies would have that could
survive above German airspace and much of Europe would be the Mosquito.
The B29 would eventually come along but it wouldn't be available in
quantity till late 1944. Becuase of the high casualities the American
would have to cut their B17 based bombing rates in half and opperate at
higher altitudes. The lack of B24s means no Ploesti raid.

Presumably Wellingtons could be fitted with two stage supercharged
merlins and a presurised fueselage.

Basically I think you are right. Bombing altitude would increase from
the usuall 20,000-25,000 to 35,000-40,000 to avoid casualites. Medium
altitdue aircraft such as the B26 Marauder and B25 become outmoded.
German industry would reamin more productive and strong. Bomb gudience
becomes essential.

[Keith W]

"Eunometic" > wrote in message
oups.com...
> As far as I can see the only aircraft the allies would have that could
> survive above German airspace and much of Europe would be the Mosquito.
> The B29 would eventually come along but it wouldn't be available in
> quantity till late 1944. Becuase of the high casualities the American
> would have to cut their B17 based bombing rates in half and opperate at
> higher altitudes. The lack of B24s means no Ploesti raid.
>

Only if you assume the proximity fuse is a 100% effective super weapon

> Presumably Wellingtons could be fitted with two stage supercharged
> merlins and a presurised fueselage.
>

Presumably NOT, a pressurised fuselage is a non trivial modn.

> Basically I think you are right. Bombing altitude would increase from
> the usuall 20,000-25,000 to 35,000-40,000 to avoid casualites. Medium
> altitdue aircraft such as the B26 Marauder and B25 become outmoded.
> German industry would reamin more productive and strong. Bomb gudience
> becomes essential.
>

Reality intrudes here, you still need to aim the gun someplace
close to where the bomber is for the fuse to work, losses
would undoubtedly rise but the presence of proximity fuses
post war didnt halt bombing and the simple reality is Germany
would have to produce em by the million and lacked the
industrial capacity to do so.

Keith




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[Andrew Robert Breen]

In article >,
Keith W > wrote:
>
>"Eunometic" > wrote in message
>Only if you assume the proximity fuse is a 100% effective super weapon
>
>> Presumably Wellingtons could be fitted with two stage supercharged
>> merlins and a presurised fueselage.
>
>Presumably NOT, a pressurised fuselage is a non trivial modn.

Actually, the flying breadbasket /was/ built in a high-altitude, pressurised
version (in fact much of the UK development of pressurisation was done
using the Wellington). Obviously the fuselage itself wasn't pressurised
(fabric not being much good for that) but a pressurised crew area
was developed and flown. The two types were the Mk.V and VI, both
fitted with pressurised cockpit and high-altitude versions of the Bristol
Hercules.

http://www.fortunecity.com/tattooine/farmer/120/welly.html

Vickers were leaders (in .uk) in working on stratospheric
aircraft - the Barnes Wallis proposals for the Victory
Bomber was one strand, the original design for the Windsor
another (hence the guns in remote-control barbettes in
the tails of the engine nacelles) and the 75- and 100-
ton giants of the 1944 programme a third. None ever
reached squadron service, but all (except the Victory)
were far more than just paper aeroplanes.

--
Andy Breen ~ Interplanetary Scintillation Research Group
http://users.aber.ac.uk/azb/
"Who dies with the most toys wins" (Gary Barnes)

[Rob Arndt]

Germany had a wide range of proximity fuses under development and/or
testing in the last year of the war:

Code Names & Descriptions:

BAD, Acoustic, under Graf Zeppelin Institute

ELKU (Elektro-Akoustic), and applied to PAPLITZ

FUCHS, Radio by AEG Berlin, intended for Hs-117, Hs-298, and other
missiles

ISEGRIMM, Electromagnetic by Orlich Institute of Danzig.

KAKADU, Radio by Donaulandische GmbH of Vienna. 3,000 were produced for
the Hs-293- used Doppler effect.

KRANICH, Acoustic by Ruhrstahl AG of Brackwerde. Highly rated German
proximity fuse.

KUGELBLITZ, Radio by Patent Verwertungs Gesellschaft of Salzvurg.
Developed for the Rhinetocktor missile. Used Doppler-shift effect.

KUHGLOCKE, Electrostatic by Rhinemetall-Borsig. Intended for missiles.
Prototypes only.

KUHGLOCKEN, Smaller version designed for AA shells.

LOTTE, Infrared for an unspecified missile- abandoned.

MARABU, Radio by Siemens-Halske under sub-contract of Rheinmetall AG.
Designed for the Hs-117, Hs-298, Rheintocktor and Wasserfall missiles.
Firing trials.

MARDER, Radio by Orlich Institute of Danzig.

MEISE, Acoustic by Neumann & Borm of Berlin.

PAPLITZ, Infrared by Elektro Akoustic Institute at Namslau then at
Kiel. A.K.A. "ELKU". Developed for Hs-117 and Wasserfall. Test firings.

PINSCHER, Radio by Orlich Institute of Danzig. Five prototypes.

PISTOLE, Photo-Electric, this project was incorporated into
WASSERMAUS.

ROULETTE, Infrared by Brickmann of Gera.

STIMMGABEL, Acoustic by the Graf Zeppelin Institute. Developed for
parachute-retarded bomb dropped over Allied bomber streams. Tested.

TRICHTER, Radio by Blaupunkt. Field tested.

WASSERMAUS, Photo-Electric, developed for the Wasserfall missile.

WIESEL, Radio by Orlich Institute of Danzig.

ZUNDER-19, Developed for 250kg bomb by Rheinmetall-Borsig. Started
1937. Cancelled 1943. Work continued into 1944.

Rob

[Rob Arndt]

The rare Windsor bomber:
http://www.jaapteeuwen.com/ww2aircraft/pictures/gallery/vickers%20windsor.jpg

Rob

[[email protected]]

Arndt the Clueless wrote:
> Germany had a wide range of proximity fuses under development and/or
> testing in the last year of the war:

SNIP

Just gazing at this list makes you realize the TOTAL madness of the
German R&D effort during WWII

While the US and Britain combined efforts in Project V of Section T of
the NDRC (hence "VT" fuze)

[[email protected]]

Eunometic wrote:

> References are "Truth About the Wunderwaffen" by Igor Witowski who
> cites "Proximity Fuse Development - Rheinmettal Borsig A.G.
> Mullhausen. CIOS report ITEM nos 3 file nos XXVI -1 (1945)
>
> Capacitance based fuses became highly developed after the second
world
> war due to their high resistance against jamming techniques.
>
> It is unlikely that the shell could have been easily degraded by
> jamming or chaff. (unlike the Allied shell).
>
>
> What would have happened if the proximity fuse was not abandoned in
> 1940 but development continued such that it entered service in 1943?

SNIP

The Allies would have developed specific ways of jamming the fuse -
nothing is unvulnerable

[GRAHAM WALKER]

British Scientific Developments - A British scientific mission carries to
the United States details of many important developments. Amongst these is
the recently invented cavity magnetron, vital for short wavelength radar and
the eventual defeat of conventional U-boats. Also for the close-proximity
fuse which becomes so important in the 1945 battles with Japanese Kamikaze
aircraft


"Eunometic" > wrote in message
oups.com...
The German proximity fuse.

The development of the US proximity fuse by the US in WW Two is
regarded as a unique allied triumph.

Little known however is that the Germans independently developed and
successfully test fired almost 1000 rounds of a similar proximity fuse
near the wars end that if introduced into service would have had a
dramatic effect. The allies estimated that the availability of the
proximity fuse would force them to abandon use of the B-24 Liberator
due to its lower flying altitude compared to the B-17.

The Allied Proximity fuse was used on both Anti-Aircraft Artillery and
anti-personnel howitzers where they were set to explode approximately
50 feet above the ground. At that height they would produce a lethal
zone over a terrifyingly wide area. When used against aircraft it
seemed to increase effectiveness of a round by 3-7 or more.

The proximity fuse was fielded as an AA weapon from ships in the
Pacific from June 1943 where it was reasoned that secrecy could not be
compromised as dud rounds would fall into the sea. (I have no
knowledge of its use against the Japanese Troops on islands). It on
one occasion apparently helped shoot down 90 of 120 attacking Japanese
planes.

It was first supplied to Britain to help overcome the V1 cruise missile
fired at London where it in combination with radar and computer
directed guns reduced the mean number of rounds expended to destroy a
V1 from 4000 to 180.

Finally there are records of it used against German troops during the
Ardennes Offensive (Battle of Bulge). It was reasoned that the
Germans would not be able to reconstruct the fuses in time to make use
of them. In fact the 'folklore' on the Internet is that they
captured some 20,000 but did not recognize them and also that they
recovered duds and reasoned that they were triggered by the Earth's
magnetic Field. (Note the magnet field theory probably came from the
troops themselves before being analysed by more technical branches of
the German forces)

The allied fuse workings.

Technically the Allied fuse was not radar: it did not send out a pulse
and listen for an echo. It had 4 tubes. One tube was part of the
oscillator. When a 'target' that was about a ½ wavelength in size
came within a few wavelengths it would load the amplifier and the anode
current would increase. Two additional amplifiers would detect this
change and then triggered the 4th valve (a gas filled thyraton) to set
of the detonator. Contrary to other reports it apparently did not
trigger on Doppler shift either or on frequency change. There were
many shock hardening techniques including planar electrodes and packing
the components in wax and oil to equalize the stresses.

The German fuse workings.

The fuse was based on electrostatic principles.

The circuitry of the German fuse is not precisely known to me as I do
not have the schematics however the details are in allied files refred
to I do not have a circuit layout drawing. It is known that the nose
of the shell was electrically insulated and isolated from the rest of
the shell. It was built by the company Rheinmetall. The program was
halted in 1940 then restarted in early 1944 and then terminated again
due to being over run by the allies at the point that it was ready for
production.

Initial fuse testing demonstrated a sensitivity of 1-2 meters and a
reliability of 80% when fired against a metal cable target. A circuit
adjustment yielded an increase to 3-4 meters and a reliability of close
to 95%.

Further work showed a 10-15 meter sensitivity. This was with 88mm
canon shells. The shell to all intents and purposes ready for
production.

References are "Truth About the Wunderwaffen" by Igor Witowski who
cites "Proximity Fuse Development - Rheinmettal Borsig A.G.
Mullhausen. CIOS report ITEM nos 3 file nos XXVI -1 (1945)

Capacitance based fuses became highly developed after the second world
war due to their high resistance against jamming techniques.

It is unlikely that the shell could have been easily degraded by
jamming or chaff. (unlike the Allied shell).

I can speculate as to several ways that this might work. It is
referred to as a "influenz zunder" based in electrostatic
principles.

Method 1: Bridge Cicuit. The shells external capacitance is made
part of a bridge circuite with an internal reference capacitor in the
other arm. Any disturbance caused by an large object such as an
aircraft would cause a current to flow across the bridge that would be
amplified.

Method 2: QT or charge transfer methods. A high speed vibrating
contact charges the shell and then discharges it into a known
capacitance which is then measured.

Method 3: making the shell body part of a resonant circuit and
detecting frequency changes.

I can not find the precise reason for the abandonment of the work in
1940 however it probably relates to the 'fuhrer befehle' or fuhrer
directive that with few exceptions all work that could not be put into
production within 6 months were to be terminated to increase resources
for those that could (in order to support operation Barborosa). It
was at this time that the Germans also abandoned their magnetron and
microwave development teams and programs. Many programs suffered
severely due to this; something that was to have far reaching
consequences for the German war effort.

What would have happened if the proximity fuse was not abandoned in
1940 but development continued such that it entered service in 1943?

[Keith W]

"Rob Arndt" > wrote in message
oups.com...
> Germany had a wide range of proximity fuses under development and/or
> testing in the last year of the war:
>
> Code Names & Descriptions:
>
> BAD, Acoustic, under Graf Zeppelin Institute
>
> ELKU (Elektro-Akoustic), and applied to PAPLITZ
>
> FUCHS, Radio by AEG Berlin, intended for Hs-117, Hs-298, and other
> missiles
>
> ISEGRIMM, Electromagnetic by Orlich Institute of Danzig.
>
> KAKADU, Radio by Donaulandische GmbH of Vienna. 3,000 were produced for
> the Hs-293- used Doppler effect.
>
> KRANICH, Acoustic by Ruhrstahl AG of Brackwerde. Highly rated German
> proximity fuse.
>
> KUGELBLITZ, Radio by Patent Verwertungs Gesellschaft of Salzvurg.
> Developed for the Rhinetocktor missile. Used Doppler-shift effect.
>
> KUHGLOCKE, Electrostatic by Rhinemetall-Borsig. Intended for missiles.
> Prototypes only.
>
> KUHGLOCKEN, Smaller version designed for AA shells.
>
> LOTTE, Infrared for an unspecified missile- abandoned.
>
> MARABU, Radio by Siemens-Halske under sub-contract of Rheinmetall AG.
> Designed for the Hs-117, Hs-298, Rheintocktor and Wasserfall missiles.
> Firing trials.
>
> MARDER, Radio by Orlich Institute of Danzig.
>
> MEISE, Acoustic by Neumann & Borm of Berlin.
>
> PAPLITZ, Infrared by Elektro Akoustic Institute at Namslau then at
> Kiel. A.K.A. "ELKU". Developed for Hs-117 and Wasserfall. Test firings.
>
> PINSCHER, Radio by Orlich Institute of Danzig. Five prototypes.
>
> PISTOLE, Photo-Electric, this project was incorporated into
> WASSERMAUS.
>
> ROULETTE, Infrared by Brickmann of Gera.
>
> STIMMGABEL, Acoustic by the Graf Zeppelin Institute. Developed for
> parachute-retarded bomb dropped over Allied bomber streams. Tested.
>
> TRICHTER, Radio by Blaupunkt. Field tested.
>
> WASSERMAUS, Photo-Electric, developed for the Wasserfall missile.
>
> WIESEL, Radio by Orlich Institute of Danzig.
>
> ZUNDER-19, Developed for 250kg bomb by Rheinmetall-Borsig. Started
> 1937. Cancelled 1943. Work continued into 1944.
>
> Rob
>

The very length of that list goes a long way to explaining
why Germany never got a working fuze into production.

The Western allies thought 2 development projects (one
British , the other American) would have been extravagantly
wasteful.

Keith

[Keith W]

"Rob Arndt" > wrote in message
ups.com...
> The rare Windsor bomber:
> http://www.jaapteeuwen.com/ww2aircraft/pictures/gallery/vickers%20windsor.jpg
>
> Rob
>

Was not a Wellington

Keith

[Joe Delphi]

"GRAHAM WALKER" > wrote in message
...
> British Scientific Developments - A British scientific mission carries to
> the United States details of many important developments. Amongst these is
> the recently invented cavity magnetron, vital for short wavelength radar
and
> the eventual defeat of conventional U-boats. Also for the close-proximity
> fuse which becomes so important in the 1945 battles with Japanese Kamikaze
> aircraft
>

I seem to recall hearing that an RAF officer developed a laboratory
prototype jet engine in the 1937-38 timeframe. I wonder why that
information was not mentioned in the British scientific mission to the
United States. The U.S. had more engineering and manfacturing resources
free at that time than did Britain. I know that the U.S. developed its own
jet engine that reached the flight test stage towards the end of WW2, but it
seems like if this prototype jet engine had been made available to U.S.
engineers and manufacturers, it could have allowed the U.S. to develop a
working jet engine much faster and maybe even introduce it into operational
service before the end of WW2.

J

[Rob Arndt]

Keith,

Andrew Breen brought up the Windsor and I provided a photo of it. Yes,
it is not a Wellington... but they are both of geodetic construction
and I was posting for those that might not have ever seen a Windsor or
knew it existed.
Maybe you should read the posts before saying something since Barnes
Wallis is connected here.

Rob

[Keith W]

"Joe Delphi" > wrote in message
.net...
> "GRAHAM WALKER" > wrote in message
> ...
>> British Scientific Developments - A British scientific mission carries to
>> the United States details of many important developments. Amongst these
>> is
>> the recently invented cavity magnetron, vital for short wavelength radar
> and
>> the eventual defeat of conventional U-boats. Also for the close-proximity
>> fuse which becomes so important in the 1945 battles with Japanese
>> Kamikaze
>> aircraft
>>
>
> I seem to recall hearing that an RAF officer developed a laboratory
> prototype jet engine in the 1937-38 timeframe. I wonder why that
> information was not mentioned in the British scientific mission to the
> United States. The U.S. had more engineering and manfacturing resources
> free at that time than did Britain.

It was

> I know that the U.S. developed its own
> jet engine that reached the flight test stage towards the end of WW2, but
> it
> seems like if this prototype jet engine had been made available to U.S.
> engineers and manufacturers, it could have allowed the U.S. to develop a
> working jet engine much faster and maybe even introduce it into
> operational
> service before the end of WW2.
>

Like the GE I-A engine , based on Whittle's designs that first ran on April
18, 1942
perhaps.

Keith

[Keith W]

"Rob Arndt" > wrote in message
ups.com...
> Keith,
>
> Andrew Breen brought up the Windsor and I provided a photo of it. Yes,
> it is not a Wellington... but they are both of geodetic construction
> and I was posting for those that might not have ever seen a Windsor or
> knew it existed.

Then you should have made that clear

> Maybe you should read the posts before saying something since Barnes
> Wallis is connected here.
>


Maybe you should do more than posting links to pictures

Keith

[Eunometic]

wrote:
> Eunometic wrote:
>
> > References are "Truth About the Wunderwaffen" by Igor Witowski who
> > cites "Proximity Fuse Development - Rheinmettal Borsig A.G.
> > Mullhausen. CIOS report ITEM nos 3 file nos XXVI -1 (1945)
> >
> > Capacitance based fuses became highly developed after the second
> world
> > war due to their high resistance against jamming techniques.
> >
> > It is unlikely that the shell could have been easily degraded by
> > jamming or chaff. (unlike the Allied shell).
> >
> >
> > What would have happened if the proximity fuse was not abandoned in
> > 1940 but development continued such that it entered service in
1943?
>
> SNIP
>
> The Allies would have developed specific ways of jamming the fuse -
> nothing is unvulnerable.

Some things are so difficult they are not realistically viable. Laser,
Photoelectric and Capacitative proximity fuses are simply very
difficult to jam or deceive. The Allied VT was based on RF (radio
frequency) methods) and it was shown to be vulnerable to predetonation
becuase it was easy to get RF energy into the detection circuity using
a mechnically swept oscilator. Capacitence based fuses use much lower
frequencies that are effectively DC. They more or less rely on
detecting changes in 'fields'. It is very hard to radiate interfering
energy into the circuity while it is easier to introduce changes to
avoid deception. Getting sufficient range is more of a struggle with
these fuses.

Fuze jamming doesn't seem to be regarded as a very viable method today
excepting the most primitive of munitions.

[Geoffrey Sinclair]

>The German proximity fuse.
>
>The development of the US proximity fuse by the US in WW Two is
>regarded as a unique allied triumph.
>
>Little known however is that the Germans independently developed and
>successfully test fired almost 1000 rounds of a similar proximity fuse
>near the wars end that if introduced into service would have had a
>dramatic effect. The allies estimated that the availability of the
>proximity fuse would force them to abandon use of the B-24 Liberator
>due to its lower flying altitude compared to the B-17.

The B-24 made up around 1/3 of the 8th Air Force and 2/3 of the
15th Air force, all up just under half the USAAF bombers. The main
deployment of B-24s to Europe was in 1944.

It was a USAAF estimate, flak losses would triple, bombing heights
would have to increase and the B-24 not used against well defended
targets. When the German flak concentration around the main synthetic
oil plants became so great the USAAF started to use cloudy days,
relying on radar aids, assuming the loss of accuracy for the gunners
was greater than that of the bombers.

Not flak losses were never above the critical loss rates, but would
have approached it if they were tripled. It took fighters to really cut
up a bomber formation.

>The Allied Proximity fuse was used on both Anti-Aircraft Artillery and
>anti-personnel howitzers where they were set to explode approximately
>50 feet above the ground. At that height they would produce a lethal
>zone over a terrifyingly wide area. When used against aircraft it
>seemed to increase effectiveness of a round by 3-7 or more.

So the 16,000 88mm shells per shoot down fired would be reduced to
2,300 to 5,300. The Germans did better early in the war in terms of
shells per aircraft but this was the sort of price paid for using effectively
reserve manpower in the flak units alongside less accurate fire control
systems.

The proximity fuse effects can be replicated by wires on the bomb
noses and by having trees in the combat area. If the shell or bomb
hits the tree the results are an airburst. You can also have time
fuses for shells. Of course none as accurate as a proximity fuse
for bursts at the optimum height.

>The proximity fuse was fielded as an AA weapon from ships in the
>Pacific from June 1943 where it was reasoned that secrecy could not be
>compromised as dud rounds would fall into the sea. (I have no
>knowledge of its use against the Japanese Troops on islands). It on
>one occasion apparently helped shoot down 90 of 120 attacking Japanese
>planes.

As has been stated the last time this information was posted,

The claim ignores the USS Helena firing proximity fused shells off
Guadalcanal in January 1943. Fuse production was 500 per day
in October 1942. Note by the end of 1944 the delivery rate was
40,000 per day, or in other words just over half an hour to equal the
entire claimed German production.

The other point was to design a shell to take the fuse, the allies
started with the USN 5 inch gun.

It should be noted the claimed major shoot down was the USN
ships reporting what they thought they had shot down.

In the fights with Kamikazes the USN ships reported they needed
to fire 100% VT (proximity) fuses, since there was normally no time
to set and use time fuses.

>It was first supplied to Britain to help overcome the V1 cruise missile
>fired at London where it in combination with radar and computer
>directed guns reduced the mean number of rounds expended to destroy a
>V1 from 4000 to 180.

The note being it was a combination of better fire control and fuses.

>Finally there are records of it used against German troops during the
>Ardennes Offensive (Battle of Bulge). It was reasoned that the
>Germans would not be able to reconstruct the fuses in time to make use
>of them. In fact the 'folklore' on the Internet is that they
>captured some 20,000 but did not recognize them and also that they
>recovered duds and reasoned that they were triggered by the Earth's
>magnetic Field. (Note the magnet field theory probably came from the
>troops themselves before being analysed by more technical branches of
>the German forces)

Ah so the folk lore is they captured a US ammunition dump with
the fused shells and then inventoried the catch, as opposed to
destroying it?

By the way the troops would not be checking the fusing of any
dud rounds, but removing the shells to a safer place. The
experts would be looking at things like fuses.

>The allied fuse workings.
>
>Technically the Allied fuse was not radar: it did not send out a pulse
>and listen for an echo. It had 4 tubes. One tube was part of the
>oscillator. When a 'target' that was about a ½ wavelength in size
>came within a few wavelengths it would load the amplifier and the anode
>current would increase. Two additional amplifiers would detect this
>change and then triggered the 4th valve (a gas filled thyraton) to set
>of the detonator. Contrary to other reports it apparently did not
>trigger on Doppler shift either or on frequency change. There were
>many shock hardening techniques including planar electrodes and packing
>the components in wax and oil to equalize the stresses.

Given we are talking about wavelengths in the order of centimetres
the axis mist have been flying very small aircraft if they were around
a half wavelength in size.

Try this for an explanation,

"One method that was experimented with used radio waves transmitted
from the ground. These radio waves would be reflected by the target and
received by the fuze. Once the radio waves were at a sufficient level, the
fuze would activate causing the shell to explode.

Another method that was more logical and became the accepted means,
was to develop a fuze which was capable of obtaining its own intelligence
and of using it to ignite the shell. When assembled this fuze consisted of
four major parts: A miniature radio transceiver, complete with amplifier
and capacitor; a battery; an explosive train; and the necessary safety
devices. The theory was that the fuze transmitter, alone, would not
produce sufficient signal intensity, to trigger a thyratron tube switch.
However, as the projectile approached a target the radio waves reflected
by the target would gradually increase and come more and more into phase
with the fuze-generated signal. Once the signal level was high enough, the
fuze would know that the shell could do a maximum amount of damage,
and the thyratron tube switch would be triggered releasing the energy in a
charged capacitor and thus igniting the shell."

>The German fuse workings.
>
>The fuse was based on electrostatic principles.

At least this hopefully stops the previous claims the Germans
handed the design to the British who then used it.

>The circuitry of the German fuse is not precisely known to me as I do
>not have the schematics however the details are in allied files refred
>to I do not have a circuit layout drawing. It is known that the nose
>of the shell was electrically insulated and isolated from the rest of
>the shell. It was built by the company Rheinmetall. The program was
>halted in 1940 then restarted in early 1944 and then terminated again
>due to being over run by the allies at the point that it was ready for
>production.

The above assumes the program was producing fused shells in 1940
as opposed to heading towards the idea. After all if the restart was
in early 1944 and the production facilities were over run something like
15 months later just as production was about to start it shows how long
things actually took. How long the Germans really were from production.

The US started work on the fuse in July 1940 and later developed
optical and magnetic proximity fuses for mines and 4.5 inch rockets.

>Initial fuse testing demonstrated a sensitivity of 1-2 meters and a
>reliability of 80% when fired against a metal cable target. A circuit
>adjustment yielded an increase to 3-4 meters and a reliability of close
>to 95%.
>
>Further work showed a 10-15 meter sensitivity. This was with 88mm
>canon shells. The shell to all intents and purposes ready for
>production.

Again no dates are given, presumably we are to believe it was ready
for production in 1940, but then shut down because it was not ready
for production within 6 months, see below, and the time it actually
took in 1944/45 above. There were considerable strides made
during the war when it came to reliability and miniaturisation of radio
parts, the later war experiments would have benefited from this.

Note the lethal burst radius for a standard 88mm shell was around
30 feet, or 9 metres. Given the standard fire control radar some
59,000 88 mm shells were needed to cover the volume the aircraft
could be in when flying at 24,000 feet.

>References are "Truth About the Wunderwaffen" by Igor Witowski who
>cites "Proximity Fuse Development - Rheinmettal Borsig A.G.
>Mullhausen. CIOS report ITEM nos 3 file nos XXVI -1 (1945)
>
>Capacitance based fuses became highly developed after the second world
>war due to their high resistance against jamming techniques.

Ah, so the plan is to stop claiming the Germans gave the fuse to the
allies but to claim they thought of it first and did it better.

>It is unlikely that the shell could have been easily degraded by
>jamming or chaff. (unlike the Allied shell).

Yes, claim it does things better. Just ignore the idea the whole idea
of window was to mimic a bomber, and all that has to be done now
is to explain how the shell would discriminate against aluminium
in falling foils and in aircraft flying along.

>I can speculate as to several ways that this might work. It is
>referred to as a "influenz zunder" based in electrostatic
>principles.
>
>Method 1: Bridge Cicuit. The shells external capacitance is made
>part of a bridge circuite with an internal reference capacitor in the
>other arm. Any disturbance caused by an large object such as an
>aircraft would cause a current to flow across the bridge that would be
>amplified.

main problem, surviving the firing accelerations.

>Method 2: QT or charge transfer methods. A high speed vibrating
>contact charges the shell and then discharges it into a known
>capacitance which is then measured.

Should be fun to create the mechanism to allow a high speed
vibrating contact, have it survive the acceleration of the firing
and then spin up to arm the shell

>Method 3: making the shell body part of a resonant circuit and
>detecting frequency changes.

Should be fun lugging the fused shells around metal guns.

>I can not find the precise reason for the abandonment of the work in
>1940 however it probably relates to the 'fuhrer befehle' or fuhrer
>directive that with few exceptions all work that could not be put into
>production within 6 months were to be terminated to increase resources
>for those that could (in order to support operation Barborosa).

So in other words in 1940 the fuse was not ready for production.

> It
>was at this time that the Germans also abandoned their magnetron and
>microwave development teams and programs. Many programs suffered
>severely due to this; something that was to have far reaching
>consequences for the German war effort.

It would be better to say scaled back as opposed to abandoned.

>What would have happened if the proximity fuse was not abandoned in
>1940 but development continued such that it entered service in 1943?

The USAAF would have flown more night missions and deployed
B-29s to Europe. The allies would have devoted more to flak
suppression. The allies would have flown more missions on
cloudy days using the better navigation aids in 1944.

Note the half way point for Bomber Command for bombs on Germany
was in late September 1944, the 8th was mid November 1944. It
was a very end loaded campaign.

The number of flak batteries out ran the German ability to provide
them with proper fire control systems. Hence there were still sound
locators in use in 1944 to use an extreme example. The idea of
massed batteries was also driven by the amount of fire control
systems needed.

Before the RAF introduced window Bomber Command was recording
that around 6 to 9% of returning aircraft on night missions had flak
damage, March to July 1943. This dropped to 2.85% in August and
averaged 2.3% for all of 1944 and 1.4% for 1945. Window remained
effective against the fire control radars for the remainder of the war.
The average for aircraft returning damaged by flak on night raids
February to December 1942 was 6.5%, for all of 1943 5.8%. In effect
a proximity fuse at around 3 to 7 times the lethality would restore to
exceed the pre window hit rates.

The USAAF carried window and active jammers but, of course, by day
the gunners could correct their aim by eye. Some batteries even had
the ability to track the H2X radars of USAAF pathfinders and use this
for ranging, electronic warfare was a 2 way street.

Geoffrey Sinclair
Remove the nb for email.

[Eunometic]

You'll find that there were at least two other allied photoelectric
based fuses. The first one entered service on rockets (it couldn't
handle the shock of a gun launch) but its photocells found application
in the punched paper tape reader of the colossus machine used in
decrypting Enigma. The second system could withstand a cannon lauch
and entered service. It used a torrodial perspex lens around the
circumference or rim of the shell that focused on a photocell.

To be fair most of these German fuses were for different purposes than
cannon shell launch. Missiles need more sophisticated and jam
resistent radio proximity fuses. In addition the Germans were clearly
hedging their bets by developing a spread of systems to reduce their
exposure to Allied Jamming attempts. The German were big investors in
both passive and active infrared technology and this was begining to
pay of in 1945.

In part the plethora of projects represents the secrecy
compartmentalisation, as well as intersevice rivalries but also a
policy of phased development was in place so that the Germans could
catch up and stay ahead in areas such as radar.

In reality relying on one proximity fuze type is a recipe for disaster.
The allies relied on secrecy and then the hope that the Germans
couldn't react in time.

The Wasserfall and Enzian Surface to Air missiles for instance had a
spread of guidence and proximity fuze systems under development.
Wasserfall had a 3 axis gyroscopic version of the two axis gyroscopic
guidence system in the V2 including apparently the PIGA accelerometer.
Even without external guidence it would have placed itself within a few
hundred meters of its target. There an infrared terminal homing system
was to be used (Madrid), or alternatively command guidence using a
radar called "Mannheim" (80 of these track-lock entered service) or
visual command guidence. There was also a semi active guidence system
under development called "Moritz". The command link was based on a
specially developed version of the "Khel/Strassbourg" system used on
Fritiz-X and Hs 293 but also on a purpose built system called
"Kogge/Brigge"

The smaller Ruhrstahl X-4 wire guided Air to Air missile opperated with
basic wire guidence and a contact fuse backed up accoustic proximity
fuse called "Kranich". A accoustic terminal homing system "Dogge" was
also under development as was an infrared terminal homing system and
proxitmity fuse. The same systems were planed for the Enzian missile
including an accoustic homing head called "Archimedes"

The accoustic homing systems worked quite well. A Me 262 Jet equiped
with accoustic homing systems could detect a bomber and its directions
to about 4-5 miles range.

There were 5 quite effective surface to air missiles bodies were
developed:
Wasserfall, Enzian, Hs-117, Rheintochter R1.and R3 but non received the
focus they needed to enter service. To one degree or another they
suffered manpower shortages or sabotage.

[Eunometic]

Geoffrey Sinclair wrote:
> >The German proximity fuse.
> >
> >The development of the US proximity fuse by the US in WW Two is
> >regarded as a unique allied triumph.
> >
> >Little known however is that the Germans independently developed and
> >successfully test fired almost 1000 rounds of a similar proximity
fuse
> >near the wars end that if introduced into service would have had a
> >dramatic effect. The allies estimated that the availability of the
> >proximity fuse would force them to abandon use of the B-24 Liberator
> >due to its lower flying altitude compared to the B-17.
>
> The B-24 made up around 1/3 of the 8th Air Force and 2/3 of the
> 15th Air force, all up just under half the USAAF bombers. The main
> deployment of B-24s to Europe was in 1944.
>
> It was a USAAF estimate, flak losses would triple, bombing heights
> would have to increase and the B-24 not used against well defended
> targets. When the German flak concentration around the main
synthetic
> oil plants became so great the USAAF started to use cloudy days,
> relying on radar aids, assuming the loss of accuracy for the gunners
> was greater than that of the bombers.
>
> Not flak losses were never above the critical loss rates, but would
> have approached it if they were tripled. It took fighters to really
cut
> up a bomber formation.


What were the critical levels? 10% losses would mean a 65% loss after
only 10 missions. 3% sounds sustainable.

>
> >The Allied Proximity fuse was used on both Anti-Aircraft Artillery
and
> >anti-personnel howitzers where they were set to explode
approximately
> >50 feet above the ground. At that height they would produce a lethal
> >zone over a terrifyingly wide area. When used against aircraft it
> >seemed to increase effectiveness of a round by 3-7 or more.
>
> So the 16,000 88mm shells per shoot down fired would be reduced to
> 2,300 to 5,300. The Germans did better early in the war in terms of
> shells per aircraft but this was the sort of price paid for using
effectively
> reserve manpower in the flak units alongside less accurate fire
control
> systems.

I suspect that the use of the proximity fuse would place pressure on
increasing accuracy. I suspect that barrels were not renewed as often
as was optimal.

The 128mm FLAK gun had a fuse setter installed on the barrel to allow
the fuse time to be set while the round was in the barrel.

It is my understanding that most 88 guns had an external fuse setting
device that was a box next to the barrel. So the FLAK crew (9 men or
children) would neet to maintain a rhythm of following the dials and
pointing the gun, inseting the round in the fuse setter removing it
inserting the round in the barrel etc.

Putting servo drives on the gun and in barrel fuse setters would I
suspect also have increased accuracy.

The problem is that there isn't enough skilled labour to build,
calibrate,maintain this equipement.



>
> The proximity fuse effects can be replicated by wires on the bomb
> noses and by having trees in the combat area. If the shell or bomb
> hits the tree the results are an airburst. You can also have time
> fuses for shells. Of course none as accurate as a proximity fuse
> for bursts at the optimum height.
>
> >The proximity fuse was fielded as an AA weapon from ships in the
> >Pacific from June 1943 where it was reasoned that secrecy could not
be
> >compromised as dud rounds would fall into the sea. (I have no
> >knowledge of its use against the Japanese Troops on islands). It on
> >one occasion apparently helped shoot down 90 of 120 attacking
Japanese
> >planes.
>
> As has been stated the last time this information was posted,
>
> The claim ignores the USS Helena firing proximity fused shells off
> Guadalcanal in January 1943. Fuse production was 500 per day
> in October 1942. Note by the end of 1944 the delivery rate was
> 40,000 per day, or in other words just over half an hour to equal the
> entire claimed German production.
>
> The other point was to design a shell to take the fuse, the allies
> started with the USN 5 inch gun.
>
> It should be noted the claimed major shoot down was the USN
> ships reporting what they thought they had shot down.
>
> In the fights with Kamikazes the USN ships reported they needed
> to fire 100% VT (proximity) fuses, since there was normally no time
> to set and use time fuses.
>
> >It was first supplied to Britain to help overcome the V1 cruise
missile
> >fired at London where it in combination with radar and computer
> >directed guns reduced the mean number of rounds expended to destroy
a
> >V1 from 4000 to 180.
>
> The note being it was a combination of better fire control and fuses.

It would appear that the 20:1 reduction came 3:1 from VT fuses and 7:1
from servo driven and computer aimed radar slaved guns. Or perhaps the
other way around.

I suspect optically directed servo driven computer aimed guns could
have been as effective on a clear day.


>
> >Finally there are records of it used against German troops during
the
> >Ardennes Offensive (Battle of Bulge). It was reasoned that the
> >Germans would not be able to reconstruct the fuses in time to make
use
> >of them. In fact the 'folklore' on the Internet is that they
> >captured some 20,000 but did not recognize them and also that they
> >recovered duds and reasoned that they were triggered by the Earth's
> >magnetic Field. (Note the magnet field theory probably came from
the
> >troops themselves before being analysed by more technical branches
of
> >the German forces)
>
> Ah so the folk lore is they captured a US ammunition dump with
> the fused shells and then inventoried the catch, as opposed to
> destroying it?

I don't know what the custom would have been. It is said they didn't
recongise the nature of the shells. However they did recover dud
shells (they must have known there was something unique about them) and
surmised that they had a electronic fuse.


>
> By the way the troops would not be checking the fusing of any
> dud rounds, but removing the shells to a safer place. The
> experts would be looking at things like fuses.
>
> >The allied fuse workings.
> >
> >Technically the Allied fuse was not radar: it did not send out a
pulse
> >and listen for an echo. It had 4 tubes. One tube was part of the
> >oscillator. When a 'target' that was about a =BD wavelength in size
> >came within a few wavelengths it would load the amplifier and the
anode
> >current would increase. Two additional amplifiers would detect this
> >change and then triggered the 4th valve (a gas filled thyraton) to
set
> >of the detonator. Contrary to other reports it apparently did not
> >trigger on Doppler shift either or on frequency change. There were
> >many shock hardening techniques including planar electrodes and
packing
> >the components in wax and oil to equalize the stresses.
>
> Given we are talking about wavelengths in the order of centimetres
> the axis mist have been flying very small aircraft if they were
around
> a half wavelength in size.

VT fuse opperated at about 220-280Mhz or so. A wavelenght would have
been about 1.5 meters. Targets would need to be 1/4 to 1/2 a
wavelenght to produce a stronger return.


>
> Try this for an explanation,
>
> "One method that was experimented with used radio waves transmitted
> from the ground. These radio waves would be reflected by the target
and
> received by the fuze. Once the radio waves were at a sufficient
level, the
> fuze would activate causing the shell to explode.
>
> Another method that was more logical and became the accepted means,
> was to develop a fuze which was capable of obtaining its own
intelligence
> and of using it to ignite the shell. When assembled this fuze
consisted of
> four major parts: A miniature radio transceiver, complete with
amplifier
> and capacitor; a battery; an explosive train; and the necessary
safety
> devices. The theory was that the fuze transmitter, alone, would not
> produce sufficient signal intensity, to trigger a thyratron tube
switch.
> However, as the projectile approached a target the radio waves
reflected
> by the target would gradually increase and come more and more into
phase
> with the fuze-generated signal. Once the signal level was high
enough, the
> fuze would know that the shell could do a maximum amount of damage,
> and the thyratron tube switch would be triggered releasing the energy
in a
> charged capacitor and thus igniting the shell."
>
> >The German fuse workings.
> >
> >The fuse was based on electrostatic principles.
>
> At least this hopefully stops the previous claims the Germans
> handed the design to the British who then used it.

I never suggested that the Allies or British coppied the German fuse,I
suggested that it accelerated the allied work. Early German
investigations seem to go back to 1935. There is British work going to
1937 and I suspect 1934 for optical fuses.


>
> >The circuitry of the German fuse is not precisely known to me as I
do
> >not have the schematics however the details are in allied files
refred
> >to I do not have a circuit layout drawing. It is known that the
nose
> >of the shell was electrically insulated and isolated from the rest
of
> >the shell. It was built by the company Rheinmetall. The program was
> >halted in 1940 then restarted in early 1944 and then terminated
again
> >due to being over run by the allies at the point that it was ready
for
> >production.
>
> The above assumes the program was producing fused shells in 1940
> as opposed to heading towards the idea. After all if the restart was
> in early 1944 and the production facilities were over run something
like
> 15 months later just as production was about to start it shows how
long
> things actually took. How long the Germans really were from
production.

In actualy fact the 1000 test firings were conducted in 1944. There
may have been firings in 1940 before cancellation but they were almost
certainly not succesfull.

>
> The US started work on the fuse in July 1940 and later developed
> optical and magnetic proximity fuses for mines and 4.5 inch rockets.
>
> >Initial fuse testing demonstrated a sensitivity of 1-2 meters and a
> >reliability of 80% when fired against a metal cable target. A
circuit
> >adjustment yielded an increase to 3-4 meters and a reliability of
close
> >to 95%.
> >
> >Further work showed a 10-15 meter sensitivity. This was with 88mm
> >canon shells. The shell to all intents and purposes ready for
> >production.
>
> Again no dates are given, presumably we are to believe it was ready
> for production in 1940, but then shut down because it was not ready
> for production within 6 months, see below, and the time it actually
> took in 1944/45 above.


No, I believe there were NO test firings in 1940 that were succesfull.

> There were considerable strides made
> during the war when it came to reliability and miniaturisation of
radio
> parts, the later war experiments would have benefited from this.

There are some notes kicking around somewhere on german techniques for
valve seals in ceramic amplifier tubes. I believe they produced quite
small ceramic valves,


>
> Note the lethal burst radius for a standard 88mm shell was around
> 30 feet, or 9 metres. Given the standard fire control radar some
> 59,000 88 mm shells were needed to cover the volume the aircraft
> could be in when flying at 24,000 feet.
>
> >References are "Truth About the Wunderwaffen" by Igor Witowski who
> >cites "Proximity Fuse Development - Rheinmettal Borsig A.G.
> >Mullhausen. CIOS report ITEM nos 3 file nos XXVI -1 (1945)
> >
> >Capacitance based fuses became highly developed after the second
world
> >war due to their high resistance against jamming techniques.
>
> Ah, so the plan is to stop claiming the Germans gave the fuse to the
> allies but to claim they thought of it first and did it better.

Electrostatic fuses are apparently intrinisically hightly resistent to
jamming.

The allies looked at using electrostatic principles but preceded with
radio methods instead. I belive the Germans struggled to get the range
up from 3-4 meters to 10-14 meters. It looks like they had to add a
small antenna cable or tailing wire to achieve this.


>
> >It is unlikely that the shell could have been easily degraded by
> >jamming or chaff. (unlike the Allied shell).
>
> Yes, claim it does things better. Just ignore the idea the whole
idea
> of window was to mimic a bomber, and all that has to be done now
> is to explain how the shell would discriminate against aluminium
> in falling foils and in aircraft flying along.

Window and Chaff could be used to form a layer below the bomber to
predetonate some of the fuses.




>
> >I can speculate as to several ways that this might work. It is
> >referred to as a "influenz zunder" based in electrostatic
> >principles.
> >
> >Method 1: Bridge Cicuit. The shells external capacitance is made
> >part of a bridge circuite with an internal reference capacitor in
the
> >other arm. Any disturbance caused by an large object such as an
> >aircraft would cause a current to flow across the bridge that would
be
> >amplified.
>
> main problem, surviving the firing accelerations.

True, but they seem to have succeded.

>
> >Method 2: QT or charge transfer methods. A high speed vibrating
> >contact charges the shell and then discharges it into a known
> >capacitance which is then measured.
>
> Should be fun to create the mechanism to allow a high speed
> vibrating contact, have it survive the acceleration of the firing
> and then spin up to arm the shell

The contact could be aligned along the axis to avoid centrifugal forces
or a rotating button could be used.


>
> >Method 3: making the shell body part of a resonant circuit and
> >detecting frequency changes.
>
> Should be fun lugging the fused shells around metal guns.
>
> >I can not find the precise reason for the abandonment of the work in
> >1940 however it probably relates to the 'fuhrer befehle' or fuhrer
> >directive that with few exceptions all work that could not be put
into
> >production within 6 months were to be terminated to increase
resources
> >for those that could (in order to support operation Barborosa).
>
> So in other words in 1940 the fuse was not ready for production.

No it wasn't.

Production of 1000 rounds occured for testing in 1944.


>
> > It
> >was at this time that the Germans also abandoned their magnetron and
> >microwave development teams and programs. Many programs suffered
> >severely due to this; something that was to have far reaching
> >consequences for the German war effort.
>
> It would be better to say scaled back as opposed to abandoned.

Abandoned is accurate. They had to get the personel back out of the
Army. They didn't even recognise the value of the magnetron since the
microwave experts werent there to look at it. It was taken by some
initally as proof that microwaves are not good for detecting aircraft.


>
> >What would have happened if the proximity fuse was not abandoned in
> >1940 but development continued such that it entered service in 1943?
>
> The USAAF would have flown more night missions and deployed
> B-29s to Europe.

The B29 wasn't reliable till late 44. The engines overheated, caught
fire (they were magnesium) and then burned through the spar. Nasty.

> The allies would have devoted more to flak
> suppression. The allies would have flown more missions on
> cloudy days using the better navigation aids in 1944.
>
> Note the half way point for Bomber Command for bombs on Germany
> was in late September 1944, the 8th was mid November 1944. It
> was a very end loaded campaign.
>
> The number of flak batteries out ran the German ability to provide
> them with proper fire control systems. Hence there were still sound
> locators in use in 1944 to use an extreme example. The idea of
> massed batteries was also driven by the amount of fire control
> systems needed.

All guns fired at once apparently.


>
> Before the RAF introduced window Bomber Command was recording
> that around 6 to 9% of returning aircraft on night missions had flak
> damage, March to July 1943. This dropped to 2.85% in August and
> averaged 2.3% for all of 1944 and 1.4% for 1945. Window remained
> effective against the fire control radars for the remainder of the
war.

An moving target indicator called k-laus that used a 2 microsecond
delay line to detect moving targets was expected to resolve window and
chaff much better than wurzlaus and nurenberg. It didn't quite enter
service.



> The average for aircraft returning damaged by flak on night raids
> February to December 1942 was 6.5%, for all of 1943 5.8%. In effect
> a proximity fuse at around 3 to 7 times the lethality would restore
to
> exceed the pre window hit rates.
>
> The USAAF carried window and active jammers but, of course, by day
> the gunners could correct their aim by eye. Some batteries even had
> the ability to track the H2X radars of USAAF pathfinders and use this
> for ranging, electronic warfare was a 2 way street.
>=20
> Geoffrey Sinclair
> Remove the nb for email.

[M. J. Powell]

In message
>, Geoffrey
Sinclair > writes
>>
snip
>
>>Method 3: making the shell body part of a resonant circuit and
>>detecting frequency changes.
>
>Should be fun lugging the fused shells around metal guns.

IIRC the fuse was inactive until fired. The shock of firing broke a
glass cell containing the battery acid, the battery then produced the
required voltage.

Mike
--
M.J.Powell

[[email protected]]

Eunometic wrote:
> You'll find that there were at least two other allied photoelectric
> based fuses. The first one entered service on rockets (it couldn't
> handle the shock of a gun launch) but its photocells found
application
> in the punched paper tape reader of the colossus machine used in
> decrypting Enigma. The second system could withstand a cannon
lauch
> and entered service. It used a torrodial perspex lens around the
> circumference or rim of the shell that focused on a photocell.
>
> To be fair most of these German fuses were for different purposes
than
> cannon shell launch. Missiles need more sophisticated and jam
> resistent radio proximity fuses. In addition the Germans were
clearly
> hedging their bets by developing a spread of systems to reduce their
> exposure to Allied Jamming attempts. The German were big investors
in
> both passive and active infrared technology and this was begining to
> pay of in 1945.
>
> In part the plethora of projects represents the secrecy
> compartmentalisation, as well as intersevice rivalries but also a
> policy of phased development was in place so that the Germans could
> catch up and stay ahead in areas such as radar.
>
> In reality relying on one proximity fuze type is a recipe for
disaster.
> The allies relied on secrecy and then the hope that the Germans
> couldn't react in time.
>
> The Wasserfall and Enzian Surface to Air missiles for instance had a
> spread of guidence and proximity fuze systems under development.
> Wasserfall had a 3 axis gyroscopic version of the two axis gyroscopic
> guidence system in the V2 including apparently the PIGA
accelerometer.
> Even without external guidence it would have placed itself within a
few
> hundred meters of its target. There an infrared terminal homing
system
> was to be used (Madrid), or alternatively command guidence using a
> radar called "Mannheim" (80 of these track-lock entered service) or
> visual command guidence. There was also a semi active guidence
system
> under development called "Moritz". The command link was based on a
> specially developed version of the "Khel/Strassbourg" system used on
> Fritiz-X and Hs 293 but also on a purpose built system called
> "Kogge/Brigge"

SNIP

See the US guided and glider bomb programs for a similar list of
proposed and experimented with guidance systems (VB/BG series)

Fletcher BG-1
After the USAAF had cancelled the order for the Fletcher PQ-11A
radio-controlled target drone, ten of the PQ-11As under construction
were completed as XBG-1 bomb gliders. In the XBG-1, the PQ-11A's engine
was replaced by a 900 kg (2000 lb) bomb. The XBG-1 was to be towed to
the target area by a larger aircraft and upon release was to be guided
to target impact by radio-commands using imagery transmitted from a TV
camera in the glider's nose. No information on the XBG-1 test program
is available, but the model was never used operationally.

Fletcher BG-2
When the Frankfort CG-1 troop-carrying glider was cancelled in 1941,
the three XCG-1s under construction were completed by Fletcher as XBG-2
bomb gliders. No information about the bomb load or the results of
tests (if any!) is available, but the BG-2 program was cancelled in
1942.

Cornelius BG-3
The BG-3 was a design with nose-mounted horizontal stabilizers and
forward-swept wings. As such it was possibly similar to Cornelius'
XFG-1 fuel glider. Although the USAAF had planned to procure one XBG-3
prototype, this order was cancelled in 1942

The VB designation was introduced by the U.S. Army Air Force in 1943,
and covered unpowered guided bombs with effectively no standoff gliding
range (i.e. "vertical" bombs).

ATSC VB-1/VB-2 Azon
In April 1942, the USAAF's Materiel Command (became part of ATSC (Air
Technical Service Command) in 1944) began the development of the Azon
family of guided bombs. The initial variant, designated VB-1, was based
on a 450 kg (1000 lb) bomb (initially the M44, but later models
apparently switched to the standard AN-M65), which was modified with a
new tail unit. The latter consisted of a gyroscopic unit to provent the
bomb from rolling, a flare for optical tracking, an octagonal shroud
with control surfaces, and a radio-command receiver. When a VB-1 was
dropped, the bombardier could track it through his bombsight and use a
joystick-type control to send corrective commands to the bomb. The Azon
guidance system allowed only lateral course corrections, but errors in
range could not be corrected (hence the name Azon = "Azimuth Only").

The Azon development phase ended in late 1943, and the VB-1 was
subsequently ordered into mass production. The second Azon variant was
the heavier VB-2, which was based on a 900 kg (2000 lb) bomb, but that
version was apparently not produced in very large numbers. The first
VB-1/2 bombs were sent to Europe in February 1944, and a total of 15000
Azons were produced until November 1944.

Because of their azimuth-only guidance, the VB-1 was particularly
suited to long and narrow targets (like bridges or railways) where
range errors would be irrelevant. For "normal" targets, however, the
VB-1 was actually not as good as unguided free-fall bombs, because a
bomber could not break away immediately after dropping the bomb, and
the accuracy was effectively not increased because of the lack of range
control. Another peculiarity of the Azon guidance set was the fact that
only five different radio channels were available for the command link,
meaning that not more than five bombs could be controlled
independently. Although in theory a whole group of bombs using the same
command channel could be controlled simultaneously, this was not
practical. The accuracy of all but the "primary" bomb (i.e. the one
which was tracked by the bombardier) in such a group was rather bad,
because the non-spinning Azon bombs showed a significant dispersion.

The drawbacks of the Azon meant that its use remained very limited.
However, it was employed rather successfully in Burma, where it was
used to destroy very vital and therefore heavily defended bridges along
the Japanese supply lines. Less the 500 Azons were needed to destroy 27
bridges.

When the war ended, the USAAF quickly removed the VB-1 and VB-2 from
its inventory. Because of the much reduced post-war funding, the USAAF
limited its guided vertical bomb research to the more advanced
VB-3/VB-4 Razon family.

ATSC VB-3/VB-4 Razon
In parallel with the Azon tests, the ATSC also developed a more
advanced variant called Razon, which was to be controllable in both
range and azimuth. The designations VB-3 and VB-4 were assigned to the
450 kg (1000 lb) and 900 kg (2000 lb) Razon versions, respectively. The
Razon guidance kit had two octagonal shrouds in a tandem arrangement.
The most problematic part in Razon development was to build a suitably
modified bombsight, which would allow the bombardier to correctly judge
the bomb's deviation in range so that the range control could be used
effectively. The Razon also had an improved radio-command link with 47
separate channels, effectively eliminating the Azon's problems with
concurrent drops by a multitude of bombers.

The VB-3/VB-4 was combat-ready in summer 1945, and about 3000 Razons
were subsequently produced, but none of them were used before World War
II was over. However, the VB-3 was operationally tested five years
later during the first months of the Korean War. B-29 aircraft, which
could carry eight VB-3s, dropped several hundred Razons on North Korean
bridges, and although the overall reliability of the bombs was rather
low, some targets were actually destroyed. However, in general multiple
hits by the small the 450 kg (1000 lb) bombs were needed to destroy a
large bridge span, and the USAF's use of guided bombs for these special
missions switched to the much larger VB-13/ASM-A-1 Tarzon.

ATSC VB-5
The VB-5 was a 450 kg (1000 lb) bomb, which used the same tandem
octagonal control shroud arrangement as the VB-3/VB-4 Razon. However,
the VB-5 was not command guided but used an autonomous light contrast
seeker. This bomb did not go into production, presumably because the
guidance mechanism didn't work as planned.

ATSC VB-6 Felix
The VB-6 Felix was a 450 kg (1000 lb) bomb with an octagonal control
shroud and a heat seeking device in the nose. Intended for use against
strong infrared emitters (like e.g. blast furnaces), the VB-6 was
tested with some success during 1945, but the program was cancelled at
the end of World War II. The U.S. Navy developed a very similar
IR-guided bomb as the ASM-N-4 Dove.

ATSC VB-7, VB-8
The VB-7 and VB-8 both used a TV/radio-command guidance, where a TV
camera in the bomb's nose transmitted the image to a display set for
the bombardier, who could then correct the bomb's course by
radio-commands. The weights of the VB-7/VB-8 are unclear, but it can be
assumed that these two guided bombs were cancelled early in the
development phase.

Douglas VB-9/VB-10/VB-11/VB-12 Roc
The Roc series of guided bombs was developed by Douglas, the MIT and
the NDRC (National Defense Research Committee). The VB-9 model was a
450 kg (1000 lb) bomb with cruciform wings and fins and a radar seeker
in the nose. The radar image was transmitted to the bombardier who
could use it to direct the bomb's path by radio commands. However, the
radar was often useless because of ground clutter, and the VB-9 program
was terminated in early 1945.

VB-9
The later Roc models all used a 450 kg (1000 lb) bomb body of 61 cm (24
in) diameter and 3 m (10 ft) length. They were fitted with two circular
shrouds, a larger one which could move around two axes for directional
steering, and a smaller one in the tail designed to slow down the bomb
to facilitate the tracking and guidance task of the bombardier. The
VB-10 had a TV camera and transmitter, so that the bombardier could
track the bomb via the image on his TV display set. The VB-11 had an
infrared seeker for autonomous heat-seeking guidance, and the VB-12 was
tracked visually (making it similar in operation to the VB-3/VB-4
Razon).

VB-10/11/12
The VB-10 (and presumably also the VB-11/VB-12 models) was tested
between September 1944 and May 1945, when the Roc program was
terminated without any model going into production.

Bell VB-13 Tarzon
The VB-13 is discussed on a separate page about the VB-13/ASM-A-1
Tarzon.

Specifications
The few available data on the dimensions and weights of the VB-series
bombs are mentioned in the main text






http://www.designation-systems.net/dusrm/app1/index.html

http://www.wpafb.af.mil/museum/arm/vb.htm





> The smaller Ruhrstahl X-4 wire guided Air to Air missile opperated
with
> basic wire guidence and a contact fuse backed up accoustic proximity
> fuse called "Kranich". A accoustic terminal homing system "Dogge"
was
> also under development as was an infrared terminal homing system and
> proxitmity fuse. The same systems were planed for the Enzian missile
> including an accoustic homing head called "Archimedes"
>
> The accoustic homing systems worked quite well. A Me 262 Jet
equiped
> with accoustic homing systems could detect a bomber and its
directions
> to about 4-5 miles range.

SNIP

I'm sorry, but I find an acoustic system that sensitive, yet able to
filter out the wind noise of going 500 mph, along with the howl of two
turbojets a bit hard to believe. Could you provide more details or a
citation?

[Jim]

Eunometic wrote:
> The German proximity fuse.
>

Not exactly an article for this newsgroup. We strive to remain on topic
and would appreciate if posters would keep this in mind.

[Tex Houston]

"Jim" > wrote in message ...
> Eunometic wrote:
>> The German proximity fuse.
>>
>
> Not exactly an article for this newsgroup. We strive to remain on topic
> and would appreciate if posters would keep this in mind.

I did not realize that naval aircraft were immune to anti-aircraft fire...be
so be it.

Tex

[Keith W]

"Jim" > wrote in message ...
> Eunometic wrote:
>> The German proximity fuse.
>>
>
> Not exactly an article for this newsgroup. We strive to remain on topic
> and would appreciate if posters would keep this in mind.

Incorrect, this is one of the rew recent threads that IS on topic.
As an example the use of proximity fuses was critical to defending
the USN against kamikaze attack in WW2

Keith

[Jim]

Keith W wrote:
> "Jim" > wrote in message ...
>
>>Eunometic wrote:
>>
>>>The German proximity fuse.
>>>
>>
>>Not exactly an article for this newsgroup. We strive to remain on topic
>>and would appreciate if posters would keep this in mind.
>
>
> Incorrect, this is one of the rew recent threads that IS on topic.
> As an example the use of proximity fuses was critical to defending
> the USN against kamikaze attack in WW2
>
> Keith
>
>
Our group is NAVAL AVIATION.

CHARTER: rec.aviation.military.naval

The purpose of this newsgroup is to facilitate open discussion about all
issues relating to Naval Aviation. It will provide a global forum for:
- pilots
- naval flight officers
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- other support personnel
- others interested in Naval Aviation

The discussions will be based upon:
- flight training
- squadron history
- aircraft carrier operations
- patrol missions
- lighter-than-air operations
- combat experiences
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- other subjects relating to and about Naval Aviation

The goal of these discussions is to provide a global community access to
discuss issues relating to Naval Aviation and foster interest in others
regarding this unique aspect of aviation.

A FAQ file(s) will be developed to include discussion topics outlined
above and other issues that will arise from the operation of the newsgroup.

The newsgroup will be unmoderated.

Commercial postings are not welcome as the group as proposed does not
require Vendors or Suppliers.

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may include reference to a URL or FTP pointing to such binary files.

[Eunometic]

M. J. Powell wrote:
> In message
> >,
Geoffrey
> Sinclair > writes
> >>
> snip
> >
> >>Method 3: making the shell body part of a resonant circuit and
> >>detecting frequency changes.
> >
> >Should be fun lugging the fused shells around metal guns.
>
> IIRC the fuse was inactive until fired. The shock of firing broke a
> glass cell containing the battery acid, the battery then produced the

> required voltage.

The initial fuses that entered service used a 'normal' battery. It
worked quite well however the batteries would degrade in only a few
months hence the above batteries were developed. Nose mounted wind
turbine driven generators were also used in experimental shells but
were rejected, probably for cost reasons.

The German electrostatic influence fuse used a battery. I don't know
what battery technology they used.


>
> Mike
> --
> M.J.Powell

[Gord Beaman]

"M. J. Powell" > wrote:

>In message
>, Geoffrey
>Sinclair > writes
>>>
>snip
>>
>>>Method 3: making the shell body part of a resonant circuit and
>>>detecting frequency changes.
>>
>>Should be fun lugging the fused shells around metal guns.
>
>IIRC the fuse was inactive until fired. The shock of firing broke a
>glass cell containing the battery acid, the battery then produced the
>required voltage.
>
>Mike

Jesus...I'd hate to be the second guy to accidentally drop the
damned thing...

--

-Gord.

Keep in mind that I'm an expert with
questions, so if you have any, fire
away.

Be aware however, that answers
quite often give me trouble.

[Gord Beaman]

Jim > wrote:

>Keith W wrote:
>> "Jim" > wrote in message ...
>>
>>>Eunometic wrote:
>>>
>>>>The German proximity fuse.
>>>>
>>>
>>>Not exactly an article for this newsgroup. We strive to remain on topic
>>>and would appreciate if posters would keep this in mind.
>>
>>
>> Incorrect, this is one of the rew recent threads that IS on topic.
>> As an example the use of proximity fuses was critical to defending
>> the USN against kamikaze attack in WW2
>>
>> Keith
>>
>>
>Our group is NAVAL AVIATION.
>
>CHARTER: rec.aviation.military.naval
>
>The purpose of this newsgroup is to facilitate open discussion about all
>issues relating to Naval Aviation.

snip

Don't be silly Jim...how close to aviation do you want?...sure
beats that political crap that we see occasionally...

--

-Gord.

Keep in mind that I'm an expert with
questions, so if you have any, fire
away.

Be aware however, that answers
quite often give me trouble.

[Geoffrey Sinclair]

Eunometic wrote in message om>...

>Geoffrey Sinclair wrote:
>> Eunometic wrote
>> >The German proximity fuse.
>> >
>> >The development of the US proximity fuse by the US in WW Two is
>> >regarded as a unique allied triumph.
>> >
>> >Little known however is that the Germans independently developed and
>> >successfully test fired almost 1000 rounds of a similar proximity fuse
>> >near the wars end that if introduced into service would have had a
>> >dramatic effect. The allies estimated that the availability of the
>> >proximity fuse would force them to abandon use of the B-24 Liberator
>> >due to its lower flying altitude compared to the B-17.
>>
>> The B-24 made up around 1/3 of the 8th Air Force and 2/3 of the
>> 15th Air force, all up just under half the USAAF bombers. The main
>> deployment of B-24s to Europe was in 1944.
>>
>> It was a USAAF estimate, flak losses would triple, bombing heights
>> would have to increase and the B-24 not used against well defended
>> targets. When the German flak concentration around the main synthetic
>> oil plants became so great the USAAF started to use cloudy days,
>> relying on radar aids, assuming the loss of accuracy for the gunners
>> was greater than that of the bombers.
>>
>> Not flak losses were never above the critical loss rates, but would
>> have approached it if they were tripled. It took fighters to really cut
>> up a bomber formation.
>
>What were the critical levels? 10% losses would mean a 65% loss after
>only 10 missions. 3% sounds sustainable.

Overall according to the USAAF statistical digest the 8th Air force
flew 1,034,052 heavy bomber sorties, 898,758 considered effective,
losing 2,439 to flak. So between a 0.23 and 0.27% loss rate. The
RAF considered 5% loss rates unsustainable long term and the
USAAF seems to have agreed.

>> >The Allied Proximity fuse was used on both Anti-Aircraft Artillery and
>> >anti-personnel howitzers where they were set to explode approximately
>> >50 feet above the ground. At that height they would produce a lethal
>> >zone over a terrifyingly wide area. When used against aircraft it
>> >seemed to increase effectiveness of a round by 3-7 or more.
>>
>> So the 16,000 88mm shells per shoot down fired would be reduced to
>> 2,300 to 5,300. The Germans did better early in the war in terms of
>> shells per aircraft but this was the sort of price paid for using effectively
>> reserve manpower in the flak units alongside less accurate fire control
>> systems.
>
>I suspect that the use of the proximity fuse would place pressure on
>increasing accuracy. I suspect that barrels were not renewed as often
>as was optimal.

Alternatively the proximity fuse could reduce the pressure for new
guns, so the savings could be used elsewhere. The flak service
needed to replace an average of 380 88mm guns a month in 1944,
thanks to wear or destruction. Even in 1942 it was 148 guns a month.

Increasing accuracy is firstly a function of the fire control systems,
something the Germans struggled to provide. Then go for barrel
wear and ammunition quality.

>The 128mm FLAK gun had a fuse setter installed on the barrel to allow
>the fuse time to be set while the round was in the barrel.

This was so the time fuses could be set at the last possible moment,
eliminating the differences in time taken between setting the fuse
then manually loading and firing the shell. The time tended to go up as
the crew tired.

>It is my understanding that most 88 guns had an external fuse setting
>device that was a box next to the barrel. So the FLAK crew (9 men or
>children) would neet to maintain a rhythm of following the dials and
>pointing the gun, inseting the round in the fuse setter removing it
>inserting the round in the barrel etc.
>
>Putting servo drives on the gun and in barrel fuse setters would I
>suspect also have increased accuracy.
>
>The problem is that there isn't enough skilled labour to build,
>calibrate,maintain this equipement.

Then add the shortage of radars to provide accurate range information,
in particular height.

(snip)

>> As has been stated the last time this information was posted,
>>
>> The claim ignores the USS Helena firing proximity fused shells off
>> Guadalcanal in January 1943. Fuse production was 500 per day
>> in October 1942. Note by the end of 1944 the delivery rate was
>> 40,000 per day, or in other words just over half an hour to equal the
>> entire claimed German production.
>>
>> The other point was to design a shell to take the fuse, the allies
>> started with the USN 5 inch gun.
>>
>> It should be noted the claimed major shoot down was the USN
>> ships reporting what they thought they had shot down.
>>
>> In the fights with Kamikazes the USN ships reported they needed
>> to fire 100% VT (proximity) fuses, since there was normally no time
>> to set and use time fuses.
>>
>> >It was first supplied to Britain to help overcome the V1 cruise missile
>> >fired at London where it in combination with radar and computer
>> >directed guns reduced the mean number of rounds expended to destroy a
>> >V1 from 4000 to 180.
>>
>> The note being it was a combination of better fire control and fuses.
>
>It would appear that the 20:1 reduction came 3:1 from VT fuses and 7:1
>from servo driven and computer aimed radar slaved guns. Or perhaps the
>other way around.
>
>I suspect optically directed servo driven computer aimed guns could
>have been as effective on a clear day.

This ignores radar's great advantage over optics, much more accurate
range information. Where optics works better is bearings, the smaller
wavelengths give greater accuracy.

>> >Finally there are records of it used against German troops during the
>> >Ardennes Offensive (Battle of Bulge). It was reasoned that the
>> >Germans would not be able to reconstruct the fuses in time to make use
>> >of them. In fact the 'folklore' on the Internet is that they
>> >captured some 20,000 but did not recognize them and also that they
>> >recovered duds and reasoned that they were triggered by the Earth's
>> >magnetic Field. (Note the magnet field theory probably came from the
>> >troops themselves before being analysed by more technical branches of
>> >the German forces)
>>
>> Ah so the folk lore is they captured a US ammunition dump with
>> the fused shells and then inventoried the catch, as opposed to
>> destroying it?
>
>I don't know what the custom would have been. It is said they didn't
>recongise the nature of the shells. However they did recover dud
>shells (they must have known there was something unique about them) and
>surmised that they had a electronic fuse.

Recovering dud shells is not something the infantry usually has time
to do, it usually requires some specialists. The recovery of some
shells is possible, but it would be alongside other dud shells. Given
the known number of dud bombs in WWII there would be plenty of
dud shells to look for.

>> By the way the troops would not be checking the fusing of any
>> dud rounds, but removing the shells to a safer place. The
>> experts would be looking at things like fuses.
>>
>> >The allied fuse workings.
>> >
>> >Technically the Allied fuse was not radar: it did not send out a pulse
>> >and listen for an echo. It had 4 tubes. One tube was part of the
>> >oscillator. When a 'target' that was about a ½ wavelength in size
>> >came within a few wavelengths it would load the amplifier and the anode
>> >current would increase. Two additional amplifiers would detect this
>> >change and then triggered the 4th valve (a gas filled thyraton) to set
>> >of the detonator. Contrary to other reports it apparently did not
>> >trigger on Doppler shift either or on frequency change. There were
>> >many shock hardening techniques including planar electrodes and
>> >packing the components in wax and oil to equalize the stresses.
>>
>> Given we are talking about wavelengths in the order of centimetres
>> the axis mist have been flying very small aircraft if they were around
>> a half wavelength in size.
>
>VT fuse opperated at about 220-280Mhz or so. A wavelenght would have
>been about 1.5 meters. Targets would need to be 1/4 to 1/2 a
>wavelenght to produce a stronger return.

So the aircraft would have to be 0.75 to 0.4 metres in size? The
system used compared the phase of the reflected wave, which is
where wavelengths come into things, it does not apply to the size
of the target.

>> Try this for an explanation,
>>
>> "One method that was experimented with used radio waves transmitted
>> from the ground. These radio waves would be reflected by the targetand
>> received by the fuze. Once the radio waves were at a sufficient level, the
>> fuze would activate causing the shell to explode.
>>
>> Another method that was more logical and became the accepted means,
>> was to develop a fuze which was capable of obtaining its own intelligence
>> and of using it to ignite the shell. When assembled this fuze consisted of
>> four major parts: A miniature radio transceiver, complete with amplifier
>> and capacitor; a battery; an explosive train; and the necessary safety
>> devices. The theory was that the fuze transmitter, alone, would not
>> produce sufficient signal intensity, to trigger a thyratron tube switch.
>> However, as the projectile approached a target the radio waves reflected
>> by the target would gradually increase and come more and more into phase
>> with the fuze-generated signal. Once the signal level was high enough, the
>> fuze would know that the shell could do a maximum amount of damage,
>> and the thyratron tube switch would be triggered releasing the energy in a
>> charged capacitor and thus igniting the shell."
>>
>> >The German fuse workings.
>> >
>> >The fuse was based on electrostatic principles.
>>
>> At least this hopefully stops the previous claims the Germans
>> handed the design to the British who then used it.
>
>I never suggested that the Allies or British coppied the German fuse,I
>suggested that it accelerated the allied work. Early German
>investigations seem to go back to 1935. There is British work going to
>1937 and I suspect 1934 for optical fuses.

The claimed German system used an entirely different idea to find
proximity but somehow this is supposed to accelerate the project
initiated in the US that used another method?

Simply it is clear, like radar, people were thinking about how they
could have the shell explode near a target. This is not the same
thing as the Germans, yet again, being claimed to help allied
technology.

>> >The circuitry of the German fuse is not precisely known to me as Ido
>> >not have the schematics however the details are in allied files refred
>> >to I do not have a circuit layout drawing. It is known that the nose
>> >of the shell was electrically insulated and isolated from the rest of
>> >the shell. It was built by the company Rheinmetall. The program was
>> >halted in 1940 then restarted in early 1944 and then terminated again
>> >due to being over run by the allies at the point that it was ready for
>> >production.
>>
>> The above assumes the program was producing fused shells in 1940
>> as opposed to heading towards the idea. After all if the restart was
>> in early 1944 and the production facilities were over run something like
>> 15 months later just as production was about to start it shows how long
>> things actually took. How long the Germans really were from production.
>
>In actualy fact the 1000 test firings were conducted in 1944. There
>may have been firings in 1940 before cancellation but they were almost
>certainly not succesfull.

So the Germans had a design in 1940 that did not work but this is
supposed to have been of help to the allies?

>> The US started work on the fuse in July 1940 and later developed
>> optical and magnetic proximity fuses for mines and 4.5 inch rockets.
>>
>> >Initial fuse testing demonstrated a sensitivity of 1-2 meters and a
>> >reliability of 80% when fired against a metal cable target. A circuit
>> >adjustment yielded an increase to 3-4 meters and a reliability of close
>> >to 95%.
>> >
>> >Further work showed a 10-15 meter sensitivity. This was with 88mm
>> >canon shells. The shell to all intents and purposes ready for production.
>>
>> Again no dates are given, presumably we are to believe it was ready
>> for production in 1940, but then shut down because it was not ready
>> for production within 6 months, see below, and the time it actually
>> took in 1944/45 above.
>
>No, I believe there were NO test firings in 1940 that were succesfull.

Well that is cleared up at least.

>> There were considerable strides made
>> during the war when it came to reliability and miniaturisation of radio
>> parts, the later war experiments would have benefited from this.
>
>There are some notes kicking around somewhere on german techniques for
>valve seals in ceramic amplifier tubes. I believe they produced quite
>small ceramic valves,

So, like radar, the proximity fuse were bleeding edge and were not
something you could do off the shelf, additional technologies had to
be developed.

>> Note the lethal burst radius for a standard 88mm shell was around
>> 30 feet, or 9 metres. Given the standard fire control radar some
>> 59,000 88 mm shells were needed to cover the volume the aircraft
>> could be in when flying at 24,000 feet.
>>
>> >References are "Truth About the Wunderwaffen" by Igor Witowski who
>> >cites "Proximity Fuse Development - Rheinmettal Borsig A.G.
>> >Mullhausen. CIOS report ITEM nos 3 file nos XXVI -1 (1945)
>> >
>> >Capacitance based fuses became highly developed after the second world
>> >war due to their high resistance against jamming techniques.
>>
>> Ah, so the plan is to stop claiming the Germans gave the fuse to the
>> allies but to claim they thought of it first and did it better.
>
>Electrostatic fuses are apparently intrinisically hightly resistent to
>jamming.

Anything passive is harder to jam, but the fuse had to measure
something to explode and jamming could provide the something.

>The allies looked at using electrostatic principles but preceded with
>radio methods instead. I belive the Germans struggled to get the range
>up from 3-4 meters to 10-14 meters. It looks like they had to add a
>small antenna cable or tailing wire to achieve this.

So the allies came to the conclusion an active fuse was possible
with early 1940's technology and this avoided things like having to
make special shells with trailing antennas, attached to the fuse.
The Germans went down the route of requiring special shells,
as opposed to the allies having the ability to use the same shell
with different fuses.

A range of 3 to 4 metres is around 1/3 to 1/2 the lethal range of the
88mm shell.

>> >It is unlikely that the shell could have been easily degraded by
>> >jamming or chaff. (unlike the Allied shell).
>>
>> Yes, claim it does things better. Just ignore the idea the whole idea
>> of window was to mimic a bomber, and all that has to be done now
>> is to explain how the shell would discriminate against aluminium
>> in falling foils and in aircraft flying along.
>
>Window and Chaff could be used to form a layer below the bomber to
>predetonate some of the fuses.

So why the assertion above?

(snip)

>> Should be fun to create the mechanism to allow a high speed
>> vibrating contact, have it survive the acceleration of the firing
>> and then spin up to arm the shell
>
>The contact could be aligned along the axis to avoid centrifugal forces
>or a rotating button could be used.

Try surviving the initial acceleration first given the parts have to then
be able to move, after presumably bleeding some of the speed to
start any vibrations.

(snip)

>> > It
>> >was at this time that the Germans also abandoned their magnetron and
>> >microwave development teams and programs. Many programs suffered
>> >severely due to this; something that was to have far reaching
>> >consequences for the German war effort.
>>
>> It would be better to say scaled back as opposed to abandoned.
>
>Abandoned is accurate. They had to get the personel back out of the
>Army. They didn't even recognise the value of the magnetron since the
>microwave experts werent there to look at it. It was taken by some
>initally as proof that microwaves are not good for detecting aircraft.

Like so many of Germany's experimental aircraft trials that were
officially shut down but continued the same applied to the electronics
sector.

>> >What would have happened if the proximity fuse was not abandoned in
>> >1940 but development continued such that it entered service in 1943?
>>
>> The USAAF would have flown more night missions and deployed
>> B-29s to Europe.
>
>The B29 wasn't reliable till late 44. The engines overheated, caught
>fire (they were magnesium) and then burned through the spar. Nasty.

One of the main problems causing engine fires were the high ambient
air temperatures at the bases used in 1944 and the heavy loads being
carried given the range to target.

England is cooler and closer to the targets, plus having more engineering
personnel available if needed. The B-29 was really a 1945 bomber.

>> The allies would have devoted more to flak
>> suppression. The allies would have flown more missions on
>> cloudy days using the better navigation aids in 1944.
>>
>> Note the half way point for Bomber Command for bombs on Germany
>> was in late September 1944, the 8th was mid November 1944. It
>> was a very end loaded campaign.
>>
>> The number of flak batteries out ran the German ability to provide
>> them with proper fire control systems. Hence there were still sound
>> locators in use in 1944 to use an extreme example. The idea of
>> massed batteries was also driven by the amount of fire control
>> systems needed.
>
>All guns fired at once apparently.

Which shows the problems with fire controls. The massed firings did
up the hit rate.

>> Before the RAF introduced window Bomber Command was recording
>> that around 6 to 9% of returning aircraft on night missions had flak
>> damage, March to July 1943. This dropped to 2.85% in August and
>> averaged 2.3% for all of 1944 and 1.4% for 1945. Window remained
>> effective against the fire control radars for the remainder of the war.
>
>An moving target indicator called k-laus that used a 2 microsecond
>delay line to detect moving targets was expected to resolve window and
>chaff much better than wurzlaus and nurenberg. It didn't quite enter
>service.

Yet again the Germans were going to have it but never did.

The average for aircraft returning damaged by flak on night raids
February to December 1942 was 6.5%, for all of 1943 5.8%. In effect
a proximity fuse at around 3 to 7 times the lethality would restore to
exceed the pre window hit rates.

The USAAF carried window and active jammers but, of course, by day
the gunners could correct their aim by eye. Some batteries even had
the ability to track the H2X radars of USAAF pathfinders and use this
for ranging, electronic warfare was a 2 way street.

Geoffrey Sinclair
Remove the nb for email.

[John Keeney]

"Gord Beaman" > wrote in message
...
> "M. J. Powell" > wrote:
>
> >In message
> >, Geoffrey
> >Sinclair > writes
> >>>
> >IIRC the fuse was inactive until fired. The shock of firing broke a
> >glass cell containing the battery acid, the battery then produced the
> >required voltage.
> >
> >Mike
>
> Jesus...I'd hate to be the second guy to accidentally drop the
> damned thing...

If you think about it, the glass cell could be amazingly tough.
What would the acceleration of the initial firing be: a few thousand g'?
A piece of glass thick enough to be virtually unbreakable under
normal circumstances would shatter under its own weight if
bridging a hole.

[Keith W]

"Jim" > wrote in message ...
> Keith W wrote:
>> "Jim" > wrote in message ...
>>
>>>Eunometic wrote:
>>>
>>>>The German proximity fuse.
>>>>
>>>
>>>Not exactly an article for this newsgroup. We strive to remain on topic
>>>and would appreciate if posters would keep this in mind.
>>
>>
>> Incorrect, this is one of the rew recent threads that IS on topic.
>> As an example the use of proximity fuses was critical to defending
>> the USN against kamikaze attack in WW2
>>
>> Keith
> Our group is NAVAL AVIATION.
>

And the US NAVY used proximity fuses

> CHARTER: rec.aviation.military.naval
>
> The purpose of this newsgroup is to facilitate open discussion about all
> issues relating to Naval Aviation. It will provide a global forum for:
> - pilots
> - naval flight officers
> - flight crew members
> - aircraft maintenance personnel
> - air traffic controllers
> - flight deck personnel
> - other support personnel
> - others interested in Naval Aviation
>
> The discussions will be based upon:
> - flight training
> - squadron history
> - aircraft carrier operations
> - patrol missions
> - lighter-than-air operations
> - combat experiences


It seems to me that discussion of technology used
for shooting down enemy naval aircraft in combat is
entirely on topic.

Keith



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[Geoffrey Sinclair]

Correction time,
Geoffrey Sinclair wrote in message >...
>Overall according to the USAAF statistical digest the 8th Air force
>flew 1,034,052 heavy bomber sorties, 898,758 considered effective,
>losing 2,439 to flak. So between a 0.23 and 0.27% loss rate. The
>RAF considered 5% loss rates unsustainable long term and the
>USAAF seems to have agreed.


The heavy bomber loss figure is correct but the sortie totals are not,
I managed to use the total sorties for all types, heavy bomber sorties
totalled 332,904 airborne and 274,921 effective, giving loss rates
for heavy bombers to flak guns between 0.73 and 0.89%, depending
whether you use airborne or effective sorties.

Sorry for the error.

Geoffrey Sinclair
Remove the nb for email.

[Eunometic]

wrote:
> Eunometic wrote:
> > You'll find that there were at least two other allied photoelectric
> > based fuses. The first one entered service on rockets (it couldn't
> > handle the shock of a gun launch) but its photocells found
> application
> > in the punched paper tape reader of the colossus machine used in
> > decrypting Enigma. The second system could withstand a cannon
> lauch
> > and entered service. It used a torrodial perspex lens around the
> > circumference or rim of the shell that focused on a photocell.
> >
> > To be fair most of these German fuses were for different purposes
> than
> > cannon shell launch. Missiles need more sophisticated and jam
> > resistent radio proximity fuses. In addition the Germans were
> clearly
> > hedging their bets by developing a spread of systems to reduce
their
> > exposure to Allied Jamming attempts. The German were big investors
> in
> > both passive and active infrared technology and this was begining
to
> > pay of in 1945.
> >
> > In part the plethora of projects represents the secrecy
> > compartmentalisation, as well as intersevice rivalries but also a
> > policy of phased development was in place so that the Germans could
> > catch up and stay ahead in areas such as radar.
> >
> > In reality relying on one proximity fuze type is a recipe for
> disaster.
> > The allies relied on secrecy and then the hope that the Germans
> > couldn't react in time.
> >
> > The Wasserfall and Enzian Surface to Air missiles for instance had
a
> > spread of guidence and proximity fuze systems under development.
> > Wasserfall had a 3 axis gyroscopic version of the two axis
gyroscopic
> > guidence system in the V2 including apparently the PIGA
> accelerometer.
> > Even without external guidence it would have placed itself within a
> few
> > hundred meters of its target. There an infrared terminal homing
> system
> > was to be used (Madrid), or alternatively command guidence using a
> > radar called "Mannheim" (80 of these track-lock entered service) or
> > visual command guidence. There was also a semi active guidence
> system
> > under development called "Moritz". The command link was based on
a
> > specially developed version of the "Khel/Strassbourg" system used
on
> > Fritiz-X and Hs 293 but also on a purpose built system called
> > "Kogge/Brigge"
>
> SNIP
>
> See the US guided and glider bomb programs for a similar list of
> proposed and experimented with guidance systems (VB/BG series)
>
> Fletcher BG-1
> After the USAAF had cancelled the order for the Fletcher PQ-11A
> radio-controlled target drone, ten of the PQ-11As under construction
> were completed as XBG-1 bomb gliders. In the XBG-1, the PQ-11A's
engine
> was replaced by a 900 kg (2000 lb) bomb. The XBG-1 was to be towed to
> the target area by a larger aircraft and upon release was to be
guided
> to target impact by radio-commands using imagery transmitted from a
TV
> camera in the glider's nose. No information on the XBG-1 test program
> is available, but the model was never used operationally.
>
> Fletcher BG-2
> When the Frankfort CG-1 troop-carrying glider was cancelled in 1941,
> the three XCG-1s under construction were completed by Fletcher as
XBG-2
> bomb gliders. No information about the bomb load or the results of
> tests (if any!) is available, but the BG-2 program was cancelled in
> 1942.
>
> Cornelius BG-3
> The BG-3 was a design with nose-mounted horizontal stabilizers and
> forward-swept wings. As such it was possibly similar to Cornelius'
> XFG-1 fuel glider. Although the USAAF had planned to procure one
XBG-3
> prototype, this order was cancelled in 1942
>
> The VB designation was introduced by the U.S. Army Air Force in 1943,
> and covered unpowered guided bombs with effectively no standoff
gliding
> range (i.e. "vertical" bombs).
>
> ATSC VB-1/VB-2 Azon
> In April 1942, the USAAF's Materiel Command (became part of ATSC (Air
> Technical Service Command) in 1944) began the development of the Azon
> family of guided bombs. The initial variant, designated VB-1, was
based
> on a 450 kg (1000 lb) bomb (initially the M44, but later models
> apparently switched to the standard AN-M65), which was modified with
a
> new tail unit. The latter consisted of a gyroscopic unit to provent
the
> bomb from rolling, a flare for optical tracking, an octagonal shroud
> with control surfaces, and a radio-command receiver. When a VB-1 was
> dropped, the bombardier could track it through his bombsight and use
a
> joystick-type control to send corrective commands to the bomb. The
Azon
> guidance system allowed only lateral course corrections, but errors
in
> range could not be corrected (hence the name Azon = "Azimuth Only").
>
> The Azon development phase ended in late 1943, and the VB-1 was
> subsequently ordered into mass production. The second Azon variant
was
> the heavier VB-2, which was based on a 900 kg (2000 lb) bomb, but
that
> version was apparently not produced in very large numbers. The first
> VB-1/2 bombs were sent to Europe in February 1944, and a total of
15000
> Azons were produced until November 1944.
>
> Because of their azimuth-only guidance, the VB-1 was particularly
> suited to long and narrow targets (like bridges or railways) where
> range errors would be irrelevant. For "normal" targets, however, the
> VB-1 was actually not as good as unguided free-fall bombs, because a
> bomber could not break away immediately after dropping the bomb, and
> the accuracy was effectively not increased because of the lack of
range
> control. Another peculiarity of the Azon guidance set was the fact
that
> only five different radio channels were available for the command
link,
> meaning that not more than five bombs could be controlled
> independently. Although in theory a whole group of bombs using the
same
> command channel could be controlled simultaneously, this was not
> practical. The accuracy of all but the "primary" bomb (i.e. the one
> which was tracked by the bombardier) in such a group was rather bad,
> because the non-spinning Azon bombs showed a significant dispersion.
>
> The drawbacks of the Azon meant that its use remained very limited.
> However, it was employed rather successfully in Burma, where it was
> used to destroy very vital and therefore heavily defended bridges
along
> the Japanese supply lines. Less the 500 Azons were needed to destroy
27
> bridges.
>
> When the war ended, the USAAF quickly removed the VB-1 and VB-2 from
> its inventory. Because of the much reduced post-war funding, the
USAAF
> limited its guided vertical bomb research to the more advanced
> VB-3/VB-4 Razon family.
>
> ATSC VB-3/VB-4 Razon
> In parallel with the Azon tests, the ATSC also developed a more
> advanced variant called Razon, which was to be controllable in both
> range and azimuth. The designations VB-3 and VB-4 were assigned to
the
> 450 kg (1000 lb) and 900 kg (2000 lb) Razon versions, respectively.
The
> Razon guidance kit had two octagonal shrouds in a tandem arrangement.
> The most problematic part in Razon development was to build a
suitably
> modified bombsight, which would allow the bombardier to correctly
judge
> the bomb's deviation in range so that the range control could be used
> effectively. The Razon also had an improved radio-command link with
47
> separate channels, effectively eliminating the Azon's problems with
> concurrent drops by a multitude of bombers.
>
> The VB-3/VB-4 was combat-ready in summer 1945, and about 3000 Razons
> were subsequently produced, but none of them were used before World
War
> II was over. However, the VB-3 was operationally tested five years
> later during the first months of the Korean War. B-29 aircraft, which
> could carry eight VB-3s, dropped several hundred Razons on North
Korean
> bridges, and although the overall reliability of the bombs was rather
> low, some targets were actually destroyed. However, in general
multiple
> hits by the small the 450 kg (1000 lb) bombs were needed to destroy a
> large bridge span, and the USAF's use of guided bombs for these
special
> missions switched to the much larger VB-13/ASM-A-1 Tarzon.
>
> ATSC VB-5
> The VB-5 was a 450 kg (1000 lb) bomb, which used the same tandem
> octagonal control shroud arrangement as the VB-3/VB-4 Razon. However,
> the VB-5 was not command guided but used an autonomous light contrast
> seeker. This bomb did not go into production, presumably because the
> guidance mechanism didn't work as planned.


I am quite aware of AZON and RAZON and TARZON. AZON was given
development impetus by US awareness of Fritz-X.

Both Fritz-X and the Hs 293 were extremely accurate and quite reliable.
The TV guidence systems the Germans latter developed didn't match
them.
Hit rate (10m dia circle) under combat conditions was 45%.

Unlike AZON they were designed from the outset for point targets and
shiping and thus had controll on all axis as well as larger fin areas
for extra range controll.

The defficiency of Fritz-X (also known as the SC1400) was that the
aircraft was limited in its range of evasive manouver. After release
the bomber would conduct a sharp pullup as this aligned the bomb flare
for tracking as well as throwing of predicted FLAK. The Hs 293
allowed more evasive manouvers and essentially replace Fritz-X.

Although allied success at jamming seems exaggerated (sigint failed to
come up with jamming that worked; only capture of the bombs in Italy
lead to jammers that MAY have worked) the last set of Hs 293 missiles
used wire guidence. About 400 were used mainly in the retreat in the
east.


>
> ATSC VB-6 Felix
> The VB-6 Felix was a 450 kg (1000 lb) bomb with an octagonal control
> shroud and a heat seeking device in the nose. Intended for use
against
> strong infrared emitters (like e.g. blast furnaces), the VB-6 was
> tested with some success during 1945, but the program was cancelled
at
> the end of World War II. The U.S. Navy developed a very similar
> IR-guided bomb as the ASM-N-4 Dove.

The Germans had several infrared seekers under development for use
against ships, aircraft and ground targets (blast furnaces) etc.

The company Kepke produced for testing "netzhaut" (means retina in
German) for attacking blast furnaces with BV 246 glide bombs (200km
range). Part of a series known as "Widder", "Netzhout" and "Krebs"

Hamburg I by the company Elac. 30mm detector with 30cm mirror for
Wasserfall warhead. 60 degree sweep, 10 degree accuracy. Intended for
Wassefall missile. It worked but needed a more sophisticated scan to
extend acquistion range to 2-5km. This more sophisticate rossete scan
was never completed. The device was known as "Kiel III".

Hamburg II replaced the Lead Sulphide Cell with a Caesium Oxide Cell
and a 14cm mirror. It was smaller but not much of an improvement but
considered good for attacking shipping. Simulated attacks using a He
111 showed that it was necessary to gyro-stabalise the head.

I believe lack of gyro-stabilisation is what reduced early TV guidence
accruacy as well.

"Embden" was an AEG competitor of Hamburg.

Kepke produced "Madrid" for use on Glide bombs and Enzian missiles.

Most "state of the art" was "armin-2" by Dr Kutscher of Elac. Armin-2
used 'thermovision'and had a range of 1.5km when tracking a He 111
bomber.
Probably used electronic spiral scaning of an image.

Kepke series of homers for ships and aircraft.

Some of the tests showed that the homers clealy worked. Usaully the
problem was inadaquet range:the powers wanted more than the 1.5km due
to inadaquet scan pattern or lack of gyrostabalisation. The fancy scan
patterns existed for scanners used on infrared imaging systems.

Gluhwurmchen (glowworm) by Rheinmetall for missiles.

Much hope was placed in these homing devices and they showed every
signe of being practical. For some reason ranges of 1.5km were never
considered adaquete.

>
> ATSC VB-7, VB-8
> The VB-7 and VB-8 both used a TV/radio-command guidance, where a TV
> camera in the bomb's nose transmitted the image to a display set for
> the bombardier, who could then correct the bomb's course by
> radio-commands. The weights of the VB-7/VB-8 are unclear, but it can
be
> assumed that these two guided bombs were cancelled early in the
> development phase.

The problem with TV guidence was the poor resolution,poor light
sensitivity (esp in europe) and poor scan update and lack of
gyrostabilisation.

Nevertheless the Germans seem to have gotten confident that it would
work both for SAM missiles and Ground attack.

>
> Douglas VB-9/VB-10/VB-11/VB-12 Roc
> The Roc series of guided bombs was developed by Douglas, the MIT and
> the NDRC (National Defense Research Committee). The VB-9 model was a
> 450 kg (1000 lb) bomb with cruciform wings and fins and a radar
seeker
> in the nose. The radar image was transmitted to the bombardier who
> could use it to direct the bomb's path by radio commands. However,
the
> radar was often useless because of ground clutter, and the VB-9
program
> was terminated in early 1945.
>
> VB-9
> The later Roc models all used a 450 kg (1000 lb) bomb body of 61 cm
(24
> in) diameter and 3 m (10 ft) length. They were fitted with two
circular
> shrouds, a larger one which could move around two axes for
directional
> steering, and a smaller one in the tail designed to slow down the
bomb
> to facilitate the tracking and guidance task of the bombardier. The
> VB-10 had a TV camera and transmitter, so that the bombardier could
> track the bomb via the image on his TV display set. The VB-11 had an
> infrared seeker for autonomous heat-seeking guidance, and the VB-12
was
> tracked visually (making it similar in operation to the VB-3/VB-4
> Razon).

The Germans were only just begining to introduce to troop testing
ground mapping microwave radars.

There was work on correlating photograhed images with a image of the
terrain below for cruise missile guidence.




>
> VB-10/11/12
> The VB-10 (and presumably also the VB-11/VB-12 models) was tested
> between September 1944 and May 1945, when the Roc program was
> terminated without any model going into production.
>
> Bell VB-13 Tarzon
> The VB-13 is discussed on a separate page about the VB-13/ASM-A-1
> Tarzon.
>
> Specifications
> The few available data on the dimensions and weights of the VB-series
> bombs are mentioned in the main text
>
>
>
>
>
>
> http://www.designation-systems.net/dusrm/app1/index.html
>
> http://www.wpafb.af.mil/museum/arm/vb.htm
>
>
>
>
>
> > The smaller Ruhrstahl X-4 wire guided Air to Air missile opperated
> with
> > basic wire guidence and a contact fuse backed up accoustic
proximity
> > fuse called "Kranich". A accoustic terminal homing system "Dogge"
> was
> > also under development as was an infrared terminal homing system
and
> > proxitmity fuse. The same systems were planed for the Enzian
missile
> > including an accoustic homing head called "Archimedes"
> >
> > The accoustic homing systems worked quite well. A Me 262 Jet
> equiped
> > with accoustic homing systems could detect a bomber and its
> directions
> > to about 4-5 miles range.
>
> SNIP
>
> I'm sorry, but I find an acoustic system that sensitive, yet able to
> filter out the wind noise of going 500 mph, along with the howl of
two
> turbojets a bit hard to believe. Could you provide more details or a
> citation?


Several accoustic homers for aircraft and missiles were under
development.

1 "Baldrin" by Messerscmitt and Telefunken. Used 16 valves and 4
microphones. Range was 350m when flown on piston engined aircraft and
several kilometers when flown on an Me 262. It had a wide 180 degree
view.

2 Parrallel development at ELAC with an estimated range of 2km but
never named or tested.

3 "Pudel" single microphone homer for the axially spining X-4 missile.

4 A Dr Trage of "Reichs Post" had a 4 microphone system under
development.

Baldrin was the only one tested.

I estimate that a 3 or 4 bladed propeller at 1500 rpm will produce 75
to 100 hertz and that a 12 to 18 cylinder exhaust will produced 150 to
225 hertz.

A 9000 rpm 60 bladed jet starts at about 4000 hertz.


The germans on their sub sonars used electro-accoustic crystals to
phase shift to use constructive interferience to determin direction and
I expect the same technique in sonic aircraft trackers.

Don't forget that sound was used to aim and range FLAK and that even in
WW1 in britain huge granit parabolic sound dishes would detect and
triangulate gotha bombers and zepplins out to 20-25 knautical miles.

Sound can locate artillery fire and can even track bullets and shells.

Its a little slow but it is apparently a concern for stealth aircraft.

[Keith W]

"Eunometic" > wrote in message
oups.com...
>

>
> The Germans were only just begining to introduce to troop testing
> ground mapping microwave radars.
>

Whereas the RAF and USAF were using them in service
by the thousand

<snip>


>
>
> Several accoustic homers for aircraft and missiles were under
> development.
>
> 1 "Baldrin" by Messerscmitt and Telefunken. Used 16 valves and 4
> microphones. Range was 350m when flown on piston engined aircraft and
> several kilometers when flown on an Me 262. It had a wide 180 degree
> view.
>
> 2 Parrallel development at ELAC with an estimated range of 2km but
> never named or tested.
>
> 3 "Pudel" single microphone homer for the axially spining X-4 missile.
>

Which was of course never deployed

> 4 A Dr Trage of "Reichs Post" had a 4 microphone system under
> development.
>
> Baldrin was the only one tested.
>
> I estimate that a 3 or 4 bladed propeller at 1500 rpm will produce 75
> to 100 hertz and that a 12 to 18 cylinder exhaust will produced 150 to
> 225 hertz.
>


Take a sound meter to an airshow, you'll get a broader band
of frequencies than that

> A 9000 rpm 60 bladed jet starts at about 4000 hertz.
>
>
> The germans on their sub sonars used electro-accoustic crystals to
> phase shift to use constructive interferience to determin direction and
> I expect the same technique in sonic aircraft trackers.
>

Submarines suffer from somewhat less flow noise than an aircraft


> Don't forget that sound was used to aim and range FLAK and that even in
> WW1 in britain huge granit parabolic sound dishes would detect and
> triangulate gotha bombers and zepplins out to 20-25 knautical miles.
>

No the sound dishes were built in the late 1920's and early 1930's

> Sound can locate artillery fire and can even track bullets and shells.
>

Lots of luck trying to track a supersonic projectile with a medium
that travels less than half as fast.

It can tell you where it WAS and perhaps even where it was fired
from but not where its now.

> Its a little slow but it is apparently a concern for stealth aircraft.
>

Indeed but the inbuilt limitations make it almost useless for targetting.

Keith



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[Paul J. Adam]

In message
>, Geoffrey
Sinclair > writes
>It should be noted the claimed major shoot down was the USN
>ships reporting what they thought they had shot down.

And, like bomber gunners, both raid count and bandits splashed were
prone to error... when Seaman Smith sees the aircraft he's hammering
with 40mm shellfire burst into flames and ditch, naturally that's *his*
kill. As it is also Seaman Jones who'd just riddled it with 20mm, and
it's also a kill claimed by the 5" teams who had been shredding it with
fragments on its way in... and every one of those claims is honestly
made.
>
>In the fights with Kamikazes the USN ships reported they needed
>to fire 100% VT (proximity) fuses, since there was normally no time
>to set and use time fuses.

However, they were told by BuOrd to use 25% time fuzed shells: the
bursts had deterrent effect, indicated the raid to other units, but
primarily it pointed up any gross errors like the director aiming at the
wrong group of aircraft.

>Before the RAF introduced window Bomber Command was recording
>that around 6 to 9% of returning aircraft on night missions had flak
>damage, March to July 1943. This dropped to 2.85% in August and
>averaged 2.3% for all of 1944 and 1.4% for 1945. Window remained
>effective against the fire control radars for the remainder of the war.
>The average for aircraft returning damaged by flak on night raids
>February to December 1942 was 6.5%, for all of 1943 5.8%. In effect
>a proximity fuse at around 3 to 7 times the lethality would restore to
>exceed the pre window hit rates.

US experience was that VT fuzing was about three times more effective
than time fuzing on a straight rounds-per-bird comparison: this rose to
nearer four times by war's end as experience was gained and reliability
improved.

--
He thinks too much: such men are dangerous.
Julius Caesar I:2

Paul J. Adam MainBox<at>jrwlynch[dot]demon{dot}co(.)uk