The German proximity fuse.

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

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/d...pp1/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?

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.

"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

"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

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.

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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

"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.

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.

Eunometic wrote in message . com...

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
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