A aviation & planes forum. AviationBanter

If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below.

Go Back   Home » AviationBanter forum » rec.aviation newsgroups » Naval Aviation
Site Map Home Register Authors List Search Today's Posts Mark Forums Read Web Partners

The German proximity fuse.



 
 
Thread Tools Display Modes
  #31  
Old May 11th 05, 07:48 AM
John Keeney
external usenet poster
 
Posts: n/a
Default


"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.


  #32  
Old May 11th 05, 09:53 AM
Keith W
external usenet poster
 
Posts: n/a
Default


"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



----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==----
http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups
----= East and West-Coast Server Farms - Total Privacy via Encryption =----
  #33  
Old May 11th 05, 01:01 PM
Geoffrey Sinclair
external usenet poster
 
Posts: n/a
Default

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.


  #34  
Old May 11th 05, 02:51 PM
Eunometic
external usenet poster
 
Posts: n/a
Default


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/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?



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.

  #35  
Old May 11th 05, 05:11 PM
Keith W
external usenet poster
 
Posts: n/a
Default


"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



----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==----
http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups
----= East and West-Coast Server Farms - Total Privacy via Encryption =----
  #36  
Old May 11th 05, 06:02 PM
Paul J. Adam
external usenet poster
 
Posts: n/a
Default

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 MainBoxatjrwlynch[dot]demon{dot}co(.)uk
 




Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
50% of NAZI oil was supplied from US Grantland Military Aviation 106 January 18th 14 08:58 PM
Fuse the Wire or Fuse the Device? ContestID67 Soaring 11 April 27th 05 03:13 AM
FDR and Bush 43 WalterM140 Military Aviation 44 June 24th 04 12:16 AM
Soviet Submarines Losses - WWII Mike Yared Military Aviation 4 October 30th 03 04:09 AM
German historian provokes row over war photos BackToNormal Military Aviation 21 October 24th 03 11:32 PM


All times are GMT +1. The time now is 01:28 PM.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 AviationBanter.
The comments are property of their posters.