German BT (Torpedo/Bomb) Projects

kiradog

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I have a series of poor images showing images of the BT series of what I gather are Torpedo/Bombs- BT200, BT400 and EB1400

I can find virtually nothing about these. Can someone in the group shed some light on these?

Thanx in advance
 

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Grzesio

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There's sadly a lot of misinformation in what Justo posted.
Except for some plans, neither Pi-Mz nor Unterwasserzuender were used in BTs. The Pi-MZ was actually found inappropriate for the BT and could not be used at all, while the Uw.Z. was not even tested. Operational BT models used standard delayed action electrical bomb fuze, mounted on a fuselage side. Generally not hydrostatic, but time, distance and proximity fuzes were considered usable.
There's no physical possibility for a BT dropped from 200 m in a 20 degrees dive to cover 2800 m, especially that the underwater trajectory was only 50-100 m long - a BT dropped this way at 600 km/h would enter the water after after some 450 m of flight. BTs were to be dropped from a climb, not dive.
Only bigger BTs (1000+) were made from welded steel plates, smaller had cast warheads.
The BT 1000 RS did not actually reach 960 km/h, this value refers to max. velocity at which usual BT could be dropped.
I don't know if BT 1850s were used against Remagen bridge, but smaller BTs were to be used (and probably were indeed) by III./KG 200 against sea targets in northern Europe.

The last picture posted by kiradog shows an EB (Eintauchbombe), not BT (Bombentorpedo) - a similar projectile developed by Henschel, while BTs came from FGZ. These are really amazing photos! :D

Regards

Grzesio
 

Michel Van

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there also this picture
me163-torpedos-jpg.20444



a Me 163B with two torpedoes


in 1992 they Discover in Aerodynamische Versuch Anstalt (AVA) at Göttingen several Files notes.
of Windchannel Model of a Me 163B with 2 Torpedo Bomb's type BT1000.

one note was of a conference between engineer Hubert (from Messerschmitt) and professor Betz from AVA
"its necessary to check the Stability Me 163B with BT1000 in a Windchannel Test"
"the soon use of Plane against Shiptarget deepens of that Test Result"
"The Model is Ready middle of February for Test of 2 Day duration.
"A longer Test has to be interrupt, because of not urgent." signature mister Hildenbrand.
the note is date 9 February 1944.
more Files notes and Photos show this Test was made

A letter from 22. September 1944 from Junkers "Flugzeugwerke und Motorenwerke" to AVA
say they receive the test result from February

the BT1000 Bomb Torpedo's
1000 kg Bomb rocket for land and sea Target
from Research's institute Graf Zeppelin in Stuttgart-Ruit

the Pilot or Bomber used a special developed "Reflexvisier" from Drop height depend the BT1000 fly 3000 Meter far
the BT1000 was Propelled by Solid rocket build by company "Rheinmetall"

Source: Flug Revue April 1992 page 49
Source: Picture Stüdienbüro für Luftfahrt, Feiler
 
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Jemiba

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In "Der Flieger", August 1963 was an article about tests with the Fw 190 and the BT-1400.
A drawing and a (probably authentic) photo is attached.
 

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Jemiba

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In the book „Me 262“ by Willy Radinger and Walter Schick, I've found a drawing showing the
Me 262 with a number of stores, including the BT 700:
 

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Jemiba

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... and the dedicated "Schnellbomber" variant of the Me 262 is shown with the BT 700, too,
on what quite probably is the facsimile of an original drawing (from "Flugzeug Classic Special 11")
 

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Wurger

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Hi Jens,
does "Flugzeug Classic Special 11!" include other goodies :) ?
 

Jemiba

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In Manfred Griehls „Typenkompass – Deutsche Raketen und Lenkwaffen“ the BT series is mentioned, too of course,
with a sideview of an Arado Ar 234 C-3 carrying a BT 1400 and a photo of a test drop from a Bf 110. The latter
maybe sutable to confirm Grzesios statement, that the bomb torpedo was released from a (slight) climb.
 

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@ndrew

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Photos posted by Kiradog were made in T.W.P. = Torpedo Waffen Platz Gotenhafen-Hexengrund.
BTW do the come from T1022?
 

Grzesio

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But was there a BT 1400 RS? :D
I've only heard about the BT 1000 RS, and yes, the engine was generally the same as in the RhB rocket assisted AP bombs - with six nozzles and a central ring nozzle acting as a reduction valve.
By the way - this Me 163 B wind tunnel model is apparently equipped with the BT 1000 RS, even if they are called BT 1000 in original drawings.

By the way 2 - something is wrong with the BT 1000 data posted by Justo above - the warhead seems to be far too short compared to the overall length.

By the way 3 - do we know how the BT 1400 looked like? Available representations differ one from another, particularly in the tail section area, is there a convincing drawing of the era?
 

@ndrew

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Here are informations with exact total lenght, diameter of BTs:
BT200 2395, 495
BT400 2946, 624
BT700 3358, 752
BT1400 4560, 1265
BT1800 4690, ?

I hope to surprise You with new informations during this weekend.

Grzesio-have You found any more detailed info about EB? I mean sketch or photos?

Regards
@ndrew
 

Grzesio

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So, waiting for the surprise B) , an illustration of the BT 1400 riddle.

1. Most common representation, continuously being repeated by scale plan authors and model makers. Very close to an enlarged BT 700, while warhead dimensions are completely different from available data, e.g. the conical section is too long.
2. OP-1666 - interesting representation of the fins, while the warhead is far too slim.
3. A 1963 drawing from Der Flieger, presented above. Even more interesting tail section. :)
4. Original German drawing of the Ar 234 armed with BT 1400. I am sadly unable to interpret details of the the tail section, which seems to be surprisingly complex in shape. Warhead dimensions and fin span are perfectly accurate, though. Also the suspension lug placement matches centre of mass location.
5. My own proposition based on OP-1666 and Ar 234 drawings.
 

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@ndrew

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Hello,

today Polish Navy Museum in Gdynia organised recovery of 2 Bombentorpedoes type BT1000 from ex-Torpedowaffenplatz Gotenhafen Hexengrund (today Gdynia Babie-Doły).
So far it looks that these pieces are the only one existing till now.
2 BTs were without engine which was recovered earlier. It has solid propellant. There was no fins attached to the main body.
We hope some new items to be found in future ;)


Regards
@ndrew
 

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Grey Havoc

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I'm somewhat surprised that the Soviets overlooked them.
 

@ndrew

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It was covered by earth. Due to the fact it was inside gorge where the ground still is unstable it poped-up itself.
I think some could be abonded by German and later captured by Soviets but there are not good sources on this subject.
 

@ndrew

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Here are close-ups on second survived engine from BT.
It seems that it's peeled off external skin.
Green colour covers inner tube.
 

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Foo Fighter

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Any inference to the squall (Skvall ?) rocket torpedo?
 

sgeorges4

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Who where the aircraft who where proposed for the BT 400 bomb?
 

Grzesio

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Fw 190 F-8/U2 (renamed into Fw-190 F-8/R15 in the end of 1944) had to carry two BT 400 under the wings. A handful of these aircraft was actiually delivered to III./KG 200 till April 1945.
Ar 234 B-2 was also considered in the summer of 1944 for carrying two BT 400 under the nacelles (plus Magirusbombe gun pod under the fuselage).
 

lastdingo

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Has anyone ever found a Rechlin (or comparable) test report about whether BTs would work anything like advertised?
The total absence of them in postwar naval airpower is suspicious.
 

Grzesio

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Rather Gotenhafen-Hexengrund than Rechlin, there are reports and the BTs worked. ;)
Similar projectiles were designed after the war in e.g. USA and USSR, but I think rapid development of guided missiles and torpedoes rendered them obsolete (just like no heavy/long range AA rockets were used after the war).
 

Darthtabby

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There's sadly a lot of misinformation in what Justo posted.
Except for some plans, neither Pi-Mz nor Unterwasserzuender were used in BTs. The Pi-MZ was actually found inappropriate for the BT and could not be used at all, while the Uw.Z. was not even tested. Operational BT models used standard delayed action electrical bomb fuze, mounted on a fuselage side. Generally not hydrostatic, but time, distance and proximity fuzes were considered usable.
There's no physical possibility for a BT dropped from 200 m in a 20 degrees dive to cover 2800 m, especially that the underwater trajectory was only 50-100 m long - a BT dropped this way at 600 km/h would enter the water after after some 450 m of flight. BTs were to be dropped from a climb, not dive.
Only bigger BTs (1000+) were made from welded steel plates, smaller had cast warheads.
The BT 1000 RS did not actually reach 960 km/h, this value refers to max. velocity at which usual BT could be dropped.
I don't know if BT 1850s were used against Remagen bridge, but smaller BTs were to be used (and probably were indeed) by III./KG 200 against sea targets in northern Europe.

The last picture posted by kiradog shows an EB (Eintauchbombe), not BT (Bombentorpedo) - a similar projectile developed by Henschel, while BTs came from FGZ. These are really amazing photos! :D

Regards

Grzesio

I'm curious about where you read up about these weapons. Is there anything more you can tell use about them? I'm particularly interested in how they were meant to be employed. Do any of your sources provide any information about the sighting system, or what sort of range the weapons could achieve using the climbing attack profile?
 

Natter

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The Pi52b was intended for use on the Bombentorpedos (it was an adaption of the Pi52 ("Pi Wien") - a passive magnetic pistol), but was still under development by the end of the war.
 

Grzesio

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I'm curious about where you read up about these weapons.
Books - like Hahn's book on Luftwaffe armament, most of the information given by Justo was taken - or actually misinterpreted - from.
Do any of your sources provide any information about the sighting system, or what sort of range the weapons could achieve using the climbing attack profile?
TSA automatic bomb release sight was intended for use with BTs, e.g. Fw 190 F-8/R15 and R16 were to be equipped with TSA 2A variant in early 1945.
It's hard to find information about BT range in air, but - as Hahn wrote - it could be in the order of 3 km in case of a release in climb. On the other hand, for example, one can estimate, during tests in Gotenhafen in 1944, BT released at 900 m height in a 20 degrees dive (not climb) covered some 1600 m before entering water, and still some 900 m released in a 30 degrees dive in 600 m height.
 

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