Characteristics of WW2 Air Launched torpedoes from different nations

[Wild_Bill_Kelso]

I have read in general sense and in some specific examples about the parameters of air launched torpedoes in WW2, to the extent that I gather there was a wide range terms of the altitude and speed of the aircraft from which the torpedo was launched, as well as range and speed of the torpedo, and general notions of reliability.

Air launched torpedoes were important weapons in the early war, sinking a large number of ships. The Japanese torpedos were notoriously very good while the US were notoriously almost useless. Eventually precision guided munitions replaced both the torpedo and the dive bomber delivered bomb, but for a while these were decisive weapons.

I'm interested in the breakdown of major types.

Japanese - Type 91 perhaps the best of the war?
US Mark 13 torpedo - "failed in 70% of drops made from AC traveling faster than 170 mph"
-----------------------(supposedly, according to the Wiki by putting wooden sabots on them, this was vastly increased to 470 mph and a height of 2400 feet, but this was probably postwar)
Britain had the Mark XV and then later the Mark XVII, and finally the Torpex
I gather that the Italian made Fiume torpedoes were very good and that the Germans were using them in preference to their own. They also made a license built copy of the Japanese type 91.

The Italians also had the motobomba which could be dropped in the midst of a group of ships and would drive in a spiral until it hit something.
I know the Russians used air launched Torpedoes in the Baltic but don't know whether they were Russian made or British ?


Does anyone know what the launch altitude and speeds were for the various major torpedo types?

 

[tomo pauk]

I know the Russians used air launched Torpedoes in the Baltic but don't know whether they were Russian made or British ?

Domestic production.

Britain had the Mark XV and then later the Mark XVII, and finally the Torpex

Torpex was a type of explosive used on some torpedo types. British torpedos worked well.

I gather that the Italian made Fiume torpedoes were very good and that the Germans were using them in preference to their own. They also made a license built copy of the Japanese type 91.

Italian torpedos were made in Fiume (today's Rijeka, Croatia) by Whitehead company (named 'Torpedo' after the war, producing farm tractors post-war, among other machinery).
German torpedoes early in the war were problematic.

 

[Wild_Bill_Kelso]

So was it one of those 'only drop this at 50' and 140 mph' types or one of the 300' and 250 mph types?

 

[cherry blossom]

The Naval Weapons site Naval Weapons of the World - NavWeaps seems to be the best single website for finding details of guns and torpedoes. Not everything is correct but, if you find an error, Tony will correct it.

 

[fubar57]

528 pages of torpedo

 

[Wild_Bill_Kelso]

Impressive... a "complete" history? I wonder if they go back to the medieval torpedoes...

 

[Wild_Bill_Kelso]

The Naval Weapons site Naval Weapons of the World - NavWeaps seems to be the best single website for finding details of guns and torpedoes. Not everything is correct but, if you find an error, Tony will correct it.

This is a fantastic resource in general though I don't see where it gives the drop speed and altitude for most of these (which were critical for efficacy). It does at least give range and speed.

It does give us some stats along these lines for a couple of the Russian torpedos. The TAV-15 was designed to be dropped from 2,000-3,000 meters and used drogue parachutes (makes me curious how do they aim it, or was it one of those circling ones.)

The site notes that the 45-36AN (17" / 45 cm) torpedo, the "main Russian aircraft torpedo of WW2" was a low-altitude weapon 'modified to survive water entry' though it doesn't give us drop height or drop speed.

Some stats from the site:

Russian 45-36AN (17" / 45 cm) torpedo, Range is given as 4,000 meters at 39 kts with a 400 kg warhead

Russian 53-39 (21") torpedo had double the range or higher speed (4,000 meters at 51 kts or 8,000 meters at 39 kts) with a 317 kg warhead.

Japanese type 91 (basic) is given as 2,000 meters at 41-43 kts. with a 240 kg warhead
Japanese type 91 (improved) is given as 2,000 meters at 41-43 knots with a 240, 308, or 420 kg warhead

British 18" Mark XII 1,370 meters @ 40 kts with 176 kg warhead
British 18" Mark XV 2,290 meters @40 kts with 247 kg "Torpex" warhead

US Mark 13 5,210 meters @ 30 kts with 178 kg TNT or (later?) 272 kg HBX warhead

Italian Fiume 17.7" F200 range 3,000 m @ 40 kts with 200 kg warhead (was used by the Germans as the F5W)
Italian Fiume 17.7" Si 200 range 3,000 m @ 40 kts with 200 kg warhead
Italian Fiume 19.7" W 120 "Motobomba" range 15,000m @ 13.5 knots decreasing to 3.9 kts, with 120 kg warhead (used by Germans as LT350)

German 17.7" F5b range 2,000 meters @ 40 kts, 6,000 meters @ 24 kts, 180-250 kg hexanite warhead.

So just based on range and speed and warhead, the Russian type looks very good. But for air launched torpedoes launch speed and launch altitude were very important.

Maybe the US should have done some reverse lend-lease and imported some Soviet torpedoes!

 

[Thumpalumpacus]

Impressive... a "complete" history? I wonder if they go back to the medieval torpedoes...

You mean the ones with oarsmen?

 

[Wild_Bill_Kelso]

You mean the ones with oarsmen?

Nope, compressed air powered. Just experimental though, it's unclear if they were ever used in battle.

A 15th Century Italian artist and engineer named Giovanni Fontana created one of several experimental types. In a famous incident when he was testing such a device in a lake near Padua, witnesses thought it worked by magic, and he ridiculed them for it.

But he also liked to create mechanical automata which were designed to take advantage of such an gullible audience.

 

[Thumpalumpacus]

Nope, compressed air powered. Just experimental though, it's unclear if they were ever used in battle.

A 15th Century Italian artist and engineer named Giovanni Fontana created one of several experimental types. In a famous incident when he was testing such a device in a lake near Padua, witnesses thought it worked by magic, and he ridiculed them for it.

Might you be so kind as to provide some sources to read?

 

[fubar57]

Impressive... a "complete" history? I wonder if they go back to the medieval torpedoes...

Part 1 starts at 1804

 

[EwenS]

There is an article in the following edition of the RAF Historical Journal on British air launched torpedoes that you might find interesting. Page 121 onwards. Highlights some of the problems of dropping torpedoes.

https://www.rafmuseum.org.uk/documents/Research/RAF-Historical-Society-Journals/Journal_45_Seminar_conventional_weapons.pdf

There is a wartime British instructional film available on YouTube about the operation of the standard British Mk.XII torpedo of the early war period. From around 16.40 it deals with the operation of the Monoplane Air Tail and Drum Control Gear which allowed torpedoes to be dropped from greater speeds and altitudes.


As for the Italians, interservice rivalries were prevalent in the inter war period. The Regia Aeronautica only formed its first torpedo bomber unit in July 1940 using the S.79 Sparviero with Whitehead torpedoes. After several failed operations, their first success was against HMS Kent in Sept 1940.

 

[EwenS]

Recent USNI article by Norman Friedman on the US Mk.13 torpedo development.

Evolution of a Ship-Sinker

The Mk 13 torpedo emerged as a devastating weapon responsible for sinking a Japanese superbattleship at the Battle of Leyte Gulf and another one off Okinawa.

www.usni.org

Edit:- USN Training films on the .mk.13

Aerial Torpedo Attack with Mk 13 Torpedo

 

[Geoffrey Sinclair]

Naval Weapons of World War Two by Donald Campbell. Ignoring the homing torpedoes.

RN
Mark XI, not used by aircraft during the war, 150 knots at up to 100 feet.
Mark XII, initially at 150 knots control in the air was unreliable, later fitted with the mark XV tail and strengthened to handle launch speeds of 250 to 270 knots. Main torpedo for the first half of the war.
Mark XV, drop speed up to 270 knots but it took time to actually make the entire torpedo strong enough
Mark XVII, under trial at end of war, 350 knots drop speed.

USN
Mark 13, pre war 110 knots from 50 feet, by 1944 "high speed" from 1,000 feet, end war 410 knots from 2,400 feet.

IJN
Type 91, early war optimum launch 180 knots from 100 metres but up to 250/260 knots from 300 metres, in 1943 up to 300 knots, in 1944 up to 400 knots

Germany,
F5 pre war 75 knots from 15 to 25 metres, in 1942 120/130 knots from 30/40 metres but 150 knots caused no serious problems.

F5W, Italian.

Italy
W and SI, no launch limits given.

 

[WARSPITER]

Swordfish release height was supposed to be 18 feet - don't know what speed but it wouldn't be quick.
An account of the Swordfish attack on Bismark tells of the observer watching over the side then calling to the
pilot when to let the torpedo go so it would start in a trough between waves and stay straight.

Torpex was a more powerful mix than normal tnt giving 150% more explosive power for the same weight. More
bang for your buck. This was also used in the 12,000lb tallboy bombs. Torpex would be poured into a bomb casing
in molten form and then left to cool, in some cases this was up to a month.

 

[EwenS]

Swordfish release height was supposed to be 18 feet - don't know what speed but it wouldn't be quick.
An account of the Swordfish attack on Bismark tells of the observer watching over the side then calling to the
pilot when to let the torpedo go so it would start in a trough between waves and stay straight.

The dropping height being taught to FAA Swordfish and Albacore crews at Crail in 1940/41 was 50ft at speeds of 90-100 knots (103-115mph). Accounts of operations rarely mention dropping heights, but more often dropping distances from the target. At Taranto for example dropping distances varied between 400 and 1,000 yards depending on where each pilot found themselves.

By 1943 Barracuda pilots were being trained at Crail to drop at 200ft and 200 knots (230mph) ideally 1,000 yards from the target.

Judging the height above the ocean was one of the more difficult skills pilots had to learn, especially at night or in bad weather. Operations in the North Atlantic and North Sea could provide very difficult torpedo dropping conditions with heavy seas in often appalling weather. During the Bismarck chase, Ark Royal's flight deck was reportedly pitching 60ft. Hence the need for the Observer to look over the cockpit side to determine the height above the sea. No radio altimeters at that time.

 

[AL90]

Swordfish release height was supposed to be 18 feet - don't know what speed but it wouldn't be quick.
An account of the Swordfish attack on Bismark tells of the observer watching over the side then calling to the
pilot when to let the torpedo go so it would start in a trough between waves and stay straight.

Torpex was a more powerful mix than normal tnt giving 150% more explosive power for the same weight. More
bang for your buck. This was also used in the 12,000lb tallboy bombs. Torpex would be poured into a bomb casing
in molten form and then left to cool, in some cases this was up to a month.

Torpex- TNT/RDX/ Aluminum Powder. Same flling as still used in 1000lb aircraft bomb @ 225lb. Highly stable explosive, ideal for slapping through a hull. Used to take us 24hrs to steam the Torpex out a 1000lb at ROF Bishopton. Gantry held 13 bombs at a time in the Big Steamy. Disposal was by burning which only happened when enough waste cordite was used.

 

[Wild_Bill_Kelso]

Might you be so kind as to provide some sources to read?

Giovanni Fontana (engineer) - Wikipedia

en.wikipedia.org

https://arxiv.org/ftp/arxiv/papers/1304/1304.4588.pdf

Bellicorum Instrumentorum Liber

The First Italian Technology Manuscript [prefiguring Khan ? - the body as machine(s)] ...

bibliodyssey.blogspot.com

https://dfg-viewer.de/show/?set[met...e-sammlungen.de/~db/mets/bsb00013084_mets.xml

 

[Wild_Bill_Kelso]

There is an article in the following edition of the RAF Historical Journal on British air launched torpedoes that you might find interesting. Page 121 onwards. Highlights some of the problems of dropping torpedoes.

https://www.rafmuseum.org.uk/documents/Research/RAF-Historical-Society-Journals/Journal_45_Seminar_conventional_weapons.pdf

There is a wartime British instructional film available on YouTube about the operation of the standard British Mk.XII torpedo of the early war period. From around 16.40 it deals with the operation of the Monoplane Air Tail and Drum Control Gear which allowed torpedoes to be dropped from greater speeds and altitudes.


As for the Italians, interservice rivalries were prevalent in the inter war period. The Regia Aeronautica only formed its first torpedo bomber unit in July 1940 using the S.79 Sparviero with Whitehead torpedoes. After several failed operations, their first success was against HMS Kent in Sept 1940.

Ultimately the Regia Aeronautica was very successful with the SM.79 torpedo bombers, especially given that the latter were basically 1930s airliners. They took a fair number of losses but hit and sank a lot of British ships, in large part probably down to the torpedoes (and I would guess, a fairly high release speed, though I don't know for sure)

 

[Wild_Bill_Kelso]

Swordfish release height was supposed to be 18 feet - don't know what speed but it wouldn't be quick.
An account of the Swordfish attack on Bismark tells of the observer watching over the side then calling to the
pilot when to let the torpedo go so it would start in a trough between waves and stay straight.

Wow 18 feet - that is low! This sounds like possibly another hidden advantage of the Swordfish, as it would have a low stall speed and good low-speed handling, probably much better suited to the earlier generations of torpedoes which weren't made to be dropped from very fast moving aircraft or at higher altitudes. And per your description, maybe much more accurate this way.

Torpex was a more powerful mix than normal tnt giving 150% more explosive power for the same weight. More
bang for your buck. This was also used in the 12,000lb tallboy bombs. Torpex would be poured into a bomb casing
in molten form and then left to cool, in some cases this was up to a month.

That sounds like a rather harrowing operation. No sudden movements and NO SMOKING!