IJN Type 91 aerial torpedo

[Bino]

Can someone please point me to technical references on the IJN Type 91 aerial torpedo?

The online stuff I can find is contradictory.  For example:

Over at Dispatch Archive it says that as used in December 1941, "The Type 91 aerial torpedo could be released from an altitude of over 300 feet and a speed of 200 mph and carried a warhead of 331 pounds of high explosive."

Meanwhile, John Parshall's Nihon Kaigun has a table which shows that the Type 91 Mod 2, in use during the Pearl Harbor attack, could be dropped at 260 kts (299 MPH) and that the warhead was 452 lbs.  No drop altitude is mentioned.  At least this web page does list a weapon reference in their bibliography, "Naval Weapons of World War Two" by John Campbell. Anyone know that book?

Thanks! 

[Helm]

I doubt that you could drop any torpedo from 300ft.  From that height the torpedo would run very deep.  The internal guidance system would be hard pressed to bring it back up to a proper attack depth usually abou 6-15 ft in depth ...it might even break up upon hitting the water.  Also the size of the War head seems too small to be effective.  .

Most movie footage I have seen of Japanese torpedo attacks look more like 50-100ft.  I've got some books at home I will check for you and see if I can find some "real" hard data for you.  Until we find other information I'd would go with the second oppion.


Helm...out

[Angus]

Bear in mind that while many torps were dropped from very low alt, that could be because the ack could not be trimmed that low.
(The defending ships I mean)

[1pLUs44]

I remember seeing footage of a P-38 dropping 2 torpedoes from 3000 feet IIRC.

[Hooligan]

Naval Weapons of World War II, John Campbell, 1985, Naval Institute Press.  Page 209 (originally published by Conway in the UK)

No data on launch altitude is given for this particular torpedo

mod 1, (1931) 260 knot max launch speed, 331 lb explosive charge
mod 2, (1941 - used at Pearl Harbor) 452 lb explosive charge
mods 3 though 7 provide progressive increases in explosive charge and launch speed up to 926 lbs of explosive and 350 knots

Hooligan

[Angus]

3000 feet wouldn't make much of a difference from 1000, - terminal velocity practically???
Bear in mind that from launch the torpedo is already doing the speed of the aircraft, then heads down and after some "X" distance hits the water facing mostly down. Now there is the question if i's strong enough for ....what?
Quite interesting really.

[Bino]

Thanks very much, gents!   

Guess I'll need to add a copy of Campbell's book to the library.