Mk 13 Air Dropped Torpedo

Originally Posted by Kyle Boatright

The Long Lance was a shipboard weapon only. It weighed something like
6,000 lbs, and was almost 30' long - a real monster. It had a range of
20,000 meters at 48 knots. On the slow setting, it had a range of 40,000
meters at 36 knots. A downsized version was used aboard submarines. It
weighed 4,000 lbs and had a 9,000 meter range at 49 knots.

The air dropped torpedoes used by the Japanese during WWII were 17.7"
torpedoes and weighed approximately 2,000 lbs depending on variant. Very
comparable to US airborne torpedos. EXCEPT for their dynamic performance,
which gave a drop speed of 260-350 knots (variant dependant), a speed of 41
knots, and a 2000 meter range.

A couple of sources, Kyle:

(1) A history of US torpedoes of all types, originally published in the Submarine Review, and I would say pretty authoritative:
www.geocities.com/Pentagon/1592/torpedoes.html
but which does not much address the subject of Mk 13 limitations. It does
mention the successor weapon, the Mk 25, which apparently was produced in very limited numbers due to the huge number of Mk 13s still in stock late in the war. Sounds like the Mk 25 would be the ultimate USN air-dropped anti-ship torpedo and the specs on it would be interesting.

(2) www.microworks.net/Pacific/armament/
which states that, by early 1944, the Mk 13 could be launched at high speed at 1000 ft altitude and that later variants were good to 410 knots/2400 ft. In this case, however, I have no feel for the validity of these numbers.