Mk 13 Air Dropped Torpedo

For a good WWII torpedo check out the Japanese Long Lance torpedo.

WDA

end

"Kyle Boatright" wrote in message
...
I just finished the book "The Last Stand of the Tin Can Sailors" and it
raised some questions about the air dropped torpedoes (the Mk 13) in use
by
the US Navy in WWII.

What drove the range/speed trade-offs for the Mk 13? According to the
spec's I've found, it had a range of ~6,000 yards and a speed of 33
knots.
With a likely launch range of 1,000 yards or less, wouldn't it have made
sense to sacrifice the 6,000 yard range to get an increase in speed?
Wouldn't a 45 or 50 knot torpedo with a 1,500 or 2,000 yard range have
been a better compromise? I'd certainly think the higher speed would
have
increased the probability of a hit, because it would have reduced the
deflection at launch by 1/3 or so. Also, it would have given the target
1/3 less time to maneuver to avoid the torpedo.

A second question addresses launch speed. Early in the war, drop speed
and altitude were in the 110 knot, 150' range. Later, a couple of
plywood
fairings were added to increase drag, lift, and stability, and these
add-ons improved the drop parameters for the torpedo. The sources I've
found have contradictions about the launch envelope after these fairings
were added. Can someone point me to a reputable source for this
information?

Thanks,

KB





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"W. D. Allen Sr." wrote in message
...
For a good WWII torpedo check out the Japanese Long Lance torpedo.

WDA

end


Which wasnt an air dropped weapon

Keith

Keith Willshaw wrote:
"W. D. Allen Sr." wrote in message
...

For a good WWII torpedo check out the Japanese Long Lance torpedo.

WDA

end



Which wasnt an air dropped weapon

Keith



I seem to recall the long lance was too an air dropped weapon. Kates
used it in Pearl Harbor...I think.

Eric

The Japanese long lance type 93 was a 24-inch monster weighing almost 6000 lbs. The air-dropped weapon was the type 91, 450mm (17.7in) in diameter with a weight in the 1700-2300 lb range depending upon mod. There were Japanese torpedoes developed using the long lance's oxygen propulsion system, but I'm not aware of any air-dropped models in service.

www.combinedfleet.com

Originally Posted by Eric Joiner

I seem to recall the long lance was too an air dropped weapon. Kates
used it in Pearl Harbor...I think.

Eric

"Eric Joiner" wrote in message
...
Keith Willshaw wrote:
"W. D. Allen Sr." wrote in message
...

For a good WWII torpedo check out the Japanese Long Lance torpedo.

WDA

end



Which wasnt an air dropped weapon

Keith

I seem to recall the long lance was too an air dropped weapon. Kates used
it in Pearl Harbor...I think.

Eric

Nope. 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.

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.

Larry Cauble wrote:

....

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

This "404s." Has it moved to a new URL?

Originally Posted by Merlin Dorfman

Larry Cauble wrote:

....

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

This "404s." Has it moved to a new URL?

Odd...I guess it just won't allow linking. You can also go to:
www.geocities.com/Pentagon/1592
and then click on the "torpedoes" button. That one does not appear to 404.

Once you're at torpedoes, you see five pdf-format parts that you must click on it turn to get the whole thing.

By the way, I think I indicated that the Mk 13 replacement (Mk 25) was fielded in small numbers near the end of WWII. I now see that is incorrect; it was only a prototype/test weapon and the Mk 13 was the last straight-running/non-homing air-dropped torpedo.

Kyle Boatright wrote:
"Eric Joiner" wrote in message
...

Keith Willshaw wrote:

"W. D. Allen Sr." wrote in message
...


For a good WWII torpedo check out the Japanese Long Lance torpedo.

WDA

end



Which wasnt an air dropped weapon

Keith

I seem to recall the long lance was too an air dropped weapon. Kates used
it in Pearl Harbor...I think.

Eric


Nope. 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.



Thanks for the education!

Eric

"Eric Joiner" wrote in message
...
Keith Willshaw wrote:

Which wasnt an air dropped weapon

Keith

I seem to recall the long lance was too an air dropped weapon. Kates used
it in Pearl Harbor...I think.

Eric

As others have pointed out the Long Lance was 30ft long and
was around 3 times heavier than the max weight a Kate could carry

Keith