Slitherine

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The early models were handicapped by the need to drop them low and slow - 50 feet (15 m) and 110 knots - which made the torpedo planes carrying them more vulnerable to attack. The torpedoes themselves were found to be prone to defects. In mid-1943, an analysis of 105 torpedoes dropped at speeds in excess of 150 knots found that 36 percent ran cold (did not start), 20 percent sank, 20 percent had poor deflection performance, 18 percent gave unsatisfactory depth performance, 2 percent ran on the surface and only 31 percent gave a satisfactory run. The total exceeds 100 percent as many torpedoes had more than one defect.

These problems were greatly reduced by the latter years of the war. Torpedoes had fin stabilizers, nose drag rings and tail shroud rings added, all of which worked to slow the torpedo after it was dropped so that it struck the water nose-first and at an acceptable speed. These improved the drop characteristics such that the recommended aircraft maximum launch parameters were increased to a height of 2,400 feet (730 m) and a speed of 410 knots.

The addition of the nose drag ring improved aerodynamic performance by stabilizing the torpedo in flight and reduced air speed by about 40 percent. It also acted as a shock absorber when the torpedo struck the water. The tail shroud ring improved the water run by reducing hooks and broaches and by eliminating much of the water roll which had characterized the earlier Mark 13s. Hot, straight and normal runs now approached 100 percent. To speed availability of the much improved torpedo, the Bureau of Ordnance had tail assemblies built with the shroud ring attached and then shipped these to the fleet for upgrading the existing inventory. By the fall of 1944, the modified torpedo was in general use by the front-line carrier units which were enthusiastic in their praise. On one occasion in early 1945, six torpedoes were dropped from altitudes between 5,000 and 7,000 feet (1,500 to 2,100 m). Five out of the six were observed to make their runs hot, straight and normal. By the end of the war, the USN considered the Mark 13 to be the best aircraft torpedo produced by any nation and it remained in service until 1950.

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A problem that plagues all aircraft torpedoes is stability on water entry. The U.S. never fully got the hang of it and experienced problems well into 1944. The major problem is spinning on entry. This causes the torpedo to "Fish Hook'' or turn sharply as the tall fins enter time water.

The Japanese approached the problem on two fronts. First they tested two types of detachable tail frames. The "box' and "X", see diagrams(click to see diagrams), were both used during WWII. While the Box was the most effective, it was impractical for confined bomb bays. Box units were used for under-fuselage and wing mounts....

Secondly, to futher combat "Fish Hooking" two small anti-spin flippers were first installed on Type 91, Mod 2 units, 1942, and all subsequent models. The pair of flippers were gyro controlled and located just forward of the tail fins. The Flippers in turn had detachable wooden fins of bath small and large designs. Small units were used more often. Both tail frames and "Flipper Slippers" slipped on and broke away on water entry.

Another problem was the drop envelope, how fast, how high, etc. The ideal condition with mast early units was at 180Kts and 350 feet with a 170 to 200 bow angle at 1000m. With, I might add, Lord knows haw many anti-aircraft guns blasting away at you. Rather unsettling thought, isn't it? An improper drop would cause the torpedo to dive to the bottom or porpoise and snap in half. A 4mm latex rubber sheath, extending back 24" from the nose aided in cushioning water impact shock. The sheath would shatter on impact.

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ORIGINAL: aztez

witpqs: Basically what you are saying is that to keep industrial hexes occupied? I'am not going into strategic bombings early on. I know I could but I want my PBEM partner to enjoy the game too. No sense of inflicting extra industrial damage at DEI early on. Another areas are diffrent story though.

Actually could already bomb his oilfields around Borneo but have chosen not to do so. We do want inflict maxium amount of damage via sabotage though.

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ORIGINAL: witpqs


BTW, in spite of months of training my Dutch air force achieved almost nothing.

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ORIGINAL: jrlans

Good news about Clark, looks like you will hold there for awhile longer. Do you think you will be able to get the majority of your foces out of Johore Baru before being overun?

Also hows are the forts on bataan coming and is it being bombed to prevent you from building them up?

Finaly I highly doubt Soryu is sunk, seems like the FOW likes to put anything with a torpedo in it as sunk. Though unless it was a glancing blow I wouldnt expect to see her for at least two months.

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ORIGINAL: aztez


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Night Time Surface Combat, near Balikpapan at 64,97, Range 8,000 Yards

Japanese aircraft
no flights

Japanese aircraft losses
No Japanese losses

Japanese Ships
CL Isuzu, Shell hits 13, Torpedo hits 1, and is sunk
CL Abukuma, Shell hits 5, on fire
CL Tama, Shell hits 7, heavy fires
CL Kiso, Shell hits 10, heavy fires, heavy damage
CL Kitakami, Shell hits 25, and is sunk
CL Oi, Shell hits 6, Torpedo hits 2, and is sunk
DD Hatsushima, Shell hits 3, Torpedo hits 2, and is sunk
DD Sawakaze, Shell hits 11, Torpedo hits 2, and is sunk
DD Yukaze, Shell hits 4, Torpedo hits 2, and is sunk

Allied Ships
CA Exeter, Shell hits 5, Torpedo hits 1, on fire
CL Dauntless
CL Ceres
CL Boise
CL Caledon, Shell hits 1
DD Stewart
DD Banckert
DD Stronghold
DD Tenedos
DD Electra
DD Encounter
DE Jumna