IJN SAM-armed AA cruisers

[Dilandu]

Well oyodo ordered in 1939, laid down in 1941 February, launched 1942 April and finished in 1943 February so a project in 1941 to finish her as a CLAA wasn't out of practicality as in mid 1941 the hull might sufficiently incomplete to be finished to such a modified design.
And here is her internal layout:

Thank you for the plan! I'm toying with the idea of AU-Oyodo refitted as a missile cruiser for adapted Funryu-2 SAM system -



- and those blueprints are very helpful.

 

[T. A. Gardner]

Thank you for the plan! I'm toying with the idea of AU-Oyodo refitted as a missile cruiser for adapted Funryu-2 SAM system -

View attachment 634667

- and those blueprints are very helpful.

That would be a big downgrade from sticking 10cm or 12cm AA guns on the ship. The Funryu-2 had a range of about 6,000 yards horizontally and about an 8,000 foot ceiling. With MCLOS guidance, it'd be a miracle if it hit a plane.

The guns have a much better chance of doing damage than a bulky, low rate of fire, virtually unguided, missile does.

 

[Dilandu]

That would be a big downgrade from sticking 10cm or 12cm AA guns on the ship. The Funryu-2 had a range of about 6,000 yards horizontally and about an 8,000 foot ceiling. With MCLOS guidance, it'd be a miracle if it hit a plane.

Well, the guns are technological dead end, after all. They are virtually useless against standoff weapons. Funryu-2 may not be a miracle, but at least it could work against high-flying planes (especially if guidance is semi-automated).

 

[T. A. Gardner]

Well, the guns are technological dead end, after all. They are virtually useless against standoff weapons. Funryu-2 may not be a miracle, but at least it could work against high-flying planes (especially if guidance is semi-automated).

Too short ranged, and slow. The Japanese dropped it in favor of the -4 model, but that had its first flight test on the day the war ended. Japan also had nothing in the way of a viable guidance system (and flying one on a manual joystick wasn't going to work. Not for them, or anybody else).

 

[Dilandu]

Too short ranged, and slow. The Japanese dropped it in favor of the -4 model, but that had its first flight test on the day the war ended. Japan also had nothing in the way of a viable guidance system (and flying one on a manual joystick wasn't going to work. Not for them, or anybody else).

1) I should point, that F-4 was considered too short-ranged and too slow against B-29 bombers. The theoretical naval implementation would not need such high parameters.

2) Well, they actually planned to develope command guidance, with one radar tracking target, the other tracking missile, and electro-mechanical calculator guiding missile to interception. Japanese, after all, weren't as technologically inept as Germans!

 

[T. A. Gardner]

1) I should point, that F-4 was considered too short-ranged and too slow against B-29 bombers. The theoretical naval implementation would not need such high parameters.

2) Well, they actually planned to develope command guidance, with one radar tracking target, the other tracking missile, and electro-mechanical calculator guiding missile to interception. Japanese, after all, weren't as technologically inept as Germans!

On 1. Let's look at the obverse here. The USN in 1944 was looking at developing a SAM for defense against bombers using stand-off weapons like Hs 293 and Fritz X. Their own Bat, Pelican, and Gargoyle stand-off weapons were going into service. All of these allowed a bomber to launch on a ship at ranges of 10 to 20 miles and at altitudes above 20,000 feet.
The result was the USN wanted a SAM that could reach 10 miles, 30,000 feet, was supersonic, and accurate to 2 mil. That became Bumblebee. The stop-gap Little Joe (better than nothing and likely never to see service) and Lark (subsonic but otherwise could meet the specifications) which would actually be the first SAM to shoot down an aircraft, were the result.

On 2, I've never doubted that Japan could come up with good technology, and sometimes ahead of other nations. They beat Britain to the cavity magnetron and had millimeter wavelength radars. But it took them 5 years to go from prototype to a working set. Britain did it in about a year. Their problem was taking an idea and turning it into a production item. Their SAM research team was about 25 people strong. That's fine if you're doing basic research, but it won't work if you plan on going to production of hundreds of missiles and dozens of launch systems at some point. The Germans were trying to figure out how to build an analog computer that could guide a SAM too, and recognized they needed millimeter wavelength radar with automatic tracking. Problem was they were nowhere near having any of that in anything other than prototypes, and most of it was only on paper.