Hypothetical Battle of the Java Sea...

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dunmunro
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Re: Hypothetical Battle of the Java Sea...

Post by dunmunro »

Bgile wrote:The smaller time segments would likely be in error because the radar wasn't that accurate, but I would think that if we take the total time and distance it should be in the ballpark. With regard to actual times, maybe the time used by the radar operator was incorrect ... I can't explain it. But what we do have is the Japanese air strike plotted from one point to another, with seemingly a good idea of about how fast it was going.

I also think the B5N cruised at about 10,000 feet. Isn't that correct from Midway attack records? I was thinking the Swordfish normally cruised at about 5,000 feet. Is that true, or do I have the wrong impression?
The problem is that we are using the first to last distance measurement to calculate the average speed. However, if the radar overestimated the initial range, and hence the high initial speed estimates, then we will be over estimating the average speed, which was very unlikely to be higher than 150mph, based upon the time from form up to attack.
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Re: Hypothetical Battle of the Java Sea...

Post by Bgile »

I actually used the second and the last, but I suspect that if we use any of the first three and any of the last three we will still come up with about the same result unless perhaps if we take the ones closest together. One measurement might be wrong, but several are unlikely to be proportionately wrong.

Your logic flies in the face of actual measurements, and in any case you seem to have now agreed that the B5N2, in service beginning in 1939, was capable of about 200 mph carrying a torpedo.
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Re: Hypothetical Battle of the Java Sea...

Post by dunmunro »

Bgile wrote:I actually used the second and the last, but I suspect that if we use any of the first three and any of the last three we will still come up with about the same result unless perhaps if we take the ones closest together. One measurement might be wrong, but several are unlikely to be proportionately wrong.

Your logic flies in the face of actual measurements, and in any case you seem to have now agreed that the B5N2, in service beginning in 1939, was capable of about 200 mph carrying a torpedo.

I have never stated otherwise, but the differences between the maximum and cruising speeds of a equally loaded Albacore, B5N2 and TBD are not nearly as great as the clean speeds for the B5N2and TBD and loaded speeds for an Albacore.

Again we have the IJN's own timing for the PH attack and it simply doesn't support the idea of ~180mph cruising speeds, unless the aircraft flew into the "Twilight Zone" for an hour or so.
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Re: Hypothetical Battle of the Java Sea...

Post by lwd »

The longer the time period the better the estimate it likely to be. The distances should be fairly good with a couple potential problems.
1) The first range estimate may be on the leading edge of the attack where the last one my be on the center of the attack or on a sub group. (using the 2nd to the last might be better for that reason.
2) The distances are radial so any movement azimuthally won't be captured.
3) Later movements may also reflect altitude changes.
4) Once the planes moved into likely detection range they may have increased speed.
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Re: Hypothetical Battle of the Java Sea...

Post by alecsandros »

lwd wrote:The longer the time period the better the estimate it likely to be. The distances should be fairly good with a couple potential problems.
1) The first range estimate may be on the leading edge of the attack where the last one my be on the center of the attack or on a sub group. (using the 2nd to the last might be better for that reason.
2) The distances are radial so any movement azimuthally won't be captured.
3) Later movements may also reflect altitude changes.
4) Once the planes moved into likely detection range they may have increased speed.
:clap:
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Re: Hypothetical Battle of the Java Sea...

Post by alecsandros »

@dunmuro
Indeed, the total strike time (6:00 - 7:50 for a 230 miles cruise) can raise a few eybrows concerning movement speed of the first wave.

However, if we take the early, 7:02AM radar blip at 137 miles, and the first attacks at 7:48, we have 46 minutes to cover 137 miles.

This would mean about 180mph, or 290km/h average speed.

What about the time period from 6:00 to 7:02 then?
Well, considering a 230 miles launch distance, and a 137 miles radar spoting distance, this would mean that the IJN first wave traveled 93 miles in 62 minutes.

However, this is misleading, because 6:00 is the time when the first fighters began taking of. I couldn't find an exact time for the last planes taking of, but my estimate is ~ 6:10-6:15. After that, the last planes must have entered formation, climb at a specific altitude, etc. This could take longer than 10-15 minutes, IMO.

So, I would say about 20-30 minutes passed until the first wave actualy headed towards Oahu. Consequently, the actual flight time until radar detection was 6:20-6:30 --- 7:02. That means 32-42 minutes to cover 93 miles, or an average speed of 133 - 174 mp/h.
As lwd sugested earlier, the planes did not fly in a straight line, there were altitude changes and heading changes.

==========

A whole lot of talking to prove something we already knew: B5N2 was the fastest torpedo-plane in the early war of the Pacific.

==========
Returning to our main discussion, I'd say the best indicator of Japanese torpedo-planes effectiveness is their hit ratio in 1941-1942. There are several battles which come to mind that point to a very, very good hit ratio (Hiryu's strike over Yorktown, Shokaku's strike over Lexington).
This is why I would expect 2 torpedo hits on the British CV.

As for the Swordfish hit ratio, if we are to consider a grouped Japanese TF (like at Midway), the sheer volume of AA fire would be a killer. Many planes would be badly damaged, others would find it impossible to achieve launch positions. Again, I think it would be interesting to find out about the aerial torpedo hits on Littorio and Vittorio Venetto in the Med.

Yes, I've read Lwd's and Dunmuro's quotes regarding Japanese early-war AA guns. Indeed, not to impressive. But at Midway, as un-impressive as they were, they turned the skies into hell. Why? Because there were hundreds of them...

Anyway, I would expect both carriers to be out of action following the air strike: the British CV with 2 torpeos in his belly, the IJN Ryho - with 1 torpedo hit.
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Re: Hypothetical Battle of the Java Sea...

Post by dunmunro »

I found the following info at Hyperwar:
Kate: (1) Nakajima "Sakae" 11, 14-cylinder, twin-row, air-cooled radial. HP:985 @ 7,500ft. Vmax: 222mph at 8,500ft, Max cruise: 166mph at 7,500ft econ cruise:131mph at 7,500 ft.

http://funsite.unc.edu/hyperwar/Japan/I ... B-4.html#V

for comparison, a Swordfish at max weight with a torpedo:
Max cruise; 128 mph @ 5000ft
econ cruise; 104 mph @ 5000ft
Ceiling; 12400ft
Vmax; Loaded Swordfish at 4750ft = 139 mph
Vmax; Loaded Swordfish at 0ft = 132 mph
Vmax; Clean Swordfish = 153 mph ( http://www.fleetairarmarchive.net/aircr ... rdfish.htm )
Albacore at max weight with a torpedo:
Max cruise 147 mph (British Naval Aircraft since 1912 states 140 mph)
econ cruise; 114 mph @ 6000ft (British Naval Aircraft since 1912 states 116 mph)
Ceiling; 20700ft
Vmax; 159 mph @ 4000ft (British Naval Aircraft since 1912 states 161mph)

(from Wings of the Navy)

and from here:
http://www.ibiblio.org/phha/KATE.html

B5N2 PERFORMANCE:
Range: 1,237 miles

Max Speed: 205 mph at sea level;
225 mph at 8,000';
235 mph at 11,800'

Ceiling: 27,100 ft

But the max range, ceiling and speed are almost certainly "clean".
Loaded, we could expect a ~10mph drop in speed and a reduction in ceiling by ~10k ft.

I am firm believer in the laws of physics.
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Re: Hypothetical Battle of the Java Sea...

Post by lwd »

alecsandros wrote:...As for the Swordfish hit ratio, if we are to consider a grouped Japanese TF (like at Midway), the sheer volume of AA fire would be a killer. Many planes would be badly damaged, others would find it impossible to achieve launch positions. ...
Yes, I've read Lwd's and Dunmuro's quotes regarding Japanese early-war AA guns. Indeed, not to impressive. But at Midway, as un-impressive as they were, they turned the skies into hell. Why? Because there were hundreds of them...
....
I think you are under some false impressions. Let's take a look at: http://www.navy.mil/midway/midway_3_TOR ... Q%208.html
It's been a very general opinion that the anti-aircraft fire shot our boys down and that's not true. I don't think that any of our planes were damaged, even touched by anti-aircraft fire. The fighters, the Zeros, shot down everyone of them, and by the time that we got into where the anti-aircraft fire began to get hot, the fighters all left us. I was the only one close enough to get any real hot anti-aircraft fire. Yet, I don't think it even touched me.
http://www.history.navy.mil/photos/even ... mid-4a.htm
also points to the CAP rather than the AA fire as being the more dangerous:
These ten torpedo planes were the first to encounter the Japanese carrier fleet, soon after 7:00 AM, and they received the intense and deadly attentions of the defending combat air patrol. Only one of the Navy TBFs survived, much shot up with one crewman killed. Two of the four Army planes got through.
and is confirmed by:
http://www.eyewitnesstohistory.com/midway.htm
Presently a report came in from a Zero group leader: 'All 15 enemy torpedo bombers shot down.'
and
Of the 14 enemy torpedo bombers which came in from starboard, half were shot down, and only 5 remained of the original 12 planes to port. The survivors kept charging in as Akagi's opened fire with antiaircraft machine guns.
...Both enemy groups reached their release points, and we watched for the splash of torpedoes aimed at Akagi. But, to our surprise, no drops were made. At the last moment the planes appeared to forsake Akagi, zoomed overhead, and made for Hiryu to port and astern of us. As the enemy planes passed Akagi, her gunners regained their composure and opened a sweeping fire, in which Hiryu joined. Through all this deadly gunfire the Zeros kept after the Americans, continually reducing their number
Note that there aren't any claims of aircraft downed by AA fire. Further note that only the Agkagi and later Hiryu are mentioned as even firing.
http://www.cv6.org/1942/midway/midway_3.htm
also makes the case for it being fighters that so badley shot up not just VT-8 but VT-6 and VT-3 as well. There simplly isn't a good case for Japanese AA fire being all that effective.
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Re: Hypothetical Battle of the Java Sea...

Post by alecsandros »

I don't know, man. Indeed, the eye-witness accounts tell a different story... I'll try to find some references also and get back to you.

Until then, good night everyone!
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Re: Hypothetical Battle of the Java Sea...

Post by dunmunro »

dunmunro wrote:I found the following info at Hyperwar:
Kate: (1) Nakajima "Sakae" 11, 14-cylinder, twin-row, air-cooled radial. HP:985 @ 7,500ft. Vmax: 222mph at 8,500ft, Max cruise: 166mph at 7,500ft econ cruise:131mph at 7,500 ft.

http://funsite.unc.edu/hyperwar/Japan/I ... B-4.html#V

for comparison, a Swordfish at max weight with a torpedo:
Max cruise; 128 mph @ 5000ft
econ cruise; 104 mph @ 5000ft
Ceiling; 12400ft
Vmax; Loaded Swordfish at 4750ft = 139 mph
Vmax; Loaded Swordfish at 0ft = 132 mph
Vmax; Clean Swordfish = 153 mph ( http://www.fleetairarmarchive.net/aircr ... rdfish.htm )
Albacore at max weight with a torpedo:
Max cruise 147 mph (British Naval Aircraft since 1912 states 140 mph)
econ cruise; 114 mph @ 6000ft (British Naval Aircraft since 1912 states 116 mph)
Ceiling; 20700ft
Vmax; 159 mph @ 4000ft (British Naval Aircraft since 1912 states 161mph)

(from Wings of the Navy)

and from here:
http://www.ibiblio.org/phha/KATE.html

B5N2 PERFORMANCE:
Range: 1,237 miles

Max Speed: 205 mph at sea level;
225 mph at 8,000';
235 mph at 11,800'

Ceiling: 27,100 ft

But the max range, ceiling and speed are almost certainly "clean".
Loaded, we could expect a ~10mph drop in speed and a reduction in ceiling by ~10k ft.

I am firm believer in the laws of physics.
In case anyone really wants to know:

Devastator TBD-1 level true airspeeds:

maximum speed at 7600lb = 181 knots at 6-8kft = 206mph
maximum speed at 7600lb = 169 knots at 0kft = 192mph
maximum speed at 9000lb = 179 knots at 6-8kft = 204mph
maximum speed at 9000lb = 164 knots at 0kft = 187mph

Vmax at 4000ft at 9000lb = 171 knots or 195mph, for a direct comparison with the Swordfish and Albacore. Although the higher torpedo drop speed of the RN torpedo would probably result in a higher average speed up to the drop point.

I was relayed this info which seems to have originated with the USN from flight testing. The 9000lb weight also assumes external drag from a torpedo, although it seems a little on the light side.
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Re: Hypothetical Battle of the Java Sea...

Post by alecsandros »

Yes Dunmuro, those are the design speeds of the TBD.

HOwever, Midway attacking pilots clearly say they couldn't go beyond 120mph MAX.
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Re: Hypothetical Battle of the Java Sea...

Post by alecsandros »

A fresh find regarding Vittorio Veneto's torpedoing in the Med:
In turns out it was attacked twice during that day - 28th of March, 1941:
- 1st attack with 6 planes (Albacores), 0 hits
- 2nd attack with 5 planes (3 Albacores, 2 Swordfish), 1 hit - near the propellers.

"A second strike against the retreating Italian warships was launched just after noon in the hope of either sinking or
crippling the capital ship so that she could be engaged on the surface in the latter instance. The five aircraft included two
Swordfish of No.829 Sqdn. led by Lt-Cdr. Dalyell-Stead. As the formation closed with their target, the Italian AA gunners'
attention was diverted by the presence of RAP Blenheims operating from Greece. The Lead Albacore gained its dropping
position and was turning away when it was smashed out of the sky and its crew killed. Observers on the other aircraft
saw how the released torpedo struck the battleship around that ever-vulnerable point on any vessel, the propeller shafts
."

[Britain's Fleet Air Arm in WW2 - pg 88, Ron Mackay]

How 5, slow, torpedo bombers, managed to hit a 30kts+ target, while 2 months later 9, and then 15 other t-bombers barely hit the Bismarck is difficult to say. Most likely, as so many other things in war, the elements of luck, timing and skill are far more important than pure technological capability...
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Re: Hypothetical Battle of the Java Sea...

Post by IronDuke »

There is a related discussion of this here...

http://alltheworldsbattlecruisers.yuku.com/topic/916
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Re: Hypothetical Battle of the Java Sea...

Post by 19kilo »

Interesting thread, but it seems to have gotten bogged down intorpedo bomber tactics and speeds. I did notice that no one mentioned that the US, Dutch, and Royal Navies hadnt really worked with each other all that much befor and had different methods of doing things, communications, etc.........This probably would have been (and indeed was) a significant handicap to the ABDA's operations against the Japanese fleet, no mater how many more ships it had. Indeed if it had caused too much trouble, I'm thinking that Nagumo's carrier force could have been called in without too much trouble, and the result would have probably been the same as what actualy happened.
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Re: Hypothetical Battle of the Java Sea...

Post by IronDuke »

If anyone wants to try this, the various Royal Navy and Commonwealth, USN and Japanese ships are available at the online game Fighting Flattops. There is a scenario designer tool too.

http://www.fightingflattops.com/
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