4E bomber effectiveness vs ships, etc. - a new idea

Please post here for questions and discussion about scenario design and the game editor for WITP.

Moderators: wdolson, Don Bowen, mogami

User avatar
treespider
Posts: 5781
Joined: Sun Jan 30, 2005 7:34 am
Location: Edgewater, MD

RE: 4E bomber effectiveness vs ships, etc. - a new idea

Post by treespider »

ORIGINAL: herwin


Imagine a large attack with at least 200 closing aircraft at 180 mph against 200 guns, so that each gun concentrates on one aircraft. Then each 5"L38 would have a 0.25 chance of shooting down its target firing one shell every 4 seconds in the 2 minutes between its maximum and minimum range. With VT fuzing, that would rise to 0.75 chance. In reality, multiple guns would concentrate on each target under the control of a single gun director. Against one gun, an aircraft has a 0.75 chance of survival; against two, that drops to 0.75*0.75 chance of survival, and so on. Multiple guns under the control of one director does two things--makes it less likely that the plane will survive, and finishes off the plane faster.

Explain 0.25 does this mean 0.25% or 25%?

In addition how do you account for multiple guns or groups of guns targeting the same aircraft....And were particular aircraft morelikely to be targetted by fire concentration...ie the leading element or the trailing element?

Here's a link to:
Treespider's Grand Campaign of DBB

"It is not the critic who counts, .... The credit belongs to the man who is actually in the arena..." T. Roosevelt, Paris, 1910
herwin
Posts: 6047
Joined: Thu May 27, 2004 9:20 pm
Location: Sunderland, UK
Contact:

RE: 4E bomber effectiveness vs ships, etc. - a new idea

Post by herwin »

ORIGINAL: treespider
ORIGINAL: herwin


Imagine a large attack with at least 200 closing aircraft at 180 mph against 200 guns, so that each gun concentrates on one aircraft. Then each 5"L38 would have a 0.25 chance of shooting down its target firing one shell every 4 seconds in the 2 minutes between its maximum and minimum range. With VT fuzing, that would rise to 0.75 chance. In reality, multiple guns would concentrate on each target under the control of a single gun director. Against one gun, an aircraft has a 0.75 chance of survival; against two, that drops to 0.75*0.75 chance of survival, and so on. Multiple guns under the control of one director does two things--makes it less likely that the plane will survive, and finishes off the plane faster.

Explain 0.25 does this mean 0.25% or 25%?
1/4 = 0.25

In addition how do you account for multiple guns or groups of guns targeting the same aircraft....And were particular aircraft morelikely to be targetted by fire concentration...ie the leading element or the trailing element?

Survival when one gun is shooting at you with a probability of kill, Pk, is (1-Pk). Survival when two guns are shooting at you is (1-Pk)*(1-Pk), and so on. See Morse and Kimball, Methods of Operations Research. (Or in Russian, Morz i Kimbal, Methody ....) The US Navy Postgraduate School teaches this stuff, and I used to do these kinds of analyses professionally.
Harry Erwin
"For a number to make sense in the game, someone has to calibrate it and program code. There are too many significant numbers that behave non-linearly to expect that. It's just a game. Enjoy it." herwin@btinternet.com
User avatar
treespider
Posts: 5781
Joined: Sun Jan 30, 2005 7:34 am
Location: Edgewater, MD

RE: 4E bomber effectiveness vs ships, etc. - a new idea

Post by treespider »

ORIGINAL: herwin

ORIGINAL: treespider
ORIGINAL: herwin


Imagine a large attack with at least 200 closing aircraft at 180 mph against 200 guns, so that each gun concentrates on one aircraft. Then each 5"L38 would have a 0.25 chance of shooting down its target firing one shell every 4 seconds in the 2 minutes between its maximum and minimum range. With VT fuzing, that would rise to 0.75 chance. In reality, multiple guns would concentrate on each target under the control of a single gun director. Against one gun, an aircraft has a 0.75 chance of survival; against two, that drops to 0.75*0.75 chance of survival, and so on. Multiple guns under the control of one director does two things--makes it less likely that the plane will survive, and finishes off the plane faster.

Explain 0.25 does this mean 0.25% or 25%?
1/4 = 0.25

In addition how do you account for multiple guns or groups of guns targeting the same aircraft....And were particular aircraft morelikely to be targetted by fire concentration...ie the leading element or the trailing element?

Survival when one gun is shooting at you with a probability of kill, Pk, is (1-Pk). Survival when two guns are shooting at you is (1-Pk)*(1-Pk), and so on. See Morse and Kimball, Methods of Operations Research. (Or in Russian, Morz i Kimbal, Methody ....) The US Navy Postgraduate School teaches this stuff, and I used to do these kinds of analyses professionally.

Edit: nevermind....

Here's a link to:
Treespider's Grand Campaign of DBB

"It is not the critic who counts, .... The credit belongs to the man who is actually in the arena..." T. Roosevelt, Paris, 1910
el cid again
Posts: 16983
Joined: Mon Oct 10, 2005 4:40 pm

RE: 4E bomber effectiveness vs ships, etc. - a new idea

Post by el cid again »

Using WWII era 3 inch 50s, with radar and VT frag, there is a better than 90% chance a two gun mounting will hit its target on the first shot (2 rounds, 1 per tube) - if the gun crew is skilled enough. We ran four such crews in competition - permitting only one round per tube - so we could evaluate if they hit or not on the first shot. It was normal to hit - abnormal to miss - and we kept score by counting misses - the lowest number was the winner (and given a reward of early liberty). This on USS Francis Marion, APA 249. If a target is flying a predictable course - not normal for a modern single attacker - but the norm for large formations (so the bombers don't hit each other and so they can line up their signts for the run) - AA should not normally miss a closing target within effective range. If it does miss - the crew is not very good - or the ship is maneuvering in a way that prevents a stable gun platform.

Contemporary AA guns are about twice as powerful as WWII era guns (measured in horsepower). Modern fire control is better in the sense it can plan for engaging more than one target per mounting. But for the single target per mount case, WWII fire control is remarkably good and similar to our own. You should get MORE than one plane per mount IF there are enough targets - provided the crew is good - and the ship is stable for firing. You will limit out when you expend ready ammo - something like 3 to 6 targets having been downed at WWII speeds - typically 2 at jet speeds.

That is the base case: remember - fire control can be messed up. So can aircraft targeting for that matter. And skill and luck matter. So does warning - big time. No warning = unmanned guns in the worst case.
herwin
Posts: 6047
Joined: Thu May 27, 2004 9:20 pm
Location: Sunderland, UK
Contact:

RE: 4E bomber effectiveness vs ships, etc. - a new idea

Post by herwin »

ORIGINAL: el cid again

Using WWII era 3 inch 50s, with radar and VT frag, there is a better than 90% chance a two gun mounting will hit its target on the first shot (2 rounds, 1 per tube) - if the gun crew is skilled enough. We ran four such crews in competition - permitting only one round per tube - so we could evaluate if they hit or not on the first shot. It was normal to hit - abnormal to miss - and we kept score by counting misses - the lowest number was the winner (and given a reward of early liberty). This on USS Francis Marion, APA 249. If a target is flying a predictable course - not normal for a modern single attacker - but the norm for large formations (so the bombers don't hit each other and so they can line up their signts for the run) - AA should not normally miss a closing target within effective range. If it does miss - the crew is not very good - or the ship is maneuvering in a way that prevents a stable gun platform.

Contemporary AA guns are about twice as powerful as WWII era guns (measured in horsepower). Modern fire control is better in the sense it can plan for engaging more than one target per mounting. But for the single target per mount case, WWII fire control is remarkably good and similar to our own. You should get MORE than one plane per mount IF there are enough targets - provided the crew is good - and the ship is stable for firing. You will limit out when you expend ready ammo - something like 3 to 6 targets having been downed at WWII speeds - typically 2 at jet speeds.

That is the base case: remember - fire control can be messed up. So can aircraft targeting for that matter. And skill and luck matter. So does warning - big time. No warning = unmanned guns in the worst case.

Radar and modern fire control will do that for you... As I recall, those 3" 50s didn't make it into WWII. They were the replacement for the quad 40s. This analysis was for pre-radar systems.
Harry Erwin
"For a number to make sense in the game, someone has to calibrate it and program code. There are too many significant numbers that behave non-linearly to expect that. It's just a game. Enjoy it." herwin@btinternet.com
Mike Scholl
Posts: 6187
Joined: Wed Jan 01, 2003 1:17 am
Location: Kansas City, MO

RE: 4E bomber effectiveness vs ships, etc. - a new idea

Post by Mike Scholl »

ORIGINAL: Dili

How much difference from a torpedo bomber? It seems even more risky.



Couple of differences. Torpedoes had to be delivered at relatively slow speeds so as not to break up on impact, and their "run time" in the water gave some time for avoidance. The best "skip bombing" A/C were the "gun-ship" modifications of the B-25, which with many .50 calibre MG's suppressing the target's flak, could approach at higher speeds and release their bombs so close that avoidance was almost impossible.
User avatar
wdolson
Posts: 7689
Joined: Tue Jun 27, 2006 9:56 pm
Location: Near Portland, OR

RE: 4E bomber effectiveness vs ships, etc. - a new idea

Post by wdolson »

ORIGINAL: Dili

How much difference from a torpedo bomber? It seems even more risky.
ORIGINAL: Mike Scholl
Couple of differences. Torpedoes had to be delivered at relatively slow speeds so as not to break up on impact, and their "run time" in the water gave some time for avoidance. The best "skip bombing" A/C were the "gun-ship" modifications of the B-25, which with many .50 calibre MG's suppressing the target's flak, could approach at higher speeds and release their bombs so close that avoidance was almost impossible.

The ultimate skip bombing B-25 had 8 guns in the nose and 4 along the side, all pointing forward. If there were no enemy fighters around, the top turret would be rotated forward and also engaged, putting 14 .50 caliber machine guns on the target. Japanese survivors said that being skip bombed by one of those B-25 gunships was terrifying. The only AA gunners who weren't cowering were either dead or in a turret.

The more typical B-25 gunship armament had only 4 .50s in the nose, so they only put 8 fixed .50s on the target, but that's still a lot of bullets flying around. For small ships like barges, just machine guns were enough to do the job.

Bill
WIS Development Team
el cid again
Posts: 16983
Joined: Mon Oct 10, 2005 4:40 pm

RE: 4E bomber effectiveness vs ships, etc. - a new idea

Post by el cid again »

ORIGINAL: herwin

ORIGINAL: el cid again

Radar and modern fire control will do that for you... As I recall, those 3" 50s didn't make it into WWII. They were the replacement for the quad 40s. This analysis was for pre-radar systems.

Actually, this is both right and wrong. Virtually every important 3 inch gun in US service afloat was a 3 inch 50 - since well before WWII. The particular 3 inch 50 we used was intended as a replacement/upgrade for the war (it was to replace quad 40mm) - and didn't quite make it in time. But even so - the guns and fire control systems we used were WWII engineering - and remain servicable to the present day. Nor were they more than marginal improvements over the earlier forms of the same class of weapon. Both the USN and the US Army (via its Coast Artillery service) solved the problems of AAA before WWII began - as did the IJN (but IJA didn't do as well - and eventually adopted naval fire control systems). In fact - IJN was technically ahead in this field in certain respects - something you don't often read about. Many commentators complain they didn't shoot practice rounds, for example - not knowing that this was not purely a matter of limiting ammunition expendature - but a function of not needing to given the sophisticated trainers used. [No other country trained gunners in all light conditions, with targets that looked like the actual targets - not even in the 1960s did we train to such standards.]

I am a technical person and I spoke precisely: we used WWII era technology and it worked superbly well - even vs much faster targets. Modern fire control is NOT a pannacea. I once was knocked off my feet by the wash of an F-5 out of Taiwan which was investigating my ship - an anti-air warfare destroyer nominally able even to engage cruise missile targets. We not only failed to detect the aircraft inbound (although obviously we had been detected ourselves), I ran to a repeater and switched channels: neither on surface search nor on 3D nor on air search could I find the plane - in spite of knowing its bearing. In 1982 a British frigate captain (of a ship that was lost) wrote that "our most important sensor was the mark one eyeball." He was astonished. I was not. AAW is a complicated game and you must be paying attention to win. But IF you pay attention, you can win. Viet Nam successfully used rocks and dynamite to bring down US F-4s. It also successfully used ancient WWII era gunfire control radars (e.g. the SCR-584) to control SAMs (an argument USN ultimately won with USAF - which said it was impossible). Do not denegrate WWII era technology. A lot of it was very fine, and most of it was adequate.
el cid again
Posts: 16983
Joined: Mon Oct 10, 2005 4:40 pm

RE: 4E bomber effectiveness vs ships, etc. - a new idea

Post by el cid again »

ORIGINAL: Mike Scholl

ORIGINAL: Dili

How much difference from a torpedo bomber? It seems even more risky.



Couple of differences. Torpedoes had to be delivered at relatively slow speeds so as not to break up on impact, and their "run time" in the water gave some time for avoidance. The best "skip bombing" A/C were the "gun-ship" modifications of the B-25, which with many .50 calibre MG's suppressing the target's flak, could approach at higher speeds and release their bombs so close that avoidance was almost impossible.

Not to mention that those many .50 cals were awful in their own right. Not nice to be outside the armored shell when they started hitting your ship. And most of the people involved with air defense were outside that shell. Many ships have no armor at all.
Dili
Posts: 4742
Joined: Fri Sep 10, 2004 4:33 pm

RE: 4E bomber effectiveness vs ships, etc. - a new idea

Post by Dili »

When skip bombing was used against hvy ships? Most of footage i only see it against cargos not against AA destroyers or cruisers.
herwin
Posts: 6047
Joined: Thu May 27, 2004 9:20 pm
Location: Sunderland, UK
Contact:

RE: 4E bomber effectiveness vs ships, etc. - a new idea

Post by herwin »

ORIGINAL: el cid again
ORIGINAL: herwin

ORIGINAL: el cid again

Radar and modern fire control will do that for you... As I recall, those 3" 50s didn't make it into WWII. They were the replacement for the quad 40s. This analysis was for pre-radar systems.

Actually, this is both right and wrong. Virtually every important 3 inch gun in US service afloat was a 3 inch 50 - since well before WWII. The particular 3 inch 50 we used was intended as a replacement/upgrade for the war (it was to replace quad 40mm) - and didn't quite make it in time. But even so - the guns and fire control systems we used were WWII engineering - and remain servicable to the present day. Nor were they more than marginal improvements over the earlier forms of the same class of weapon. Both the USN and the US Army (via its Coast Artillery service) solved the problems of AAA before WWII began - as did the IJN (but IJA didn't do as well - and eventually adopted naval fire control systems). In fact - IJN was technically ahead in this field in certain respects - something you don't often read about. Many commentators complain they didn't shoot practice rounds, for example - not knowing that this was not purely a matter of limiting ammunition expendature - but a function of not needing to given the sophisticated trainers used. [No other country trained gunners in all light conditions, with targets that looked like the actual targets - not even in the 1960s did we train to such standards.]

I am a technical person and I spoke precisely: we used WWII era technology and it worked superbly well - even vs much faster targets. Modern fire control is NOT a pannacea. I once was knocked off my feet by the wash of an F-5 out of Taiwan which was investigating my ship - an anti-air warfare destroyer nominally able even to engage cruise missile targets. We not only failed to detect the aircraft inbound (although obviously we had been detected ourselves), I ran to a repeater and switched channels: neither on surface search nor on 3D nor on air search could I find the plane - in spite of knowing its bearing. In 1982 a British frigate captain (of a ship that was lost) wrote that "our most important sensor was the mark one eyeball." He was astonished. I was not. AAW is a complicated game and you must be paying attention to win. But IF you pay attention, you can win. Viet Nam successfully used rocks and dynamite to bring down US F-4s. It also successfully used ancient WWII era gunfire control radars (e.g. the SCR-584) to control SAMs (an argument USN ultimately won with USAF - which said it was impossible). Do not denegrate WWII era technology. A lot of it was very fine, and most of it was adequate.

Putting it together into a devastating AA system was a late-war innovation. We went to the dual 3"L50 system to give us longer range firepower against kamikazes, but it was built around the proximity fuse. The quad 40s were a bit short-ranged, although they were a good substitute for a 5"L38 gun on a one-for-one basis, providing closer-in protection. The 20mm cannon was too short ranged to drop a kamikaze before it went into its final dive. The 5"L38s were used in barrage fire rather in engagements with individual aircraft. Pre VT, you either had to use barrage fire, or you had to hit the target. Pre radar, you had to guess the range at which to set the fuze.
Harry Erwin
"For a number to make sense in the game, someone has to calibrate it and program code. There are too many significant numbers that behave non-linearly to expect that. It's just a game. Enjoy it." herwin@btinternet.com
User avatar
treespider
Posts: 5781
Joined: Sun Jan 30, 2005 7:34 am
Location: Edgewater, MD

RE: 4E bomber effectiveness vs ships, etc. - a new idea

Post by treespider »

ORIGINAL: Dili

When skip bombing was used against hvy ships? Most of footage i only see it against cargos not against AA destroyers or cruisers.


I wonder if there has been any analysis done on target types for skip bombers... I imagine it would be slightly harder for the bigger planes to stay aligned on target with a fast maneuverable warship which may be firing back as opposed to a slow not very manueverable merchie...
Here's a link to:
Treespider's Grand Campaign of DBB

"It is not the critic who counts, .... The credit belongs to the man who is actually in the arena..." T. Roosevelt, Paris, 1910
el cid again
Posts: 16983
Joined: Mon Oct 10, 2005 4:40 pm

RE: 4E bomber effectiveness vs ships, etc. - a new idea

Post by el cid again »

ORIGINAL: Dili

When skip bombing was used against hvy ships? Most of footage i only see it against cargos not against AA destroyers or cruisers.


A destroyer is a "major surface combattant." And surely a cruiser is a "heavy ship" - although not apparently in WITP code - where "heavy" = battleship.

The question may not be germane: when was skip bombing an option against "heavy ships?" The last US cruiser lost was to submarine torpedoes. And Yamato was engaged by carrier bombers. Nagato - the only remaining heavy - was essentially hiding in Hokkaido - most of the Navy had been formally decomissioned and Nagato was not in good operational condition. I suppose - had we found it - we might have bombed it with long range bombers. It is the only case I can think of that might have happened.
el cid again
Posts: 16983
Joined: Mon Oct 10, 2005 4:40 pm

RE: 4E bomber effectiveness vs ships, etc. - a new idea

Post by el cid again »

ORIGINAL: herwin

ORIGINAL: el cid again
ORIGINAL: herwin




Radar and modern fire control will do that for you... As I recall, those 3" 50s didn't make it into WWII. They were the replacement for the quad 40s. This analysis was for pre-radar systems.

Actually, this is both right and wrong. Virtually every important 3 inch gun in US service afloat was a 3 inch 50 - since well before WWII. The particular 3 inch 50 we used was intended as a replacement/upgrade for the war (it was to replace quad 40mm) - and didn't quite make it in time. But even so - the guns and fire control systems we used were WWII engineering - and remain servicable to the present day. Nor were they more than marginal improvements over the earlier forms of the same class of weapon. Both the USN and the US Army (via its Coast Artillery service) solved the problems of AAA before WWII began - as did the IJN (but IJA didn't do as well - and eventually adopted naval fire control systems). In fact - IJN was technically ahead in this field in certain respects - something you don't often read about. Many commentators complain they didn't shoot practice rounds, for example - not knowing that this was not purely a matter of limiting ammunition expendature - but a function of not needing to given the sophisticated trainers used. [No other country trained gunners in all light conditions, with targets that looked like the actual targets - not even in the 1960s did we train to such standards.]

I am a technical person and I spoke precisely: we used WWII era technology and it worked superbly well - even vs much faster targets. Modern fire control is NOT a pannacea. I once was knocked off my feet by the wash of an F-5 out of Taiwan which was investigating my ship - an anti-air warfare destroyer nominally able even to engage cruise missile targets. We not only failed to detect the aircraft inbound (although obviously we had been detected ourselves), I ran to a repeater and switched channels: neither on surface search nor on 3D nor on air search could I find the plane - in spite of knowing its bearing. In 1982 a British frigate captain (of a ship that was lost) wrote that "our most important sensor was the mark one eyeball." He was astonished. I was not. AAW is a complicated game and you must be paying attention to win. But IF you pay attention, you can win. Viet Nam successfully used rocks and dynamite to bring down US F-4s. It also successfully used ancient WWII era gunfire control radars (e.g. the SCR-584) to control SAMs (an argument USN ultimately won with USAF - which said it was impossible). Do not denegrate WWII era technology. A lot of it was very fine, and most of it was adequate.

Putting it together into a devastating AA system was a late-war innovation. We went to the dual 3"L50 system to give us longer range firepower against kamikazes, but it was built around the proximity fuse. The quad 40s were a bit short-ranged, although they were a good substitute for a 5"L38 gun on a one-for-one basis, providing closer-in protection. The 20mm cannon was too short ranged to drop a kamikaze before it went into its final dive. The 5"L38s were used in barrage fire rather in engagements with individual aircraft. Pre VT, you either had to use barrage fire, or you had to hit the target. Pre radar, you had to guess the range at which to set the fuze.

James F Dunnigan writes that the problem of kamakazes was never solved - and remains unsolved to this day. I agree with his view. Consider the F-5 experience described above: a human controlled aircraft flying below the radar on a target vector determined by some off platform sensor (originally) should be just about impossible to defeat UNLESS your lookouts sight it on the final run in. Even if they do - a ship is not normally ready to shoot. Even if it is, the guns will nor normally be already turned to the target bearing. Kamakazes led to SAMs too - but they were long ineffective. [See When the Bird's Didn't Fly, USNI Proceedings. In Viet Nam we averaged 60 SAMs per kill.] The AAW problem is a tough one - and really more about sensors than weapons. IF you are ready to engage - AND IF you are any good - AAA is devistating - at least for the first wave. There was a move to do away with AA guns - but it has died out - and some navies (notably the Israeli one) depend wholly on guns even now. Guns work - and work well - if you are at stations and if you detect the target - big if's IRL.

Our game problem should probably focus much more on Japanese AAA. Here too it is naval mountings and naval fire control which matter. [Something like 114 twin 100mm were mounted ashore, along with vast numbers of 120mm and significant numbers of 127mm, all in naval mounts - even if not in naval service. There were also six inch naval AA mountings ashore - about which we know little - and we just found two eight inch single AA guns at Singapore - which no one has studied in any detail (yet).] It appears that USAAF believed - and found in post war analysis - that this AA was a significant issue - and it was a factor in the decision to abandon the bombing doctrine we had built the planes to implement (along with the bombs could not hit the target due to cloud cover and winds). Going over to low altitude approach meant that it was very hard to detect the raid in time to engage it - and while Japanese raid warning apparently NEVER was less than two hours - that did not solve the tactical defense problem. Similarly, it was also hard to intercept - and these raids went in almost unarmed - with all but the tail gun removed. Coming in at traditional bombing altitudes is close to suicide vs modern (by which I mean WWII and later era) air defense. Particularly in large formations which cannot jink (both to avoid hurting each other and to permit accurate bomb delivery). The entire idea was probably marginal by WWII - and the British were probably right to abandon dailight bombing in ETO. The US policy of continuing to practice it was never wholly justified if measured in terms of cost (see Freeman Dyson, a famous nuclear physicist who, during the war, was the statistical analyst for Bomber Command - and the only person given all the data during the war: "I knew how much we were failing to achieve our objectives." He says the Germans had to spend about 1/3 the resources to repair the damage as it cost us to inflict it.)
el cid again
Posts: 16983
Joined: Mon Oct 10, 2005 4:40 pm

RE: 4E bomber effectiveness vs ships, etc. - a new idea

Post by el cid again »

ORIGINAL: treespider

ORIGINAL: Dili

When skip bombing was used against hvy ships? Most of footage i only see it against cargos not against AA destroyers or cruisers.


I wonder if there has been any analysis done on target types for skip bombers... I imagine it would be slightly harder for the bigger planes to stay aligned on target with a fast maneuverable warship which may be firing back as opposed to a slow not very manueverable merchie...


The plane does not maneuver with the target. Instead, it calculates a trajectory based on the present course of the target and the expected tactics of the target. That is why it failed vs Hara. The bomber assumed he would circle - it was doctrine and the Japanese always did. He did not - and the target lead value was wrong. He compounded that by ordering flank speed - also not doctrinal. [His men were somewhat mystified by his orders - but trusted his judgement and implemented them anyway] As with most things, both sides could change tactics. Since the planes were designed and trained to aim at a particular point - that is what they did. They just came up with a clever and mostly correct way to determine that point.
User avatar
wdolson
Posts: 7689
Joined: Tue Jun 27, 2006 9:56 pm
Location: Near Portland, OR

RE: 4E bomber effectiveness vs ships, etc. - a new idea

Post by wdolson »

ORIGINAL: Dili
When skip bombing was used against hvy ships? Most of footage i only see it against cargos not against AA destroyers or cruisers.
ORIGINAL: treespider
I wonder if there has been any analysis done on target types for skip bombers... I imagine it would be slightly harder for the bigger planes to stay aligned on target with a fast maneuverable warship which may be firing back as opposed to a slow not very manueverable merchie...

As far as I know, it was never used against anything bigger than a destroyer. Possibly a light cruiser, but that would be about the maximum belt armor a skip bomb could punch through. The Japanese lost a fair number of setroyers to skip bombers.

Bill
WIS Development Team
User avatar
wdolson
Posts: 7689
Joined: Tue Jun 27, 2006 9:56 pm
Location: Near Portland, OR

RE: 4E bomber effectiveness vs ships, etc. - a new idea

Post by wdolson »

ORIGINAL: el cid again
Our game problem should probably focus much more on Japanese AAA. Here too it is naval mountings and naval fire control which matter. [Something like 114 twin 100mm were mounted ashore, along with vast numbers of 120mm and significant numbers of 127mm, all in naval mounts - even if not in naval service. There were also six inch naval AA mountings ashore - about which we know little - and we just found two eight inch single AA guns at Singapore - which no one has studied in any detail (yet).] It appears that USAAF believed - and found in post war analysis - that this AA was a significant issue - and it was a factor in the decision to abandon the bombing doctrine we had built the planes to implement (along with the bombs could not hit the target due to cloud cover and winds). Going over to low altitude approach meant that it was very hard to detect the raid in time to engage it - and while Japanese raid warning apparently NEVER was less than two hours - that did not solve the tactical defense problem. Similarly, it was also hard to intercept - and these raids went in almost unarmed - with all but the tail gun removed. Coming in at traditional bombing altitudes is close to suicide vs modern (by which I mean WWII and later era) air defense. Particularly in large formations which cannot jink (both to avoid hurting each other and to permit accurate bomb delivery). The entire idea was probably marginal by WWII - and the British were probably right to abandon dailight bombing in ETO. The US policy of continuing to practice it was never wholly justified if measured in terms of cost (see Freeman Dyson, a famous nuclear physicist who, during the war, was the statistical analyst for Bomber Command - and the only person given all the data during the war: "I knew how much we were failing to achieve our objectives." He says the Germans had to spend about 1/3 the resources to repair the damage as it cost us to inflict it.)

The reason I've always read for going over to low altitude bombing was the jet stream, which is very strong over Japan. It would scatter the bombs all over the countryside when dropped from 30,000 feet.

This document: http://www.au.af.mil/au/afhra/aafsd/aafsd_pdf/t165.pdf

Total bomber losses by the 20th AF were: 414
Of those, they broke down as follows
Enemy Aircraft: 74
Flak: 54
Flak and enemy aircraft: 19
Other causes: 267

Most of those other causes were engine fires. B-29s were plagued by them. Taking off fully loaded, a B-29 needed to fly for about 100 miles at low altitude before the engines would cool off enough to climb up to altitude. The engines used magnesium parts to save weight, but these parts had a nasty habit of catching fire if the engine got too hot. The problems were solved after the war.

Flak only accounted for 54 planes. The 20th AF switched over to low altitude bombing in March 1945. 39 of the loses from flak were after March 1945. 17 of the 19 combined losses from aircraft and AA were after March.

I think it's obvious that large caliber Japanese flak was not a concern to the B-29s. Switching over to low altitude caused more flak losses.

My father was doing recon of all the targets in Japan before the B-29 offensive got fully underway. They would fly to Japan with the bomb bay completely loaded with fuel. They missions were 14+ hours. They would film the run in fr several targets on each mission. He's never talked about any Japanese flak, though he recalls seeing Japanese fighters clawing for altitude trying to intercept.

Bill
WIS Development Team
el cid again
Posts: 16983
Joined: Mon Oct 10, 2005 4:40 pm

RE: 4E bomber effectiveness vs ships, etc. - a new idea

Post by el cid again »

ORIGINAL: wdolson
ORIGINAL: Dili
When skip bombing was used against hvy ships? Most of footage i only see it against cargos not against AA destroyers or cruisers.
ORIGINAL: treespider
I wonder if there has been any analysis done on target types for skip bombers... I imagine it would be slightly harder for the bigger planes to stay aligned on target with a fast maneuverable warship which may be firing back as opposed to a slow not very manueverable merchie...

As far as I know, it was never used against anything bigger than a destroyer. Possibly a light cruiser, but that would be about the maximum belt armor a skip bomb could punch through. The Japanese lost a fair number of setroyers to skip bombers.

Bill

The great danger to ships is fires. Bombs will take out the superstructure and AAA and radar and communications - and start fires - even on a battleship. Fires on a carrier are usually fatal. They were not used vs larger ships mainly due to a lack of them to be used against. Indeed - if you look at the other side - you will see bombs were used against all types of US and Allied ships even late in the war.

The main reason not to use skip bombing is that glide bombing is also very accurate. But it is similar in that it usually hits a ship at a shallow angle - and the armor issues will be the same. IRL a plane must use the weapons it has. And no one ever liked getting hit by a 1000 pound bomb.
User avatar
treespider
Posts: 5781
Joined: Sun Jan 30, 2005 7:34 am
Location: Edgewater, MD

RE: 4E bomber effectiveness vs ships, etc. - a new idea

Post by treespider »

from:

http://www.afa.org/magazine/valor/1290valor.asp

Skip-Bombing Pioneer


In the fall of 1942, a better way of sinking Japanese ships had to be found. Ken McCullar was one of the first to master the new tactic.

A priority task for the few Fifth Air Force B-17s of the 19th and 43d Bombardment Groups during the summer of 1942 was interdicting the Japanese sea line of communications from Rabaul, New Britain, to enemy forces on New Guinea. AAF doctrine then held to bombing from altitude with nine-plane (when that many were available) squadron formations. Results had not been good, especially against maneuvering ships. Only about 1 percent of bombs dropped were hitting their targets. Clearly a better way had to be found.
Promising experiments with skip bombing were under way in the US, based on RAF experience. Lt. Gen. George Kenney, commander of Fifth Air Force, was enthusiastic about the new technique. The 63d Squadron of his 43d Bombardment Group set to work in September, testing skip bombing with B-17s against a wrecked ship in Port Moresby Harbor. Approaching the target at 200 mph, aircraft released bombs at 200 feet or lower, about 300 yards from the hulk. The bombs would skip across the water into the side of the ship--if airspeed, altitude, and range were properly coordinated. Modified Australian fuzes were used in the absence of suitable US stock.

Capt. Kenneth McCullar already was credited with sinking or damaging four Japanese vessels, using conventional tactics. He soon became one of the most proficient practitioners of skip bombing, with 60 percent hits in practice runs. Skip bombing looked like the answer, but it added another element of danger to the normal hazards of combat. Chief among these was the nerve-racking experience of flying at point-blank range directly into the muzzles of deck guns on enemy ships. Since the older B-17s didn't have enough forward firepower to keep those guns down, early skip-bombing attacks were made at night, by the light of the moon or flares.

The Japanese were introduced to skip bombing at Rabaul Harbor on the night of Oct. 23, 1942. While six B-17s of the 64th Squadron bombed from 10,000 feet, six 63d Squadron bombers came in at 100 feet to skip their bombs into the sides of Japanese ships. McCullar reported sinking a destroyer with two hits amidships. Two nights later the 63d returned to Rabaul with eight B-17s, about a third of the Fifth Air Force's operational heavy bombers at the time. McCullar was one of four to score hits.

McCullar flew many more skipbombing missions; one of the most notable was on the night of Nov. 24, when he and other B-17 crews attacked an enemy convoy by flare light. His first run at 200 feet scored a near miss on a destroyer. On his second run, McCullar set the destroyer afire.

Coming back once more, his No. 1 engine was knocked out by flak, and the propeller couldn't be feathered. Too badly shot up for another low attempt, McCullar made a conventional bomb run at 1,200 feet and again was hit. He then climbed to 4,000 feet for a fifth attack and lost No. 3 engine to enemy fire. With only two engines running and three wounded men aboard, he was faced with a return to Port Moresby over 13,000-foot peaks. No. 3 finally was brought in at greatly reduced power. "Two and a half hours later," McCullar reported, "we were at 10,000 feet, our ceiling, and luckily we found a pass to sneak through, landed OK, and forgot about it."

Twice more McCullar brought his B-17 home on two engines, once from nearly 600 miles from Rabaul where he was on a photo-reconnaissance mission. Seventy miles short of Rabaul, a supercharger blew up, killing both engines on the left wing. McCullar completed the mission on two engines and flew back to Port Moresby with excellent photos of the Rabaul area. Two days later, on Dec. 7, he helped turn back a Japanese convoy, returning with more than 100 machine-gun and 20-mm holes in his B-17.

McCullar, by this time a major, led a charmed life, it would seem. His skill as a pilot and his determination to complete every mission regardless of the odds had earned him a Distinguished Service Cross. Then, as with so many other combat heroes, the odds caught up with him. On April 12, 1943, while taking off for an attack on a convoy, his B-17 crashed in flames.

"His exploits were already legends that would be told and retold long after the war," Kenney said. McCullar was a symbol of valor i n the dark days of the Pacific war. His courage and resolution should remain an inspiration to those who follow almost a half-century later.


Here's a link to:
Treespider's Grand Campaign of DBB

"It is not the critic who counts, .... The credit belongs to the man who is actually in the arena..." T. Roosevelt, Paris, 1910
el cid again
Posts: 16983
Joined: Mon Oct 10, 2005 4:40 pm

RE: 4E bomber effectiveness vs ships, etc. - a new idea

Post by el cid again »

ORIGINAL: wdolson
ORIGINAL: el cid again
Our game problem should probably focus much more on Japanese AAA. Here too it is naval mountings and naval fire control which matter. [Something like 114 twin 100mm were mounted ashore, along with vast numbers of 120mm and significant numbers of 127mm, all in naval mounts - even if not in naval service. There were also six inch naval AA mountings ashore - about which we know little - and we just found two eight inch single AA guns at Singapore - which no one has studied in any detail (yet).] It appears that USAAF believed - and found in post war analysis - that this AA was a significant issue - and it was a factor in the decision to abandon the bombing doctrine we had built the planes to implement (along with the bombs could not hit the target due to cloud cover and winds). Going over to low altitude approach meant that it was very hard to detect the raid in time to engage it - and while Japanese raid warning apparently NEVER was less than two hours - that did not solve the tactical defense problem. Similarly, it was also hard to intercept - and these raids went in almost unarmed - with all but the tail gun removed. Coming in at traditional bombing altitudes is close to suicide vs modern (by which I mean WWII and later era) air defense. Particularly in large formations which cannot jink (both to avoid hurting each other and to permit accurate bomb delivery). The entire idea was probably marginal by WWII - and the British were probably right to abandon dailight bombing in ETO. The US policy of continuing to practice it was never wholly justified if measured in terms of cost (see Freeman Dyson, a famous nuclear physicist who, during the war, was the statistical analyst for Bomber Command - and the only person given all the data during the war: "I knew how much we were failing to achieve our objectives." He says the Germans had to spend about 1/3 the resources to repair the damage as it cost us to inflict it.)

The reason I've always read for going over to low altitude bombing was the jet stream, which is very strong over Japan. It would scatter the bombs all over the countryside when dropped from 30,000 feet.


It was one reason. Another was that Japan is clouded over about 84% of the time - making the chance you get to use a bomb sight very small. Another was that if you do attack in good visibility in daylight in a non-maneuverable bombing formation, you are going to optimize losses to AAA. These could become significant. Certain targets were not bombed due to the presence of tiny numbers of very good guns. Yet another reason was philosophy: USAAF was MORE effective with mines than bombs - but it was not to USAAF taste to deliver mines.
Post Reply

Return to “Scenario Design”