# Most accurate divebomber



## gjs238 (Mar 8, 2013)

Everything else being equal and overlooking things like vulnerability, what was the most accurate WWII dive bomber?
If they could all be tested under the most controlled circumstances as possible, which was the most balls-on?


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## davebender (Mar 8, 2013)

Junkers Ju 87 - Wikipedia, the free encyclopedia


> Eric "Winkle" Brown RN, a British test pilot and Commanding Officer of Captured Enemy Aircraft Flight section, tested the Ju 87 at RAE Farnborough. He said of the Stuka, "I had flown a lot of dive-bombers and it’s the only one that you can dive truly vertically. Sometimes with the dive-bombers...maximum dive is usually in the order of 60 degrees.. When flying the Stuka, because it’s all automatic, you are really flying vertically... The Stuka was in a class of its own."



Ju-87 was more then just bombing accuracy. Ju-87B routinely carried 500kg. Ju-87D routinely carried 1,000kg. Ju-87D had significant protection against ground fire. When equipped with cannon (ILO bombs) the aircraft was a stable and maneuverable gun platform for attacking ground targets.


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## GregP (Mar 8, 2013)

I believe the most accurate dive bomber of the war was the Aichi D3A Val. During the course of the Second World War, the Val dive bomber sank more Allied warships than any other Axis aircraft. Of course, it never got a chance to bomb a lot of land targets, but bombing moving ships is a tough task for the pilot and the Val was outstanding.


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## Denniss (Mar 8, 2013)

The Ju 87 was not used vs allied ships in this large scale as the D3A because the initial versions lacked range and germany had no operational carriers. But the Ju 87s sank a lot of ships, too.


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## davebender (Mar 8, 2013)

On the other hand ships are large compared to bunkers and other such land based targets.


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## GregP (Mar 8, 2013)

Yeah they are, but they keep moving out of the way of your aim ... sometimes at 30+ knots.


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## Ascent (Mar 10, 2013)

Surely this come down to pilot training rather than the abilities of the aircraft?

otherwise I'd possibly vote for the Vultee Vengance as used by 84 and 110 Sqn's in India. A vertical dive means that the bomb can be aimed true.


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## VBF-13 (Mar 10, 2013)

Any trained pilot in any of these aircraft could put those bombs in a pickle barrel. Well, in a manner of speaking. But just look at what our "Speedy Ds" (as they were affectionately referred to) did at Midway. Those pilots were scoring hits in 60-degree dives in the middle of the night on illuminated die markers floating up and down and rolling from side to side in the Gulf and the Atlantic well before they ever got around to the real thing. The aircraft is going to behave slightly-differently due to differences in aerodynamics but the pilots are accustomed to those nuances and know how to get it to where it has to be. All it takes is the right guy there at the stick.


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## gjs238 (Mar 10, 2013)

Is an aircraft that dives at 90 degrees inherently more accurate than one that dives at 60 degrees?


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## VBF-13 (Mar 10, 2013)

gjs238 said:


> Is an aircraft that dives at 90 degrees inherently more accurate than one that dives at 60 degrees?


I wouldn't think so. A 90 would have to pull out sooner meaning it would have to make its drop sooner. They're not easy to pull out of, either, going in at that breakneck speed. Don't forget, these pilots were momentarily blacking-out when they came out of their dives, and as such were trained to complete them just so (think of the importance of the follow-through in a golf swing). A 60 can get virtually right on top of its target and swing away a lot less stressed. A lot of the boys in the SBDs were scoring 5-for-5s in terms of hits in their training, once they got the knack of it.


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## tyrodtom (Mar 10, 2013)

In a vertical dive you're aiming the bomb as if it was a slow bullet, all you've got to worry about is wind drift, and target movement if there is any. Gravity is going to try to pull your bomb straight down after release.
In a 60 degree dive, there's going to a interplay of the forces acting on the bomb, the direction and speed the bomb is going when released at 60 degrees, and gravity, which wants to pull it straight down, plus wind drift and target movement.

So divebombing straight down is a much simpler equation. Fewer forces that have to be taken into account.

But vertical dives is much rougher on plane and pilot.

One of the advantages the Ju87 had was it had some automatic systems that aided the pilot in recovery, as long as the altimeter was set right, and the target's real altitude was know, the Ju87 would pull out even if the pilot was unconscious.


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## VBF-13 (Mar 10, 2013)

The pull-outs were basically just a jerk on the stick, the aircraft already having been trimmed-up for it. But Tyrodtom, I've seen the film of those JU87s coming in at near-vertical. They had that down to a science.


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## yulzari (Mar 10, 2013)

In aiming at moving ships a vertical dive means the pilot can adjust to any change in direction by simply rotating during the dive and AA fire is much more difficult against a vertical target. Many mountings do not even manage a vertical elevation.

What about the Swedish dive bombers? They went to a lot of trouble and research on dive bomb sights for the B18 and B17.


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## buffnut453 (Mar 10, 2013)

Hope Wildcat reads this 'cos I'm going to put a vote in for the Vengeance. Peter Smith, who never met a dive bomber he didn't like, wrote that the Vengeance, "carried out its function with the _maximum _number of direct hits and in reply took the _minimum _number of losses from enemy action than almost any other aircraft of World War II" (in "Vengeance: the Vultee Vengeance Dive Bomber". Peter C. Smith,Airlife, p.1 - author's italics not mine).

Also, according to the frontispiece of Smith's book, "[The Vengeance] was the only dive-bomber designed from the outset for vertical attacks."


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## davebender (Mar 10, 2013)

> according to the frontispiece of Smith's book, "[The Vengeance] was the only dive-bomber designed from the outset for vertical attacks."


We know that isn't true as Ju-87 was designed for 90 degree dive right from the start. Makes me wonder what else the author got wrong.


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## Aozora (Mar 10, 2013)

A useful primer on dive bombing:


_View: https://www.youtube.com/watch?v=lOz_i_2USkY_

My guess is that with proper training, and all things being equal etc all of the key dive bombers of WW2 were pretty similar in accuracy - any differences in numbers of ships sunk or other targets destroyed came down to how and where they were deployed, and under what conditions.


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## Shortround6 (Mar 10, 2013)

You would need all contenders flown by the same group of rotating pilots on the same days (conditions) to really judge any difference between the planes ( same bombs would help too). Otherwise there are just too many variables to make a valid judgment.


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## stona (Mar 11, 2013)

Ascent said:


> Surely this come down to pilot training rather than the abilities of the aircraft?



Not entirely. 
Stability and controllability in the dive are important factors. Aircraft specifically designed as dive bombers are generally better than other types which may have been pressed into service in the role,but they were by no means all equal.
In the instructions for dive bombing with a Typhoon the RAF was keen to impress on the pilots the need to minimise slipping or skidding which the aircraft tended to do. It obviously was designed as a fighter,not a dive bomber.
A dive bomber also needs a system for recovering the dive without tearing the wings off or hitting the ground. Some dive bombers had some relatively sophisticated automated systems for this and again,some were better than others.
The Ju 87 recovered itself and the pilot didn't use the elevators at all,so no quick "jerk on the stick".
I don't know about the Japanese aircraft but in the European war the Ju 87 was probably the supreme diver. Even allied pilots who flew it were impressed with its characteristics in the dive.
After that it's down to the pilot.
Cheers
Steve


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## VBF-13 (Mar 12, 2013)

But Steve, when it comes down to "accuracy," which was the question, here, these really can't be differentiated in any meaningful respect. Differentiate them structurally from the fighters pressed into the service, as I'm hearing you just did. But the SBDs and the Val's were crackerjack dive-bombers, and all these really took we're skilled pilots who understood how these behaved and knew what to expect when they came out of their dives. Believe it or not an untrained pilot will freak at that point and the disorientation will invariably cost him in terms of recovery. Once they let go of their drops, the aircraft also lightens, and picks up speed. I'm not saying in a controlled test these aircraft couldn't be rated by some standards or other, they probably could. It would almost be suicide in an SBD to attempt a vertical drop, while in the Stuka, that was for the most part a breeze. I'm just saying it's misleading to suggest any of these aircraft were the more or less "accurate" due to any structural nuances or how they were designed to complete the job. They were different, but not in that respect, where it really meant anything.


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## tyrodtom (Mar 12, 2013)

Read about all the things that the Stuka had that adapted it particually well to dive bombing.
Like the sight hole in the floor, when the pilot saw his target thru a window in the floor, he'd do the standard roll over dive, and the target would be in his windscreen view, ready for minor control corrections to line up the sights, once the bomb was released, the recovery automatically started without pilot input, but could be over ridden if desired.
That and a some other adaptions in the Stuka meant a trained Stuka pilot could put more concentration on what mattered most, putting his bomb on target.

Everyone knows I hate to praise anything from the axis, but you've got to admit the Stuka was a little more able than the rest of the dive bombers.


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## gjs238 (Mar 12, 2013)

I suppose I could invert one of my questions.
If a 90 degree dive is not inherently more accurate than a 60 degree dive, then why develop 90 degree dive aircraft and techniques?


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## stona (Mar 12, 2013)

VBF-13 said:


> But Steve, when it comes down to "accuracy," which was the question, here, these really can't be differentiated in any meaningful respect.



Maybe not. I don't really know enough about the ther two to make a properly informed assessment. I agree that it isn't really a matter of one aircraft being intrinsically more accurate than another,but you have to look at the whole package,including the crew.
The point I'm trying to make is that a better designed dive bomber will perform better in the hurly burly of service life. A good design must make it easier and more sympathetic to fly and that must have an effect on average accuracy. There is no doubt that a highly skilled pilot will achieve good results in any of the types mentioned,I certainly don't disagree with that contention,but not all pilots are equal. The easier the aircraft is to fly in its intended role the better results your units will achieve.
Cheers
Steve


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## VBF-13 (Mar 12, 2013)

Never knew about that floor window, but what a nice adaptation. But, yeah, I'll go there, the Stuka was somewhat unique. Just from the film I've seen, those were coming in like Kamikazes. They were very good at what they were designed for, there's no question about it. 

On the question of why the 90s, in one word, "Blitzkrieg." These Stukas just pounced on their targets. In a 60, you can see the aircraft coming. In a 90, it's literally like they just drop right out of the sky. But Steve can tell you a lot more about that than I can, I'm sure. I just know what I know from the film I've seen.


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## barney (Mar 12, 2013)

VBF-13 said:


> It would almost be suicide in an SBD to attempt a vertical drop, while in the Stuka, that was for the most part a breeze.



What was keeping the SBD from doing a vertical drop?


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## Shortround6 (Mar 12, 2013)

It might be news to some SBD pilots that they couldn't do a vertical dive (or close to it).

Some (all?) SBDs had window in the cockpit floor, usually covered with oil.


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## VBF-13 (Mar 12, 2013)

barney said:


> What was keeping the SBD from doing a vertical drop?


I don't know that they could come out of one going in that "hot." I know the Navy had a means of monitoring their angles in their training. I know it went into their scores and that when they came in too steep they aborted and didn't drop. I just always assumed there was a structural reason for that (i.e., the aircraft couldn't recover well enough?), but that might not be the case, it might just be due to the stresses on the pilot, as that's a much more demanding dive to make and pull out of (think of glide-bombing, which is understandably the easiest). That's just guessing, though, based on assumptions I've formed, and I really don't "know." If I had to bet, an SBD couldn't come out of a vertical dive-bombing pass, there is a structural reason for it, otherwise they'd have practiced it. Think of dive-bombing, now, which is a rather abrupt swing-out, as opposed to a gradual, once that altimeter says they're at that moment of truth. They didn't practice it, because the aircraft wasn't built for it, that's what I think. But, again, I don't "know."


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## barney (Mar 12, 2013)

I can't see speed making a difference. Speed was limited by dive flaps. 

The Ju 87 has a bomb cradle that flips down so that the bomb is released below the propeller arc. So, did the SBD have any mechanism for keeping the bomb out of the prop? If no, then that wouldn't keep a SBD from diving vertically so long as it wasn't vertical when the bomb was released.

I remember that the Mustang handbook includes a warning about bombing vertically due to a chance of hitting the prop.


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## GregP (Mar 12, 2013)

The SBD has enormous dive brakes and absolutely CAN dive vertically. A 90° diving attack is no more accurate than a 60° diving attack. 

Once you get the aiming device set correctly, the CEP is the same. Ask the guys who used to fly them in wartime. They know. It's a matter of correct procedure.


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## tyrodtom (Mar 12, 2013)

GregP said:


> The SBD has enormous dive brakes and absolutely CAN dive vertically. A 90° diving attack is no more accurate than a 60° diving attack.
> 
> Once you get the aiming device set correctly, the CEP is the same. Ask the guys who used to fly them in wartime. They know. It's a matter of correct procedure.



If that's true, then a 60 deg diving attack is no more accurate than a 30 deg diving attack, and a 30 deg diving attack is no more accurate than a level bomb drop.

And we all know how accurate level bombing is, all they have to do is set the bombsight right.


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## GregP (Mar 13, 2013)

Sounds like you have it all figured with inductive reasoning. Please continue.


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## VBF-13 (Mar 13, 2013)

barney said:


> I can't see speed making a difference. Speed was limited by dive flaps.
> 
> The Ju 87 has a bomb cradle that flips down so that the bomb is released below the propeller arc. So, did the SBD have any mechanism for keeping the bomb out of the prop? If no, then that wouldn't keep a SBD from diving vertically so long as it wasn't vertical when the bomb was released.
> 
> I remember that the Mustang handbook includes a warning about bombing vertically due to a chance of hitting the prop.


Barney, they could dive vertically, they just never dropped like that. Maybe you have one of the reasons, right there. Again, I know they never trained in vertical drops.



tyrodtom said:


> If that's true, then a 60 deg diving attack is no more accurate than a 30 deg diving attack, and a 30 deg diving attack is no more accurate than a level bomb drop.
> 
> And we all know how accurate level bombing is, all they have to do is set the bombsight right.


The bombs are dropped at different heights, Tom, that's all. They hit what they're aiming at.


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## Aozora (Mar 13, 2013)

tyrodtom said:


> If that's true, then a 60 deg diving attack is no more accurate than a 30 deg diving attack, and a 30 deg diving attack is no more accurate than a level bomb drop.
> 
> And we all know how accurate level bombing is, all they have to do is set the bombsight right.


 
Take a look at the U.S training film which explains the principles: guaranteed the Ju-87 did not normally dive at 90 deg, although it might have done so in propaganda films, because it wasn't necessary to dive 90 deg to achieve good accuracy, and it was far too stressful for the aircrew and airframe. If anything trying to dive at 90 deg is counter-productive because it allows absolutely no scope for corrections. BTW the Ju 87 was not unique in having sighting windows, bomb cradle and pull out equipment.


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## cimmex (Mar 13, 2013)

Aozora said:


> BTW the Ju 87 was not unique in having sighting windows, bomb cradle and pull out equipment.


Interesting, please tell more. Would like to know what models.
cimmex


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## Aozora (Mar 13, 2013)

cimmex said:


> Interesting, please tell more. Would like to know what models.
> cimmex



Forgot auto pilot on American aircraft did not incorporate auto pull out, otherwise SBD Dauntless, all models - bomb cradles, sighting windows. SB2C Helldiver all models - closed bomb bay, bomb cradles, sighting windows. TBF/TBM etc etc...


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## cimmex (Mar 13, 2013)

thank you, I’m not very familiar with US planes, do you have a link?
cimmex


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## Shortround6 (Mar 13, 2013)

The Ju 87 had an automated pull out device, that was about it for differences. 

as for the bomb cradle;







Dauntless bombed at 70-80 degrees in the early part of the war. One pilot describes that as the angle of the flight path. 

By 1940 the Americans had been dive bombing for over 20 years, first _purpose built_ American dive bomber was a Curtiss _delievered in 1929_.






The idea that 10 years later the US would make a dive bomber that couldn't do a vertical dive with coming apart is ludicrous.


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## tyrodtom (Mar 13, 2013)

I did look at the training film, and saw the importance of keeping a exact dive angle of 60 deg., because that's what what they trained with and the sights were set up for.
Every correction for wind drift and target movement wouldn't be the same at different angles, and there's a difficulty in attaining that right 60 deg angle if you start out from a different angle.
When you drop anything from anything less than vertical you're tossing it, like the difference in trying to get something in a trash can. Drop it from straight above, not too hard, now get off to the side, it gets more difficult. Now add that you're moving toward the trash can, and there's a wind, and maybe the trash can is moving too. And add someone at the trash can shooting at you.
The further away you get from that straight drop from staight above the more difficult it becomes.


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## Ainene (Mar 13, 2013)

cimmex said:


> Interesting, please tell more. Would like to know what models.
> cimmex






).
Me-210A, Me-210c(Hungarian).
Me-410A-1, Me-410B-1.


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## VBF-13 (Mar 13, 2013)

Aozora said:


> Take a look at the U.S training film which explains the principles: guaranteed the Ju-87 did not normally dive at 90 deg, although it might have done so in propaganda films, because it wasn't necessary to dive 90 deg to achieve good accuracy, and it was far too stressful for the aircrew and airframe. If anything trying to dive at 90 deg is counter-productive because it allows absolutely no scope for corrections. BTW the Ju 87 was not unique in having sighting windows, bomb cradle and pull out equipment.





Aozora said:


> Forgot auto pilot on American aircraft did not incorporate auto pull out, otherwise SBD Dauntless, all models - bomb cradles, sighting windows. SB2C Helldiver all models - closed bomb bay, bomb cradles, sighting windows. TBF/TBM etc etc...


That's all right. Credit me as being one of those suckered-in by the propaganda films, principally the familiar ones over Poland showing the Stukas peeling off nose-down. My Dad qualified on a Speedy-D and I'm embarrassed to say I never knew it had one of those sighting-windows in the floor. I did know about everything else, though, so at least that's something, lol.

Back to the vertical dives, yeah, there's probably a reason the Navy never trained on those. There's somewhat more of an element of surprise, as it's just a lightning-quick drop out of the sky, and they're probably harder to pick-off, too, coming in like that, but the countervailing factors being the stresses to the craft and crew and the fact they're gaining nothing in terms of accuracy probably dictated why those nose-dives were never bothered to be trained on. As I see it, now, anyway.


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## tyrodtom (Mar 13, 2013)

According to several websites on Stukas, they were taught the ideal dive angle was 85 deg, and to not exceed that. It would be hard to tell the difference in a film between 90-85-80 degrees. But the Stuka, and probably other dive bombers too, had slant marks on the sidewindow to judge you dive angle from, they went to 90 degrees.

And I fail to understand why anyone would think that in a vertical dive,or near vertical dive, a aircraft would have no ability to correct it's aiming point.


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## Shortround6 (Mar 13, 2013)

The idea of the dive brakes was to slow the rate of decent so that more time could be taken to aim or correct aim, that a lower altitude drop could be used ( pulling out at say 240mph/knts instead 350 or more) also increasing accuracy and that at the lower speed the controls were still effective.


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## GregP (Mar 13, 2013)

In a 90° dive, you have to release the bomb in coordinated flight, with no slip or skid or pull-up or push-over, or you will miss rather widely. In a 60° dive you can use very minor corrections, reacquire the target, and resume coordinated flight quickly. In a 90° dive, you have to use gross corrections because there is so little room for error, and reacquiring coordinated flight is more difficult while remainiing on target. Going straight down, a 20° bank won't doo much for you in the way of moving the impact point. In a 60° dive a 20° bank for a couple of seconds will move the aim point a few degrees.

If you actually try to hit a target from directly above, you will have a real CEP (circular error of probability). In a 60° dive, they are almost always on or very close to target left and right, and usually have either overshoot or undershoot if they miss. The CEP is more oval and most pilots, in the USA anyway, learned how to narrow the oval with practice so the error was quite small. The Germans and Japanese were pretty good at it, too, and there was likely little to choose between good dive bomber pilots of any nationality.

The real trick was to not get shot down by your target if the target happened to be a heavily-armed ship and then avoiding the single engine fighters that were always looking to shoot you down. In that regard, the SBD was probably the dive bomber best suited to fighter tactics for survivial once the bomb had been dropped. It gave a very good account of itslef in the war in the Pacific and was used as a fighter on several occasion with relatively good results.

If you open the dive brakes in an SBD while in level crusing flight, it feels like you just flew through Elmer's Glue and you lose speed RIGHT NOW ... feels like you just deployed a parachute! I have several friends at the museum who have experienced just that in our SBD, and they were all taken by surprise at the g-foprce deceleration despite being warned the dive brakes were about to be deployed. The camera plane leapt ahead like a Cheetah on full sprint and the SBD pilot had to close the dive brakes rather quickly to avoid losing more than 40 knots in an instant. I have heard the terminal speed of the SBD in conversation, but can't recall it just now. I'll ask this coming weekend.


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## tyrodtom (Mar 13, 2013)

In any form of bombing, from vertical drops, to level drops , the bomb has to be released while in coordinated flight, or where you're aiming with the bombsight means nothing.


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## GregP (Mar 13, 2013)

That's true for dumb bombs in WWII. 

If you have smart bombs, then it really doesn't matter since they guide themselves after release. Still, I'd think that even with smart bombs, you'd want to be at least closely coordinated just to get a good separation from externally-mounted ordnance. If it comes from a bomb bay, it might not matter much these days with smart weapons.

My point, as I'm sure you know, is that making small corrections while going straight down is tougher than in a steep but not vertical dive. Why make it harder on yourself and the aircraft?

Good pic of the SBD above, Shortround. Shows the dive brakes and bomb trapeze very well.


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## tyrodtom (Mar 13, 2013)

I can see in a vertical or near vertical drop, you'd have to start your dive very close to straight over the target, because you can't toss the bomb from a vertical dive, and your ability to move the aircraft laterally, or steepen or lessen the dive to line up in that way can only do so much.
But early war Stuka pilots were supposed to be the cream of the crop, more elite than fighter pilots.

I know smart bombs have changed things greatly, but they still have to be dropped within certain parameters, even a smart bomb can be stalled.


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## Shortround6 (Mar 13, 2013)

The SBD pilots description is a little confusing to me but then I am not a pilot. He describes the fight path as a 70 degree dive but the plane as being vertical. A chart from the pilots manual shows that with the dive flaps open in a terminal velocity dive about 4.75 degrees of nose down angle of attack is needed for a 70 degree angle dive. For 80 degree dive angle about 5.2 degrees down angle is needed. 

This may be a reason _true_ 90 degree dives were not done. From the chart a _true_ 90 degree flight path requires the plane to be 5.6 degrees _beyond vertical. _

The plane may certainly have _felt_ vertical


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## Aozora (Mar 13, 2013)

While the U.S Navy refined the principles of dive bombing (the original concept was devised by the British during WW1) and developed the bomb crutch, the USN pilots didn't want the automatic pull-out:










Interesting comment on pilots misjudging the dive angle, so having the guidelines painted on the side of the canopy must have helped. Another factor not mentioned is that at dive angles greater than about 65 deg pilots felt as though the aircraft was diving beyond the vertical

(from Peter C. Smith, _Douglas SBD Dauntless_, Crowood 1997, pages 9 10)

Some more reading...






(Smith 1997 page 46)


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## VBF-13 (Mar 14, 2013)

If anybody is curious the actual training in the SBDs took about two months, then they went off for their carrier-quals. Total time, over 100 hours. Different characters on the flights, ranging from familiarity and practice, to gunnery and bombing, instruments, night flying, you name it. On many days, they went up two or three times. Here's a blown-up scan of a 35mm negative of the old man and his gunner, probably over the Atlantic. I just recently found it stuck in between the pages of his scrap book, and I don't even know if he ever even saw it. I've been meaning to take it to Walgreen's, but I don't know if they even know how to develop these, anymore, and I'd really hate like heck to freak them out, lol. But, anyway, here's my contribution to the snapshots. Great information, here, too, I learned a lot...


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## Ascent (Mar 14, 2013)

These next few quotes are from a pilot on 110 Sqn in India flying Vengances, taken from this thread Gaining An R.A.F Pilots Brevet In WW11 - PPRuNe Forums

The first is about learning to bomb in the Vengance (he was expecting Spitfire's) one about the vengance generally and the last is from his first sortie. The whole thread is an interesting read but these are relevant to the thread.

1."Training started at once. Really it was simple, we had to learn to dive-bomb and to fly any position in a box-of-six which was to be our normal tactical formation. A range was set up on a big sandbank (it was the dry season) on a bend in the river Damodar, about 30 miles from Madhaiganj. Who supplied the observers, and what equipment they had, I do not know. There must have been two of them at a safe distance, with lines of sight at right angles and some form of theodolite. 

We went to work on this range right away. All we were concerned about was results, and with practice these became quite good. Four 11 1/2 lb smoke bombs were carried on a rack under the left wing, and dropped one per dive. The trip to the range took about 15 minutes, and by then you'd climbed to bombing height of 10 - 12,000 ft.

The trick was to fly up to the target in such a way as to be vertically above it when you rolled over. The best method was to keep it in view, running along tight against the left side of the fuselsge from the nose back until it slid under the wing, count ten and go over, crouched, standing on your rudder pedals on the way down.

The steeper the dive, the better the result. You "throw" your aircraft at the target much as a darts player "throws" his wrist at the board. You must not forget to (a) use the dive brakes and (b) pull out in good time. As to what constituted "good time" we experimented, pulling out high to start with and then reducing until we'd established the lowest safe height. This was reckoned to be when the altimeter passed 3500 ft above ground, although the aircraft would be lower at this point, as the instrument lagged by several hundred feet.

Having planted your first bomb and swung round to see where it had gone, you climbed up and dived three more times, then home. As such a climb and repositioning took you ten to fifteen minutes, two or three aircraft could space themselves out and use the range together.

These sorties lasted little more than an hour and formed the greater part of our training. We improved with practice: at the end almost all bombs would go in a 100-yard circle."



2."Incredibly, the lockable tailwheel also retracted - an unnecessary complication in an aircraft with absolutely no need for it ! (Neither the Spitfire nor Hurricane had them). Hydraulics also powered flaps, bomb doors, cowl gills and the dive brakes.

These last are the most important fitments on a dive bomber, and the Vengeance had splendid ones. Massive grids extended above and below the wings * On the upper surfaces the grid was hinged on the front,* so airflow would tend to force it shut. On the lower, the hinge was at the rear, with the opposite effect. Top and bottom were coupled, so the forces cancelled out.

These brakes could be opened at any speed, partially or completely, and when fully open restricted the terminal velocity to about 300 mph (knots did not come in till much later). They did not interfere with control or trim in any way, for they were well clear of the wing surfaces when fully extended and so did not obstruct the airflow over or under them. This low terminal speed gave us plenty of time in the dive to draw a bead (in our case the yellow line) on the target. 

Two unique design features improved dive stability. The angle of Incidence was zero, the Vengeance being AFAIK the only dive bomber designed from the outset to dive vertically. The side effect was a comical tail-down "sit" in the air in level flight. A Vengeance "dragging its a###" could be recognised miles away. 

Flying slowly, as in coming in to land, this combination of tail-down attitude and long nose meant no forward vision. We had to put up with that, after all the Spitfire had been almost as bad. In the same way the fin was fitted without the usual small offset to compensate for the gyroscopic effect of the propeller.

With powerful dive brakes and these novel features, the Vengeance made an excellent dive bomber. In a vertical dive, it was smooth and stable (with only 20 seconds to line up, you don't want your nose swanning about round the target). Judged purely as a flying machine, it was useless. Ponderous, awkward and slow, all was forgiven for the sake of that dive. One-trick pony it may have been, but it did its one trick very well indeed, and that was all that mattered to us."


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## Ascent (Mar 14, 2013)

3."I've said that we normally put up only six aircraft at a time. On this single occasion, we scraped up twelve - six from 110 and six from 82 Sqdn. 82 ("Out of the blue came Eighty-Two!") were to go in first. As a new boy on 110, I flew the 6 position, which would mean I would be the last man of all to go down. As I never flew in a 12-ship strike again, this was the only time I was able to watch all the action from the air.

Topper was leading our six. We came in from the North at 12,000 ft with 82 ahead. It was afternoon. As we reached the island, the heavies opened up. Our two formations were "weaving", flying a slow zig-zag with a course change every twenty seconds or so. This confuses the gun predictors, so the flak bursts were 2-300 ft off to the side, but uncomfortably accurate for height. We overflew the island, then turned left in a wide sweep over the mainland, flying right round until we reached Akyab again, but this time coming out of the haze and gloom of the eastern sky.

It was a clever ruse (if it was a ruse - perhaps the 82 leader had simply misjudged his first run-up). Later intelligence confirmed that the Jap had put out an air raid warning the first time. But as we didn't bomb, they assumed that we were going on somewhere else and sounded the all-clear. Second time round, we caught them napping, sitting with their evening rice.

The jail was a bomber's dream target. Built on the cart-wheel plan, I suppose it was 2-300 ft across. It was unmissable. It must have been the largest building on the island. As the last man on the line, I could allow myself room to watch the action. 82 were a mile ahead, so I watched them all go down. They were like beads sliding down a string, three spaced out at a time. I could see the bomb flashes dead on target, billowing up in smoke and dust.

Then it was our turn. Topper waggles his wings. This is the signal for the rear "vic" to drop back and move into echelon starboard. A few seconds later, he waggles again and opens his bomb doors. All open theirs. 3 and 6 (me) swing across into echelon on 2 and 5 respectively. Now we're all in a diagonal line like a skein of geese. (This formation change is made only at the last moment, for although it looks nice on the newsreels, it leaves you practically at the mercy of an attacker - and it advertises your imminent attack to any watcher on the ground).

Mechanically I go through my drill: Canopy shut, check bomb doors open, bomb switches "live", trims neutral, 2100 rpm, mixture rich, gyros caged, cowl gills closed, straps tight.

The first three go down. A few seconds later 4 goes over, settles in the dive and puts his brakes out. 5 puts his out as he rolls over. I put mine out, throttle back to a third and then roll. This gives us an extra bit of spacing for safety.

After that, it's simply "doin' what comes nacherly". Rolling over, I throw my head back and look straight down on the dust cloud over the jail - or what's left of it. Then it's just a matter of sighting down the yellow line and "flying" it onto the target. Feet braced on my big fat rudder pedals, I sense the dive is as near vertical as dammit - you can feel it with practice. Topper has done us proud, for this is a follow-my-leader operation, and if he's off vertical, then the whole thing will be a mess.

I can see 4 and 5 ahead for a few moments, then 4 pulls away from my field of vision. Bomb flash. I'm snatching quick glances at my altimeter, which is spinning like a broken clock, one sweep of the "big hand" every two or three seconds. 5 pulls away, keep line on target, bomb flash, 5000 ft, check line, 4000, check, 3500, press button (on throttle grip) and pull, pull, pull for dear life - literally - five seconds too late and you're dead. 

Things go dark and I'm crushed down in my seat by "G" for a few moments, then I relax a bit and vision clears. Brakes in, we're in a 40-degree dive from a thousand feet, still with most of the 300 mph we picked up on the way down.

The sky looks like a dalmation dog, for light AA has been pumping away merrily for a minute or two. Surprised, it dawns on me that they're still firing at us. I feel quite indignant. Poor little me, what have I done to deserve being shot at at like this?

This dangerous reverie exasperates the battle-hardened Robbie behind. "Get weaving, Skipper", he roars, sees a gun position on the ground and gives it a long burst to distract the gunners from their aim. That wakens me up.

No time to ruminate - jink and get down on the deck as fast as you can! At this point I should explain that aircraft come out of the dive heading every which way, depending on where they were facing when they pressed the button, and that has been affected by the amount of "weathercocking" which they'd had to do on the way down. It was rather like a Red Arrow "bomb burst", only in sequence.

So you had to pick up your bearings, decide which way was home, and pull round onto it. It must have life more difficult for the AA, as no two of us were following the same path, and this was all to the good.

Now I'm sailing over the tree tops and out of most harm's way. Not entirely, any Jap with a rifle or LMG is going to try a potshot if he sees me in time and in range. It was not uncommon for aircraft to come back with small arms hits.

Dive bombers are a very hard target for AA. Before diving, they can weave as we did to keep out of trouble. Diving, they are well nigh impossible to hit. Pulling out, they are going so fast and low that aimed fire is ineffective. All the gunners can do is to put up a barrage through which they hope we might fly. If they get one it's pure luck. Having said that, I must admit there were cases of people just not pulling out of a dive. No one could say whether they'd been hit or not. The probability is that they were concentrating too hard and left the pull-out too late. The margin for error was tiny.

Once level, you can open your canopy and close bomb doors to reduce drag - but not while you're still pulling "G" in the turn onto the home straight! In a dive, the two internal 500 lb bombs, if simply dropped from the racks, might hit the front wall of the bay, or drop into the arc of the prop. Either way would be disastrous.

To avoid this each bomb is carried in a fork pivoted at the front of the bay. Round the bomb is clamped a "trunnion band" which carries the two "trunnions" - projections which engage in slots on the ends of the forks. Released, the bomb flies out and then off - safely - for you! (the Stuka used the same idea).

On pulling out, centrifugal force will continue to hold these forks out against the pull of "bungee" cords, even after the bombs have gone. There's always one who's too keen to pull in his doors - and traps them against the forks! Everything about a VV is massive - no damage is done. Following crews enjoy the spectacle of a big daddy-long-legs, slowed down by the dangling forks and half-open doors. It can take quite a while before the penny drops in the cockpit concerned."

Incedentally the yellow line he mentions was a line painted on the cowling which was what they used as a bomb sight.


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## VBF-13 (Mar 14, 2013)

Enjoyed this very much. A few observations. Going in groups of six was pretty much standard all around from what I understand. You'll note the five planes in my negative, and that you see five in many such photos. The sixth was operating the camera from the second seat. On the accuracy of a vertical dive, again, I don't know that it was any the more accurate. If you'll look at how this pilot describes his virtual immunity from fire while in the vertical dive, yeah, that's probably one of the reasons, one of the advantages of those dives, over the more lateral dives. Or, such would make sense. Finally, on the pulling out, that's quite literally a "pull" (hence, the characterization). Those vertical dives had to be the most demanding, though, not only on the pilot and crew, but on the plane, we'll definitely give them that.


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## stona (Mar 15, 2013)

gjs238 said:


> Is an aircraft that dives at 90 degrees inherently more accurate than one that dives at 60 degrees?



According to the 8th AF the answer is yes.






Despite this a compromise dive angle of 60 degrees was generally adopted.

Cheers

Steve


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## tomo pauk (Mar 15, 2013)

Great contribution, many thanks, people


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## VBF-13 (Mar 15, 2013)

The Navy pilots I know trained at 60 but it wasn't uncommon once they got the hang of it to dive at 70 when the situation dictated. As Ascent showed us, the steeper the dive, the harder they were to hit.


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## VBF-13 (Mar 15, 2013)

Steve, maybe that's because the P-47s were "adapts?" Maybe that's the only way they knew how to get the bomb on target in those things, i.e., letting go of it going straight down. I'm just speculating.


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## stona (Mar 17, 2013)

VBF-13 said:


> Steve, maybe that's because the P-47s were "adapts?" Maybe that's the only way they knew how to get the bomb on target in those things, i.e., letting go of it going straight down. I'm just speculating.



The P-47 was of course not a "natural" dive bomber,but I think the principal applies to dive bombing in general.

As early as 1934 the Flygvapnet (Royal Swedish Air Force) had conducted dive bombing tests with three Hawker Harts,purchased from the RAF. In this biplane they established an 80-85 degree dive angle to be the most accurate.

The Luftwaffe too discovered that "near vertical" dives gave the best results but most attacks by Ju 87s appear to have been delivered in a dive of about 70 degrees. There is a diagram in a Junkers handbook,which has been variously reproduced,illustrating different pull outs with or without dive brakes which shows an angle closer to 80 degrees. Unfortunately I can't scan it at the moment.

Cheers

Steve


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## VBF-13 (Mar 17, 2013)

Steve, but think it out. There could be any number of reasons for the facts you just related. For one, the biplanes wouldn't want to come in broad. At that snail's pace under any kind of fire encountered they'd likely get torn to pieces before they got anywhere near their drop point. The P-47s, they didn't train in dive-bombing for two months, and neither was that aircraft suited to brake, as were the SBDs, to maneuver into position for the broader drops. The Navy pilots, by contrast, did train for two months, and in every aspect, imaginable. By the time they were dive-bombing, which consisted of some 15 or so days of that training, they were going up two-hours at a hop, and making five runs and drops at their targets. It's all in the release, right? You want to throw strikes, for the curveball, that's different than for the fastball? The same logic, here. It's just different drop points. You're trained on a 60 degree dive and you want to combat on a 70 degree dive, it's mathematics, that's all, and you're there.

Respectfully, don't accept everything you read, just because it's from a good source. Scrutinize the substance of it, then draw your inferences. A 60 degree dive is just a different drop point. That's all. Put another pitcher in there, he's unfamiliar with that pitch, fine. Throw it the way he wants, so long as he gets it there. But don't discredit two months of putting those bombs on the nose just because he never had it. People unfamiliar might believe him. That's what's wrong with that. 

PS: Then it might get into Wikipedia, and everybody will believe it.


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## J.A.W. (Mar 17, 2013)

Although design-capable of divebombing, the Do 217 was the 1st aircraft to sink a battleship at sea [the Roma, which was located/examined recently] using diabolical Nazi smart-bomb [Fritz-X] technology, Stukas did n't quite get there with capital ships..

the Hellcats had no trouble smothering the Yamato et al with bombs rockets , seemed to make the Helldiver [but not the torpedo Grummans]somewhat redundant..


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## VBF-13 (Mar 17, 2013)

J.A.W., the Hellcats were crackerjack dive-bombers, and the pilots got a lot of training in that aspect, too. EDIT: They were bombing-fighting aircraft, by design.


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## tyrodtom (Mar 17, 2013)

J.A.W. said:


> Although design-capable of divebombing, the Do 217 was the 1st aircraft to sink a battleship at sea [the Roma, which was located/examined recently] using diabolical Nazi smart-bomb [Fritz-X] technology, Stukas did n't quite get there with capital ships..
> 
> the Hellcats had no trouble smothering the Yamato et al with bombs rockets , seemed to make the Helldiver [but not the torpedo Grummans]somewhat redundant..


 You're forgetting about the HMS Prince of Wales, a battleship sunk at sea by the Japanese airpower alone on Dec.10th 1941, several years before the Roma.


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## J.A.W. (Mar 17, 2013)

"using a... smart bomb"- Actually, P.o.W. Repulse, while damaged by bombs, were actually sunk by the numerous torpedo hits, were any other manouevring battleships in fact sunk by bombs alone in WW2 combat?


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## tyrodtom (Mar 17, 2013)

You made the statement that the Do217 was the first aircraft to sink a battleship at sea, it wasn't.
When a ship goes down in the middle of a battle, struck by several kinds of ordanance, do you really think anyone has the time to determine exactly what is most responsible for sending it to the bottom? 
That's for Robert Ballard or some armchair expert to figure out years later.


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## J.A.W. (Mar 17, 2013)

USING A...SMART BOMB,[clear, now?] indeed, Navies [ Airforces]are most interested/invested in what weapons/damage are "most responsible for sending it to the bottom" - during wartime..since they really want ships to sink - or stay afloat, depending on giving or taking..


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## tyrodtom (Mar 17, 2013)

Evidently if it wasn't sunk by a diabolical Nazi smart bomb,( Fritz X) it doesn't count then.


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## J.A.W. (Mar 17, 2013)

Well, its a bit harder to sink a battleship by blasting air in from above the waterline, than by letting water in from below, The Fritz-X [ the Tallboy, -albeit its easier if the Tirpitz is berthed] had the punch to do both...but could any actual divebomber do this? [Rudel, probably, being a diabolical Nazi weapon personified..]


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## barney (Mar 18, 2013)

_View: https://www.youtube.com/watch?v=iL1sfS1USpE_

Some You Tube footage supposedly taken from SBD's. Notice how they twist around when attacking ships. I have a hard time believing the aircraft can maintain any particular angle of dive when doing this. I also find it amusing that some of the pilots appear to be staying in their dives to view their bomb's impact.


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## J.A.W. (Mar 18, 2013)

There is some good USN combat footage of dive-bombing included in the Howard Hughes movie 'Flying Leathernecks'.

The Pilots Notes for the Typhoon states re dive-bombing; 
" The diving speed must not exceed 450 IAS when carrying bombs" [ or 480 IAS with rockets 525 IAS clean]


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## stona (Mar 18, 2013)

VBF-13 said:


> Respectfully, don't accept everything you read, just because it's from a good source. Scrutinize the substance of it, then draw your inferences. A 60 degree dive is just a different drop point.



A drop point which is harder to achieve. That was the conclusion of the Swedish and German air forces. You can choose to believe them or not. They both found near vertical dives to be more accurate as did the USAAF with the P-47. I'm not sure that there is a more reliable source than reports by the men who actually carried out the trials! If we don't believe their conclusions then what should we believe?
Cheers
Steve


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## J.A.W. (Mar 18, 2013)

Using Spitfires to dive-bomb V-1 'ski-ramp' launch sites, P.Closterman reckoned, "If you bomb at 45`, aiming is very difficult."
but worried that, "If you bomb vertically the propeller is torn off by the bomb."
He settled for "75`"


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## VBF-13 (Mar 18, 2013)

stona said:


> A drop point which is harder to achieve. That was the conclusion of the Swedish and German air forces. You can choose to believe them or not. They both found near vertical dives to be more accurate as did the USAAF with the P-47. I'm not sure that there is a more reliable source than reports by the men who actually carried out the trials! If we don't believe their conclusions then what should we believe?
> Cheers
> Steve


Steve, I'm not saying impeach the sources, I'm saying cross-examine the testimony. There's no testimony here that a P47 in a vertical dive is any the more accurate than an SBD in a broader dive. The testimony, rather, if it's anything, is that a fighter in a vertical dive is more accurate than a fighter in a broader dive. That's where you're missing the boat.


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## VBF-13 (Mar 18, 2013)

Adding: (1) And these Air Force fighters didn't have two months of intensive training in broader dive-bombing (did they?); (2) And they weren't constituted for that, anyway (were they?).


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## VBF-13 (Mar 18, 2013)

FWIW, here's about two weeks of their training in the SBDs on these 60-degree dives. The "G" is for bombing. The red entries are night tactical, and "LINK" is the LINK Trainer.


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## cherry blossom (Mar 18, 2013)

At the risk of introducing serious thread drift, it might be possible for dive bombers to sink some battleships. The first requirement is a semi-armour piercing bomb with a fairly long delay. If such a bomb hits any battleship outside the armoured citadel, it may cause serious flooding of the ends of the ship (the bomb hit on Prince of Wales might be an example although not from a dive bomber and possibly PoW was sinking anyway). If it hits the armoured citadel, it probably won't penetrate the main armour deck in a condition to explode (one hit on Tirpitz did penetrate but did not explode). However, some battleships have a potential weakness at the sides. If you look at http://www.warship.org/images/no21987-Midship.jpg showing HMS Hood, you can see that a bomb could end up behind the main armour belt. If it exploded there, it might blow the armour outwards and cause serious flooding. Bismark and Tirpitz were designed with 45 mm armour dividing the area above the low main armour deck into 17 sections, so that such flooding should not be catastrophic. The other battleships built after Washington had armoured main decks well above the waterline. However, older battleships were vulnerable and Ise, Hyuga and Haruna were actually sunk by the above mechanisms http://www.fischer-tropsch.org/prim...ports/USNTMJ-200H-0660-0744 Report S-06-1.pdf.


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## J.A.W. (Mar 18, 2013)

Cool post, Ta.
Do you have any data about the effectiveness of the FAA [carrier-born] dive-bomber attacks on Tirpitz?
Did the [carrier-plane] available weapons have the critical mass to 'nut-cracker' open up those battleship armour complexes like the Fritz-X or Tallboy?


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## cherry blossom (Mar 18, 2013)

There are actually postings here, especially by Parsifal, http://www.ww2aircraft.net/forum/aviation/ww2-aviation-mythbusters-31085-10.html describing the attacks on Tirpitz. Tirpitz - The History - Operation "Goodwood" gives details of the hit which pentrated both armoured decks. There is a discussion at Bismarck/Tirpitz = most powerfull European battleships - Naval History Forums of exactly what the bomb penetrated.


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## barney (Mar 18, 2013)

Sinking a battleship can't be difficult. 

Last winter my wife was sick. First, she couldn't walk, then she had trouble using her arms too. Scary stuff, the local neurologist hadn't a clue. Finally, the lab came back with a result – Lyme Disease. Thirty days of pill taking and she was cured.

During her illness we did jigsaw puzzles to pass the time. When that got old I suggested we build a model. I returned to the house with tube of glue and a 700:1 scale BB57 South Dakota.

This model is interesting in that it can be built as a waterline model or with the entire hull. Set on a flat surface as a waterline model it looks like a raft. Here's a picture to give you an idea of what the waterline model looks like. It is the vessel on the right. 

File:The Monitor and Merrimac.jpg - Wikipedia, the free encyclopedia

Okay, I exaggerated but not by much. The South Dakota was always overloaded and had added during the war 66 barrels of 40mm antiaircraft guns. She was two thirds sunk when she left the dock. That's the thing with these armored leviathans, the more armor that was added them to keep them from blowing up or sinking the more they sunk from their own weight. 

So, just from looking at this freeboard lacking model makes me think these ships were more vulnerable to sinking then what is generally acknowledged.


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## Shortround6 (Mar 18, 2013)

Cracking open a _modern_ battleship with the size bombs that carrier planes could carry was pretty unlikely, which is why the carriers carried torpedo bombers. 

Battleships were _designed_ to stay afloat with certain percentages of the "ends" flooded. The citadel was not only supposed to protect the magazines and machinery but enough buoyancy to stay afloat. Battle damage did not always go according to plan however. 

The US 1600lb AP bomb carried 209lb of burster (13%) and was supposed to penetrate a 5in deck when dropped from 7500ft or from 4500ft in a 300kt 60 degree dive. If dropped from a lower altitude the impact speed was less and penetration reduced. The 1000lb MK 33 AP bomb had a 15% burster and could defeat a 5in deck from 10,000ft or from 6500ft in a 300kt 60 degree dive. 

The M59 SAP bomb of 1000lb had a 30% burster but Campbell doesn't list penetration. A 1000lb HE bomb has about 50-52% burster by weight.


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## J.A.W. (Mar 18, 2013)

Yes indeed, since those Battlewagons were built tough-enough to wear a good walloping from salvos of one-ton armour piercing ballistic projectiles slamming in at supersonic speeds from their bretheren, then they ought to be able to shrug off a few air-directed lumps of lesser mass on their upperworks too..


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## tyrodtom (Mar 18, 2013)

The Arizona's top armor was penetrated by a 1700 lb bomb ( a converted artillery shell ), that's what blew the magazine. The bomb was dropped from Kates used as horizontal bombers.


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## tyrodtom (Mar 18, 2013)

They were dropped from 3000 meters, these very streamlined bombs probably were supersonic, and going straight down, instead of a angle like a artillery shell.


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## J.A.W. (Mar 18, 2013)

Arizona was an old ship, at her berth, in peacetime..


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## Shortround6 (Mar 18, 2013)

Yes it was a converted 16 in AP shell. It also had a burster weight of 2.8% or about 50lbs of HE. While it could certainly do a lot of damage without the "help" of the target ships own ammunition it may not have the ability to "crack open" the ship with a single hit. A 12,000lb Tallboy carried 5,200lb of explosive. I don't believe ANY actually exploded _inside_ a ship??? 

The Fritz X carried over 700lbs of explosive, depends on which source as to how much over 700lbs?


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## tyrodtom (Mar 18, 2013)

J.A.W. said:


> Arizona was an old ship, at her berth, in peacetime..



At her berth and in peacetime is immaterial when it comes to bomb penetration.
The Arizona was of the same generation as most of the US Navy's WW2 battleships fleet, most were WW1 era modernized ships.
It deck armor was thicker than the Bismarck's.


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## J.A.W. (Mar 19, 2013)

Ju 87D could loft a 1800kg/3968lb bomb, [diabolical Nazi weapon personified] H-U. Rudel dropped a 'special 1000kg' bomb in a dive-attack from 300m [flying a Ju 87B] to destroy the Soviet battleship [at berth in Kronstadt naval base] Marat, on Sept 23 `41..


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## J.A.W. (Mar 19, 2013)

Irrelevant? Don't think so, its much harder to hit a moving ship, different dynamics are involved.. WW1 battleships took a real hiding in WW2,- not being designed to the same protection levels as modern ships,'modernisation' notwithstanding, wartime damage control protocols are much more stringent..As for Bismarck comparison, see the previous posts which show the effects of carrier plane bombing attacks on her sister, Tirpitz..


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## silence (Mar 19, 2013)

A few things to remember about Arizona's armor is that the steel at best was of WWI grade, which was significantly less "tough" than that used in WW2.

Her horizontal armor was mainly three laminated plates totaling 3" thickness backed by a splinter deck 1.5 - 2" thick. As a WWI design, this armor is designed to defeat capital ship shells coming in at a relatively shallow angle rather than the almost perpendicular hit resulting from level bombing.

And her armor was not thicker than Bismarck's. Bismarck had an upper deck 50-80mm thick, a splinter deck below that of 20mm structural steel, then a main armor deck of 80-120mm, for an aggregate of 130-200mm (175mm over the magazines) plus the 20mm battery deck depending on location. This armor was also WW2 grade homogenous armor rather than WWI and cast in single plates rather than laminated layers.

All that said, no battleship floated - not even Yamato - had enough armor to keep out Arizona's fateful hit. Prob your best bet is to take the hit in open water and hope the shell exits out your bottom a good way before it explodes.


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## J.A.W. (Mar 19, 2013)

Yamato was... quite likely... designed to handle US 16" AP shells plunging in at high ballistic angles from long range shots...it was torpedo hits that sealed her fate [put her under], like most every other modern BB sunk at sea in WW2 - 'cept maybe Roma..


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## Shortround6 (Mar 19, 2013)

J.A.W. said:


> Ju 87D could loft a 1800kg/3968lb bomb, [diabolical Nazi weapon personified] H-U. Rudel dropped a 'special 1000kg' bomb in a dive-attack from 300m [flying a Ju 87B] to destroy the Soviet battleship [at berth in Kronstadt naval base] Marat, on Sept 23 `41..



And here you have the contradiction. The Germans had 5 different 1000kg bombs. AP bombs have to be dropped from medium altitude (6000-12,000ft) to reach the velocities needed to get max penetration. They can be dropped from dive bombers a bit lower but dive bombers usually drop from much lower heights to ensure accuracy. 

The Marat was laid down in 1909 and had about 2in of deck armor. She ( and her sisters) were sort of a hybrid battleship/battlecruiser. Faster than normal battleships but not quite as fast as battlecruisers. Their armor was also sort of in between.


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## tyrodtom (Mar 19, 2013)

J.A.W. said:


> Irrelevant? Don't think so, its much harder to hit a moving ship, different dynamics are involved.. WW1 battleships took a real hiding in WW2,- not being designed to the same protection levels as modern ships,'modernisation' notwithstanding, wartime damage control protocols are much more stringent..As for Bismarck comparison, see the previous posts which show the effects of carrier plane bombing attacks on her sister, Tirpitz..



You asked the question , could carrier born aircraft carry a weapon with enough critical mass to penetrate a battleship's armor. The Arizona's loss to a carrier aircraft's bomb answers that. You never asked how likely the same hit would be on a manuvering ship at sea.


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## Tante Ju (Mar 19, 2013)

Shortround6 said:


> And here you have the contradiction. The Germans had 5 different 1000kg bombs. AP bombs have to be dropped from medium altitude (6000-12,000ft) to reach the velocities needed to get max penetration. They can be dropped from dive bombers a bit lower but dive bombers usually drop from much lower heights to ensure accuracy.
> 
> The Marat was laid down in 1909 and had about 2in of deck armor. She ( and her sisters) were sort of a hybrid battleship/battlecruiser. Faster than normal battleships but not quite as fast as battlecruisers. Their armor was also sort of in between.



AFAIK/IIRC Rudel used rocket assisted AP bombs against Marat (RS series PC 1000)


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## fastmongrel (Mar 19, 2013)

tyrodtom said:


> They were dropped from 3000 meters, these very streamlined bombs probably were supersonic, and going straight down, instead of a angle like a artillery shell.



Is it possible for a free falling object to break the speed of sound. I have read claims that Tallboys went supersonic but never come across any conclusive proof.


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## Shortround6 (Mar 19, 2013)

They were designed to go supersonic but since the only supersonic objects were bullets/shells and some rockets the body of knowledge on supersonic shapes was rather limited. 
It also required them to dropped from _VERY_ high altitudes which could not be reached by the planes that wound up carrying them.


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## barney (Mar 20, 2013)

You can list the fine steel, the thickness of the belt, the plating on the decks, how well the magazines or the barbettes were protected but what I reiterate is that as you add this protection you are removing reserve buoyancy. There is no way around it, it is the other side of the coin. So, while a battleship may be more difficult to damage, once that damage occurs to the point of flooding, the vessel is immediately in more danger than a lessor armored vessel. Cruisers were able to steam to port with bows missing and keels broken. Then consider all the upper hamper battleships acquired during WWII and an already serious vulnerability increases. 

This is just from memory but I think the South Dakota had seven bulkheads between machine spaces and outer hull. The designers knew there was a problem.


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## Shortround6 (Mar 20, 2013)

The ships were DESIGNED with reserve buoyancy. That is one reason Battleships have more beam than cruisers. It is one reason they have as much or more draft. They also have a lot more water tight compartments. South Dakota had seven Bulkheads as part of the torpedo protection. They hoped to limit the the damage of the torpedo. The cruiser would have a flooded engine/boiler room and might have to be towed home, if it survived. The Cruiser has no more reserve buoyancy than the battleship.


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## barney (Mar 20, 2013)

Shortround6 said:


> The ships were DESIGNED with reserve buoyancy. That is one reason Battleships have more beam than cruisers. It is one reason they have as much or more draft. They also have a lot more water tight compartments. South Dakota had seven Bulkheads as part of the torpedo protection. They hoped to limit the the damage of the torpedo. The cruiser would have a flooded engine/boiler room and might have to be towed home, if it survived. The Cruiser has no more reserve buoyancy than the battleship.



Reserve bouyancy is the difference between the volume of a hull below the designed waterline and the volume of the hull below the lowest opening incapable of being made watertight. Battleships had a lot of submerged hull because they were heavy. They had to have a wide beam in order to not sit so deep as to preclude entering harbor or, in the case of U. S. Battleships, transiting the Panama Canal. Designing a vessel to be wider increases the underwater volume in proportion to the above water volume and the reserve buoyancy is unchanged.


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## cherry blossom (Mar 21, 2013)

Battleships built in the Thirties and Forties tended to have enough volume in the armoured citadel to keep the ship afloat, even if the ends were flooded. Some of the earlier ships had been bulged to improve their ability to survive torpedo hits and to increase the volume of the lower hull to compensate for extra weight, such as armour and anti-aircraft guns. Those ships were vulnerable to dive bombers because a bomb might end up in a bulge if it either landed just short of the ship or deflected off the waterline belt downwards. If a bomb exploded inside a bulge, it could be more damaging than a torpedo as the explosion was nearer the centre of the ship and would also blow the bulge outwards.

ps. The Wikipedia article http://en.wikipedia.org/wiki/Anti-torpedo_bulge shows pictures and discusses bulge history.


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## Shortround6 (Mar 21, 2013)

The British were building enough reserve buoyancy into their battleships to keep them afloat with with certain percentages of their ends riddled in the 1880s and 1890s. I doubt they got sloppier with design after that. Granted some of the calculations were a bit unrealistic ( roughly equal flooding fore and aft and settling on an even keel, little or no listing). There was a lot of arguing at the time over what the percentage should be. Some of these old ships used iron or plain steel "armor" and had belts up to 24 in thick on 10,000 ton ships. 
Obviously there was a continuing race between both torpedoes and guns vs armor and flotation. Torpedoes went from a few dozen pounds of wet gun cotton to over 600lbs of torpex. Guns went from solid shot or small black powder bursters to HE. 
At one point some designers of cruisers favored boiler rooms split on the center line while others favored boiler rooms that went across the the ship. The split boiler room helped preserve buoyancy but the one big room, while allowing the ship to settle more, did so on an even keel and helped prevent capsizing. Pick the way the ship sinks? 

Any metal ship will sink if you let enough water in. The trick was limiting the amount of water that could get inside. A lot of that was done using lots of water tight compartments. And warships didn't have 16 like the Titanic, battleships had hundreds, the Yamato had just over 1,000.


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## Readie (Mar 21, 2013)

Shortround6 said:


> And warships didn't have 16 like the Titanic, battleships had hundreds, the Yamato had just over 1,000.



Having the water tight bulkheads go from keel to deck also helped !
Cheers
John


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## Denniss (Mar 24, 2013)

In a russian book I found this speed profile of various Ju 87 with typical loadouts, may be of interest.
Is anybody able to translate what's written under Ju 87 R-1 on the left and the (unloaded?) Ju 87 B-2 and D-1 on the right?


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## tomo pauk (Mar 24, 2013)

Ju-87R-1 with drop tanks and SC250;
Ju-87B-2 without bombs;
Ju-87D-1 without bombs.

Now if you could point me to that book...


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## Denniss (Mar 24, 2013)

Uups, actually a polish book. AJ-Press Monografie Lotnice "Ju 87 Stuja" ISBN 83-86208-22-8


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## barney (Mar 28, 2013)

Going into more detail on the subject of battleship vulnerability I'll continue to use the South Dakota as an example. 

Using caisson tests after the South Dakota was built, it was discovered that her torpedo protection was flawed. This is attributed to the side armor that extended all the way to ships triple bottom not allowing for the flex that was found in previous vessels. The previous North Carolina class was designed to be able to absorb three hits on one side without sinking. Of course, the designers knew nothing of the more powerful torpedoes the Japanese would employ. I assume the South Dakota was built to the same specification.

Like its predecessors, the South Dakota was a Washington Treaty capital ship limited to 35,000 tons (ready for sea in wartime). Ready for sea in wartime needed a little redefining CNO Admiral Leahy determined. It really meant no boats on board, no water in the machinery, not all of the libricating oils being counted, a standard amount of ammunition (about 60% of capacity), less potable water and less food. Actual full load was estimated to be close to 45,000 tons. 

Then came the war with much increased upper hamper. This consisted mostly of light antiaircraft guns and the introduction of radar. In 1945 the BuShips set the maximum allowable displacement for the class at 47,000 tons
for “a draft of 36' 9” and an armored freeboard of 5'” - Friedman. Since the side armor came up to the main deck this meant the distance from waterline to weather deck was 5' plus one deck. The 40mm gun tub on the bow was not usually manned for fear the crew would drown. 

Part of the problem was where the South Dakota served for much of the war – in the Western Pacific. And, so, because of the long distances traveled she was usually loaded to the gills.

The result is a vessel designed as a 35,000 ton Washington Treaty vessel (achieved with some admitted number fudging) going to the war loaded to 47,000 tons or possibly more.

In action against Kirishima in November 1942 the South Dakota took a number of hits to her starboard side but only one was a main gun hit, a HE shell at her bow. The other hits were smaller caliber shells and while they did little damage seams opened up all along underwater parts of South Dakota's hull. 

So, the people here keep saying that these ships were very difficult to damage. However, as I have pointed out before, if damage did cause flooding, the amount of reserve buoyancy was small.


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## cherry blossom (Mar 29, 2013)

If we assume that South Dakota is a rectangular block and use your figures, we find that displacement increases by one foot for every 1279 tons of water, which is pessimistic as the bottom is curved. Thus assuming that the ship had just filled its tanks to the brim before damage, it would need to take in 6394 tons of water to bring the waterline to the top of the armour belt and 17904 tons to cover the weather deck. Interestingly, I have seen an estimate that HMS Prince of Wales had taken on 18,000 tons of water before being abandoned.

Most of that generation of battleships were about the same size. Wikipedia gives displacements of 42,237 (1940) to 44,460 tons (1944) at full load for the King George V class, 46,700 long tons for North Carolina, 45,029 long tons for Vittorio Veneto and 47,548 metric tons for Richelieu (after 1943 refit). Bismarck at 49,500 long tons and Vanguard at 51,420 long tons are slightly bigger, while the Iowas at 57,000 tons and the Yamatos at around 70,000 tons are significantly heavier.

We have estimates of the flooding due to torpedo hits on Vittorio Veneto at Matapan with 4,000 tons from a hit aft in the unprotected region (see picture at Italian battleship Vittorio Veneto - Wikipedia, the free encyclopedia) and around 2000 tons after being torpedoed by HMS Urge on 14th December 1941 in the protected area. North Carolina was reported to have taken on an excess weight of 970 tons on 15th September 1942 as “The total weight of liquid in the damaged area prior to damage was 597 tons”. 

Thus we can expect battleships of that generation to survive up to three torpedoes but perhaps not too many more. Prince of Wales was hit by four but suffered poor damage control. Littorio at Taranto suffered severe damage because the magnetically fused torpedoes exploded beneath the ship after passing under the anti-torpedo netting.


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## barney (Mar 29, 2013)

Hello cherry blossom

I have some numbers for the Massachusetts which are in close agreement with your calculations.

Draft of 34.625 feet at 43884 tons
Draft of 36.083 feet at 46041 tons
or 1479 tons per foot of freeboard

At the max loaded condition of 47000 tons the vessel would have about 13' of freeboard amidship. Therefore, to sink the vessel on the level to the weather deck would require 19227 tons.


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