British Dive Bombers or lack thereof

[Wild_Bill_Kelso]

If you look at online sources, dive bombing is considered anything from 45 to 60 degrees, some sources state as high as 80 degrees. I look at 45 degrees at the "glass half empty or half full." I've flown aircraft in a 45 degree dive, it's pretty steep IMO

Oh I bet it is!

From a WW2 perspective - the highly trained dive bomber crews, and the aircraft which could do the true steep angle dive bombing, went well together. The Ju 87 had the considerable benefit of an automatic pullout system which made the dive bombing much safer.

Navy SBD crews tended to do much better in terms of getting hits than Marine SBD crews who in turn did a lot better than USAAF SBD (A-24) crews. The Navy crews also seemed to survive at a higher rate but that's another issue.

The Navy crews did do steeper angle dive bombing, but you could get hits at the shallower angles for sure. And some fighter-bomber pilots did much steeper than 45 degree angle dives.

No World War 2 aircraft was accurate in the way we think of accuracy today, but a well trained dive bomber crew in a real dive bomber could achieve some scary / impressive results.

 

[tomo pauk]

What would qualify as a fast dive-bomber? The only aircraft I can think of that fit that description operationally was the A-36.

A-36 certainly. The D4Y from the Japanese.
Pe-2 from the Soviets. German bombers were not that zippy.
There was a host of fighters that were doing just fine in steep dive bombing, like the P-47 or F4U.

We'd probably want a ww2 bomber to achieve at least 90% of speed of the common fighters in order to be considered fast?

 

[Shortround6]

Could be.
One bomb set a fire that reached the depth charge racks.

Sister ship.
They were part way between a US four stack and the first US interwar destroyers.

 

[Shortround6]

What would qualify as a fast dive-bomber? The only aircraft I can think of that fit that description operationally was the A-36.

Everything is relative.
The Albacore had trouble exceeding 204kts (mph?) in a dive let alone level flight. Ability to deal with interceptors (especial with slow control response) was not great and ability to deal with AA guns operating in daylight..........not great.

Now were run into one of the great dive bomber conundrums.

The greater the angle of the dive the greater the accuracy. Simple geometry. A nearly circular impact area will be smaller than on ellipse and the shallower angle the greater the length of the ellipse for the same width.

However.

The lower the altitude of the bomb release the greater the accuracy. The steeper angle requires a higher release so the plane clears the ground.

Now number 3.

The faster the attacking plane dives, the higher the release point must be in order to allow the plane to pull out, clear the ground, blast radius. One big reason for dive brakes.

So we have conflicting requirements as to speed and altitude of release and the angle of release. (shallow angle makes pullout easier).

Please note this is only in regards to the actual attack/bomb run and nothing to do with the approach to the target or the egress from the target.

A plane like the A-36 might be able to penetrate further into enemy airspace with it's high cruising speed, or avoid interception without jettisoning bombs. It might be able to avoid enemy interceptors after the bomb run and on the way home.
However, right at the start of the bomb run the plane may have to slow down in order to deploy the dive brakes. The dive brakes limit the speed in the dive (they are not quite the same as airbrakes), the A-36 may chose not the use the dive brakes and use higher speed to reduce ground AA fire effectiveness, but that means a higher release altitude and reduced accuracy. A-36 with dive brakes deployed needs more time to accelerate back up to "fighter" speed after the pull out. Of course after doing a 4-6 G pullout the plane is NOT going to be doing 350mph either.

A lot depends on expectations of accuracy as to what attack angle/profile is going to be used. Everything is a compromise.

 

[Admiral Beez]

A lone F4F bombed and sank an enemy destroyer by bombing it during the battle for Wake Island. Dive bombing?

I suppose that providing the prop can be cleared, anything that can carry a bomb can utilize a deep descent angle to improve accuracy.

 

[Shortround6]

I suppose that providing the prop can be cleared, anything that can carry a bomb can utilize a deep descent angle to improve accuracy.

View attachment 699826

Some of this may depend on the pull out.
If your biplane (or slow monoplane) is doing 200mph in the dive the bomb might out accelerate the plane and hit the propeller.
Now at 350mph it may not a be problem.
Once the bomb is released from the rack/crutch the only thing that can accelerate the bomb is the force of gravity overcoming drag.
The force of gravity is constant. At the speeds given above the faster bomb has over 3 times the drag as the slower bomb at point of release.
Depending on shape/weight of the bomb the bomb will go faster, it just isn't going to accelerate as fast in comparison.
In a vacuum the bomb will accelerate at 32fps/ps and will fall 16 ft the first second, Plus the speed of the plane in the dive.
Also note that in a less than 90 degree dive the bomb will start to diverge from the planes path and will slowly assume the vertical trajectory.
Sometimes the bomb crutch was there to guarantee the separation due to wing currents around the plane or incase of accidental release at less than ideal angle.

 

[Thumpalumpacus]

I was under the impression that having seen the Luftwaffe's work in Europe inspired this decision. In the USAAC, they were generally seen as slow and clumsy, lacking the range, payload, and defensive capability of the heavy bomber.

As I recall, the Germans were inspired to go with dive-bombers by dint of Udet observing a USAAC dive-bombing demonstration, going back to Germany, and encouraging RLM to get to work on it. Didn't he buy a Curtiss Shrike at that time on Germany's behalf?

So while the RAF may have been inspired by the Luftwaffe, they in turn copped it from USAAC, even though the latter did nowhere near development on the technique that the Germans did.

Funny how his stuff works.

SaparotRob , not sure if the destroyer-sinking you mention was a Wildcat dive-bombing or glide-bombing. It did result in setting off the destroyer's depth charges (as mentioned above), and sinking the orc. It was a 100-lb bomb. Either way, the Japanese were stuffed until their CarDiv Five (Hiryu, Soryu) showed up and cleared the skies for the invasion force.

 

[Wild_Bill_Kelso]

As I recall, the Germans were inspired to go with dive-bombers by dint of Udet observing a USAAC dive-bombing demonstration, going back to Germany, and encouraging RLM to get to work on it. Didn't he buy a Curtiss Shrike at that time on Germany's behalf?

So while the RAF may have been inspired by the Luftwaffe, they in turn copped it from USAAC, even though the latter did nowhere near development on the technique that the Germans did.

Funny how his stuff works.

R rob Saparot, not sure if the destroyer-sinking you mention was a Wildcat dive-bombing or glide-bombing. It did result in setting off the destroyer's depth charges (as mentioned above), and sinking the orc. It was a 100-lb bomb. Either way, the Japanese were stuffed until their CarDiv Five (Hiryu, Soryu) showed up and cleared the skies for the invasion force.

Kinda reminds me of the bazooka / panzershreck lineage

 

[Thumpalumpacus]

Kinda reminds me of the bazooka / panzershreck lineage

Or the Brooklyn/Mogami thing. It's an arms race, baby.

 

[swampyankee]

As I recall, the Germans were inspired to go with dive-bombers by dint of Udet observing a USAAC dive-bombing demonstration, going back to Germany, and encouraging RLM to get to work on it. Didn't he buy a Curtiss Shrike at that time on Germany's behalf?

So while the RAF may have been inspired by the Luftwaffe, they in turn copped it from USAAC, even though the latter did nowhere near development on the technique that the Germans did.

Funny how his stuff works.

SaparotRob , not sure if the destroyer-sinking you mention was a Wildcat dive-bombing or glide-bombing. It did result in setting off the destroyer's depth charges (as mentioned above), and sinking the orc. It was a 100-lb bomb. Either way, the Japanese were stuffed until their CarDiv Five (Hiryu, Soryu) showed up and cleared the skies for the invasion force.

Just as an aside, the reports I've read is that the USMC developed dive bombing during one of the periodic US invasions of one Central American country or another.

 

[Thumpalumpacus]

Just as an aside, the reports I've read is that the USMC developed dive bombing during one of the periodic US invasions of one Central American country or another.

Yeah, I'm not saying USAAC originated it, just that Udet saw it and liked it, to my reading. Myself, I bet it came about in airfield/trench raids in WWI.

 

[swampyankee]

Yeah, I'm not saying USAAC originated it, just that Udet saw it and liked it, to my reading. Myself, I bet it came about in airfield/trench raids in WWI.

Probably true, as dive bombing is really a pretty obvious extension of strafing. I wouldn't be surprised if it was independently developed by several air forces, roughly simultaneously.

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One of the stories I've heard about the RAF and FAA and dive bombing is that they recognized that the bombs of the time (early to mid 1930s) practical for carriage by carrier aircraft wouldn't be able to penetrate capital ships' deck armor (probably true, and probably true until the development of PGM), so a more effective technique than heating the ship would be to drop a high-explosive bomb so it would detonate adjacent to the ship's side. This required a sophisticated sight which could never be made to work right.

Of course, PGM were a much better plan. One wonders what would happen had the RAF and FAA spent some serious coin on developing a guided AP bomb that could be dropped from 20,000 ft or so and hit and penetrate a battleship's deck armor. Too bad the Germans developed one first. One wonders what a precision-guided Tallboy would do to the Yamato.....

 

[Thumpalumpacus]

Probably true, as dive bombing is really a pretty obvious extension of strafing. I wouldn't be surprised if it was independently developed by several air forces, roughly simultaneously.

-----------------

One of the stories I've heard about the RAF and FAA and dive bombing is that they recognized that the bombs of the time (early to mid 1930s) practical for carriage by carrier aircraft wouldn't be able to penetrate capital ships' deck armor (probably true, and probably true until the development of PGM), so a more effective technique than heating the ship would be to drop a high-explosive bomb so it would detonate adjacent to the ship's side. This required a sophisticated sight which could never be made to work right.

Of course, PGM were a much better plan. One wonders what would happen had the RAF and FAA spent some serious coin on developing a guided AP bomb that could be dropped from 20,000 ft or so and hit and penetrate a battleship's deck armor. Too bad the Germans developed one first. One wonders what a precision-guided Tallboy would do to the Yamato.....

Or on the other hand understand, and roll with, plopping them alongside and hoping for the best. PGMs were sketchy even by 1943-45, but breaking plates with hydrodynamic pressure was already fairly well understood, and it allows for near-misses as well as dead-strikes.

A near-miss from a 1000-lb bomb on a battleship might be even better than a direct hit atopdecks. Water isn't compressible until about 30,000 psi, so near-misses on BBs can be useful, insofar as they open up the hull rather than wreck the topsides. Depends on the sitch, no? Water-hammer is a thing.

 

[EwenS]

Or on the other hand understand, and roll with, plopping them alongside and hoping for the best. PGMs were sketchy even by 1943-45, but breaking plates with hydrodynamic pressure was already fairly well understood, and it allows for near-misses as well as dead-strikes.

A near-miss from a 1000-lb bomb on a battleship might be even better than a direct hit atopdecks. Water isn't compressible until about 30,000 psi, so near-misses on BBs can be useful, insofar as they open up the hull rather than wreck the topsides. Depends on the sitch, no? Water-hammer is a thing.

Except "aiming to miss" is even harder than trying to hit the target. The bomb has to be very close to do any serious damage. For example:-

Standard 250lb Mk.VIII airborne depth charge - contained 170lb of Torpex explosive (50% more powerful than TNT). Its lethal range against a U-boat was 28ft. And that U-boat was going to be close to the surface when the aircraft was dropping these (they were fused to explode at 25ft).

German 1,000kg (2,200lb) AP bomb containing 350lb of TNT that hit Formidable in May 1941, passing through the ship, before exploding underwater, only caused some relatively minor flooding to some stern compartments. It exploded about 40ft from her side. There wasn't a massive hole. It merely dished the plating between the frames causing the rivets to pop so allowing the water in.

The more normal SC 500 (1,100lb) HE weapon used by the Luftwaffe only contained 490lb of explosive.

Illustrious has the same experience both while at Malta in 1941 and then in 1945 with a large bomb from a kamikaze exploding close to her hull. The only noticeable effect from the latter was a vibration through the ship that only became unsustainable at speed (she was already limited to 24 knots before that). It was only when they put divers down after they got to Leyte that the full extent of the damage was found. But there was no flooding. That bomb was estimated at 1,700lb (probably a 800kg weapon used in the D4Y3 kamikaze aircraft) and exploded about 50ft from her side.

Of course the depth of the explosion makes a difference. But the naval architect DK Brown noted that, in relation to torpedo explosions against ships but it seems equally valid for near miss bombs, the effects of underwater explosions were exceptionally variable and difficult to predict (see Nelson to Vanguard).

Major warships (capital ships and aircraft carriers) of the period had extensive torpedo protection systems covering much of their vital length. Layers of side compartments some empty, some liquid filled plus armour plate, designed to absorb the effects of underwater explosions.

Here is a photo of damage to Illustrious in 1941 show the external effects of a near miss. Note the damage is under her armour belt. But she was still able to sail away from Malta to be repaired in the USA.

Britain developed a couple of novel weapons designed to attack the unprotected underside of major warships. The first was the 'B' or Bouyancy Bomb.

Bomb, 250 lb Buoyancy, Mk 4

Description The bomb consists of a truncated, cone-shaped charge case with a concave nose welded on, a buoyancy chamber secured to the charge case by twelve nuts, and a clip-o

bulletpicker.com

And the second was the 600lb Johnnie Walker Bomb which only seems to have been used on one occasion, unsuccessfully against Tirpitz in Sept 1944.

Hogmanay toast to Johnnie Walker!

Helensburgh Heritage Trust

www.helensburgh-heritage.co.uk

 

[Thumpalumpacus]

Except "aiming to miss" is even harder than trying to hit the target. The bomb has to be very close to do any serious damage.

Right, which is why I didn't suggest any such effort.

 

[pinehilljoe]

I had forgotten Illustrious was repaired and refitted in Norfolk Navy Yard, in the Summer of 1941.

 

[Zipper730]

If you look at online sources, dive bombing is considered anything from 45 to 60 degrees, some sources state as high as 80 degrees.

So, there wasn't exactly a specific angle that was uniformly used?

A lone F4F bombed and sank an enemy destroyer by bombing it during the battle for Wake Island.

Was this a night-operation? I do remember an F6F-3E/N or F6F-5N doing a dive-attack on a destroyer at night which either sank it or disabled the ship in 1944.

A-36 certainly. The D4Y from the Japanese. Pe-2 from the Soviets.

Understood.

We'd probably want a ww2 bomber to achieve at least 90% of speed of the common fighters in order to be considered fast?

Was that actually the criteria that was used for being competitive? I do remember some dive-bomber concepts such as the XA-41 which was considered inadequate in speed because it wasn't competitive with fighters (top speed was 333 at sea level; 363 at altitude and 354 at some altitude).

Ability to deal with interceptors (especial with slow control response) was not great and ability to deal with AA guns operating in daylight..........not great.

Out of curiosity, what qualities were generally desired in a WWII dive-bomber from a handling stand-point? It seemed the USN and USAAF had different ideals for what they wanted (the USAAF seemed to have higher g-load requirements).

A lot depends on expectations of accuracy as to what attack angle/profile is going to be used. Everything is a compromise.

Yeah, so you'd want a plane that has very good aerodynamic breaking so it can dive suitably steep without picking up too much speed, while being able to release suitably low and not rip the wings off the plane, incapacitate the pilot, or get hit by shrapnel?

In a vacuum the bomb will accelerate at 32fps/ps and will fall 16 ft the first second, Plus the speed of the plane in the dive.

Why would it fall 16 f/s in the first second and not 32?

As I recall, the Germans were inspired to go with dive-bombers by dint of Udet observing a USAAC dive-bombing demonstration, going back to Germany, and encouraging RLM to get to work on it. Didn't he buy a Curtiss Shrike at that time on Germany's behalf?

I think it was an F11C actually.

 

[FLYBOYJ]

So, there wasn't exactly a specific angle that was uniformly used?

From what I've seen and read not really although it seemed the USN favored 60/70 degrees (I think that's mentioned in the video clip I posted earlier).

 

[EwenS]

I had forgotten Illustrious was repaired and refitted in Norfolk Navy Yard, in the Summer of 1941.

Followed by Formidable in the autumn

Edit. In fact in Nov 1941 you might have seen Illustrious, Formidable and Indomitable at Norfolk at the same time. Their fighter direction officers all met to share experience and radar information.

 

[Shortround6]

What the "near miss" did was widen the target area, if it is thought about correctly.
Which it may not have been.
Aiming for a narrow band of water on either side of the ship's hull when you are having trouble hitting the ship itself certainly seems like a fools errand.
Designing special bombs or fuses for such use seems to indicate somebody has gone off the rails (not saying it wasn't done, there were plenty of projects that had little hope of actual success).

For the British in the 1930s the basic problem was they had an atrocious selection of bombs to use. Like no 1000lb bombs of any type. None, zero, zip, nada.
They may have been thinking of of them or putting pen to paper but they had none to test let alone issue.
Any talk about effects of hypothetical near miss explosion in regards to the RN in the 1930s are just that. hypothetical.
What the Skua got stuck with is the 500lb SAP bomb. Which may have been a sort of "universal" bomb for the Skua. Something they could carry and drop on just about anything but actual ideal for no known target. It was lacking in something for any potential target.

Once you can deploy 1000lb or larger HE bombs the idea of using the band of water to widen the target area may make sense. However any bomb that cause damage to the hull like seen in the photo of the Illustrious Unless going for 2000lbs) is not going be very good at armor penetration although it might be very good at destroying AA guns, gun directors, range finders, radar/radio equipment, funnels, searchlights and other "stuff" either not armored or lightly armored. If you can't hit the hull itself then a big bomb going off 20-30 ft away can cause damage.

The British 500lb SAP held 89-90lbs of TNT so it's miss distance was very small, assuming the fuse malfunctioned and the bomb went off without plunging dozens of feet lower than the hull.

The 500lb SAP could not deal with thick armor, like the sisters, and it was too much AP for destroyers and light cruisers.
A 500LB bomb like the American GP bomb (about 250lb) or the German SC series bombs (275-287lbs) against DDs (no deck armor) and light cruisers (not much deck armor) also have enough HE to damage hull from near misses (DDs and light cruisers have thinner hull plates and thinner frames). If you are trying to bomb DDs that are usually less than 40ft wide having an extra 10ft on each side that may cause damage is good thing (50% increase in target area?).

Fusing may be problem. The HE bombs need to go off fairly quick on hard targets and with a bit more delay on soft targets or near misses(?).


Going back to DIve Bomber Problems, in order to get the best penetration from an AP (or SAP) you need to drop from higher altitude and/or higher speed than you would use for HE bombs. This may complicate training. Having different bombs may complicate magazine storage.