Dive Bomber Comparison

[davebender]

Ju-88A. Requirement issued August 1935. Operational fall of 1939.
This is a 1942 version. That's when the 1,400 hp Jumo 211J engine entered service.
2 x Jumo 211J V12 engines. 1,400 hp each.
317 mph max speed. (Clean configuration).
7,937 lbs max bomb load. Normally carried externally due to bomb bay being rather cramped.
1,429 miles max range on internal fuel.
Can deliver weapons very accurately due to being a dive bomber.

AD-1 Skyraider. Prototypes ordered July 1944. Operational 1947.
This is the early version. Vietnam era versions had 2,700 hp.
1 x Wright R-335-24W radial engine. 2,500 hp.
321 mph max speed. I assume this is clean configuration.
7,000 lbs max bomb load. All external. Later versions could carry 8,000 lbs.
1,553 miles max range on internal fuel.
Can deliver weapons very accurately due to being a dive bomber.

Perhaps a meaningless comparison.
- Land based vs CV based.
- 1935 design vs 1944 design.

However I find it interesting that speed, weapons load, bombing accuracy and range are similiar for these dive bombers. Perhaps Germany would have considered replacing the Ju-88A dive bomber with something similiar to the AD-1 if the 2,500 hp Jumo222 engine had entered mass production.

 

[gorizont]

However I find it interesting that speed, weapons load, bombing accuracy and range are similiar for these dive bombers. Perhaps Germany would have considered replacing the Ju-88A dive bomber with something similiar to the AD-1 if the 2,500 hp Jumo222 engine had entered mass production.

For what sake? In a role of dive bomber Ju-88 (as Ju-87 too) was to be substituted by Me-210.

 

[davebender]

In a role of dive bomber Ju-88 (as Ju-87 too) was to be substituted by Me-210.

I agree. That was the historical plan.

However having a 2,500 hp engine gives you another option. You can achieve similiar combat performance using a single engine aircraft. Less expensive to produce and a smaller target for enemy ground fire.

 

[gorizont]

I agree. That was the historical plan.

However having a 2,500 hp engine gives you another option. You can achieve similiar combat performance using a single engine aircraft. Less expensive to produce and a smaller target for enemy ground fire.

Germans have 2.500 Hp engine neither in 1942 nor in 1945. As mentioned in a topic in "Technical", Jumo 222 was planned to be 2000 hp class engine, and from beginning his take-off power proposed to be of 2000 hp. This variant wasn't ready for mass production due to technical problems which hadn't been overcame. As for more powerful variants of the engine.

As you know Junkers worked at another variant of Shtuka - Ju-87F, with Jumo 213A, but in 1943 it was cancelled.

P.S. and please remember that Skyraider is a post-war aircraft. Americans didn't manage to produce this aircraft before war ended. And R-3350 variants which were produced in mass during war period didn't produce 2,500 hp.

And finally - single-engined aircraft is cheaper but more vulnerable

 

[VG-33]

I agree. That was the historical plan.

If you consider the historical plan, in 1935 it was never concieved from the mainstream as a diver but as a schnellbomber, later modified by Udet cause to is own hobby for dive bombers.
But reading some late-war american repports in fact, as french user's experience it soon appeard than except in some german propaganda publications it never had 100% success in that rule as Ju-87, Pe-2, Helldivers did, as structure being a little to weak for such efforts. So 70° max with severe restrictions, 40-60° dive as usual. So we should call it limited-dive bomber. For instance:

However having a 2,500 hp engine gives you another option.

Yes of course, having some..., my auntie would be my uncle.

You can achieve similiar combat performance using a single engine aircraft.

At night, in stormy weather, over London ? With what navigation features to reach such a target?
And what about catching Lancasters at night, are you sure the Skyraider would be better?
Moreover, you should be more accurate in your performance table.
What range, at what speed and with what load altogether for different values. And not independently one from the other.
Even in 1935 with bomb load carried in internal (limited drag), the Ju-88 was able to go far, and fast...

Other way, hard to compare apples and oranges.

Regards

 

[davebender]

If you consider the historical plan, in 1935 it was never concieved from the mainstream as a diver but as a schnellbomber, later modified by Udet cause to is own hobby for dive bombers.

I don't think Udet's hobby had anything to do with the German decision to emphasize dive bombing.

HyperWar: The Battle of Britain--A German Perspective

Bombing Accuracy. Dive-bombing offered several advantages over level bombing. The limited bomb loads and the relative inaccuracy of the level bombers currently available required large numbers of aircraft to achieve the same level of results as dive-bombing could provide. As an example, the Ju87B-1 (the model in service in 1939-1940), "was to prove effective in the hands of expert pilots, who, in dives of eighty degrees to within 2,300 feet from the ground, could deliver a bomb with an accuracy of less than thirty yards. Even average pilots could achieve a twenty-five percent success rate in hitting their targets, a far higher proportion than that attained in conventional, horizontal attack bombers."26 By comparison, US Army air forces typically designated a radius of 1,000 feet as the "target area" aim point for the "pickle-barrel" bombing conducted in Europe. "While accuracy improved during the war, [US Strategic Bombing] Survey studies show that, in the over-all, only about 20% of the bombs aimed at precision targets fell within this target area."27

Generaloberst Hans Jeschonnek, chief of the General Staff of the Air Force from 1939-1943, and at the time head of the operations staff of the General Staff, saw dive-bombing as "the ideal solution to the bomber problem of 1937." That bomber problem was primarily the lack of an effective bomb sight for use with the level bombers. The standard sight was inaccurate and would require considerable practice to achieve acceptable results even for area bombardment. In 1938, "even well-qualified bomber crews could achieve only a two percent bombing accuracy in high-level, horizontal attacks (up to 13,500 feet), and twelve to twenty-five percent accuracy in low level attacks against targets of between 165 to 330 feet in radius, and to make matters worse, the bomb load of the German bombers was very low; only four 550 lb. bombs were carried by the Do17 and six by the He111. Thus, if the target were to be completely destroyed, the only way to compensate for inaccuracy would be to employ large numbers of aircraft."28 The Luftwaffe General Staff announced that, "the emphasis in offensive bombardment has

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clearly shifted from area to pin-point bombardment."29 The best solution to inaccurate bomb sights, limited bomber payload, and economics was to adopt a dive-bomber doctrine.
Eventually the twin-engine Ju88 "wonder bomber" (as the propaganda of the day called it), and even the He177 "heavy bomber" were to fall victim to the momentum of the dive-bomber craze. The original specifications and indeed the early prototypes of the Ju88 were quite good when compared to the fighters actually available during the Battle of Britain. "In March 1939, one of the first prototypes established a new 621 miles closed-circuit record by carrying a 4,409 lb. payload at an average speed of 321.25 m.p.h.."30 (The maximum speed for the Spitfire Mk 1: 355 mph, and that of the Hurricane Mk 1: 328 mph.) But, following extensive (about 25,000) modifications to meet the "dive-bomber" specifications and to provide for additional armament as well as a fourth crew member, the performance of the final production models of the Ju88 were disappointing. As an example, when the production version, Ju88A-1, arrived in September 1939 it had a maximum speed of only 258 mph, and a range of 550 miles with a 2,000-pound bomb load. With a maximum bomb load of 3,800 pounds performance was further reduced to 190 mph with a radius of just 250 miles! However, and this is significant in light of the reasons for the modifications to the original design: a production model, when properly flown under test conditions, could deliver 50 percent of its bomb load within a 50-meter circle.31

The German Air Staff would remain divided on the subject of dive-bombing and the concepts for employing the Ju87. The general consensus was that the Ju87 could be used both for strategic operations and for support operations with the Army. From a functional standpoint the Luftwaffe leadership believed, "the employment of the dive bomber was in German Air Staff opinion not to be very different from that of the long-range bomber."32

Unlike the USA and Britain, the Luftwaffe conducted serious testing during the 1930s to determine bomber accuracy. Dive bombers were over 10 times as accurate as level bombers. That's why the Ju-88 was developed into a dive bomber and why RLM initially wanted the larger Do-217 and He-177 to dive bomb also. This was cutting edge technology during the 1930s. Nobody knew what the maximum size was for a dive bomber so they had to experiment. Dive bomber requirements for the Do-217 and He-177 were dropped after engineers determined it could not be made to work.

 

[Juha]

Hello Dave

Quote: "…US Army air forces typically designated a radius of 1,000 feet as the "target area" aim point for the "pickle-barrel" bombing conducted in Europe. "While accuracy improved during the war, [US Strategic Bombing] Survey studies show that, in the over-all, only about 20% of the bombs aimed at precision targets fell within this target area."

and

Quote: "…when properly flown under test conditions, could deliver 50 percent of its bomb load within a 50-meter circle"

My interpretation is that USSBS gave actual results and the German result is a test result, and if so you really cannot compare the two results, you need test results from both types of bombing or and this is very much better option, the actual wartime results for both. And one must remember that around mid-war Germans stopped to use Ju 88s as dive bombers, removed the dive-brakes and used it as glide- or level-bomber only.

Juha

 

[gorizont]

My interpretation is that USSBS gave actual results and the German result is a test result, and if so you really cannot compare the two results, you need test results from both types of bombing or and this is very much better option, the actual wartime results for both. And one must remember that around mid-war Germans stopped to use Ju 88s as dive bombers, removed the dive-brakes and used it as glide- or level-bomber only.
Juha

As far as I remeber among reasons were not only a weak to some dergee airframe but implementing new sights - Lofte 7 for horizontal bombing and Shtuvi 5 for dive-bombing. The last provided german bombers ability to achieve such an accuracy from glide-bombing (or shallow-dive bombing) that approximated to an accuracy of steep-dive bombing with common reflector sights.

 

[Shortround6]

Unlike the USA and Britain, the Luftwaffe conducted serious testing during the 1930s to determine bomber accuracy. Dive bombers were over 10 times as accurate as level bombers. That's why the Ju-88 was developed into a dive bomber and why RLM initially wanted the larger Do-217 and He-177 to dive bomb also. This was cutting edge technology during the 1930s. Nobody knew what the maximum size was for a dive bomber so they had to experiment. Dive bomber requirements for the Do-217 and He-177 were dropped after engineers determined it could not be made to work.

The US certainly did conduct tests and also conducted some combat operations using dive bomber techniques during the 30s. Now maybe the Navy/marines weren't talking to the Army but the tests were being done.

The aircraft engineers might have had a better idea than the German air staff as to what was possible since by popular history none of the companies making the larger aircraft wanted them to be dive bombers and usually fought against it.
In fact the engineers probably had a very good idea of what the dive bomber requirement was costing them.
Assuming the large twin engine (or 4 engine) plane can dive bomb at all the heavier structure is going to cost in speed, or range, or bomb load or a combination of the three.
Assuming you have 2400hp to play with (two 1200hp engines) you then have to decide how big the airplane is going to be, this depends on payload, range requirement, speed, landing speed and other performance requirements. The more "G"s you want the plane to pull ( and how many times, metal fatigue) the more weight goes into structure and the less weight is available for something else. The higher the empty weight (or low loaded weight ) the higher the landing speed and Junkers had already figured out quick dumping fuel tanks to lower the landing speed of commercial aircraft that had trouble on take off. You can't jettison structure.

It doesn't matter how accurate your dive bomber is, if it can't reach the target (lack of range) or if it can't find the target (bad navigation skills/equipment) it is so much wasted metal and labor sitting on the runway or wandering about the sky.

Turret fighters like the Defiant and bomber destroyers like the Airacuda were also considered cutting edge in 1937. Doesn't mean they were a good idea.

 

[Juha]

Hello Gorizont
and IIRC Lofte 7 and US Norden sight were about equally accurate, IIRC in fact Lofte 7 was much based on Norden, Germans got Norden secrets by one agent. And yes, Stuvi 5 was an excellent sight, Finns also used Ju 88A-4s during the war.

Juha

 

[gorizont]

Hello Gorizont
and IIRC Lofte 7 and US Norden sight were about equally accurate, IIRC in fact Lofte 7 was much based on Norden, Germans got Norden secrets by one agent. And yes, Stuvi 5 was an excellent sight, Finns also used Ju 88A-4s during the war.
Juha

Hello Juha
For Lofte - as far as I know the only thing which is the same in Lofte and Norden - methods of calculation and algorithm of working. Both sights function in the same pattern. But technically they had absolutely diifferent designs.
Stuvi 5 was dive-bombing sights and on twin-engined germans bobmers it was assisted by BZA ="computer block". It works (automatically putting corrections to the position of a mark on sight glass according inputs of wind, speed etc processed by BZA) in range of dive angles from 25 to almost 90 as far as I know.

On Ju-88 and Do-217 usually were installed both sights (from 1942), Lofte for horizontal bombing and Shtuvi for shallow -dive bombing.

P.S. I was surprized then got to know from P. Smith' book about Skyraider, that americans used on it a rather simple reflector sight and pilot estimeted corrections in the same fashion as Dontless pilots did it in 41-42.

 

[Juha]

Hello Gorizont
yes, Stuvi was a dive-bombing sight, even its designation gives that away.

BTW, what was the normal dive angle of Skyraider during dive-bombing attack during the Korean War?

Juha

 

[gorizont]

Hello Gorizont
yes, Stuvi was a dive-bombing sight, even its designation gives that away.
BTW, what was the normal dive angle of Skyraider during dive-bombing attack during the Korean War?
Juha

Juha, as far as I know Skyraider pilots were trained to attack from steep dive up to 70 degrees. They used fixed dispositions - they learnt by heart charts for deflections for angles of dive: 30, 50 and 70 dergee with charts of corrections for altitude, wind and speed.
But They hardly used steep-dive attack in Korea. As far as I guess steep-dive attack was proposed mainly vs naval vessels especially warships, aircraft carriers and cruisers, but in reality Skyraiders never had opportunity to strike such opponents.

 

[Juha]

Thanks a lot for the info, Gorizont!

IIRC while most of the AD bomb attacks were made much shallower angles they sometimes used divebombing when they attacked bridges, which was a rather common target during the Korean War, maybe also during attacks on some other targets in mountainous areas.

Again Thanks!
Juha

 

[gjs238]

Not planes that could be used as dive bombers ala Ju-88, or were converted, but true blue dive bombers.

- Ju 87
- SBD Dauntless/A-24 Banshee
- SB2C Helldiver/A-25 Shrike
- D3A Val
- B-24 Skua
- He 118
- D4Y Judy
- Hs 123
- Hs 129 (not really a dive bomber?)
- Fairey Barracuda
- A-31 Vengeance
- SB2U Vindicator
- Northrop BT
- maybe others I've omitted

 

[BombTaxi]

The crux of dive-bombing is having highly skilled crews - both the Stuka and Val became less effective as crews became less skilled. On the other hand, a formation of B-17s needs one guy who can use a Norden sight, and a large group of guys who can pull a toggle... It's cheaper, if less accurate. But unless you're going after ships or bridges, accuracy is less vital than the ability to put a lot of bombs into a relatively small area.

 

[davebender]

Not planes that could be used as dive bombers ala Ju-88, or were converted, but true blue dive bombers.

??
The Ju-88A was a "true blue" dive bomber complete with dive brakes and proper dive bomber sight.

 

[gorizont]

The crux of dive-bombing is having highly skilled crews - both the Stuka and Val became less effective as crews became less skilled.

There is another way - more sophisticated aiming devices than simple optic or reflector sight - the way chosed germans and japanese.So demand for skill - not disappearing - was diminished to some degree. Anyway successful use of dive-bombers demands at least local air superiority and/or good tactic including coordination between groups in airstrike and surprise of attack.
In 1941 two Italian low-level aircraft provided success of attack Shtukas on Illustrious by drawing british attention away from incoming dive-bombers. And you know factors which gave such a success to dive-bomber attack at Midway.

On the other hand, a formation of B-17s needs one guy who can use a Norden sight, and a large group of guys who can pull a toggle... It's cheaper, if less accurate.

I don't think that this is cheaper unless You mean bombing for area in the depth of hostile territory. But dive bombers hardly reach such objects.

But unless you're going after ships or bridges, accuracy is less vital than the ability to put a lot of bombs into a relatively small area.

Shtuka CEP was 30 metres. What was CEP for B-17?

 

[BombTaxi]

Shtuka CEP was 30 metres. What was CEP for B-17?

My point is that you don't need a 30m CEP unless you're going after a ship or a bridge. So for most targets, level bombing or shallow-dive attacks will do. In the specific case of a B-17, most targets were so big that getting the bombs into the correct postcode would do the job.

I don't think that this is cheaper unless You mean bombing for area in the depth of hostile territory. But dive bombers hardly reach such objects.

Again my point is that dive bomber crews needed very detailed training and plenty of experience to deliver an very specialised skill that was in decreasing demand. By 1945, where were dive-bombers being used in numbers other than in the Pacific? Aircraft like the Typhoon and IL-2 were carrying the Stuka's intended role as flying artillery without any need for expensive crew training in dive-bombing.

Furthermore, when RAF's 2 Group wanted to down a bridge or other precision target, they didn't use dive bombers - they did it with level bombers attacking from very low level. The dive bomber skill was simply redundant by 1942-43, except on carriers where only dive bombers were small enough to be carried aboard.

There is another way...

The more complicated the device, the harder it is to teach someone to use it. The other way is, as I have said, to replace dive-bombers with with ground-attack aircraft using rockets, and medium bombers operating at very low level. There simply wasn't a need for dive-bombers (except on carriers) after 1943-42. That's why no more entered service...

 

[gorizont]

The more complicated the device, the harder it is to teach someone to use it. The other way is, as I have said, to replace dive-bombers with with ground-attack aircraft using rockets, and medium bombers operating at very low level. There simply wasn't a need for dive-bombers (except on carriers) after 1943-42. That's why no more entered service...

The question of use of dive bombing is rather complicated so I answer you later dut this aspect I would make clear by now.
The principle is different. More complicated device is means of simplification of operator's acting.
In this case (jf dive -bombing) pilots "learned the subject for several years to became a good bombardirs, using simple reflector sight. they must get an ability to estimate all the corrections (wind, speed, dive angle etc) in short period of time using just visual observation. The task became more complex in case of attacking naval vessel. Such a target was in constant motion and moreover in the moment of attack could change its course and speed. Very difficalt tartget to achive a direct hit.
And using semi-automatic and fully-automatic sights for dive bombing made pilots training shorter and easier. And in battle it made a procedure of putting corrections easier and depended not on bombardir gift but on his skill to make proper manipulations in proper order.