Dive Bomber Comparison

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davebender said:
??
The Ju-88A was a "true blue" dive bomber complete with dive brakes and proper dive bomber sight.
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From another board:

Ju 88
wasn't a dive bomber in same sense like Ju 87, Blackburn Skua or Douglas SBD Dauntless, A-4 was optimized for 60deg dive bombing, and it seems that earlier A-5 (in essence A-4 with earlier, less powerful engines) was optimized for 50 deg dives, which in fact means glide-bombing. In 43 Germans were modifying also A-4s for glide bombing, removing dive-brakes, calibrating automatic dive-bombing sight for shallower dive angles etc in order to use 88s as level bombers or glide-bomber which used 30 deg dives.

After dive brakes were removed Finns used 45 deg dives with their Ju 88A-4s.

That means the Spitfire was also a dive bomber as it dove at 60 deg.
 
In my opinion, there is no question that divebombing was a far accurate form of ordinance delivery. But it comes at a price. I think there are two major problems that takes the shine off the concept. The first is the vulnerability of the aircraftboth to fighters and flak. us navy tests in 1944 demonstrated that with vt fuses and good radar fc it took about 500 rounds to destroy db a/c. by comparison it was taking the germans around 16000 rounds to bring down a heavy bomber. against fighters it was a similar story. because a lot of weight had to devoted to airframe strength, d/b aircraft tended to be lightly armed and lacking in armour, and relatively speaking were poor performers. There were a number of reasons for this....level bombers could fly high whereas d/b had to generally drop to below 5000ft to releaease their ordinance. Whilst in the dive the aircraft was flying straight and to be accurate, slow. The combination of these factors made theem very vulnerable whilst attacking. And nearly useless against hevay targets like factories......

compare the performance of the ju88a-4 with something contemporary to. the a-4 with 2 x 1350 hp engines had a maximum speed of 292 mph. It had an empty range of 1696 miles (with any warloads it was a LOT less) . It could carry a max bombload of 5500 lbs, for short distances, but typically carried no more than 2000 lbs. As a divebombers it was only a qualified success. Against RN targets it was asessed as a moderate threat, the more lethal Ju87s were feared much more because of their steeper angle of attack. The Ju-88a-4 began to enter service in large numbers in 1939-40

I am tempted to make a comparison with the Mosquito, but this would be slightly unfair, since the Mossie was a slightly later and was more powerful than the Ju88. Perhaps a more reasonable comparison would be the LeO451. The French bomber had the following characteristics. It had a top speed of 317 mph, and a range with 1100 lbs of bombs of 1450 miles and a maximum bombload of 4500 lb, but usually it was 2200 lbs. The powerplant of the french bomber was 2 x 1140 hp radials

The German bomber in 1940 carried a defensive armament of 5-7 mgs, whilst the French bomber carried a long range and hard hitting 20mm cannon and two mgs. In my opinion, the German aircraft paid a price for its divebombing ability in terms of its range, payload and performance, as compared to the French contemporary
 
German aircraft paid a price for its divebombing ability in terms of its range, payload and performance
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Let's examine those items in detail. 1942 was the mid point for the European portion of WWII so I will use aircraft from that year.

B-17E.
Cost = $258,949 (per USAF statistical digest)
Bomb bay can hold up to 8,000 lbs. However 4,000 lbs was typical. Those 9 defensive machineguns plus gunners plus their equipment ate up the rest of the payload.
317 mph max speed.
Cruise speed with payload was 165 to 185 mph.
Bombing accuracy (during 1943). 16% of bombs fell within 1,000 feet of the aiming point.
Combat radius with 4,000 lb payload. ??
I could not find a combat radius (with normal 4,000 lb payload) for the B-17E. I would hazard a guess it was about 500 miles. Late war B-17s (F and G models) increased this with additional fuel tanks.

Ju-88A4. With 1,400 hp Jumo 211J engines.
Cost = $68,242 (170,605 marks during 1942. Assume 2.5 marks per dollar.)
.....You can purchase almost 4 Ju-88s for the price of 1 B-17E.

317 mph max speed.
.....Similiar to B-17E. However this figure makes little difference. Cruise speed with payload is what counts.

Up to 7,937 lbs of bombs can be carried (internal plus external). I assume about 4,000 lbs was typical.
.....Amazingly enough a typical Ju-88 payload was similiar in size to the much larger B-17E.

Cruise speed with payload was 211 to 239 mph.
.....About 50 mph faster then the B-17E. That makes the Ju-88 more difficult to intercept and to hit with ground based AA fire.

Bombing Accuracy. 50% of bombs fall within 50 meter circle under test conditions.
.....You won't achieve that level of accuracy under combat conditions. However it's readily apparent the Ju-88 was far more accurate then the B-17E. Perhaps 10 times as accurate.

It's worth noting that German bombers began receiving gyro stabilized bomb sights beginning during 1941. So a Ju-88 bombing during 1942 will probably use a 60 degree dive angle rather then a vertical dive. That increases Ju-88 survivability vs AA fire and places less stress on the airframe.

Combat radius with bomb load. About 400 miles.

What price did a 1942 Ju-88 pay in terms of performance compared to the American B-17? The Ju-88 was superior in every way except combat radius. And B-17E combat radius (with bomb load) wasn't that much better.

If you extend the comparison to 1943 then it's the B-17F vs the Me-410A dive bomber. The Me-410 has a much greater advantage in aircraft survivability while losing none of the of the advantages in bombing accuracy or aircraft production cost.
 
It (Ju88 ) could carry a max bombload of 5500 lbs, for short distances, but typically carried no more than 2000 lbs.
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Up to 7,937 lbs of bombs can be carried (internal plus external). I assume about 4,000 lbs was typical.
.....Amazingly enough a typical Ju-88 payload was similiar in size to the much larger B-17E.
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When is 2000lb similar to 4000lb?

You can't compare cost as there are many other factors to consider, for instance, wages.
 
You can't compare cost as there are many other factors to consider, for instance, wages.
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When I purchase a car I am interested in performance and cost. If I were to purchase an aircraft the same factors matter. I don't care what the production workers get paid.

However there are indeed other factors to consider.
A B-17E requires a crew 3 or 4 times as large. Trained aircrew are probably more expensive then the aircraft itself.

The B-17 requires at least twice as much fuel per mission. Another expensive item.

The B-17 is more expensive to maintain.

The larger B-17 requires a better equipped and therefore more expensive airfield from which to operate.
 
davebender said:
Let's examine those items in detail. 1942 was the mid point for the European portion of WWII so I will use aircraft from that year.
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Another biased comparison?

Range with 4,000lbs was 2000miles, this turns into 600-700miles of radius?
Or try this:
http://www.zenoswarbirdvideos.com/Images/B-17/17TRC.pdf
Use the right had chart and cut bomb load to 4,000lbs. Seems like the speeds are a little better than you are claiming.
davebender said:
Ju-88A4. With 1,400 hp Jumo 211J engines.
Cost = $68,242 (170,605 marks during 1942. Assume 2.5 marks per dollar.)
.....You can purchase almost 4 Ju-88s for the price of 1 B-17E.
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This one is so far off it is laughable. If you really believe this one I have a bridge in New York City I can sell you. Cheap to. o
Calling it 3 1/2 Ju 88s to one B-17 just to be nice, Do you really believe that you can build 7 twelve cylinder liquid cooled engines for the actual cost of 4 nine cylinder air cooled engines? or 7 constant speed propellers?
How about the extra instruments and radios? or the 2000 sq ft of wing compared to the the single B-17s 1420 sq ft?
You have been told before about comparing prices of aircraft using currency exchange rates. You have to know if the currency exchange rates were artificially limited or not. You also have to know EXACTLY what the contract price covered. Some contracts stated XXX number of aircraft for YYY amount of Currency but Included varying percentages of spare parts.
davebender said:
317 mph max speed.
.....Similiar to B-17E. However this figure makes little difference. Cruise speed with payload is what counts.
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True enough. except the JU-88's speed at max loaded weight was 269mph at 14,765ft.
davebender said:
Up to 7,937 lbs of bombs can be carried (internal plus external). I assume about 4,000 lbs was typical.
.....Amazingly enough a typical Ju-88 payload was similiar in size to the much larger B-17E.
Click to expand...

Where are you getting 7,937 lbs from aside from Wiki? and look at it for a minute. One book gives a max loaded weight of 30,865lbs for a JU-88A-4, with an empty equipped weight of 21,737lbs. subtract 800lbs for the 4 man crew and parachutes then subtract that 7,937lb bomb load and you are left with about 400lbs for fuel and oil. Even lowering the empty weight a few thousand pounds (and there is a difference between empty and empty equipped) doesn't leave all that much for fuel. Standard tankage was for 637Imp gallons(?) or 4777lbs of fuel. Guess we can see why the standard bomb load was closer to 4000lbs. Also on the A-4 model only ten 110lb fit inside. any additional bomb load went out side adding to the drag.
davebender said:
Cruise speed with payload was 211 to 239 mph.
.....About 50 mph faster then the B-17E. That makes the Ju-88 more difficult to intercept and to hit with ground based AA fire.
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I am not sure I am buying the cruise speed difference but go for it.
You did forget to mention the difference in cruising heights though which also affects the accuracy of ground based AA fire. Shorter flight times to lower altitudes means less error in the time fuses and faster corrections of the fire control solution. the lower altitude also means that the planes are with in range of a given gun or battery for a longer period of time.

Ok, I will give you this one but then again the B-17s are not DIVING down to an altitude at which anything more powerful than Grandad's old WW I service revolver can shoot at it.
Ok, that is an exaggeration but the B-17s are well above the range of 37-40mm guns let alone 20mm and smaller. What was the release hight needed to get the accuracy you claim?



Want to review that again.
 
davebender said:
When I purchase a car I am interested in performance and cost. If I were to purchase an aircraft the same factors matter. I don't care what the production workers get paid.
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you might want to consider if you can actually get the car for the price "advertised".

Wages were controlled in both countries at the time. Price of the aircraft might or might not include "government furnished equipment. Or the Price "quoted" might be from adding in all the prices from the various suppliers.

Gee, Mr bender, here is your new car, please write one check to the frame/body maker. One check to the engine maker, one check to the rear axle/ drive shaft maker and a few more to the dashboard and radio makers. we may have forgotten one or two, they will bill you later.
And by the way, car "A" comes with free parts, labor and oil changes for the next 5 years and care "B" doesn't. (spare parts)

Still comparing performance and "cost"?

car "A" may be paying their workers more but with so many other variables how do you know that is why the cost is higher?
 

Above the battle field B-17 is almost useles moreover it is a danger to own troops. B-17 is almost useless in the case of attacking enemy ships of major classes in sea. Some success in attacking japanese vessels in sea B-17 achieved by skip-bombing and low -level bombing - and such patterns didn't allow to use the main mode of work for Norden - synchronous mode, because it couldn't work in this mode at alltitudes under 1000 metres. And in this case even destroyers became a hard nut to crack for Flying Fortress because of size of B-17 and its unperfect maneuverability. B-17 is useless for attacking concrete bunkers and so on.
 
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Some thoughts on dive bombing;

1. It works really great on small high value targets like ships or bridges.
2. It brings the attacking planes into AA range of practically any gun that can be pointed skyward bigger than Granddads WW I service revolver.
3. High value targets are often easy to spot. Dive bomber against ship means the dive bomber has to distinguish between ship and ocean. Not that hard to do even if you misidentify the ship (mistake DD for cruiser or oil tanker for carrier), Bridges too are not that hard to spot. Bombing factories is a bit harder. "was that 7 or 8 streets east of the RR tracks that the factory is located?" now count streets in the dive. and hope some joker hasn't painted a fake street on the factory roof.
4. Small, high density high value targets are easier to hurt. A single 500-1000lb is going to mess up a ship pretty well. A single such bomb is going to stop production at a factory for how long?
5. Combining #2 and #4. How many planes are you willing to trade for a destroyer or a cruiser or battleship?
How many planes are you willing to trade for the only supply bridge for miles over the river or the only retreat route for miles?
A destroyer can take around 2 years to build and is crewed by several hundred men. A big Cruiser can take 4 years to build and is crewed by a thousand men or more. Loosing even a couple of dozen planes might be considered a good trade.
Factories turned out to be much harder to actually destroy than most people thought. large machine tools almost need direct hits to destroy, a bomb hit even a few dozen yds away doesn't really bother them aside from perhaps cutting of their power. Blowing the roof off or all the windows out makes working conditions uncomfortable but aside from a few days clean up and perhaps destruction of work in progress may not affect next weeks or next moths production all that much. Please note that this reality was much different that what pre-war planners thought or even what some mid war planners thought.
How many planes were you willing to loose to take a factory out for a few days or weeks.
6. Fog or low clouds will screw up dive bombers every bit as much as level bombers, you can't hit what you can't see.
7. Trying to dive bomb early war airfields won't give that much better results because thats what airfields were. Fields. a large expanse of grass with no runways. Fighters left the flight line after looking at the wind sock and taxied to the edge of the field away from were the wind was coming from and then took off into the wind. Landing was pretty much the same way in reverse.
There is no runway to "cut" with a few well placed bombs. You need to take out the hangers/fuel (granted easier with dive bombers ) and then blanket the entire airfield with bomb craters. this last is harder to do with limited bomb capacity dive bombers.

Each type has it's Place and use. Trying to build Strategic range dive bombers was a joke, although it didn't stop a few other air staffs from specifying it. Fortunately for the air forces involved the engineers managed to convince the air staff before the planes were actually built.
 

Dive-bombers for success needed airsuperiority for part which used this aircraft. Airsuperiority which could be temporary and local but it was urgently needed. Attack of dive - bombers isn't usually so surptising as attack of low-level or strafing aircrafts.
Besides dive-bombing attack is more dangerous for attacking aircraft because of dive -bombers are highly vulnarable in a moment of recovering from dive. It can hardly be compared with danger to aircraft made a fast pass.
But in comparison with a straifing or low-leveling aircrafts dive-bombers are far less vulnarable to AA fire in the moment of attack (final dive)- if we talking of period WWII. But It couldn't compansate a degree of vulnarability of dive-bombers at moment of recovering.
So germans were forced to change their tactic because of loss of superiority and the fact that AA defence became to the end of war much more powerful.
So they used new devices to provide new tactic. Although using new bombing gyro-sights might help them to keep the high level of accuracy for dive-bombing despite of loss of many expirienced pilots or even to improve it.
Unguided rockets gave attack planes new oppotrunity - to launch a strike over the limits of effective fire of AA automatic guns. But they didn't have put a damage which could put a heavy bomb so in many cases they couldn't substitude heavy bombs.

As for germans you know that they started to use another methods and devices which let them attack out from zone of effective fire of AA guns against naval vessels - I mean Golden Zung and implementing guided weapon.
 
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Good post, Shortround6
 
My 5c
IIRC average bombload for Ju 88A-4 was 1500kg (3300lb)
But was Ju 88 more accurate against ships than well trained levelbomber crews? During the attack in Dec 41 against Force Z IJNAF, besides the numerous torpedo hits by torpedo bombers which sank PoW and Repulse, 34 Japanese level bombers, most carrying one 500kg bomb, few carrying two 250kg bombs, got one 250kg hit on Repulse and one 500kg hit on PoW. PoW was hit when it was already badly crippled by torpedoes but Repulse was hit in undamaged conditions and while manoeuvring at high speed, and Repulse was manoeuvring very skilfully. IMHO Ju 88 wasn't more effective in similar conditions. Of course most level bomber crews were not as well trained in anti-ship operations than those Japanese but for ex Ju 87s and Vals were clearly more effective against big warships than Ju 88 early in the war, later CAP and AA became too deadly for dive-bombers.

Juha
 
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Hello Gorizont
There were problems during the Cobra bombing producing numerous US casualties, but I cannot recall were the culprits heavy or medium bombers but anyway the massive bombing effectively weakened German defence. During Goodwood the bombing was effective to certain depth of Germans defence, but because German defence had more depth than British were anticipated, south of the bombing zone British ran into grievous problems. Goodwood showed the strong and weak points of heavy bomber ground support. Heavy bombers could deliver stunning amount of destruction but they were very inflexible. In unexpected situation one could ask via radio dive-bombers or fighter bombers to try to eliminate the new danger, but heavy bombers could not be used in fluid situation.

Juha
 
Any bomber needs air superiority for success. Unless you get lucky and the enemy are caught napping as happened at Pearl Harbor and Bari. However a low level attack improves the chances for achieving surprise.

Cruising across enemy airspace at 20,000+ feet practically guarantees the enemy will know you are coming.
 
Hello Davebender
now if one want to do some dive bombing one needs to approach at fairly high level.

Ju 88A bombers had 4 crewmembers, B-17E-G had 10 IIRC, not 3 or 4 times more.

Juha
 
I second, good description of the different target aspects where dive or level bombing make more sense. I'd also add that even bridges sometimes turned out practically more suited to level bombing attack than dive as one type of interdiction target among a whole portfolio of others (railyards, supply depots, or 'suspected'* supply depots etc) gone after by the same force, for example US 9th AF medium bombers. The mediums had flexibility to strike, reasonably effectively, all the major types of fixed supply interdiction targets, and combat losses of 9th AF mediums to targets only defended by light AA were minimal (interception by German fighters was relatively unusual compared to what the heavy bombers faced; most 9th AF medium losses were to the limited number of heavy AA defended targets). Divebombers would have been suffered constant losses to light AA on what were effectively milk runs for the mediums (albeit level bombing mediums had to spend more fuel and bombs to get the job done v a point target like a bridge), and the targets defended by heavy AA would have had light AA also. So even besides truly strategic bombing, it's highly questionable IMO to suggest divebombers replace level bombers in a mission like 9th AF mediums in ETO.

Even v ships, in the Pacific, 5th AF mediums had tremendous success v ships with longer reach and less vulnerability to fighters (B-25 was relatively hard to catch, though not immune to interception, for most early to mid war Japanese fighter types down low, B-26 more so), using low altitude strafing/skip bombing. The A-24 (Army version of SBD) would be a questionable replacement for the B-25 in that role, against the particular types of ships attacked. Maybe against carriers the A-24 would be superior, but against merchant types and DD/escorts, armed as the Japanese ones were, the B-25 was highly effective with strafe/skip tactics. And again range was a major advantage v the particular types of divebombers which would have substituted, though a longer range divebomber could be built.

I think a fighter-divebomber like A-36 as subsitute for a fighter-bomber is a more serious question, and no the dive brakes on A-36's were not disused and finally wired shut, that's either a complete myth or was at most only the opinion of some units at certain times: others used the true dive bombing capability of that a/c to the fullest.

*IOW to add to your point about easy to spot high value targets being suitable for divebombers, w/ some targets like supply concentrations it was a hard for even good recon and intel to be sure the target really existed in the place the bombers were sent to hit, but they had to try those likely locations if they were ever to succeed in destroying some of the supplies. In these cases it was especially hard to justify losses of divebombers to light AA which might happen to be around anyway (Germans ca. 1944 had a it practically everywhere), as divebombers were demonstrating with their small CEP's v. the buildings the targeters had sent them after...but which didn't actually contain any military supplies.

Joe
 
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davebender said:
Cruising across enemy airspace at 20,000+ feet practically guarantees the enemy will know you are coming.
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Dive bombers are not low level bombers.

They are mid level bombers that release at low altitude.

At what altitude they start the dive?

Cruising across enemy airspace at at 10-15,000ft doesn't give much more of a surprise factor that flying at 20,000+ feet.

And cruising along at under 1000 ft and then climbing to 10,000ft+ in the target area tends to blow the surprise too.
 
I agree.

My point is that practically all bombing conducted during the daytime requires fighter escort. A high cruise speed (with bomb load) helps some by limiting the amount of time over enemy territory but does not eliminate the chance for enemy interception.
 
Im glad you correcte your Post 35 in your post 39. Whilst it is generally true that air superiority is needed, in most situations, wher you have aircraft of exceptionally high performance or there is some technology or technique or enemy weakness being exploited, this does not apply.


In 1940, for many months, the germans found they could bomb British targets with near impunity, at night, despite the British having maintained control over their daytime airspace. The reason was because the British did not have a credible night fighter force at that time. In 1945 the US B-29s were able to bomb targets by day over Japan, because the Japanese did not have a day interceptor that could operate effectively at B-29 operating altitudes. From 1942 through to 1945, Mosquito intruder bombers operated in many situations with rrelative impunity because they could often use their speed to get them out of trouble. Sturmoviks were far from invulnerable, but they often operated over battlefields where the Luftweaffe theoretically possessed air superiority, using their numbers and the heavy armour that protected them to get them through and achieve the mission. The operation of the AR234s at the end of the war are another example.

It is not valid to generalise about the vulnerability of bombers. There are many notable and strategically relevant exceptions to the statement.

being e
 
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