I hope this is where this belongs. How accurate were the big bombers of WW-2 ? And what methods did they use to get there bombs on target? I know the US had a good bomb sight, cant remember the name. But I was thinking It would take a lot to get there bombs on target , and be accurate! There would have to be a formula and a chart they would have to go by. Taking in the facts of:
Air speed
Altitude
Rate of bomb desent
Distants to target
So would the Bomber always be at the same air speed for every bomb run. And always drop the payload at the same altitude. And drop a certian known bomb size , at the same distance everytime! This seems like a lot to figure into every mission, in combat situations!

Does anyone know just how they did this ?

TIA,
Garry

garrybeebe - the bomb sight you refer to is the "NORTON Bomb sight", it was very accurate for it's day, when on the "bomb run" the bombadier was flying the plane with the bomb site thereby taking into account the speed and attitude of the aircraft. The Norton sight was considered Top Secret until after the end of the war. Did they always hit what they aimed at ? No, just like today Murphy's Law always applies.

Edit: I stand corrected it's the Norden bombsight.

It's the Norden sight, and it's actually a combination of automatic pilot and ballistic computer. The Norden actually allowed the bombardier to take limited control of the plane (in the case of the B-17 at least, although variations of the sight were also used on the TBD Devastator and the B-24), program in the bomb type and factor in aircraft drift, ground speed and altitude to calculate a ballistic solution to drop the bomb load.

The sight had various setting knobs to "program" in altitude and weapon type, and gyroscope elements allowed the bombardier to input motion factors by optically tracking the target for a set period.

Now, that all sounds good and well, and the Norden was a pretty impressive piece of applied technology. But, we're also talking about dropping bombs from 20,000-plus feet, with all the inherent effects of winds along the bomb's path, storage damage to the bomb's fins, and in-flight damage to fins (part of the Manhattan Project's bomb casing development showed a pretty high failure rate of standard USAAF bomb fin assemblies).

And buffeting from flak, evasive action from attacking fighters and high altitude winds could also introduce solution errors or cause the bombardier to have to drop with an incomplete solution.

Also remember that the USAAF early in the war used the Norden to drop bombs on moving ships at Midway and during the defense of the Phillipines. That throws in a another variable that's awfully hard to if not impossible to account for, especially if the ship is not moving in a straight line.

The old "bomb in a pickle barrel from 20,000 feet" concept of the Norden is pretty far from reality. But you could still get a fair circle error of probability under some combat conditions or with a skilled bombardier. And in a lot of cases, USAAF bombing raids had a relatively more accurate targeting pattern than what you'd find with early RAF (pre Arthur Harris) Bomber Command planes and sights.

That's why USAAF heavies depended on box formations, interlocking fields of fire and escort fighters - to increase the odds of undisturbed bomb runs.

HTH

The innacuracy of early bombing led to the development by the RAF of the pathfinder system, where the best crews dropped markers on the target and everyone else dropped on the markers. At intervals during the raid the markers would be 'topped-up' as the first ones dropped faded or were blown away by the winds. They also developed Oboe & H2S airborne radar to enable bombing in bad weather or cloud cover.
The radar system was accurate enough to allow Lancasters to bomb within 200yards of the Allied front line in Normandy without causing casualties to our troops.
The problem with box formation was that everyone bombed when the leader bombed, so if the leader was on target, 'tail-end charlie' was still along way short when he dropped his!
My Wife's cousin was in the 4th Canadian Armoured Div. during the Invasion - to save embarrassment I won't actually say who bombed them twice in one day whilst they were 5 miles behind our own lines!

There are lots of good reference materials on this, including a post-WWII US Strategic Bombing Survey. I don't have a copy, but plenty of books have the library of congress information in their bibliographies.

Basically, accuracy was abysmal. There are instances, early in the war, of the RAF launching night raids with hundreds of bombers against a city with less than 10% (IIRC) ever even finding that city. While the pathfinders, radar navigation, and other methods improved the results a little, the RAF Bomber Comand never felt confident in its ability to hit anything larger than an entire city.

The USAAF, by virtue of its willingness to bomb in the daylight, was slightly more accurate, but "accurate" is a relative term. Even under ideal conditions, more bombs would land outside a 2 mile circle around a target than inside it!

Bottom line: level bombing was almost completely incapable of hitting any point target. You could flatten sections of cities (while sometimes leaving a factory in the middle of the section unscathed), and you could (ala operation Cobra in Normandy) blast massive corridors through enemy lines. If you had something particular you wanted to hit, though, you'd have to either send hundreds of bombers (often multiple times) or use dive/tactical bombing.

Norden Sight



When shot down, the Bombardier was to put a bullet through the bombsight, so the enemy couldn't copy it.



Claimed to be really accurate. In my opinion, I think that the Americans were more accurate then the British. I mean you can see more in the day than at night.

In terms of accuracy in the early years none were that accurate. The RAF's Pathfinder force and H2S sets help a lot. The big myth is that the americans used precision bombing. In actual fact they were as often or not as inaccurate as the british. It is not until later in the war that bombing becomes more accurate. The bomber was also not suited to support land ops either as they typically ended with blue on blue casualties.

In actuality the Norden Bomb Sighting System was extremely accurate for the technology of the day, IN TESTING. I t was much more accurate over Germany than it was over Japan, as winds over Japan were more difficult to perdict due to Japan being surrounded by oceans & seas that heavily influenced the weather.

But as stated above, add flak, fighters, clouds, navigation errors, loose formations (due to flak 7 fighters) and accuracy dropped rapidly.

The technology employed by the British helped the night bombers to find the target area, but due to width of the beams, etc., the accuracy still never rivalled accuracy of daylight bombing. The USAAF also used radar to allow more accurate bombing thru clouds.

In Japan, the B-29s, bombing at night dropped to 10,000-12,000 feet to improve bombing, something that would have been suicide over Europe.

One problem with bombing in Europe, was the fact that the allies may destroy the factory, that machinery most often survived - big stamping machines could survive anything short of a direct hit by a 500 ib bomb!!! The Germans would just relocate the machinery and have the factory back in operation from a safer location.

Jeff

One other factor that I don't see listed here is the skill of the bombardier. The USAAF tried to compensate for this by having a lead bombardier be responsible for dropping the bombs. All other bombardiers would toggle their bombs at the same time. This would ensure the bombs came close to the target, but with the box being spread out it wouldn't mean they would all hit the same place. If the lead plane was shot down succeeding planes would take over, with possibly lesser trained or skilled bombardiers in therm.