wuzak
Captain
I wouldn't be surprised if 80-85% was the percentage of bombs dropped on the country that was the target of the raid.
Aerial Bombing Question
- Thread starter Zipper730
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I wouldn't be surprised if 80-85% was the percentage of bombs dropped on the country that was the target of the raid.
GregP
Major
I would.
Wikipedia says that coastal command mosquitos which used the Mk.XIV with a radar Altimeter didn't have the 10'second run up restriction which to me suggests that the 10 second run up was only to let the altimeter or variometer stabilise. Post war V force bombers received a Doppler navigation radar to update the INS "green satin" that could measure true ground speed and drift and this could be fed into the Mk.14 directly rather than being manually set. At that point the SABS had no advantage. When Britain dropped its first a-bomb in Maralinga from a Vulcan it was from 30,000ft using the MK.XIV after a radar run up. The bomb was of target 40 yards in azimuth and 100 yards down range. Besides bomb fall times of 50 seconds and targets that were 10km ahead of the bomber couldn't realistically be tracked.
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Mean racial error is roughly standard deviation. If you assume a Gaussian or Normal curve distribution 68% of bombs should fall within one standard deviation. Since CEP is 50% of bombs so mean radial error is roughly 36% greater than CEP. (From 68/50) Bomb accuracy like IQ is Bell Shaped.
Roughly 50% of bombs within one CEP, 47% greater than one CEP but less than two CEP and 3% outside of that.
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- Thread starter
- #265
I would have never thought they'd have developed the Mk.XIV over a gyro-stabilized system, but looking at Koopernic's data regarding the Vulcan's bomb/nav system using data fed from the doppler-updated INS into the Mk.XIV, those accuracy figures look fantastic.
Provided the numbers are right, that provides mean radial error (for an oval at least) of 271.7 feet, and a CEP of 213.9 to 215.6 feet. That looks better than our B-52's at the same altitude. I'm not sure what era this was from, but that looks better than some of our stats from Vietnam.
Makes sense to me
What period of time was the Doppler and Green-Satin system used?
Wait... it successfully landed a bomb 300 feet ahead of and 120 feet to the side of the aim point?
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63 + 27 = 90
63% +27% only equals 90% when they are percentages of the same.
Gaussian function - Wikipedia
Standard deviation - Wikipedia
- Thread starter
- #267
I give up.
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- #269
I dont know it is not my subject and it wasnt my post, I just pointed out that 26 + 64 doesnt equal 100 On almost every issue you seem to want the most simplistic answer to complex questions. To understand CEP read about it but to understand it you need a basic knowledge of statistics.
wiki says this.
The original concept of CEP was based on a circular bivariate normal distribution (CBN) with CEP as a parameter of the CBN just as μ and σ are parameters of the normal distribution. Munitions with this distribution behavior tend to cluster around the mean impact point, with most reasonably close, progressively fewer and fewer further away, and very few at long distance. That is, if CEP is n meters, 50% of rounds land within n meters of the mean impact, 43% between n and 2n, and 7% between 2n and 3n meters, and the proportion of rounds that land farther than three times the CEP from the mean is approximately 0.32%.
If this is Operation Buffalo, then a low yield (3 kiloton) version of the 40 kiloton 'Blue Danube' weapon was dropped from 35,000 ft and from a Valiant on 11th October 1956. The aircraft was WZ366 of 1321 Flight, 49 Squadron, piloted by Squadron Leader T Flavell. Both he and the bomb aimer, Flight Lieutenant E Stacey, were awarded the Air Force Cross for their part in the operation.
There has been much criticism of this series of tests, but the original plan, to drop a 40 kiloton weapon to explode at 1,200 ft was abandoned because of worries that the fuzing system might fail causing an explosion at ground level. The 3 kiloton weapon, which functioned perfectly, exploding at 500 ft as planned, was a safety compromise.
Operation Antler, a series of tests designed to perfect the Blue Danube and Red Beard warheads were planned for Maralinga in September/October 1957, but were cancelled when plans were made for the the second phase of the British nuclear programme, the dropping of the first thermo-nuclear megaton weapons in what would be known as Operation Grapple. Maralinga was not a suitable venue, Christmas (Kiritimati) Island and Malden Island were the selected venues instead.
Incidentally the first series of Grapple tests, between 15th May and 19th June 1957, three weapons were dropped dropped from 45,000ft, again by three different Valiants (XD818, XD822 and XD833) of 49 Squadron, exploding at 8,000ft above Malden Island to prevent the fireball touching the ground and causing "excessive radiation problems." Further weapons were dropped in subsequent tests over Christmas Island before the final two were detonated, suspended from tethered balloons. In September 1958 Britain's 'H-Bomb' was available to the V bomber force.
The Valiant was the only British bomber to drop a live nuclear weapon, neither the Victor nor the Vulcan ever did. The ban on atmospheric testing probably ensured this.
Cheers
Steve
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The "book" I used was on the Topic of the Vulcan, however description for the 3kt blue Danube test did mention that the Valiant was used.
Bomb error was 100 yards down range of target and 40ft (not 40 yards) cross range to 40ft.
Old Wizard
2nd Lieutenant
Zipper you seem to misunderstand what statistics are about. People collect information and compile them to make sense and draw conclusions. The normal or gaussian curve is frequently used because many sets of data form a Gaussian curve or spread. In specific fields with specific data the gaussian curve may be useless or inaccurate. In tems of new born babies (as an example) babies height and weight will have a spread which is Gaussian or normal but the spread of boys and girls isnt because 99% are either boys or girls and about 51% of babies are boys. CEP was developed because munitions are specific, bombs and missiles spread around an aiming point are similar to a Gaussian spread in some cases and different in others. CEP was developed to provide useful information on targetting, it may be possible to convert to another measure or it may not. Some Laser guided missiles hit the target or they self destruct and so they have no spread on impact. CEP is also not a measure of accuracy it is a measure of "grouping" around a mean point, the difference between this point and the aim point is the "bias" which is also a useful measure as it shows up errors in the aiming system.
Robert Porter
Senior Master Sergeant
To add to what pbehn said above. Statistical analysis is certainly useful, but typically the more variables involved, the more difficult it gets to derive useful information from the data collected in a statistical fashion. And of course that assumes the data collected is both accurate and complete. The fact that there are many sources of data for bombing campaigns in WW2 is the source of a lot of confusion. Since there is no single agreed to source. Different groups gathered different data during different years etc. For instance there is not even an agreed to percentage of total bombs dropped to total of unexploded bombs. It varies, depending on the source, from a low of about 2% to figures as high as 40% that I have seen. I would imagine the truth is somewhere in between.
There were times when bomb damage assessment could not reliably be performed, weather, other priorities, equipment failure etc. Then there is of course a somewhat subjective nature to BDA, when one is counting impacts in a built up area it can be difficult to discern each individual impact, some are buried under rubble some were obliterated by subsequent overlapping impacts.
All of this means that while every effort was made to obtain accurate information for each bombing it was just not always possible. In some cases statistical means were used to "fill in the gaps" in data, in other cases there was a real effort to identify effectiveness of certain formations, bomb size and type, bomb loads etc. Very little of this data was gathered during peacetime, a lot of it was done "on the fly" during the war.
In essence any effort to apply mathematically rigorous analysis to something that happened almost 80 years ago with missing and conflicting data sources is foredoomed to failure. There is a lot of good data to be derived but there is no one magic formula such as you appear to be trying to apply. This truly requires extensive research almost month to month and being aware of how data collection, and with what emphasis, was used. It is why authors, good ones anyway, spend literally years in musty archives attempting to tease out ever last piece of relevant data.
There were times when bomb damage assessment could not reliably be performed, weather, other priorities, equipment failure etc. Then there is of course a somewhat subjective nature to BDA, when one is counting impacts in a built up area it can be difficult to discern each individual impact, some are buried under rubble some were obliterated by subsequent overlapping impacts.
All of this means that while every effort was made to obtain accurate information for each bombing it was just not always possible. In some cases statistical means were used to "fill in the gaps" in data, in other cases there was a real effort to identify effectiveness of certain formations, bomb size and type, bomb loads etc. Very little of this data was gathered during peacetime, a lot of it was done "on the fly" during the war.
In essence any effort to apply mathematically rigorous analysis to something that happened almost 80 years ago with missing and conflicting data sources is foredoomed to failure. There is a lot of good data to be derived but there is no one magic formula such as you appear to be trying to apply. This truly requires extensive research almost month to month and being aware of how data collection, and with what emphasis, was used. It is why authors, good ones anyway, spend literally years in musty archives attempting to tease out ever last piece of relevant data.
Robert, good post, only one thing I would add is that in WW2 your enemy deliberately tried to stop you getting good data and introduced false data for propaganda and defense purposes, I am thinking here about the lies spread about V1 and V2 hits on London, British lies that resulted in changes to the targeting that produced less hits not more for the Germans.
This happens even today, with the tragic arguments about whether a building is or was a hospital and who told who what and when.
This happens even today, with the tragic arguments about whether a building is or was a hospital and who told who what and when.
To add to the excellent points above, the Americans used group pattern analysis precisely because they couldn't distinguish individual bomb strikes, but could more often (but by no means always) discern group patterns. The US analysts used 'vertical' photographs taken by PR aircraft accompanying the missions, 'vertical' photographs taken by some of the bombers and, for blind bombing, 'scope' photographs taken of the H2X display (one every sixteen seconds on the bomb run up to bomb release, others less frequently).
The Americans analysed each group's bomb fall, from all its aircraft, as if it was the result of a single aiming operation.
The British, by night, didn't even attempt to to see individual bomb strikes, they were estimated by a rather complicated extrapolation from the bombing photograph which all the bombers took.
Both air forces undertook BDA by photographic reconnaissance, but this too was fraught with difficulties, some mentioned above. The best data came very late in the war, when the men of the various allied ORS were able to examine recently bombed areas as they fell into allied hands. This is why some of the data for tactical operations, and for the strategic bombers in a tactical role, in direct support of ground operations, is so good.
Cheers
Steve
The Americans analysed each group's bomb fall, from all its aircraft, as if it was the result of a single aiming operation.
The British, by night, didn't even attempt to to see individual bomb strikes, they were estimated by a rather complicated extrapolation from the bombing photograph which all the bombers took.
Both air forces undertook BDA by photographic reconnaissance, but this too was fraught with difficulties, some mentioned above. The best data came very late in the war, when the men of the various allied ORS were able to examine recently bombed areas as they fell into allied hands. This is why some of the data for tactical operations, and for the strategic bombers in a tactical role, in direct support of ground operations, is so good.
Cheers
Steve
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Another point just occurred to me. Watching old video on "The World at War" some USA bombers released all bombs together, while others were on some sort of spaced release about half a second between each bomb. In the latter case only the first bomb was actually released onto the target.
There was discussion about the US intervalometer (British automatic bomb distributor) earlier. The settings obviously altered the size of each bomber's pattern, or more correctly the distribution of its salvo. An American analysis from 1943 explains.
"A ship's load will be dropped in a train, by intervalometer or manually, producing a "stick" of bursts along the track. From typical altitudes (20,000-25,000 feet) the sticks from each plane depart widely from the theoretical rectilinear equispaced configuration, and sticks from different ships are usually mingled in quite haphazard fashion. The resulting aggregate of bomb bursts on the ground take the form of a very irregular cluster or "blob", in which practically no system or order is discernible. This cluster is known as the "pattern" but it should of course be pointed out that it is a pattern by courtesy only; the many careful probability studies which have been made on the assumption that aircraft can drop bombs in a true pattern with equally spaced rows and columns bears no relation to the type of bombing now under discussion."
The size of a bomb pattern varied widely according to many factors, intervalometer settings, altitude, type of ordnance etc., but the average US pattern in 1943 covered an area 3,700 feet (1128 m) long and 2,500 feet (762 m)wide.
Cheers
Steve
"A ship's load will be dropped in a train, by intervalometer or manually, producing a "stick" of bursts along the track. From typical altitudes (20,000-25,000 feet) the sticks from each plane depart widely from the theoretical rectilinear equispaced configuration, and sticks from different ships are usually mingled in quite haphazard fashion. The resulting aggregate of bomb bursts on the ground take the form of a very irregular cluster or "blob", in which practically no system or order is discernible. This cluster is known as the "pattern" but it should of course be pointed out that it is a pattern by courtesy only; the many careful probability studies which have been made on the assumption that aircraft can drop bombs in a true pattern with equally spaced rows and columns bears no relation to the type of bombing now under discussion."
The size of a bomb pattern varied widely according to many factors, intervalometer settings, altitude, type of ordnance etc., but the average US pattern in 1943 covered an area 3,700 feet (1128 m) long and 2,500 feet (762 m)wide.
Cheers
Steve
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- #280
I understand that, so there's no confusion here...
So, in some cases they aren't even compatible? Certain laser-guided ordinance being an example?
I thought accuracy was basically how close you hit to where you actually intended to hit?
I'm surprised nobody connected the dots. I'd have figured if the bombs came out in 3-6 seconds, I'd have started bomb-release 1.5 to 3 seconds before the target was reached. That way if some bombs landed long, the earlier releases would have struck their target, if I landed short, the late releases would smack the target. Also when it came to releases, it seemed the first few bombs started to come out, then the bulk came out in the middle, then a few more came out at the end (at least looking at the B-52, it looked like that).
There were photo-reconnaissance P-38's and stuff along with B-17's and B-24's with photo-flash bombs and the H2X scopes to analyze impacts (how does that work, when the radar return starts changing from a building being altered in shape)?
And since we had been planning to use formation bombing for self-defense, it was the most simple way of analyzing all the data in one fell swoop...
And they collated all the photographs, and then used them to roughly estimate each aircraft's accuracy, each squadron, and so on...
So all the bombs sort of mixed in with the bomb-trains of all the other aircraft in the formation?
And, to recap, the formations used in 1943 were around 2340 feet wide, and narrowed to 500 yards or 1500 feet by 1944?
