33k in the air
Staff Sergeant
- 1,261
- Jan 31, 2021
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Not true. Both the 4,000lb and 8,000lb bombs were fitted with a cylindrical tail. See below (which had links to official bomb manuals)Hey all,
Does anyone have or know of any reports or studies comparing the ballistics of the British HC bombs to their GP and MC counterparts?
I ask because the shape of the HC bombs was not particularly aerodynamic and thus it would seem to me more difficult to aim accurately. The 4,000 lb and 8,000 lb HC were flat-ended cylinders with no tail fins of any kind, while the 2,000 lb HC was a long cylinder that had a tail consisting of a cylinder the same diameter as the bomb body which had large slot openings cut into it. The 12,000 lb HC bomb was a blunt-nosed cylinder that at least had a conventionally shaped tail fin assembly.
It would be interesting to see the 4,000 lb HC compared to the 4,000 lb GP and 4,000 lb MC bombs as these latter two had a conventional streamlined bomb shape with tail fins. A comparison of the 2,000 lb HC to the 1,900 lb GP would likewise be interesting.
I presume the aimability of the 12,000 lb HC bomb was not too different from that of the 12,000 lb DP/MC "Tallboy" given the former's more conventional shape.
Unfortunately I do not have any info on the specifics of aiming these bombs, i.e, the settings and targeting data that were used to aim the specific weapons. However, be assured that free-fall weapons of different size, aerodynamics and Mass will all vary in their flight path. That said, different size, shape and weight bombs can be made to approximate the flightpath of other bombs, generally by aerodynamic modifications. Taking for example more recent weapons, the UK 1000lb bomb could be imitated in freefall with a 28lb practice bomb and the same 1000lb bomb with a high drag retarder for low-level retarded delivery could be imitated with a 3kg hi-drag plastic case practice bomb. So, bomb flight characteristics could be modified, but it is unclear how much these aspects were incorporated in WW2 bombs and aiming tactics. IMO, The streamlined Tallboy and Grandslam bombs will have had big differences to the blunt 4/8/12 thousand pound MC bombs. Also, I believe there is film of the big HC bombs dropping together with the very lightweight incendiary firebombs and it would be interesting to know if there was any correlation between the expected fall of that combination?!Hey all,
Does anyone have or know of any reports or studies comparing the ballistics of the British HC bombs to their GP and MC counterparts?
I presume the aimability of the 12,000 lb HC bomb was not too different from that of the 12,000 lb DP/MC "Tallboy" given the former's more conventional shape.
This is one photo showing the dropping of a 4,000lb "Cookie" and incendiaries.Unfortunately I do not have any info on the specifics of aiming these bombs, i.e, the settings and targeting data that were used to aim the specific weapons. However, be assured that free-fall weapons of different size, aerodynamics and Mass will all vary in their flight path. That said, different size, shape and weight bombs can be made to approximate the flightpath of other bombs, generally by aerodynamic modifications. Taking for example more recent weapons, the UK 1000lb bomb could be imitated in freefall with a 28lb practice bomb and the same 1000lb bomb with a high drag retarder for low-level retarded delivery could be imitated with a 3kg hi-drag plastic case practice bomb. So, bomb flight characteristics could be modified, but it is unclear how much these aspects were incorporated in WW2 bombs and aiming tactics. IMO, The streamlined Tallboy and Grandslam bombs will have had big differences to the blunt 4/8/12 thousand pound MC bombs. Also, I believe there is film of the big HC bombs dropping together with the very lightweight incendiary firebombs and it would be interesting to know if there was any correlation between the expected fall of that combination?!
Eng
Not true. Both the 4,000lb and 8,000lb bombs were fitted with a cylindrical tail. See below (which had links to official bomb manuals)
Bomb, 4000 lb HC, Mk 1
Description The body is a cylindrical shell which has a hollow, conical nose piece welded to it, parallel sides, and a closing plate bolted to an angle ring. The angle ring iswww.bulletpicker.com Bomb, 4000 lb HC, Mk 2, Mk 3, Mk 4, Mk 5, Mk 6
Description The body consists of a fabricated steel, cylindrical shell with a domed plate welded to the nose end, parallel sides, and a closing plate bolted to the angle ring,www.bulletpicker.com Bomb, 8000 lb HC, Mk 1, Mk 2
Description The bomb consists of two cylindrical sections, each approximately 4 ft. long and 3 ft. 2 in. in diameter, connected together by bolts. The front section has a domewww.bulletpicker.com
The bombs were originally intended for low level bombing, a type of operation not normally undertaken by Bomber Command at this period. Small numbers of these bombs were dropped on city targets from high altitude, but accurate photographic assessment of the results was never possible, and, as 4,000-lb HC bombs were in good supply, the use of MC bombs against this type of target did not appear to be justified. During the autumn of 1944, 4,000-lb MC bombs were used by Mosquito aircraft for high altitude night bombing, as the ballistics of these weapons are much superior to those of the 4,000-lb HC bomb; it was also used with success to breach the dykes on Walcheren Island. Partly because only one could be carried by Lancaster aircraft and none by Halifaxes, however, it never became a widely used store in Bomber Command.
A drum tail was designed during the early months of 1942 by the Armament Department of A. & A.E.E., and ballistic trials gave satisfactory results. 3
Most of the "High Capacity" bombs had slightly domed front ends and flat sheet steel back ends with flat sheet steel rolled to form a cylinder. These bombs did not make any significant fragments and thus their only effect was "Blast" against soft targets. Their bombing accuracy was abysmal, even from the low altitudes they were mostly used. CEP = 1/2 mile from 10,000'! The higher they went, the more exaggerated the dispersion, IE almost one mile from 15,000'!Hey all,
Does anyone have or know of any reports or studies comparing the ballistics of the British HC bombs to their GP and MC counterparts?
I ask because the shape of the HC bombs was not particularly aerodynamic and thus it would seem to me more difficult to aim accurately. The 4,000 lb and 8,000 lb HC were flat-ended cylinders with no tail fins of any kind, while the 2,000 lb HC was a long cylinder that had a tail consisting of a cylinder the same diameter as the bomb body which had large slot openings cut into it. The 12,000 lb HC bomb was a blunt-nosed cylinder that at least had a conventionally shaped tail fin assembly.
It would be interesting to see the 4,000 lb HC compared to the 4,000 lb GP and 4,000 lb MC bombs as these latter two had a conventional streamlined bomb shape with tail fins. A comparison of the 2,000 lb HC to the 1,900 lb GP would likewise be interesting.
I presume the aimability of the 12,000 lb HC bomb was not too different from that of the 12,000 lb DP/MC "Tallboy" given the former's more conventional shape.
The RAF's post war report on bombing effects stated that typical accuracy was 50% inside the Target aria! The "Target Area" being the entire city!In other words, similar to the 2,000 lb HC, so my question still stands. Did such non-conventional tails provide much in the way of aiming ability as compared to the more traditionally shaped 4,000 lb GP and MC bombs?
Harris' Despatch on War Operations 1942-1945 has this passage regarding the 4,000 lb MC bomb which prompted my question (emphasis added):
"Much superior" ballistics of the MC over the HC according to Harris. It'd be nice to see that quantified in some manner.
Define "very un-reliable"?Most of the "High Capacity" bombs had slightly domed front ends and flat sheet steel back ends with flat sheet steel rolled to form a cylinder. These bombs did not make any significant fragments and thus their only effect was "Blast" against soft targets. Their bombing accuracy was abysmal, even from the low altitudes they were mostly used. CEP = 1/2 mile from 10,000'! The higher they went, the more exaggerated the dispersion, IE almost one mile from 15,000'!
The tallboy/grand slam streamlined bombs had good aerodynamic properties, but the Lancaster's dropping latches/mechanisms were very un-reliable, and the scatter was huge!
The experience from WW2 was that using a level bomber, 4 engined or not, to attempt to hit a ship, stationary or not, and regardless of the size of bomb used, was not as easy as you might think. Near misses, especially from large weapons as Tallboy, could add significantly to the damage caused.Both long and short and side to side! Look at the map of bomb impacts from the Tirpitz raids! One hit and two near misses, IIRC, out of over thirty drops??? Some 1-1/2 miles away from the target from 17-19,000'???
The first USAAF Tallboy tests were authorised in Feb 1945 at which point a single aircraft 42-63577 was being modified by Bell to carry a single Tallboy in a modified bomb bay with cut-away doors. By the time the final report was produced on 15 June 1945 it was noted that the AAF Proving Ground was testing an aircraft modified to carry both Tallboy & Grand Slam. "should this new installation prove to be functionally reliable, it is believed that this installation would be more desirable than the B-29 modified to carry only the 12,000lb Tall Boy bomb". 3xB-29A modified to carry a single Tallboy or Grand Slam (45-21747, 45-21750, 45-21751) were sent to Britain in March 1946 to participate in Projects Ruby and Harken.Late in the war, we rigged a couple of B-29s to carry two Tallboys on inboard wing pylons, or one Grand slam/T12? Cloud maker with cut away bomb bay doors. Bombing accuracy Varied from less than 100' or so to over 500' CEP from 20-30K'. After the war, we installed racks for all three types of bombs in the B-36 and dropped two T-12?s from 30K' and 40K' or three to four Grand slams, or Tall boys per mission. Minimum bombing altitude was over 30K' and maximum was over 45K' for the last Tall boy! Accuracy ranged from under 100' to under 600' CEP!
The Lancaster Archive details a fair number of the bomb loads carried by that aircraft. Note how each was designed to deal with a particular type of target.I expect that much of the RAF Bomb Aiming and Release Trials would have been done by the A&AEE based at Boscombe Down from Sep '39. We have read so far that there does seem to have been a big spread on the fall of the blunt 4/8/12000lb HC bombs. However, given their widespread use, there must have been a considerable amount of policy on use and aiming these weapons. Furthermore, the large blast effect was employed on specific factory targets and that would require fairly accurate aiming. So, I hope someone knows more of the details? Please tell us!
Eng
The RAF's post war report on bombing effects stated that typical accuracy was 50% inside the Target aria! The "Target Area" being the entire city!
The ballistic trials were completed in November when four bombs were released singly from a Halifax, each simultaneously with a 250 lb G.P. bomb, from approximately 5,000 feet.[2]
The Lancaster Archive details a fair number of the bomb loads carried by that aircraft. Note how each was designed to deal with a particular type of target.
You will note that for attacking factories etc the bomb load was codenamed "ABNORMAL" and consisted of 14x1,000lb MC or GP bombs.
Yes, Thanks. We know that the thin case "blast bombs" were not totally effective against hard targets like reinforced concrete emplacements and some very heavy industrial machinery. That is Weapons Effect Planning. What I am asking about is the aiming of the HC bombs. There must have been laid-down aiming regulations for all these different loads and I am interested in that. Also, when referring to bombing TI's, that is similar to visual aiming. There must have been strict targeting instructions. Beyond that, I am pretty certain that A&AEE will have done loads of work on this. Must be someones specialist subject?The Lancaster Archive details a fair number of the bomb loads carried by that aircraft. Note how each was designed to deal with a particular type of target.
You will note that for attacking factories etc the bomb load was codenamed "ABNORMAL" and consisted of 14x1,000lb MC or GP bombs.
4,000lb Cookies were used in conjunction with loads containing a lot of incendiaries. IIRC the RAF found that using a Cookie with its large blast effect was relatively poor at destroying machinery in a factory. It would often blow a factory building apart but leave the heavy indutrial machinery intact. The rubble would be cleared away, a temporary roof fitted and production could restart. It was very good at opening up residential / office buildings to let incendiaries inside to really cause damage. It was also used in loads designed for the NOBALL V1 sites.
Most of the "High Capacity" bombs had slightly domed front ends and flat sheet steel back ends with flat sheet steel rolled to form a cylinder. These bombs did not make any significant fragments and thus their only effect was "Blast" against soft targets. Their bombing accuracy was abysmal, even from the low altitudes they were mostly used. CEP = 1/2 mile from 10,000'! The higher they went, the more exaggerated the dispersion, IE almost one mile from 15,000'!