57 Squadron Avro Lancaster with the “Usual” area bombing load of a 4,000lb bomb and 12 Small Bomb Containers, each filled with 4lb incendiary bombs.
4,000 lb bomb being loaded onto de Havilland Mosquito.
A blockbuster bomb or cookie was any of several of the largest conventional bombs used in World War II by the Royal Air Force (RAF). The term blockbuster was originally a name coined by the press and referred to a bomb which had enough explosive power to destroy an entire street or large building through the effects of blast in conjunction with incendiary bombs.
An important feature of the Lancaster was its large 33 ft (10.05 m) long bomb bay. Initially, the heaviest bomb carried was the 4000 lb (1814 kg) high capacity (HC) ‘Cookie’. Bulged doors were added to 30% of the Lancaster force to allow the aircraft to carry 8000 lb (3628 kg) and later 12,000 lb (5443 kg) ‘Cookies’.
The first type of aircraft to carry bombs operationally was the Wellington, but they later became part of the standard bomb load of the RAF’s heavy night bombers, as well as that of the Mosquitoes of the Light Night Strike Force, whose aircraft would sometimes visit Berlin twice in one night carrying bombs, flown by two different crews. The 8,000 lb (3,600 kg) and the 12,000 lb (5,400 kg) could be carried only by the Avro Lancaster which needed to be slightly modified with bulged bomb-bay doors.
The first use of the 8,000 lb was by 15 Squadron Lancasters against Berlin on 2 December 1943. Bad weather and other factors meant their effectiveness was not noted.
The 4,000 pounds (1,800 kg) “cookie” was regarded as a particularly dangerous load to carry. Due to the airflow over the detonating pistols fitted in the nose, it would often explode even if dropped, i.e., jettisoned, in a supposedly “safe” unarmed state. The Safety height above ground for dropping the 4,000 lb “cookie” was 6,000 feet (1,800 m); any lower and the dropping aircraft risked being damaged by the explosion’s atmospheric shock wave:
We were flying at 6,000 feet which was the minimum height to drop the 4,000 pounder. We dropped it in the middle of town [Koblenz], which gave the aircraft a hell of a belt, lifted it up and blew an escape hatch from out of the top.
— Jack Murray, pilot of “G for George”, reporting on G for George’s mission on 17th April 1943.
In August 692 Squadron [Mosquitos] at Graveley had a run of bad luck. On the 25th Squadron Leader W.D.W. Bird and Sergeant F.W. Hudson were killed when they crashed at Park Farm, Old Warden near Bedford. It was believed that the pilot misread his altimeter. On 27 August 1944 on a trip to Mannheim Flight Lieutenant T.H. Galloway DFM and Sergeant J. Murrell swung on take-off, caught fire and blew up. The ‘Cookie’ went off, but was not detonated, so it did not cause too much damage. Galloway and Murray got out when the Mosquito caught fire and ran to safety. Over the target Flying Officer S.G.A. Warner and Flying Officer W.K. McGregor RCAF were shot down and killed and the searchlights and flak followed them all the way down. On 10/11 September it was the old Milk Run again to Berlin. Terry Goodwin DFC DFM a 692 Squadron pilot at Graveley flew this operation, his last on the Mosquito and he had a rather anxious time, as he recounts:
After Hugh Hay had finished his tour I had several good navigators with nothing to worry about. However, when my last trip was coming up there was a new navigator posted in. He was a Warrant Officer with no trips in at all. I just could not figure that out when all crews at that time had a tour under their belts and knew what the score was. I took him for a cross-country, which was not satisfactory as he had trouble with the Gee. I did not know whether it was a ‘short’ or a ‘long’ trip: either the Ruhr or Berlin. It turned out to be the ‘big city’.
The night was clear. The take-off with the 4,000lb ‘Cookie’ was good. The aircraft was singing right along with all gauges OK. The track was out over the North Sea towards Denmark then a sharp turn right south-east to a point just west of Berlin then straight east for the bombing run. When we were approaching this turning point it was clear with no moon. I could see the coast outline right from Denmark south. The tram trolleys of Hamburg were still making their blue sparks and then shut down fully. Then the sprog navigator said to me, “I don’t know where we are!” I told him to get the course from the turning point and I would tell him when to start all over again. He did and got us just west of Berlin on time or at least I thought we were on time. I told him to log the time, then go and dump the Window down the chute. There was no action outside as we ran up looking for the ‘TIs’. Jerry was playing it very careful giving nothing away. Where was that PFF type? The TIs should be going down! Then all hell broke loose. Every searchlight in the city came on right on us and the flak was too damn close. I turned sharp right and dived 2,000ft, straightened out back on course, held it, turned left and climbed and got more flak but further away. And this kept on and on. Finally the lights were bending east so I thought we should be through the city. I turned back west and still no PFF. I told the navigator to drop the ‘Cookie’ (I don’t think we got a proper picture) because the flak was hard at us again. Then the TIs went down right ahead of us so we were pretty close. But the flak kept on and I twisted and dived and climbed and kept that up. I knew we were down to about 17,000ft when I suddenly saw the light flak opening up. You knew it was pretty if it was not so damn serious. I turned and climbed out on the west side of Berlin. I told the navigator to log the time. We had been in it for 11 minutes with Jerry’s undivided attention. Were there any fighters? Not that I saw, maybe I was just too busy. It would not have been a safe place for them with all that flak around. We did get home and logged 4 hours and 30 minutes. The next morning the Flight Sergeant found me and then showed me the aircraft. It was full of flak; the main spar of the tail plane was getting an 18-inch splice. He dug a piece of flak out for me. One piece had just nicked the intercooler rad, then the fairing for the main rad. but not the tubes, but was spent as it bounced around the engine.
Berlin at this time was the ‘favourite’ destination for the Mosquitoes. ‘A’ and ‘B’ Flights at 8 (PFF) Group stations were routed to the Big City over towns and cities whose air raid sirens would announce their arrival overhead, although they were not the targets for the Mosquitoes’ bombs. Depriving the Germans of much needed sleep and comfort was a very effective nuisance weapon, while a 4,000pounder nestling in the bomb bay was a more tangible ‘calling card’. The ‘night postmen’ had two rounds: After take-off crews immediately climbed to height, departed Cromer and flew the dog-leg route Heligoland-Bremen-Hamburg. The second route saw departure over Woodbridge and went to The Ruhr-Hannover-Munich. Two Mosquito bombers, which failed to return from the attack on Berlin on 13/14 September, were claimed shot down south-east of the capital by Oberfeldwebel Egbert Jaacks of I./NJG10 and at Braunschweig by Leutnant Karl Mitterdorfer of 10./JG300.
The ever-increasing Mosquito strength was put to good effect on 1/2 February, 1945 when 176 Mosquito sorties were flown on eight separate targets. Ludwigshafen, Mainz, Siegen, Bruckhausen, Hannover, Nuremburg and Berlin were all hit; the latter involving 122 Mosquitoes. Berlin would suffer mercilessly at the hands of the LNSF during the final months of the war and, from 20/21 February, the capital was attacked on 36 consecutive nights. Averaging 60 Mosquitoes per raid, 2,538 sorties were flown to Berlin, of which 2,409 were successful. Some 855 cookies were dropped on the city during this period alone and the LNSF continued to bomb Berlin right up to the arrival of the Russian forces in late April 1945.
4000 lb HC bomb
Mark I: first production design
Mark II: three nose pistols
Mark III: no side pistol pockets
Mark IV: no stiffening beam
Mark V: U.S. production
Mark VI: U.S. production
Filling was Amatol, RDX/TNT, Minol, or Torpex. In 1943, 25,000 of these were used; this rose to 38,000 in 1944. In 1945 up to the end of the war a further 25,000 were used.
8,000 lb HC
Filling was Amatex or Torpex. Bombs were produced from 1942 to 1945.
12,000 lb HC
Filling was Amatex or Torpex. 170 were used in the last two years of the war.