"the noise of its fall would be heard after that of the explosion."
First there was Tallboy, then there was Grand Slam.
Unconventional bombs, used by the British in World War Two [WW2]. Unconventional bombs, used in an unconventional manner, producing results that could be not obtained by other methods. Differed from your average-ordinary-everyday aerial bomb in that:
* "Impact close to the target" but not necessarily hitting directly.
* NOT necessarily destroying the target in the conventional sense of the term as generally understood. Often rendering the target unusable or ineffective, or creating enough damage that repair was economically unacceptable.
One plane - - dropping one bomb - - hitting with enough precision to "destroy" targets that prior had been the objective by multiple raids by hundreds of massed bomber aircraft, dropping literally thousands of bombs, results often being meagre at best!! One plane - - one bomb- - able to achieve in an instant what much more massive forces could NOT!!
"The Tallboy was an earth quake bomb . . . brought into operation by the British in 1944. It weighed five tons and . . . was effective against hardened structures"
"It was ballistically perfect and in consequence had a very high terminal velocity, variously estimated at . . . about 2,500 mph / 4,000 km/h . . . the noise of its fall would be heard after that of the explosion."
"The Grand Slam was a 10,000 kg ( 22,000 lb ) earthquake bomb used by RAF Bomber Command against strategic targets during the Second World War."
"It [Grand Slam] was a scaled up version of the Tallboy bomb"
"the Grand Slam would reach near sonic speed approaching 320 m/s, and penetrate deep underground, with the explosion causing a camouflet (cavern) and shifting the ground to undermine a target's foundation."
Bombs, shaped and designed to resemble an airfoil, aerodynamic fins creating a stabilizing spin for accuracy, dropped from high-altitude, hand-built, expensive, not expendable "items", giving results against "hardened" targets of great importance to the Nazi war machine. The destruction of those targets actually influencing the course of the war to a desirable end for the allied forces.
"The bomb [Tallboy/Grand Slam] was designed to impact close to the target, slide into the soil or rock on which the target was built, and then detonate, transferring all of its energy into the structure, or creating a camouflet into which it fell. This 'earthquake' effect caused more damage than even a direct hit which penetrated the armour of a target, since even a burst inside a bunker would only damage the immediate surroundings . . . An earthquake impact, however, shook the whole target, and caused major structural damage to all parts of it, making repair uneconomic."
"ca⋅mou⋅flet - – noun 1. an underground explosion of a bomb or mine that does not break the surface, but leaves an enclosed cavity of gas and smoke. 2. the pocket formed by such an explosion."
The Tallboy/Grand Slam, exploding underground and NEXT to the hardened target, creates a void called a camouflet, the weakened, unsupported and cracked foundation and base of the target collapsing as a result. Target "destroyed" in a manner not possible by any other means!!