Originally Posted by
orca
The other section of the fuse would have a timing delay, triggered at release, after which it would need to sense the deceleration of a hit. Drop from too low and weapon hits, then arms, no deceleration, no explosion.
Drop from too low implies insufficient time for the SAFU - Safe Arming and Fusing Unit, ie the vaned cap, to unscrew. That was not the case.
"Sense a deceleration" implies a sophisticated fusing system with possibly a mecury switch. More likely it was an impact pistol but because of the low trajectory had a graze impact which was an insufficiently strong impact to function. I grant you that not impacting would lead to a lack of decelaration so it is a bit of semantics.