Bell profiles

[Bill and Margaret Hibbert]

Is there anyone out there attempting to measure the shapes of bells. The
only written reference to this I am aware of is Elphick's trapeziums (see
Craft of the Bellfounder). I have recently taken measurements of two peals -
Towcester and Imperial College - and I have uploaded plots of the trapeziums
to the photos page. Unlike Elphick, as well as mouth radius, shoulder radius
and shoulder height I have also tried to estimate crown height, though I am
not yet happy with the way I do this. All the plots are normalised to unit
radius at the lip.

The plot of Towcester shows that all twelve bells are remarkably similar in
shape, despite the front four being almost a century newer. On the other
hand, the two trebles at Imperial are much taller than the back eight, which
is obvious as soon as you look at them in the tower.

I'm doing this, of course, as a precursor to investigating how profile
affects sound and in particular partial intensity. Before doing this it
would be interesting to know if anyone else is taking similar measurements.

By the way, if anyone doubts what enormous differences can be found in bell
profiles and sizes, I suggest they look at the picture of the 'Gilletts'
peal at Bow on Dickon Love's London bells website - especially the back five
(three Gilletts, two Lester and Pack).

Bill H