vickers vimy/alcock and brown question

Hi All, when Alcock and Brown took off from St. John's, Newfoundland in
1919 for the first non-stop transatlantic flight they used my
great-grandfathers farm field (Agustus Lester) in St. John's. He picked
up a piece of the original vimy from the field and it has been in our
family ever since. I'm not 100% sure where the piece belongs on the
vimy or if the piece has any historical significance, but I do have
this illustration of the piece and a similar piece on model vimy...any
information or help would be appreciated.

Illustration: http://www.nfinteractive.com/vimy.jpg