I am posting this for author Carl Vincent:
" While going through the photos for the pages in my current Blenheim/Bolingbroke opus which will feature photos of Blenheims with only marginal Canadian connections, I have come across this one. I got the original snapshot more than 40 years ago from the gentleman who was the Engineer Officer of 403 Squadron RCAF for the relevant period. It was taken on or about 13 August 1942 when the unit was detached to Manston in support of the Dieppe operation. It features a Blenheim of 13 Squadron RAF that was involved in smoke laying during the operation. What I am wondering about is the gizmo under the nose which is depicted in the enlargement. Is it some form of smoke laying equipment, a noisemaker or what? I would like to include a little hard information in the caption. "
It just so happens that I have a bit of information on this device. It is a siren. I have this photo taken from Vol.1 No. of PLANES magazine, Summer 1982, page 110.
Chris