[Matti Salonen]

Martin, Stig and others,

This is getting interesting. British aircraft are outside my limited expertise and Pentti would like to discuss this topic by himself, but unfortunately he is unable to register (when trying it he gets the message "Sorry, registration has been disabled by the administrator").
I'll try to explain our thoughts.
Bristol engines had in fact two serial numbers: Bristol number and Air Ministry number, which were successively arranged in the same row in the manufacturing plate. Bristol number was on the left and Air Ministry number on the right (example S.3147 A130021). In Finland we used always the OEM serial numbers, in this case Bristol number. The British Air Ministry numbering system had no importance in Finland and was not used. In Bristol number the letter “S.” means Shadow factory, but we don’t know its location.
So, when speaking about engine numbers we should know the correspondence between both numbers and the logic, how numbering system worked between the industry and Government.
Based on the data in F.78 for L9026 it seems plausible that BL-123 (possibly) was L9026, but to us the engine data is still obscure and we would like to improve our knowledge base. Bristol piston engine experts, please, open your information chests.

Matti