'Air Board Technical Notes issued by Controller - Technical Department'. P/b. 14 x 20cm., November 1917 and January 1918 print dates. Looseleaf with pages inserted/bound with brass split pins. Note on the front cover states that information within is not to be communicated to any person not holding an official position within His Majesty's Service. This book covers engines and has sections on the 90 HP RAF 1.A, 120 HP Beardmore, 80 HP Gnome, 80 HP Le Rhone, 200 HP RAF 3.A, 240 HP Hawker Siddeley Puma and 110 HP Clerget engines. There are lots of excellent photographs, diagrams and text information. The cover, illustrated with Royal Naval Air Service and Royal Flying Corps badges, is heavily creased and worn with edge tears. The inner pages are a little yellowed and some are annotated. Named to owner on cover. A super period document. Stock code P22802.