Figure 8. The ‘Cork Helmet-Aviation’ or RAF ‘Type-A Flying Helmet’. In 1922 these were given RAF stores reference number 22c/13, but later (~1940) it was renumbered and occupied the stores range 22c/274 to 22c/284 denoting 10 different sizes from 6 ½” to 7 ¾”. All those seen by the author with an Air Ministry acceptance stamp seem to be fitted with ‘Comfortilet’ liners, a registered patent of Charles Owen & Co., London, hence they were probably the manufactures of these official RAF issued helmets.