Starting with Frame5 which is the Spitfires engine firewall assembly and wing front attachment point.The lower assembly is made up of a front and rear web,spaced out with aluminium spacers and C section brackets.On the front and back are the wing main spar attach spars.There are two upper and two lower spars.
Up the top is the engine firewall which is a sandwich of two thin sheets of .022" aluminium and a 3mm sheet of asbestos or fireproof board..Mounted to the firewall are the various parts and brackets like the hydraulic tank,filters and other fittings for the Merlin.
