USAAF P-47 Aircraft Flight Operation Cards

Aircrew flight operation/cruising guide cards for the USAAF P-47 N 1 to 25 (Republic 'Thunderbolt') aircraft.  Information based on T.O. 01-65BD-1.  Set of 4 plastic cards approximately 14 x 8cm. These appear to have information about the aircraft's engines pertaining to different scenarios such as the loading weight of the aircraft with wing tanks, belly tanks, external bombs and/or rocket projectiles etc.  They have information on RPM limits, climb data, maximum range and so on,  Probably carried on the aircraft to be used as an aide-memoire.  The cards are in excellent condition and come in the original paper envelope.  Stock code P20308.