Spitfire MK I and Mk Ia, this two type of Spitfire sems to be underestimate climb way. More than 20Min for 10.000 feet is to much. It should be half that time min. Normaly 2500 ft/min or 10.000 ft in 5 min (for the Mk Ia).
And the fuel gauge does not work in this to type of Spitfire.
