The gun pac was updated to four 20mm with 120 rounds per gun. You can tell by the placement of the guns as seen from the front.
:: is 60 rounds per gun, .... is 120 rounds per gun.
At speeds over 360mph, "manoeuvrability as superior to both a Spitfire 1 or Hurricane".
At low alts (under 10,000 feet) faster than Spit 1.
With 100 octane fuel rather than 87 speed was expected to be 422.
ALL Whirlwinds except the first ptototype were used by combat units.
Not Bad for 1940.
