The last ace to fly a Messerschmitt variant was Rudolf Augarten, a Jewish American who had scored his first two victories–both Me-109s–in World War II while flying P-47Ds with the 406th Fighter Squadron. Augarten was flying S-199 serial No. D-121 (Czech built Bf-109s renamed Sakin operated by the nascent Israeli Airforce) when he downed an REAF (Egyptian) Spitfire on October 16, on the same day that Modi Allon, the most successful Sakin pilot, fatally crashed near Hertzeliya. Rudy Augarten later downed three more Egyptian aircraft while flying Spitfires and P-51Ds.”
Climb Rate – Nothing climbs like a K, which makes it the plane of choice for many dedicated Boom and Zoom pilots.
Firepower – The single 30mm cannon is enough to do serious damage to any aircraft it hits.
Maneuvering – Further increases in the weight of the series reduced its maneuvering ability, although the additional power of the 605DCM engine makes it more survivable than the Gustav.
Ammo Load – The 60 rounds of 30mm get expended far too quickly to allow the plane to be used against numerous targets.
Durability – The 109 was a small plane and not capable of absorbing much combat damage.
By 1944 the Gustav had become both slow and heavy, which combined with poor pilot training to create ever higher fighter losses. Additionally, the dispersal of the German aircraft industry caused by the American daylight raids had resulted in a sort of chaos in 109 production that was impacting aircraft availability. This chaos also meant that different versions of the same production series began to appear in service, complicating maintenance.
The K series was an attempt to incorporate all the various improvements found in the G-14 and G-10 versions, as well as a few improvements of its own. Coming from the G-10 was the 2,000 hp DB-605DCM, which was a modification of the DB-605AS utilizing a larger supercharger.
Also standard were the high-visibility Erla Haube canopy (also known as the “Galland” hood), the taller wooden tail and retractable tail wheel. The 30mm Mk-108 had been tried in various versions of the Gustav, including the G-6. But problems with jamming prevented its widespread use. However with these problems finally fixed, it replaced the 20mm MG-151 as the standard engine cannon. Equipped with 60 rounds, its hit was devastating and finally gave the 109 bomber-killing power without the use of Rüstätz kits.
Only about 700 K-4s were produced, but it served with a number of different units, including JG 2, JG 3, JG 27, JG 51, JG 52, JG 53 and JG 77.