MESSERSCHMITT DBU, BF110 DROP TANK FUEL CAP

One of the biggest challenges for the Luftwaffe in the lead up to and during the Battle of Britain was that Germany’s primary escort fighter, the BF 109 had small fuel tanks resulting in an extremely limited operational range. The Bf 109 had barely minutes over the target area before it had to head for home, leaving the bomber fleet at the mercy of the RAF’s Spitfires and Hurricanes.

Unfortunately for the Luftwaffe, it was not until late October 1940 that the modified Bf 109 E-7 entered service with the capacity to carry one or two 300 lt Fuel Drop Tanks.

This led to the twin-engined Messerschmitt Bf110 being forced to provide the bulk of bomber protection but this also made the high speed fighter/bomber equably vulnerable to British fighters due to it having to reduce speeds to maintain cover for the lumbering Luftwaffe bombers. 

The Luftwaffe had actually introduced the use of Drop Tanks much earlier on the JU87R (a long range version of the Stuka Dive Bomber) and the twin-engined Bf110 which were used to good effect during the German invasion of Norway but the capacity to carry the 300lt light aluminium alloy or thin zinc steel Drop Tanks for their Messerschmitt Bf 109 and later Focke Wulf Fw190s took a while to come into play.

Whilst the Ju87 could carry two 300lt tanks (one under each wing), the more powerful Messerschmitt Bf110 had the capacity to also carry the 600lt and even heavier 900lt fuel drop tanks.

Manufactured by the German Deutsche Benzin-Uhrin (DBU Works), the central Cap cast markings read 'KRASTSTOFF' or 'FUEL'.

Made from an Electron magnesium, the DBU works produced four types of Fuel Caps, vented, unvented and two generic unvented versions, but used the same casting for each of the non-generic versions as indicated by the common part number 8-4520A cast into the reverse of the small attachment screw arm. 

One of DBU's 'Generic’ Drop Tank Fuel Caps was known as the R series which did not carry the large DBU markings but rather, serial numbers on the upper sides of both locking arms.

Primary aircraft fuel tanks on the Bf109, Focke-Wulf Fw190 and the Bf 110 required a ventilated fuel cap, so five small holes were drilled into the middle of the casting and a small spring loaded padded washer pressed into the recessed housing beneath. 

Even though labeled as ‘ventilated’, fuel caps without the hole and valve modification had no ventilation and were installed at the top of the 300lt aluminium drop tanks carried by the Bf109, Focke-Wulf Fw190, Ju87 and Bf 110. The same was true for the larger 600 and 900lt drop tanks carried by the Bf 110.

Secured by two 8mm studs which were screwed down over the cap’s arm cutouts, drop tanks required air pressurisation to transfer the fuel up into the aircraft system and so, they featured the 'sealed' cap version as seen here. 

Electron magnesium was subject to sever pitting and corrosion over time and this WWII veteran is a prime example of that although it still retains its internal synthetic inner cap seal.

Mounted on its 100 yr old Mango Wood stand with a highly detailed hand crafted and airbrushed model of the iconic German twin-engined fighter/bomber - the Messerschmitt Bf110 and informative Fact Sheet, this would make an extraordinary and highly valued, original memento of Luftwaffe air power for any aviation enthusiast.

This Messerschmitt BF 110 Collectable comes complete with detailed Scale Model, Mango Wood Stand & Plaque plus Printed Fact Sheet featuring photo of instrument in aircraft cockpit.

Return to Messerschmitt Bf 110 MAIN PAGE