Daimler-Benz DB 602 (LOF-6) V-16 Diesel Airship Engine

By William Pearce

Around 1930, Daimler-Benz* developed the F-2 engine, initially intended for aviation use. The F-2 was a 60 degree, supercharged, V-12 engine with individual cylinders and overhead camshafts. The engine had a 6.50 in (165 mm) bore and an 8.27 in (210 mm) stroke. The F-2’s total displacement was 3,288 cu in (53.88 L), and it had a compression ratio of 6.0 to 1. The engine produced 800 hp (597 kW) at 1,500 rpm and 1,000 hp (746 kW) at 1,700 rpm. The engine was available with either direct drive or a .51 gear reduction, and weighed around 1,725 lb (782 kg). It is unlikely that the Daimler-Benz F-2 powered any aircraft, but it was used in a few speed boats.

The rest of the story: Daimler-Benz DB 602 (LOF-6) V-16 Diesel Airship Engine

The last Peashooters

Not all WWII fighter planes remained in use after WWII, and even fewer pre-WWII designs. One surprising exception was the 1930s-vintage P-26 Peashooter which was still in use in Guatemala as late as 1957.

The Peashooter was developed from Boeing’s private Model 266 design. It arrived at a unique time in military aviation history; an unusual and brief period where bomber development was outstripping that of fighters. For example, the B-10, which equipped three US Army squadrons in the mid-1930s, was an all-metal, enclosed-cockpit, retractable-undercarriage  monoplane bomber with a top speed of 180 kts. This compared to the wooden P-6 Hawk biplane fighter that flew alongside it, which topped out at 168 kts and likewise the P-12 mixed metal/wood biplane with a maximum speed of 165 kts.


(The B-10 bomber.)


(The P-26 Peashooter’s predecessors, the P-12 and P-6 Hawk fighters.)

The US Army Air Corps reasoned that bombers of other countries would progress on a similar scale, so clearly it was unacceptable to have fighters inferior to the bombers they were supposed to shoot down.

The Peashooter was the US Army Air Corps first all-metal fighter, the first with landing flaps, and the first with a low-mounted wing. It was the first monoplane fighter to achieve squadron-level service in the US Army and the first with a 200 kts+ combat speed.

At the same time, the Peashooter was the last US Army fighter with an open cockpit, the last with externally-braced wings, and the last with fixed landing gear.


(US Army Air Corps P-26 just before WWII, still with the 1918-style roundel. The red dot in the star was deleted in May 1942 as it was being mistaken for the Japanese rising sun. The current American “star & bars” insignia was introduced in September 1943.)

In some ways, the Peashooter was a step backwards. Other designs already had retractable landing gear and enclosed cockpits, and internal wing spars had already been developed to replace external struts and wires. The obsolescent features were mainly chosen for cost, as they would allow Boeing to quickly build and sell planes within the US Army’s Depression-era budget. The cost-cutting was successful, and each Peashooter was actually about $210 cheaper than the obsolete biplanes they replaced.

The P-26 was 23’7″ long with a 28′ wingspan. It was powered by a Pratt & Whitney R-1340-27 Wasp air-cooled piston engine. The plane weighed 2,196 lbs empty. The Peashooter had a top speed of 203 kts, which was roughly 20% faster than the fighters it replaced.

The odd name came from the tubular reticle-type gunsight in front of the cockpit. When the P-26 debuted, the general public was still used to seeing cockpit-seated guns in the World War One style, and wondered why this new fighter was armed with such a dinky little peashooter. (The actual armament was two belt-fed M1919 .30cal machine guns inside the fuselage, firing through the propeller area via interrupter gears.) US Army pilots were apparently amused enough that the name stuck and became semi-official.

Head over to wwiiafterwwii for the rest (and some really neat Peashooter pics!): The last Peashooters

Supermarine Walrus


A Supermarine Walrus in testing, circa 1938. They were carried by most British battleships and cruisers during the Second World War, providing an independent reconnaissance asset. Ungainly as they were these things were actually the first British aircraft to enter service with a fully retractable main undercarriage, completely enclosed crew accommodation and an all-metal fuselage.

via apostlesofmercy