Mercedes D.II

The Mercedes D.II was a six-cylinder, SOHC valvetrain liquid-cooled inline aircraft engine built by Daimler during the early stages of World War I. Producing about 110 to 120 hp, it was at the low-end of the power range of contemporary engines, and was generally outperformed by rotaries whose power-to-weight ratio tended to be much better. It also had stiff competition from the Ferdinand Porsche-designed 120 hp Austro-Daimler 6. The D.II was produced only briefly as a result, but its design formed the basis for the later Mercedes D.III which saw widespread use throughout the war.

Design and development

The D.II was based on the Austro-Daimler to a large degree. Like the Austro-Daimler, it was built up from the crankcase, which was milled from two pieces of cast aluminum bolted together at their midline. The cylinders were separately milled from steel and bolted to the top of the crankcase. Steel sleeves were fitted over the cylinders and welded on to form a cooling jacket. Much of this complexity is due to the differential rates of expansion of steel and aluminum, which precluded screwing the cylinders into the crankcase, and the alloys of the era meant that an aluminum cylinder was not possible. Both engines also used a scavenger pump to pump oil out of the crankcase to a separate cylinder, where a second high-pressure pump supplied oil to the engine. This arrangement allowed for a much smaller "sump" on the bottom of the crankcase, reducing the overall size of the engine, although in the case of the D.II it was not nearly as much as the Austro-Daimler.

3-D Thunder Ceptor II

3-D Thunder Ceptor II (3-DサンダーセプターII, Surī-Dī Sandā Seputā Tsū) (or just Thunder Ceptor II) is a 3D shooter arcade game, which was released by Namco in 1986. As the name suggests, it is their sequel to Thunder Ceptor (which was released earlier in the year) and it runs upon the same dedicated hardware, meaning it equaled its predecessor (which had usurped Libble Rabble and Toy Pop) as Namco's most powerful 8-bit game.

Gameplay

For a second time, the player has to take up control of the Thunder Ceptor (which has undergone a colour change); there are also two more commands in this sequel than there were in the original game, and two different types of powerups have been introduced. The colour of the enemies has been changed from gray to green, and most of the older ones have been renamed - several new ones have also been introduced as well, and the obstacles (there are also three new types of them as well here) can now be killed by firing a bomb at them (which means the player will no longer have to fly into them all to remove them from the game at the expense of having the Thunder Ceptor's power decrease by one once it is resurrected). This was also the only game with 3D glasses support that Namco released during their time in the arcades.

D2

D2, D02, D.II, D II or D-2 may refer to:

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Douglas D-558-2 Skyrocket

The Douglas D-558-2 Skyrocket (or D-558-II) was a rocket and jet-powered supersonic research aircraft built by the Douglas Aircraft Company for the United States Navy. On 20 November 1953, shortly before the 50th anniversary of powered flight, Scott Crossfield piloted the Skyrocket to Mach 2, or more than 1,290 mph (2076 km/h), the first time an aircraft had exceeded twice the speed of sound.

Design and development

The "-2" in the aircraft's designation referred to the fact that the Skyrocket was the phase-two version of what had originally been conceived as a three-phase program. The phase-one aircraft, the D-558-1, was jet powered and had straight wings. The third phase, which never came to fruition, would have involved constructing a mock-up of a combat type aircraft embodying the results from the testing of the phase one and two aircraft. The eventual D-558-3 design, which was never built, was for a hypersonic aircraft similar to the North American X-15.

When it became obvious that the D558-1 fuselage could not be modified to accommodate both rocket and jet power, the D558-2 was conceived as an entirely different aircraft. A contract change order was issued on 27 January 1947 to formally drop the final three D558-1 aircraft and substitute three new D558-2 aircraft instead.