The Curtiss D-12 (military also Curtiss V -1150 ) is a water -cooled V-12 aircraft engine of the U.S. manufacturer Curtiss Aeroplane and Motor Company Incorporated.
The cylinder angle is 60 °. Both banks of cylinders are cast in each block, which were bolted to the crankcase top half. , Each cylinder has two intake and two exhaust valves, which are actuated by an overhead camshaft per cylinder bank. The camshafts are driven by bevel. The cylinders of both banks are located directly opposite. The flasks were therefore connected through a main and an auxiliary connecting rod with the seven -bearing crankshaft.
Since the reduction gear of the Curtiss K -12 constantly caused problems, decided Arthur Nutt, omit this. From the K -12 was created as an intermediate step in the Curtiss CD - 12th However, the propeller used so far made of wood required to limit the possible motor speed and therefore a reduction in performance. Sylvanus Albert Reed succeeded in producing a metal propeller, which allowed a higher propeller speed, and so was able to restore the full engine power can be retrieved. The "D " in the name means it direct.
The performance of the first prototype was 316 hp, which has steadily increased in volume production. The motor was in both the CR-1 Curtiss and in Curtiss and Curtiss CR 2 R 6 for use. Besides its use in Curtiss- racing and fighter planes, he was also used in the Boeing PW -9. The first mission took place in 1921 at the Pulitzer Trophy Air Race on Long Iceland, which was won by the Curtiss CR-2. The engine made 400 hp at 2000 rpm while. Curtiss used the unit for record flights. So reached a CR-2 on 13 October 1922, 358.836 km / h setting a new world record, even with a special wooden propeller. The compression was increased to 5.8:1 and the engine so made 450 hp.
For use in the Curtiss R6 engine to 117 mm was drilled and then the Curtiss D -12A was briefly with 460 hp at 2400 rpm with a compression ratio of 5.3:1. With a compression ratio of 6:1 were possible with this engine, 495 hp. Further stages of development for military use were the variants D -12C ( Curtiss V -1150 -1) and D- 12D (V -1150 -3), each with 435 hp continuous duty.
In the UK, the engine as the Fairey Felix was produced under license. As a performance increase with the D -12 was no longer possible, designed Nutt 's successor Curtiss V- 1570th