Continental XI-1430
| Continental Motors | |
|---|---|
 I-1430-9 in the National Museum of the United States Air Force |
|
| Continental XI-1430 | |
| Production period: | unknown |
| Manufacturer: | Continental Motors |
| Working principle: | Otto |
| Motor design: | hanging V-engine |
| Drilling: | 139.7 mm |
| Hub: | 127 mm |
| Displacement: | 23350 cm 3 |
| Mixture preparation: | |
| Engine charging: | turbocharger |
| Cooling system: | Water cooling |
| Power: | 1000-2100 kW |
| Dimensions: | 733 kg |
| Previous model: | none |
| Successor: | none |
The Continental XI-1430 Hyper Engine (often referred to as IV-1430) was a water-cooled aircraft engine that was developed in the United States in cooperation with the US Army Air Corps and Continental Motors . Officially, the engine was the result of the "Hyper Engine" project that began in 1932. The "Hyper Engine" was never built in large numbers because it was not superior to any of the available engines. In 1939, the I-1430-3 was selected to drive the Curtiss XP-55 , an unusual fighter for the time in a pusher configuration , but which never went into production.
development
In the late 1920s, Harry Ricardo wrote a paper on the construction of sleeve valves that inspired the US Army Air Corps to develop the Hyper Engine. Ricardo claimed it was impossible with a poppet valve engine a performance of a PS per cubic inch displacement to achieve. The USAAC engineering team at Wright Field decided to refute this claim. The I-1430 was the result of an attempt to build a high performance cylinder with conventional poppet valves. The engineers, led by Sam Heron, used various techniques to increase the maximum speed. This was the key to increasing performance without increasing displacement.
USAAC wanted to construct very large bombers and needed engines sunk into the wings to improve aerodynamics . Based on this requirement, the engineers developed a twelve-cylinder boxer engine with individual cylinders. Although this type of construction with cylinders separated from each other and from the crankcase are arranged in the water-cooled six-cylinder in-line engines of central powers during the First World War - such as the Mercedes D III - and in use the Liberty L-12 of Allied was very successful, it has already been replaced by monoblock engines with an engine block that united the cylinder and crankcase, as this allowed more stable designs with higher performance.
The USAAC planned an engine with a displacement of around twenty liters in the hope that a smaller engine would reduce drag and thus increase the range. In 1932, USAAC efforts led the US Army to sign a contract with Continental Motors to develop the engine, with the contract limiting Continental's involvement to construction and testing, which left development and design to the US Army .
The "Hyper No. 1 “a second cylinder was added to evaluate a twelve-cylinder boxer engine. After test runs of this machine with various combinations of bore and stroke , it turned out that the high coolant temperatures required to maintain high performance were not practical. Another high-performance single-cylinder engine with lower operating parameters was then designed. This single cylinder engine was named "Hyper No. 2 "and used as a test engine for developing the cylinders for the later Continental O-1430 -" O "stands for" opposed "(boxer). Development took ten years during which the design was changed from a standing V-12 to a hanging V-12 before the engine was reliable enough to go into production as the Continental I-1430 in 1943.
During the long development period, interest in the concept of the motor that could be integrated into the wing began to wane. Improvements in the aerodynamics of conventional engines, especially by means of the NACA canopy , eliminated the need for a retractable engine to increase efficiency. In addition, the beginning of production of bomber designs such as the B-17 , which were powered by radial engines, made the need for new bomber designs less urgent and the US Army turned its attention to new fighter machines . For this application, however, the O-1430 was not useful and Continental changed the design to the V-12 engine I-1430.
construction
The I-1430 has cylinders with hemispherical combustion chambers and - like the Junkers Jumo 211 from 1936 - two exhaust valves , the I-1430 being equipped with sodium-filled exhaust valves. Although the separate cylinders were retained, the change in design to a V design allowed the individual cylinder heads to be manufactured from a single cast . Mounting a Y-shaped sheet metal to cover the camshaft drive at each end improved the rigidity. Continental built the first I-1430 engine in 1938 and carried out the first successful test run in 1939. With an output of at least 1,300 hp (956 kW ) from a displacement of 23 liters, the engine was very competitive in its time. The Rolls-Royce Merlin offered at the same time developed around 1,000 hp (735 kW) with a displacement of 27 liters. The Daimler-Benz DB 601 - competitor of the Junkers Jumo 211 with a displacement of 35 liters - produced a little more with 1,100 hp (809 kW), but was considerably larger with a displacement of 33 liters. Around 19,000 different versions of this engine were sold.
While the engine had an exceptionally high output for its cubic capacity, its weight was probably one reason why it did not go into series production. Both the Rolls-Royce Merlin V-1650 and the Allison V-1710 , both of which produced similar performances, were mass-produced. However, both engines had a better power-to-weight ratio . The V-1710 was 385 lb (175 kg) lighter than the I-1430 with a power to weight ratio of 1.05 at 1,395 lb (633 kg ). The Merlin V-1650 weighed 1,640 lb (744 kg) 25 lb (11 kg) more than the smaller and untested Continental engine, but had about the same power-to-weight ratio. So it didn't seem like the XI-1430 was the solution to any significant problem. It was not until 1943 that the IV-1430 with 1,600 PS (1,177 kW) was extensively tested in the Lockheed XP-49 , a modified version of the P-38 Lightning . It should also be tested in the Bell XP-76 , which was never built in series. In 1944 the engine was also tested in the McDonnell XP-67 .
By then, interest in the engine had declined significantly, as piston engines with the same or higher power were readily available. The Merlin, for example, had been greatly improved and developed at least 1,500 hp (1,103 kW). Furthermore, the US military and aircraft manufacturers are already concentrating on turbine engines .
Only 23 units of the I-1430 were delivered and later renamed the XI-1430 to mark purely experimental use.
The XH-2860 - an H-engine with 24 cylinders - was developed on the basis of the XI-1430, but probably never built.
Web links
Individual evidence
- ↑ a b c d e Gerald Balzer: Secret American Pusher Engine Fighters of World War II . Specialty Press, Minnesota, USA 2008, ISBN 978-1-58007-125-3 , pp. 28 (English).
- ^ A b c d Graham White: Allied Aircraft Piston Engines of World War II . Society of Automotive Engineers, Inc, 1995, pp. 375-378 (English).
- ↑ Gerald Balzer: Secret American Pusher Engine Fighters of World War II . Specialty Press, Minnesota, USA 2008, ISBN 978-1-58007-125-3 , pp. 27 (English).
- ↑ Robert J. Neal: Packard as an Aero Engine Builder - Spark-Ignition Engines: 1923-1939 . In: Torque Meter . tape 7 , no. 3 , 2008, p. 36 (English).
- ↑ I-1430 fact sheet. National Museum of the USAF.
