Allison V-1710

Allison V-1710; Wikipedia.en

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The Allison V-1710 [Vous devez être inscrit et connecté pour voir ce lien] engine was the only indigenous [Vous devez être inscrit et connecté pour voir ce lien]-developed V-12 liquid-cooled engine to see service during [Vous devez être inscrit et connecté pour voir ce lien]. A sturdy and trustworthy design, it unfortunately lacked a two-stage [Vous devez être inscrit et connecté pour voir ce lien].

Versions with a [Vous devez être inscrit et connecté pour voir ce lien] gave excellent performance at high altitude in the twin-engined [Vous devez être inscrit et connecté pour voir ce lien], and turbosuperchargers were fitted to experimental single-engined fighters with similar results.

The preference for turbosuperchargers, arguably to the neglect of mechanical supercharger development, reflected [Vous devez être inscrit et connecté pour voir ce lien] philosophy, and not the inherent qualities of the Allison engine.


Design and development


The [Vous devez être inscrit et connecté pour voir ce lien] Division of [Vous devez être inscrit et connecté pour voir ce lien] began developing the [Vous devez être inscrit et connecté pour voir ce lien]-cooled engine in 1929 to meet a [Vous devez être inscrit et connecté pour voir ce lien] need for a modern, 1,000 hp (750 kW), engine to fit into a new generation of streamlined bombers and fighters.

To ease production the new design could be equipped with different propeller gearing systems and superchargers, allowing a single production line to build engines for everything from [Vous devez être inscrit et connecté pour voir ce lien] to [Vous devez être inscrit et connecté pour voir ce lien].

The [Vous devez être inscrit et connecté pour voir ce lien] purchased the first V-1710s, the B model (the only V-1710 that did not have a gear-driven supercharger) in 1931 and installed them on the airships [Vous devez être inscrit et connecté pour voir ce lien] and [Vous devez être inscrit et connecté pour voir ce lien].

The U.S. Army Air Corps purchased its first V-1710 in December 1932.

The [Vous devez être inscrit et connecté pour voir ce lien] slowed development, and it was not until December 14, 1936 that the engine next flew in the [Vous devez être inscrit et connecté pour voir ce lien] testbed.

The V-1710-C6 successfully completed the Army 150 hour Type Test on April 23, 1937 at 1,000 hp (750 kW), the first engine of any type to do so.

The engine was then offered to aircraft manufacturers where it powered the [Vous devez être inscrit et connecté pour voir ce lien].

All entrants in the new pursuit competition were designed around it, powering the [Vous devez être inscrit et connecté pour voir ce lien], [Vous devez être inscrit et connecté pour voir ce lien] and [Vous devez être inscrit et connecté pour voir ce lien].

When war materiel procurement agents from England asked [Vous devez être inscrit et connecté pour voir ce lien] to build the P-40 under license, NAA instead proposed their own improved aircraft design, using the V-1710 in their [Vous devez être inscrit et connecté pour voir ce lien].

Technical description


The V-1710 has 12 cylinders with a bore and stroke of 5.5 by 6 inches (140 by 150 mm) in 60° V-format, aggregating to 1,710.6 cu in (28.032 L) total displacement, with a compression ratio of 6.65:1.

The engine design benefited from the General Motors philosophy to build-in production and installation versatility.

The engine was constructed around a basic power section from which different installation requirements could be met by fitting the appropriate Accessories Section at the rear and a tailored reduction gear for power output at the front.

This approach allowed easy changes of the supercharger(s) and supercharger drive-gear ratio.

That gave different critical altitude ratings ranging from 8,000 to 26,000 feet (2,400 to 7,900 m).

It allowed a variety of propeller drives and also remote placement of the reduction gear.

The P-39, P-63, and XB-42 installations used V-1710-E series engines that exchanged the integral reduction gear for an extension shaft that drove a remotely located reduction gear and propeller.

Aircraft such as the P-38, P-40, P-51A, and P-82 used close-coupled propeller reduction gears, a feature of the V-1710-F series.

Another feature of the V-1710 design was its ability to turn the output shaft either clockwise or counter-clockwise by assembling the engine with the crankshaft turned end-for-end, by installing an idler gear in the drive train to the supercharger and accessories and by installing a starter turning the proper direction.

So, there was no need to re-arrange the ignition wiring and firing order, nor the oil and Glycol circuits to accommodate the direction of rotation.