Alvis Pelides

The Alvis Pelides was an unflown British air-cooled radial aero engine first developed in 1936. The Pelides Major was a projected but unbuilt development as were the Alcides, Alcides Major and the Maeonides Major, the Alvis aircraft engine range taking their names from Greek mythology.

Design and development
The Pelides was the first aero engine of Alvis design; the company had previously only built the French Gnome-Rhône Mistral Major under license. With the two companies working closely together the 14 cylinder radial layout of this engine retained metric dimensions but substituted metric screw threads with British fasteners such as BSF and Whitworth. Material specifications were different as were the detail design of internal parts such as the crankpin. The Pelides passed a 50-hour Air Ministry type test in 1937 where it produced 1,065 hp (794 kW) but no aircraft application was found and only 15 engines were built. The onset of the Second World War caused the abandonment of any further development of the Pelides and its related designs.

Variants (projected)

 * Pelides: 1000 / 2-row 14-cylinder radial, 5.75 x (bore x stroke), 38.67 L, LH or RH, d/d, 13:19 or 0.5:1.
 * Pelides Major:The Pelides Major was a version retaining the same dimensions as the Pelides but with improvements to the supercharger, only built in small quantities for testing at 1000 hp.
 * Alcides:The Alcides of 1937 was a powerful supercharged 18-cylinder two-row radial engine, with a power output of 1650 /. 2-row 18-cylinder radial, 5.75 x (bore x stroke), 54.24 L, LH or RH, d/d, 13:19 or 0.5:1.
 * Alcides Major:The Alcides Major was an improved supercharged version of the Alcides.
 * Maeonides Major:Also designed in 1937, the supercharged Maeonides Major was effectively a smaller version of the Pelides with a power output of 680 hp. 2-row 14-cylinder radial, 4.803 x (bore x stroke), 18.98 L, LH or RH, 5:7.