Engineering:Engine gun

French Hispano-Suiza 12Y aircraft engine (cylinders removed) with Hispano-Suiza HS.404 engine gun mounted

Luftwaffe soldier inspects the engine gun alignment of a Bf 109 fighter aircraft

Firing channel on a Daimler-Benz DB 605 for an engine gun.

An engine gun, or engine cannon (from German: Motorkanone, "motor cannon"), is an aircraft gun mounted behind and through the cylinder block of an inline aircraft engine (most often a V engine) with a reduction drive that displaces the propeller axle to be in line with the gun so that gunfire is allowed through the propeller hub. This allows for nose-mounted weaponry on aircraft without the need for synchronization gear while also permitting higher calibers for nose-mounted weaponry, which otherwise would be hard to adapt for synchronization gear.

The first time this was done was during World War I when the French modified the Hispano-Suiza 8 engine to be able to install a 37 mm autocannon. The concept was used widely before the Jet Age.

Historical engine guns

Finnish guns

• 12.7 mm VKT 12,70 LKk/42 (single use on a Morane-Saulnier MS.406)

French guns

• 7.5 mm MAC 1934
• 20 mm Hispano-Suiza HS.404
• 37 mm SAMC (Semi Automatique Moteur Canon)

German guns

• 7.9 mm MG 17 machine gun
• 20 mm MG 151 cannon
• 30 mm MK 103 cannon
• 30 mm MK 108 cannon

Soviet guns

• 12.7 mm Berezin UB
• 20 mm Berezin B-20
• 20 mm ShVAK cannon
• 23 mm Nudelman-Suranov NS-23
• 37 mm Nudelman-Suranov NS-37
• 37 mm Nudelman N-37
• 45 mm Nudelman-Suranov NS-45

Swiss guns

• 20 mm Oerlikon FF

Engine gun installations

A geared-output shaft HS 8C engine for a SPAD S.XII WWI aircraft, showing the elevated intake manifold to clear the 37 mm cannon (shown to the right) mounted in the "V" between the cylinder banks.

French engines

• Hispano-Suiza 8 (various models)
• Hispano-Suiza 12Y

German engines

• Daimler-Benz DB 603
• Daimler-Benz DB 605

Soviet engines

• Klimov M-105
• Klimov VK-106
• Klimov VK-107

Swiss engines

• Saurer YS-2
• Saurer YS-3

Aircraft with engine guns

Czechoslovak aircraft

Czechoslovak Avia Bk-534, a biplane with a 20 mm engine gun

• Avia Bk-534
• Avia B-135

Finnish aircraft

• Mörkö Morane

French aircraft

French SPAD S.XII, a World War I aircraft with a 37 mm engine gun

• Dewoitine D.500
• Dewoitine D.520
• Loire-Nieuport LN.401
• Morane-Saulnier M.S.405
• Morane-Saulnier M.S.406
• Morane-Saulnier M.S.410
• Morane-Saulnier M.S.411
• Morane-Saulnier M.S.412
• Morane-Saulnier M.S.450
• SPAD S.XII

German aircraft

• Blohm & Voss BV 155
• Dornier Do 335
• Heinkel He 100
• Heinkel He 112 ("kanonenvogel")
• Messerschmitt Bf 109
• Focke-Wulf Fw 190 (D-12, D-13 Variants)
• Focke-Wulf Ta 152

Italian aircraft

Fiat G.55 Centauro with engine gun (MG 151/20)

• Fiat G.55 Centauro
• Fiat G.56
• Macchi C.205 Veltro
• Reggiane Re.2005 Sagittario
• Savoia-Marchetti SM.92

Soviet aircraft

Yakovlev Yak-9K with the 45 mm Nudelman-Suranov NS-45 engine gun mounted

• Lavochkin-Gorbunov-Gudkov LaGG-3
• Yakovlev Yak-1
• Yakovlev Yak-3
• Yakovlev Yak-7
• Yakovlev Yak-9

Swedish aircraft

• SAAB 23

Swiss aircraft

Swiss EKW C-3604, an attacker with a 20 mm engine gun

• C-35
• C-3603
• C-3604
• D-3800
• D-3801
• D-3802
• D-3803

Yugoslavian aircraft

• Ikarus S-49
• Rogožarski IK-3