What you are looking at is a "COW" gun fitted to I think a Vickers Type 161.
"At the end of the first World War, the Coventry Ordnance Works were producing a 37-mm cannon for aircraft use, known as the 1½ pdr COW gun. This was a fairly large weapon, weighing 95 kg, and firing a 37 × 190 cartridge. It was relatively slow-firing at 100 to 120 rpm, and the muzzle velocity was 580 to 610 m/s. This was a modest performance, similar to that of the 37 mm M4 cannon which armed many P-39 Airacobra and P-63 Kingcobra fighters during WWII."
Source - http://users.skynet.be/Emmanuel.Gustin/history/NoAllowance.htmlThe type 161 single-seat fighter returned to a old formula: It was a pusher biplane with twin tail booms. It was designed to carry the 37mm COW gun, which was fixed in a 45 degrees upward firing position. The 161 was of all-metal contruction and flew well, but the interest in the type vanished together with the interest in its armament. One built.
Function: fighter
Year: 1931 Crew: 1 Engines: 1 * 530hp Bristol Jupiter VIIF
Wing Span: 9.57m Length: 7.16m Height: 3.76m Wing Area: 25.08m2
Empty Weight: 1080kg Max.Weight: 1520kg
Speed: 298km/h Ceiling: Range:
Armament: 1*g37mm
Source - http://www.csd.uwo.ca/Elevon/gustin_military/db/br/VICKER06.htmlHere's a link to Nic Braas image of a Type 161
http://1000aircraftphotos.com/Contributions/Braas/4037.htm