During the interwar years, the RAF began seeking a replacement general-purpose aircraft for its aging fleet of WWI planes. Due to a lack of funding however, the Air Ministry sought an aircraft with an increased bomb load and better reliability that also used as many DH.9A components as possible. The winner was the Westland Wapiti, and the biplane entered service with the RAF in 1927. Some 512 examples were built for the RAF, and another 500 for export. The planes was also license-built in South Africa. About 80 Wapitis were still in service with the RAF in India until 1942.
The Mark IIA was the main production version. It could be fitted with wheels or float landing gear. It burns 18 gallons of aviation fuel per hour at routine usage. A full load of fuel and ammo (excluding bombs) costs $22.
Westland Wapiti Mk IIA
Subassemblies: Light Fighter chassis +3; Heavy Fighter wings with Biplane option +2; 2 fixed wheels +0.
Powertrain: 358-kW aerial HP gasoline engine with 358-kW old prop and 60-gallon standard fuel tank [Body]; 4,000-kWs battery.
Occ.: 2 XCS Body
Cargo: 7 Body
Armor F RL B T U
Body: 2/2 2/2 2/2 2/2 2/2
Wings: 2/2C 2/2C 2/2C 2/2C 2/2C
Wheels: 2/3 2/3 2/3 2/3 2/3
Aircraft LMG/.303 Vickers [Body:F] (500 rounds).
Aircraft LMG/.303 Lewis [Body:B] (500 rounds each).
580 lbs. Bombs [Wings:U].
Body: Navigation instruments, medium radio transmitter and receiver, casemate and high-angle mount for the rear MG. Wings: Two hardpoints at 290-lbs. each.
Size: 32'x46'x12' Payload: 0.80 tons Lwt.: 2.7 tons
Volume: 144 Maint.: 49 hours Cost: $16,907
HT: 7 HPs: 50 Body, 360 each Wing, 8 each Wheel.
aSpeed: 140 aAccel: 3 aDecel: 48 aMR: 12 aSR: 1
Stall Speed: 47 mph. Take-Off Run 245 yards. Landing Run 221 yards.
gSpeed: 184 gAccel: 9 gDecel: 10 gMR: 0.5 gSR: 2
Ground Pressure: Very High. 1/8 Off-Road Speed.
Historical wing area was 468 sf. The fuel capacity was based on a rough calculation between range (530 miles) and gas consumption, as no historical value could be located. MG load outs are a guess. Design payload was 1,420 lbs; the historical value has been substituted. Design aSpeed was decreased 2 mph to the historical; design weight was decreased 7% to the historical. Performance calculations were based on historical values for wing area and loaded weight. The front Body MG is synchronized, lowering RoF by 10% (see p. W:MP8).
The Mk I was the initial production version with a 313-kW engine.
The Mk IA increased engine output to 358-kW; 38 were built for the RAAF.
The Mk IB introduced divided landing gear and a 410-kW engine.
The Mk II introduced an all-metal basic structure.
The Mk III was license-built in South Africa with a 365-kW engine.
The Mk V was built from the MK IV project and featured a lengthened fuselage, a 410-kW engine, and other refinements.
The Mk VI was a dual-control trainer version.
The Mk VII was a single experimental plane.
The Mk VIII were four planes built for the Chinese government with 382-kW engines.
From the Aerodrome for GURPS
© 2008 by Jim Antonicic