Avro 627 Mailplane

Development

The Avro 608 Hawk was a proposed two-seater fighter variant of the Antelope, which was planned to be powered by a Bristol Jupiter radial engine. Although construction of a prototype began, it was incomplete when it was redesigned with a 540 hp (400 kW) Armstrong Siddeley Panther engine as the Avro 622.

Following interest by Canadian Airways, who had a possible requirement for a mail plane, Roy Chadwick again redesigned the incomplete prototype to the Avro 627 Mailplane . This was a single-engine, single-bay biplane, powered by a 525 hp (391 kW) Panther engine and fitted for wheel or float operation. The sole prototype (G-ABJM) was certificated on 2 August 1931, and was shipped to Canada for operational trials. While these trials were successful, the Canadian government cut the subsidy for civil aviation and so Canadian Airways was unable to afford new aircraft, so the mailplane was returned to England.

The Mailplane was converted in 1933 to a high-speed test bed for the Armstrong Siddeley Tiger engine, the revised aircraft being known as the Avro 654.

Operational history

On return from Canada, the Mailplane was entered in the 1932 King's Cup Race, where it recorded the fastest speed of 176 mph (283 km/h), although owing to the handicap system, it came 29th.

After conversion to the Avro 654, the aircraft operational life was short, it being dismantled at Woodford Aerodrome in 1934.

Variants

Avro 608 Hawk

Proposed two-seat fighter, powered by 425 hp (317 kW) Bristol Jupiter engine. Prototype incomplete.

Avro 622

Redesigned Avro 608, powered by 540 hp (400 kW) Armstrong Siddeley Panther II engine. Incomplete prototype converted to Avro 627.

Avro 627 Mailplane

Single-seat mailplane, powered by 525 hp (391 kW) Armstrong Siddeley Panther IIA engine. One prototype built.

Avro 654

Conversion of Avro 627 as high-speed test bed.

Specifications (Avro 627 Mailplane)

Data from Avro Aircraft since 1908

General characteristics

Crew: One

Capacity: 40 ft³ mail compartment

Length: 30 ft 10 in (9.40 m)

Wingspan: 36 ft 0 in (10.98 m)

Height: 10 ft 10 in (3.30 m)

Wing area: 381 ft² (35.4 m²)

Empty weight: 3,077 lb (1,399 kg)

Loaded weight: 5,150 lb (2,341 kg)

Powerplant: 1 × Armstrong Siddeley Panther IIA 14 cylinder two-row radial engine, 525 hp (391 kW)

Performance

Maximum speed: 148 kn (170 mph, 274 km/h)

Cruise speed: 128 kn (147 mph, 237 km/h)

Range: 487 nmi (560 mi, 902 km)

Service ceiling: 19,000 ft (5,800 m)

Rate of climb: 1,200 ft/min (6.1 m/s)

Wing loading: 13.5 lb/ft² (66.1 kg/m²)

Power/mass: 0.102 hp/lb (0.167 kW/kg)