Fly Past

12 RAF CENTENARY CELEBRATION PATROLLERS AND AIRLIFTERS

1918 2018

Above right

Blackburn Iris III S

Leda was delivered

to 209 Squadron at

RAF Mount Batten,

Plymouth in January

1930. That summer
      it was to be fl own to
      Reykjavik in formation
      with S1264 to represent
      Britain at the Icelandic
      Parliament Millenary
      Celebrations, but it was
      forced to return due to
      fuel contamination. The
      aircraft was written off
      when it collided with a
      dockyard launch after
      landing on Plymouth
      Sound on January 12,
      1933 and sank. Of the
      nine crew, seven were
      injured and 20-year-old
      Leading Aircraftsman
      Dore Slater drowned.
      ANDY HAY/WWW.FLYINGART.
      CO.UK

Below

Iris III S1263 was named

Leda and in 1931 it fl ew

Chief of the Air Staff, Sir

John Salmond, on an

inspection of the RAF

overseas. KEY

1930 TO 1934

Type: Five-crew general reconnaissance fl ying boat

First fl ight: June 19, 1926; entered service 1930

Powerplant: Three 675hp (573kW) Rolls-Royce Condor piston engines

Dimensions: Span 97ft (29.57m), length 67ft 5in (20.55m)

Weights: Empty 19,301lb (8,755kg), all-up 29,000lb (13,154kg)

Max speed: 118mph (190km/h) at sea level

Range: 470 miles (756km)

Armament: One .303 gun in bows, one amidships and one in tail. Bomb load:

2,200lb (998kg)

Replaced: Felixstowe F.

Taken on charge: 5

Replaced by: Blackburn Perth

BLACKBURN IRIS III

D

uring their brief period of

operation, five Blackburn

Irises were the largest flying

boats in RAF service.

The Iris was Blackburn’s first

large seaplane venture but the type

benefited from the manufacturer’s

previous experience with smaller

aircraft such as the N.1B and Pellet.

Development began in 1924

when the Air Ministry issued

Specification R.14/24 for a long-

range reconnaissance flying boat.

Blackburn created the R.B.

(Reconnaissance Biplane 1) to meet

the requirement; the aircraft having

three 675hp (503kW) Rolls-Royce

Condor engines and a wooden hull.

Its three tail fins and equal-span

wings were of mixed wood-and-

metal construction. The powerplants

were designed to drive four-bladed

propellers and were mounted in neat

aerodynamic nacelles.

WOOD TO METAL

The R.B.1 was renamed Iris I

ahead of its maiden flight on June

19, 1926. Following testing at

the Marine Aircraft Experimental

Establishment at Felixstowe, Suffolk,

the prototype (N185) was returned

to the factory where its wooden

hull was swapped for a metal

replacement, thus creating the Iris

II. The new aircraft also had more

powerful engines and an additional

gunner’s position in the tail.

In August 1927 the Iris II joined

the prototype Short Singapore

I, an experimental metal-hulled

Supermarine Southampton, and the

prototype wooden-hulled Saunders

Valkyrie on a 3,000-mile (4,828km)

tour of Scandinavia and the Baltic.

The Iris performed well and on

February 4, 1928, a contract was

placed for three Iris III aircraft,

similar to the Iris II but with fabric-

covered metal wings.

The new version flew on

November 21, 1929 and entered

service with 209 Squadron in

Plymouth, in January 1930. The

first Iris III was later destroyed in a

fatal crash when the pilot misjudged

a landing approach over glassy-

smooth water and a replacement was

ordered. All Iris IIIs were upgraded

with more powerful 825hp

(615kW) Rolls-Royce Buzzards

from 1932, and the Iris II was

given 800hp (697kW) Armstrong

Siddeley Panther radial engines

(with the centre engine in a pusher

configuration) to become the Iris IV.

In 1935, the Irises were replaced by

four Blackburn Perths [see p.16].

“The fi rst Iris III was later destroyed in

a fatal crash when the pilot misjudged a

landing approach over glassy-smooth water

and a replacement was ordered.”

IRIS

BLACKBURN