The Aviation Historian — January 2018

Issue No 22 THE AVIATION HISTORIAN 77

B

Y THE AUTUMN of 1929 modifications

to the Armada Argentina battleship

ARA Rivadavia — primarily the

installation of an aircraft deployment

system and recovery crane — had

been completed, and on October 2 that year

Fairey IIIF Mk IIIM (Special) coded AP-2 (c/n

F.1123) participated in trials at Base Naval (BN)

Puerto Belgrano, near Bahía Blanca. The results

were very promising, and the age of Argentinian

shipborne naval aviation had begun.

In the meantime, the Argentinian government

had made the decision to acquire a fleet of naval

aircraft, and on July 28, 1928, Capitán Pedro M.

Escutary, chief of the Comisión Naval Argentina

(CNA) in the USA, signed a contract with the

Chance Vought Corporation for four O2U-1A

Corsair biplanes with floats.

On July 5, 1931, the Armada took delivery of

the Italian-built cruisers ARA 25 de Mayo and

ARA Almirante Brown, the first Argentinian ships

designed to operate shipborne aircraft, each

being fitted with a Gagnotto catapult on the bow

and a hangar for two aircraft. The Corsairs served

aboard the cruisers in the reconnaissance role for

the next three years.

SEAGULLS FOR ARGENTINA

The Armada continued with its fleet expansion

through the mid-1930s, and on March 17, 1937,

the Vickers-Armstrongs shipyard at Barrow-in-

Furness, Lancashire, launched ARA La Argentina,

a modified Arethusa-class light cruiser. The vessel

required two dedicated spotter aircraft and back

in January 1935 Argentina’s Ministerio de Marina

had ordered two Supermarine Seagull Mk Vs

with 625 h.p. Bristol Pegasus IIL.2P engines from

Vickers-Supermarine at a unit price of £12,365.

The first of the Fleet Air Arm’s Walruses, as the

aircraft was renamed for Royal Navy service,

came off the production line in March 1936, the

first two — K5772 and K5773 — both going to the

the Marine Aircraft Experimental Establishment

(MAEE) at Felixstowe on the 28th of that month.

All these early Seagulls and Walruses except one

were powered by the 620 h.p. Pegasus IIM.2P

engine, slightly less powerful than the IIL.2P

fitted to the prototype, K4797. The exception was

K5773, which was fitted with the first Pegasus

VI, rated at 775 h.p. for take-off. When available

in quantity, the Pegasus VI was to become the

standard powerplant for the Walrus.

Argentina’s naval air arm, the Aviación Naval

(AN), expressed concern about the performance

of the Pegasus IIL.2P, but in a letter to Capt Mario

Fincati of the CNA, Supermarine explained that

“the Seagull V is the prototype of the Walrus, and

the characteristics of the aircraft included in the

specifications to our proposal of your training

cruiser in 1935, and incorporated later in the

contract documents, were those of the Seagull V.

“It is understood that the Seagull was carrying

out extensive trials during the period of the

negotiations relating to the contract of the

training cruiser and, as a result of these tests,

some modifications were introduced (with Air

Ministry approval), motivating the differences

between the characteristics indicated in the

contract specifications and those indicated in

Specification 441B, submitted last November.

The new aircraft has been renamed Walrus and

we have in production large quantities that have

to be delivered in accordance to orders placed by

the Air Ministry.”

There were indeed differences between the

Seagull V and the Walrus; the Handley Page

wing slats fitted to the Seagull Vs of the Royal

Australian Air Force (which retained the name)

were not fitted to the Walrus, as the aircraft was

found to have inherent short take-off qualities

without them. The Seagull V’s jury struts were

stowed in the aft hull except when fitted for wing

folding, while the Walrus’s struts were generally

not removed. On both types the wing sections

aft of the rear spar and inboard of the lower

ailerons were hinged to allow folding of the

mainplanes; however, the Seagull sections folded

downwards, the Walrus sections upwards. The

Seagull retained the water rudder/metal rudder/

tailwheel combination which protruded beneath

the keel and presented a further planing surface,

which caused a slight tendency to push the bow

into the water on take-off, alleviated by increased

back-pressure on the control column.

Satisfied, the CNA accepted Supermarine’s

offer of the new version powered by the more

powerful Pegasus VI in place of the original

Pegasus IIL.2P. On January 29, 1937, the Director

of Materiel, Contraalmirante Francisco Stewart,

reported that acceptance of the aircraft was

based on the condition that any modifications

made to RAF or Royal Navy Walruses before

January 1, 1937, would also be incorporated

into the Argentinian examples at no extra

cost. Supermarine agreed and commenced

production of the Walruses at its Woolston works

in Southampton as the Supermarine Type 236,

to Air Ministry Specification No 441B. The Air

Inspection Directorate (AID) agreed to conduct

inspections during construction.

OPPOSITE PAGE, TOP Walrus Mk I 2-O-23 was the first of the second batch to be acquired by the Aviación Naval,

all eight of these having been former RAF examples bought back by Supermarine for refurbishment and sale. It is

seen here at Hamble with Argentinian crew members during acceptance flights.ALEX REINHARD VIA THE LATE ERIC B. MORGAN