The transition from the fabric covered biplane to the sleek, all-metal monoplane produced
some interesting results in the 1930s, and one of these was the Curtiss A-12 Shrike.
In 1930 the Army Air Corps was looking for a new attack aircraft to replace the Curtiss
A-3 and De Havilland DH-4 biplanes operated by the 3rd Attack group.
Though there was a reluctance to transition to the monoplane, with many not wishing to
waste money innovating during a time of peace, isolationism, and of course, the great depression,
aircraft performance was increasing with each passing year, and senior officers could not
deny the march of progress.
In response to an Army Request to investigate the possibilities of a monoplane attack aircraft,
Curtiss developed the model 59.
The Army approved the design and ordered a prototype to be built as the XA-8.
This was a major advance for Curtiss in several respects, being their first monoplane design
and the first to have both an all metal structure, and all metal coverings instead of fabric
or wood.
But in other ways, the design was still decidedly old-school, and it reflected an attempt to
balance budgets, available technology, and the conflicting opinions of designers and
military officials.
Structurally, the aircraft was an innovation.
The fuselage was constructed in two main parts.
The rear section was built as a monocoque with duralunimium skin, stringers, and bulkheads.
The forward section, beginning in front of the observers position, was built from welded
steel tubing that had two heavy struts on each side to support the wing stubs.
The engine mount was a separate unit, for ease of maintenance, though this too appeared
to be made from steel tubing.
Attached to the underside of the wing-stubs was the aircraft’s fixed landing gear.
Though at first glance it appeared simple, it was in fact rather complex.
The wheel was held by a horizontal jointed yoke which was hinged at the rear to allow
the wheel to move up and down.
It was possible to latch the wheels in place before take-off, so that most of them were
concealed within the streamlined fairing, and they could then be lowered in flight before
landing so that the wheels could better absorb the impact.
Though the construction of the fuselage could be considered cutting-edge, and the landing
gear at least contemporary, the decision to use wire braced wings was (which with the
exception of the Douglas O-13 and Boeing P-26) an anachronism not seen since the days of
the first world war.
But despite this archaic design choice, they were the first Curtiss wings to feature both
trailing edge flaps and full-span leading edge slats – the latter of which would make
the aircraft popular with its crews due to its low-speed handling.
Speaking of the crew, the XA-8 had a crew of two, a pilot and an observer who also acted
as a rear gunner.
The pilot controlled four .30 calibre machine guns mounted in the undercarriage fairings
where their rate of fire would not be slowed by a synchronisation gear.
The rear cockpit was fitted with a single .30 calibre gun in a flexible mount.
Vertical racks mounted behind the pilot could carry up to 400lb (181 kg) of bombs or chemical
tanks.
In the interest of giving the observer excellent visibility, Curtiss placed the second cockpit
quite far to the rear.
This not only gave the aircraft some deeply unflattering lines, but it would also make
communication for the crew exceedingly difficult.
Upon completion, the XA-8 was fitted with a 600hp liquid-cooled Curtis Conqueror (V-1570C)
driving a three-blade fixed-pitch propeller, and was first flown in June 1931.
Boasting a top speed of 184mph, it entered into trials against the competing Fokker XA-7.
The Curtiss won, and an order was placed for thirteen service test models.
The first five would be built as the YA-8, with the same V-1570C engines, and the remaining
eight were ordered as the Y1A-8 with the updated V-1570F engine.
Eleven of these planes joined the 3rd attack group, at Fork Crockett, Texas, during 1932
and they served alongside the unit’s other Curtiss attacker, the A-3B, for about two
years.
The trials had shown that there was room for improvement, and two of the service test aircraft
would be kept back for extensive modifications and testing.
The first aircraft from the batch was re-engined with a 9-cylinder Pratt & Whitney Hornet radial
engine; at the same time the thirteenth aircraft was also re-engined but with a geared version
of the Curtiss Conqueror.
The Conqueror-powered model was known as the Y1A-8A.
Along with boasting an extra 75hp thanks to the new engine, the aircraft also had a slightly
revised wing – though the details of said revision seem to be unknown.
Despite the increased power, the modifications to the aircraft added a quarter of a ton onto
the weight, and its top speed dropped slightly to 181 mph.
This wasn’t enough to dissuade the army, and owing to the favourable performance of
the service test aircraft an order was placed for 46 as the Curtiss A-8B.
Now this lasted all of five minutes, metaphorically speaking, as the testing of the radial-powered
YA-8 had gotten underway.
Delivered to Wright Field in September 1932, the aircraft was now known as the XYA-10,
a new number designating being felt suitable owing to the new powerplant.
Though, like its competitor, the added weight of modifications reduced the aircraft’s
top speed, it was considered a more than acceptable price to pay.
Many agreed that the radial engine was far more suitable for an attack aircraft, it being
more reliable from the points of cooling and its ability to absorb battle damage, and because
of this the existing order for 46 A-8s was superseded by a new order for 46 radial-engined
versions instead.
Before production got underway, some additional changes were made to the aircraft’s design.
Some of these were based on field evaluations, and some were based on feedback provided by
officers of the 3rd Attack Group.
The pilots cockpit now had just a simple windshield, with many complaining that the sliding canopy
was unreliable and reduced visibility; owing to comments about observers needing to pay
postage every time they sent messages to the pilot, the observers station was moved significantly
forward; and the engine was changed to the 690hp Wright R-1820 Cyclone, which was a much
newer engine than the Hornet.
These changes were significant enough for curtiss to redesignate the aircraft as the
Model 60, and its production number was also redesignated as A-12.
The first A-12s were delivered in late November 1933.
The first three of the 46 produced were retained for service testing, one going to Wright Field,
one to the Edgewood Arsenal, and one to the Aberdeen proving ground, and the rest were
delivered to the 3rd Attack Group with the last arriving on February the 20th 1934.
As with many aircraft developed in this period in the United States, the A-12s enjoyed a
varied but relatively peaceful service life.
Just weeks after their arrival, one of their more notable operations began during the Air
Mail crisis – an event that also involved a couple of other aircraft we’ve already
covered on this channel, and yes, it is getting its own video in the future, eventually.
Following proven allegations of corruption with the allocation of service contracts,
the Government suspended the commercial flying of air mail, and, without warning handed the
entire responsibility over to the Army Air Corps.
Unprepared for such a task, the Air Corps scrambled to get together enough pilots and
suitable aircraft to do the job, and the A-12s found themselves being used as impromptu postal
aircraft.
Operating in the Central Zone of the Air Route, 41 A-12s from the 3rd Attack Group would aid
in the flying of mail for approximately three months.
During this time most of them had their rear cockpits modified to better facilitate the
carrying of mail; some had a lockable cover placed over the canopy for protection, but
other had the canopy completely replaced with metal panelling.
The Air Mail crisis unhappily coincided with some of the worst weather seen in decades,
with winter refusing to give way to spring.
Multiple aircraft were lost due to poor weather, including two A-12s, and this forced a reduction
of routes and schedules.
Other A-12s were also severely damaged during this time, with at least one more being written
off due to airframe damage, and it was with some relief that their pilots went back to
regular service after the embarrassing saga of the Air Mail crisis had concluded.
As the A-12s of the 3rd Attack Group settled down into their peacetime routine of flying
exercises and war games, Curtiss were busy working on an export model.
This had begun as soon as the last production model had been delivered for the Army.
Curtiss advertised the aircraft for a number of roles, allowing for modifications that
could see it used as either an attacker, an observation plane, or even a light bomber.
In the end its curious design, being a halfway house between the old and the new, only secured
one customer: China.
Ten export models were delivered to the Chinese government in May of 1936, and another 10
were ordered following favourable demonstrations.
It only differed from the production variant in two ways: it had a more powerful engine,
producing 775hp, and there was provision to have camera equipment installed.
The aircraft were assembled at Hangzhou, and the Chinese pilots were trained by an American
volunteer, Luke Williamson.
It was in Chinese service that the A-12 would see its combat debut, and indeed its only
wartime operations.
The first reported operations of Shrikes was by the 3rd Attack Group in August 1937, and
this included one of the few reported dogfights including the type, with Chinese A-12s facing
off against Japanese D1As.
Numbers are sketchy, but it appears the Shrike scored either two or four aerial victories
against the carrier-based dive bombers during the battle of Shanghai.
Aside from two or three other actions in October, which appeared to have been ground attack
missions, not much is known about the Shrike’s performance in Chinese service.
Considering none appeared to have survived past January of 1938, said performance was
probably lacklustre at best, as by this time the aircraft was certainly being outclassed
by those fielded by the Japanese army and navy.
The Mitsubishi A5M for example, which was fielded by the Japanese Navy, had a top speed
that exceeded the A-12 by 100mph.
Back in the United States this obsolescence had been observed for some time.
The 3rd Attack group began converting to the Northrop A-17 in late 1936.
Due to various accidents, only 35 of the 46 A-12s remained, and 21 of these would eventually
wind up in Hawaii.
Here they equipped the 26th Attack squadron who, to alleviate the tedium of peacetime
training and formation flying, came up with a diverting new exercise.
Commanders at Wheeler field quickly noticed that their aircraft were coming back to base
with what appeared to be squiggles on their wingtips.
Incredibly bored, and incredibly enterprising officers had invented the practice of wingtip
singing.
One pilot would fly perilously close to another, dip one of his wings down, and the observer
in the other aircraft would reach out and sign their name on the wingtip.
This was repeated throughout the flight until all aircraft returned to base bearing the
name of its companion officers.
This was a testament to the monotony of peacetime operations, and the complacency of Air Corps
doctrine in the Pacific, and it was probably the most exciting thing to happen to the A-12s
at Hawaii until the attack on Pearl Habor.
None appeared to have been lost in the attack, for there were only 9 remaining on the island
and these in storage, and the remaining aircraft lived out their days as either trainers or
instructional airframes.
As always, thank you all so much for watching, and a big thank you of course to the Patrons.
Now that I’m back from my slightly extended break, things should settle into a more normal
routine again until I head overseas in the middle of the year.
I’ve got plans for some long videos, some short videos, and some new video formats as
well, more news on that soon.
A big thank you of course to our wing commander tier patrons, our highest tier members.
This month’s q&a thread is now live on patreon for officer tier members too, so be sure to
head over and ask your questions and they will be answered in the next hangar debrief.
And hopefully, there should be some exciting behind the scenes stuff being posted on there
later this month.
But, thank you all for your continued support, and I’ll catch you all next time.
Goodbye.