The Curtiss SB2C
Helldiver is perhaps the best example of a potentially excellent aircraft
design being ruined by uncompromising requirements. Entering service in 1942,
at the height of the Pacific war between the United States and Japan, it was meant to be a
replacement for the SBD Dauntless. The Helldiver was meant to be faster, better armed, and was
meant to drop a far more potent payload onto the decks of various Japanese warships. It was also
intended to be mass produced on a scale not yet seen, thus equipping the US Navy (and Army) with
an endless supply of dive-bombing aircraft. But, and oh my goodness is this a big but,
the Helldiver would quickly earn such a poor reputation that it is often considered the
trigger-point for the downfall of Curtiss as an aircraft manufacturer. It’s problems included,
but were not limited to: poor power-to-weight performance, leaking hydraulic systems,
leaking fuel tanks, flaps that failed to retract, electrical systems that felt their
use was optional rather than mandatory, landing gear legs that broke due to excessive weights,
and the early models had such poor directional stability that the Captain the Carrier USS
Yorktown suggested they be pulled from service and used as sea anchors, he hated them that much.
Today’s video should be considered an introduction to the saga that is the Helldiver,
giving a general overview of the aircraft, and in the future we’ll be covering the
problem-plagued history of this machine in much more detail, specifically with a focus
on its early development and why Curtiss was not to blame for this flying disaster.
But today, we’re focusing more on the aircraft itself, rather than the political and bureaucratic
battle that raged behind the scenes. This video is also very kindly sponsored by
Ikarus Art, who produce beautiful aviation-themed prints and posters. They’ve recently added a few
new items to their collection, including a piece depicting the battle of Britain,
and another, which has instantly become a favourite of mine, is of the Junkers Ju 290,
an aircraft we covered quite recently. You can purchase them as printed canvas,
or posters, and the prices start for as little as $10. So to check out their collection, click on
the link below or go to ikarusart.net and use the code REX to get a 10% discount on your order.
Now, lets take a quick look at the ill-fated Curtiss Helldiver.
Its origins can be traced back to 1938. Though the project that would materialise into the
Douglas SBD Dauntless was still hammering out the final details of the first production model, the
US Navy was already contemplating its successor. Rapid developments in aero engine technology
led the bureau of aeronautics to believe that an aircraft could be built along similar principles
to the SBD, but on a slightly bigger scale, and with a much more powerful engine, and thus could
carry their 1000lb bombs faster and further. Early in 1938 they issued a requirement for such
a design. It was to be powered by the 1500hp, 14-cylinder, Wright R-2600 Twin Cyclone;
it was to carry a greater fuel load than the SBD without drop tanks;
it was to carry a 1000lb bomb in an internal bomb bay; and it was to be sufficiently compact enough
that two of these dive bombers could fit onto the main elevator of US Navy fleet carriers.
This final requirement is where everything went wrong, because the US Navy was asking
manufacturers to build an aircraft with greater internal capacity than any built before,
whilst also limiting the maximum external dimensions, which as many can appreciate is
something of a contradictory set of requirements. Specifically, this would have an impact on the
overall length of any aircraft designed, and as such Curtiss engineer Ray Blaylock was forced
to submit a proposal for an especially short and broad aircraft, one that already looked a
little unstable, that the Navy then ordered as the prototype XSB2C-1 in May of 1939.
As originally planned, it was a two-seat, monoplane dive-bomber. One of its most innovative
features was an extensive hydraulic system, which would operate the landing gear, flaps, bomb bay,
and the wing folding mechanisms (obviously with manual backups as well). Armament would consist of
two forward firing 50 calibre machine guns mounted in the nose, and two defensive 30 calibre machine
guns were mounted on a ring in a similar fashion to those found on the SBD Dauntless. Airframe
construction was metal, of course, the fuselage being a semi-monocoque, the wings built up on two
spars in four sections, and everything bar the control surfaces had a stressed metal skin.
As Curtiss-Wright’s manufacturing plants were already committed to producing the P-36 and P-40
fighter aircraft, and as the Navy indicated they wanted a lot of these new dive bombers,
construction of a new factory was initiated in Columbus, Ohio. Factories, however,
did not sprout from the ground overnight, and the prototype helldiver was mostly constructed in a
cattle barn on the state fairground. From this interesting beginning,
problems soon began before the prototype was even completed. In February of 1940 wind tunnel tests
on a scale model revealed unacceptably high stall speeds, to the point that the approach speed for
carrier landings was considered dangerous. This necessitated the hasty redesign of the wings,
which also increased their total area by about 10%, which increased weight, and this leads into
the other problem. The aircraft’s shape and mass would cause it to accelerate excessively when put
into a dive for a bombing run, but due to time constraints, the only change made to address
this was to provide variable opening capabilities of the flaps to act as impromptu dive breaks.
With further modifications made, the XSB2C-1 was completed and rolled out
on December the 13th 1940, and although it had not even been tested in its new configuration,
the Navy had already placed a production order for 370 aircraft. Said order would not be
completed for some time though, as the prototype experienced a truly calamitous testing program.
From its first flight, on December the 18th, it was apparent to everyone that the XSB2C
had some serious stability problems. The low speed characteristics, as predicted
by wind tunnel tests, were questionable at best and downright dangerous at worst,
it had horrible stability in the yaw axis, and only marginal stability in pitch, and then there
was the engine. Though the R-2600 was becoming a reliable workhorse, its current configuration,
combined with a new, experimental three-blade propeller, resulted in multiple failures,
one of which led to a hard landing on February the 9th which broke the prototype’s back.
Following repairs, testing continued throughout 1941 and revealed both the
complexity of the design and its problems. During the year multiple changes were made,
including the lengthening of the nose and forward fuselage, lengthening the bomb bay,
extending the cowl flaps, and making multiple alterations to the air scoops and cooling systems.
The tail was also increased in size to try and fix some of the worst of the stability problems,
and things seemed to be somewhat improved when it was put through a new test program that ran from
October the 20th…until the prototype was destroyed on December the 21st when it broke up in a dive.
Thankfully the test pilot, Baron Hulse, was able to bail out, as the wing and tail disintegrated
at a fairly high altitude. But this catastrophic loss could not have been worse timed. Not only
had the Navy increased its production order to well over 1,000 aircraft, but the US was now at
war with Japan, and everybody was screaming for as many aircraft as they could get.
The first production Helldiver should have rolled out of the new Columbus plant in December of 1941,
but due to the ongoing problems and delays, this would not happen until April of 1942. By
this point there were 4,000 Helldivers already on order, 3,000 to be built by Curtiss for the
US Navy and another 1,000 to be built in Canada, some also intended for the US Navy,
but some were also aimed at the Royal Navy. Due to the loss of the only prototype, and due to the
many unanswered questions about the aircraft’s general performance and structural integrity,
the first 14 production Helldivers would be retained for research development and testing.
To keep things simple for now, we’re just going to look at the major production variants operated
by the United States, and the other models will be covered in the deep-dive video I have planned,
which will also focus on the experimental variants of the Helldiver as well and go
into its service history in more detail. The SB2C-1 was not only the first production
model, but it also served as an extension of the prototyping phase, as early models went through
an extensive series of design revisions. Between the date of the original Curtiss proposal and that
of spring 1942, the expected features of a modern combat aircraft had changed. The prototype did not
include things such as self-sealing fuel tanks, a DF loop, radar, or armour protection for the crew
to name a few – the Production SB2C-1s did. Unfortunately, this increased the empty weight
from 7,122 lbs to 10,144 (4,600 kg), which had a knock-on effect on its performance.
This was then further compromised by modifications to the armament,
which now amounted to four 50 calibre machine guns in the wings (not the nose), and a single
50 calibre machine gun in the rear for defence. Throughout 1943, a huge list of modifications
began to build up, and as production of the Helldiver was well and truly underway,
a second production line had to be set up purely to update the earlier models to the revised
specifications. The SB2C-1 came in a Mod 1, Mod 2, and a Mod 3 variant, the last of which, when
compared to the original design, featured almost 900 design changes, and it was not until the 601st
Helldiver rolled out of the factory that all of the previous models had finally been brought up to
a standard that the Navy would actually accept. By this point, the cumulative changes were
recognised in a new model designation: the SB2C-1C, which technically began production
after the 200th -1 model had been produced, but would still receive modifications for some time.
The biggest change found on the -C was the armament, with the four 50 calibre machine
guns in the wings being swapped out for a pair of 20mm cannons. The -1C would become
the main production version of this initial series, with approximately 778 being built
before things switched over to the -3 variant. The -1C was the first Helldiver to go to sea
aboard a carrier as an active unit, with VB-4 and VB-6 working up with the type aboard USS Yorktown
in May of 1943. By this point the Helldiver already had a poor reputation, and it was often
referred to as the ‘Big Tailed Beast’, or simply as the ‘Beast’, and some claimed its designation
of SB2C stood for ‘Son-of-a-b*tch, Second Class’. There were in fact several other more imaginative
and less delicate names for the Helldiver as well, but I’ll talk about those later.
The Yorktown’s early experiences with the Helldivers was not pleasant at all. There
was an exceptionally high attrition rate due to landing accidents, either due to hook bouncing,
landing gear collapse, or plain old-fashioned poor handling. The situation became so poor
that near the end of the working up period, with deployment to the front looming, the Yorktown
elected to swap back to the older SBD Dauntless, its crews believing they needed much more time to
get to grips with this new, recalcitrant dive bomber. Because of this last minute change,
it would be the Helldivers of USS Bunker Hill that would see the types combat debut,
striking Rabaul on November 11th 1943. After the Helldiver’s disastrous start,
the SB2C-3 represented the first shift in the right direction. Even with all the improvements,
the -1C models still had their problems. They were still difficult to control at low speeds, which
led to numerous take-off and landing accidents; they could not be put into a clean dive, as they
encountered extreme tail buffeting which then led to a fatal loss of control, and then a high-speed
plunge into either the ground, the ocean, or the deck of a Japanese warship; and they still
suffered from the occasional mechanical problems, specifically hydraulic leaks and engine trouble.
Now, some of these problems did stem from sub-par workmanship coming out of the new columbus factory
and were not a direct result of a design defect, so today I’m just going to focus on the design
changes that improved the Helldiver, and we’ll look at the others in the deep-dive video.
The biggest improvement found in the -3 was an upgrade in the powerplant,
as it was felt the -1C was underpowered. The R-2600-20 version of the twin cyclone
was installed, and producing a healthy 1900hp, driving a new four-blade propeller,
it made for a huge improvement. Not only did the top speed increase from 281 to 294 mph (473 km/h),
but the added power gave pilots a bit more wiggle room when it came to carrier landings.
This was further improved with later -3 models, when perforated flaps and dedicated dive-brakes
were added. This further improved low-speed handling and the number of deck accidents aboard
carriers began to drop off dramatically. Approximately 1112 -3 models were built
by Curtiss, plus another 413 SBW-3s and 150 SBF-3s were built by manufacturers in Canada,
before things moved onto the SB2C-4. This was the most produced model of the Helldiver,
with Curtiss producing 2,045 -4 variants alone. It inherited all of the improvements found on the -3,
and the only major differences was the addition of a prop spinner, the deletion of the small windows
behind the pilot’s seat, and the fitting of four zero-length rocket launchers under each wing. Some
-4’s were also equipped with airborne search radar and these were known as the SB2C-4E.
By this time, it was late 1944, and although the Helldiver was finally performing well,
indeed performing exceptionally well after roughly 1,000 modifications to the original design spec,
the role of the dedicated dive-bomber was becoming rapidly obsolete. The latest
generation of carrier-born fighter aircraft were able to carry the same amount of ordnance,
up to 2000lbs of bombs, from the same carriers and at a higher speed- and of course,
they were fighters, which meant they could do considerable damage to enemy air units as well.
This also meant that a version of the Helldiver intended for the Army Air Corps, known as the A-25
Shrike, was all but unneeded when it was finally ready for service in late 1943 – thanks to the
advent of the P-47 Thunderbolt. Approximately 900 of the A-25s were built, and after some
negotiations, around 410 of these were reassigned to the Marine Corps. These would not see combat,
however, as they were based on an earlier, less refined version of the Helldiver and were instead
used as trainers or target tugs. The Marine corps would use the -4 variant of the Helldiver
alongside the Navy, though many pilots would have gladly taken a F6F Hellcat instead.
The Helldiver still had some advantages though, it could deliver its bombs more accurately as
a dive bomber, and it could carry them across a greater range. This it did to admiration in the
naval and land battles of the last 18 months of the Pacific war. Helldivers were put to especially
good use during the battle of Leyte Gulf, where they took part in the aerial beatdown of the
Yamato-class Battleship Musashi in the Sibuyan Sea. During the course of the engagement with the
64,000-ton battleship, Helldivers from no less than five different US carriers would take part
in Musashi’s gradual demise, scoring several direct hits without their wings coming off in
a dive- much to the relief of their pilots. While the -4 Helldivers were busy earning a
belated, and semi-decent reputation for themselves, production of the last major
variant, the -5, was getting underway. As the design was now considered mostly viceless,
the improvements found on the -5 were subtle. Internal fuel tankage was increased by around
35 US Gallons; a new frameless canopy provided better visibility for the pilot; a four-blade
paddle prop without a spinner was installed; the ASB radar was deleted, with an AN/APS-4 radar
pod as an optional modification instead; and the tailhook was now fixed in the extended position,
owing to several mishaps with previous models that saw Helldivers shoot off the
carrier deck and into the pacific ocean. Production of the -5 began in February 1945,
and approximately 970 had been built by wars end, which saw the cancellation of future orders. The
-5 became the standard post-war dive bomber in naval squadrons, and although it was quickly
replaced by the AD Skyraider, it is significant that the Helldiver was one of the few aircraft
designed before the Pacific War that saw real service after its conclusion. The
only other aircraft that outlasted it in this regard would be variants of the F4U Corsair.
But, By 1950, the Helldiver had been entirely retired from active duty,
with aircraft being relegated to either training or testing roles if they weren’t scrapped,
and by the mid-1950s they had disappeared from the Navy inventory altogether.
At the conclusion of its production run, 7,140 SB2C’s had been produced across more
than a dozen different variants. They would see service not just with the United States,
but with Australia, Britain (though none saw action), France, Greece, Italy, Portugal, and
Thailand. When it was retired, the aircraft was a far cry from the unreliable, slow, and dangerous
beast that had first taken to the skies in 1940. But in many ways the damage had been done.
The start of the Helldiver’s career had been so spectacularly awful that its reputation never
fully recovered, and by extension it was viewed as a black mark on the record of Curtiss-Wright.
Indeed, the early problems and production delays led to the project being investigated
by the Truman Committee, which had been set up to investigate a whole series of delays,
issues, and expenditure concerns found within the National Defence Program.
This was the start of a troubling period for the company, one that saw it put most
of its efforts into existing designs, such as modifying the P-40, or fixing the Helldiver,
and because of this Curtiss-Wright began to lag behind in terms of aircraft development. In the
postwar years their failure to secure several key contracts for military aircraft projects, and
an inability to adapt to the civil market, would lead to them pulling out from the
aircraft manufacturing business altogether. How much influence the Helldiver had on this
fate is still up for debate, but it certainly had an impact. Unfortunately, this does nothing
to improve its reputation, which is a bit of a shame because once the thousand-odd kinks
had been worked out, the SB2C became a pretty decent dive bomber. It fought in a multitude of
creditable actions, contributed to the sinking of a large amount of Japanese tonnage, and it even
saw some postwar action with foreign operators. Had the Navy started with a more flexible design
requirement from the outset, the future of the Helldiver, and perhaps Curtiss-Wright,
could have been very different. All of this, and more, will be explored in a deep-dive video that
I’m gradually working on. Its going to be pretty in depth, covering the full saga of its early
development problems, looking at the Truman Committee, the Helldiver’s wartime service,
foreign use, and some interesting experimental programs, including attempts to convert it into
a torpedo bomber. But that is a much, much longer video for another day.