Today we’re taking a look at the Lockheed Model 10 Electra, this was the first in a
moderate line of twin-engine aircraft designs that emerged in the 1930s.
Notable for their exceptionally sleek lines and beautiful looks, most were used in the
civil market, primarily as passenger airliners, but a few military designs emerged as well.
I plan to cover all of these over the next month or so, so consider this the beginning
of a sort of disjointed mini-series that will continue after I return from my overseas trip
next month.
The Electra story begins in depressing times, literally.
In 1932 the Lockheed Aircraft Company was a ill-fated subsidiary of the defunct Detroit
Aircraft Corporation.
Though the company had produced some good designs, including the world famous and record-setting
Lockheed Vega, it had not enjoyed huge commercial success.
This would soon change when the Lockheed Aircraft Company was purchased and reformed into the
Lockheed Aircraft Corporation in June 1932.
Much of the finance was brought in by Robert E Gross, an investment banker, and the company’s
management team soon elected a new president: Lloyd Stearman, himself already a well-established
aircraft designer and manufacturer.
At first, the new company planned to build a ten-seat, single-engined, all-metal transport
which Stearman had drawn up earlier while doing work for Stearman-Varney inc.
However, convinced that the future of passenger transport would depend on the development
of clean and fast twin-engine aircraft, Robert Gross convinced his associated that they should
abandon their single engine design and go for a twin-engine design instead.
This proved to be exceptionally fortuitous, as just a couple of years later, single-engine
aircraft operating in the United States would be forbidden to carry passengers on scheduled
flights at night, or over terrain unsuitable for emergency landings – and considering
vast swathes of the US fit into that category, with the Rocky Mountains to the west and the
Appalachians to the east, this could have been a real problem had Lockheed gone with
the single-engine approach.
This new aircraft continued the trend of Lockheed using celestial-themed names, and the Model
10 Electra was drawn up in the latter part of 1933.
To be built as a low-wing, cantilever monoplane, it was to have accommodation for a crew of
two and ten passengers.
It was to be powered by a pair of Pratt & Whitney R-985 Wasp Juniors, air-cooled 9-cylinder
radial engines, enclosed by NACA-style cowlings, and driving two-blade variable-pitch propellers.
Before construction of a prototype was completed, scale models were tested in a wind tunnel
at the University of Michigan.
Initially, the design had a single vertical tail, wing-to-fuselage fillets, and a forward-raked
windshield.
However, an assistant to Professor Edward Stalker, the aerodynamicist who’d been entrusted
with the testing, identified these features as likely to cause stability problems.
The assistant’s name was Clarence L Johnson, though most of us would know him simply as
Kelly Johnson, one of the most prolific and influential US aircraft designers to ever
live.
But his future fame in working on such projects as the P-38 Lightning, the U-2, F-104, and
SR-71 Blackbird to name just a few, was still ahead of him, and Professor Stalker did not
believe Johnson’s report that the Model 10 would be unstable.
Not long after this in 1933, Kelly Johnson completed his master’s degree, and he ended
up Joining the design team at Lockheed.
The Model 10 was still incomplete by this stage, encountering various delays, and he
convinced Hall Hibbard, the chief engineer, that he believed it was still unstable, and
he asked permission to conduct further tests.
After wind-tunnel testing of additional endplate fins near the end of the tailplane, Johnson
proposed a twin-fin and rudder design, and this proposal was quickly accepted, with the
Model 10 now featuring what would rapidly become a trademark tail design for Lockheed
aircraft in the interwar period.
The prototype Electra was finally completed in February of 1934.
On the 23rd of that month, and powered by 450hp Wasp Junior SB’s, it was flown for
the first time at Burbank, with pilot Marshall Headle at the controls.
The initial test flight results soon confirmed Johnson in his other recommendations, that
the wing fillets (curved fairings at the wing roots) should be removed, and that the windshield
should be modified to a different shape.
This was experimented with, and a finalised windshield would not be settled upon until
production of the Electra was already underway, with the fifth production aircraft being selected
for the final design.
With the modifications made, the performance and handling characteristics of the aircraft
were deemed to be excellent, and the prototype Electra completed its Airworthiness trials
at Los Angeles in the Spring.
Following this, the Electra went through the process of getting its CAA Approved Type Certificate,
allowing it to be operated commercially, and Lockheed began to rapidly collect production
orders from various customers throughout the spring and summer months.
Production models of the Electra would eventually total 148 aircraft built across four commercial
and five military variants.
By far the most numerous produced was the first, the Electra 10-A, with 101 of the 148
total being of this type.
These were delivered to four US airlines, ten overseas airlines, a few private customers,
and a couple went to various governments.
In its original form, it had a wingspan of 55 feet, a length of 38 feet 7 inches, and
a height of 10 feet 1 inch.
It was good for a top speed of 210mph, and a cruising speed of 190 mph over a maximum
range of 810 miles.
After the Model 10-A, there was the 10-B through to E. Eighteen 10-Bs were built and they were
the only major variant to not use the Wasp Junior, instead being powered by 440hp Wright
R-975-E3 Whirlwinds.
They were sold to three US Airlines, Eastern Airlines being the dominant customer, one
foreign carrier, and a private customer.
The Model 10-C was the result of interest by Pan American Airways, who requested the
engine to be changed to the 450Hp Wasp SC1, an engine they had in surplus.
Eventually eight aircraft were produced to this modified specification, with delivery
being complete by May of 1935.
The Model 10-D was a projected military development of the Electra, but it was never built, and
the Model 10-E was another order for Pan American and its subsidiaries.
This model came with more powerful engines, the 660hp Wasp S3H1, and it also found customers
in the private market who valued high-performance designs.
A few Electras were also built for experimental use, the most notable becoming known as the
XC-35.
This was a single, unique version of the aircraft that had been ordered by the War Department
as a testbed for pressurised cabins and high-altitude operations.
Lockheed designed a new fuselage of circular cross-sections, with heavy doors, smaller
windows, and internal bracing to cope with the stresses of pressurisation, but the original
wing and tail surfaces remained the same.
To provide cabin pressurisation, and the necessary high altitude performance, the experimental
& turbosupercharged Pratt & Whitney XR-1340-43 engine was selected.
Ground testing began in early 1937, and the aircraft was soon nicknamed the boiler…on
account of some deeply distressing noises made by the doors, which leaked noisily when
cabin pressure was first applied.
After some modifications, the aircraft ceased sounding like an aggravated tea kettle, and
it went up for its first flights in May of that year.
With many of the tests conducted at the able hands of Lieutenant Ben Kelsey, the XC-35
provided the Air Corps and the aircraft industry with vital research data and experience in
the use of pressurised cabins and tubrosupercharged engines.
Moreover, it made some spectacular and record-setting flights, including one from Chicago to Washington
where it averaged 350mph at 20,000 feet.
In terms of its actual service life, the Model 10’s was especially varied.
It began primarily as it was intended, as a commercial transport.
It was operated in the United States by Chicago & Southern, Continental, Delta, Eastern, Hanford,
National Airways, Northwest, and Pan American.
Like the larger Boeing 247 and Douglas DC-2, the Electra offered a degree of comfort not
previously experienced in US Commercial aviation, and its high cruising speed – 190mph, the
same as the DC-2 despite the electra having far less power- endeared it to its passengers.
The Electra was beautiful, sleek, fast, and comfortable.
Unfortunately, its smaller size let it down when it came to the most important metric
in commercial air travel: and that was cost.
Its seat cost-per-mile was slightly higher than its competition, and this, combined with
the reduced seating capacity, 10 on the electra versus 14 on the DC-2, reduced the Electra’s
attractiveness to major airlines during a time of exceedingly fierce competition, as
America’s economy was finally bouncing back after the Great Depression.
Because of this, several airlines replaced their Electra’s with larger aircraft in
the late thirties and early forties.
By 1942, of the US Domestic fleet of 322 aircraft, just sixteen were model 10 Electras.
But this was not the end of the Electra, not by any measure.
Some would still be operated commercially in the United States well into the late 1960s,
obviously on smaller routes, but still in service nonetheless.
Additionally, a large number of Electras were pressed into use as military transports during
the war.
In the US they were redesignated as the C-36A, B, and C, and they were used almost exclusively
within the continental united states.
However, several Electras were also purchased by the British, and these saw widespread use
as general and personal transports, with one being used by the RAF as the personal transport
for the governor of Bengal.
Of course, perhaps the most famous event tied to the Electra happened before the second
world war, way back in 1937.
In July 1936, a special version of the Model 10-E was built to the specifications of aviation
pioneer Amelia Earhart, who was planning a series of flights to circumnavigate the world.
Modifications included the installation of large fuel tanks in the fuselage, taking the
capacity from 200 to 1,200 US Gallons (or 4,542 litres), and additional navigational
equipment was also installed, notably a D/F loop above the cabin.
Earhart made her first attempt on March the 17th 1937, with Captain Harry Manning as her
navigator, assisted by Fred Noonan, but it did not succeed.
Having started from Oakland, California, they were taking off from Luke Field, Ford Island,
when the aircraft entered an uncontrolled ground loop that damaged the landing gear,
fuselage underside, and both propellers.
There was much debate on the cause of the incident, some claimed a burst right tyre,
some blamed a landing gear collapse, and some blamed pilot error, but either way the flight
was severely delayed as repairs had to be made.
This had a knock-on effect, that has been considered by some to be significant in Earhart’s
disappearance.
Captain Manning, who was not only a navigator, but also a pilot and the only one of the three
considered to be a skilled radio operator, abandoned his assistance in the flight as
it had already taken up a lot of his planned absence.
This left just Earhart and Noonan, who made their second attempt once repairs had been
completed.
Flying west-to-east, their Lockheed Electra carried them from Oakland to Miami, then through
the Caribbean, south America, Africa, India, and Southeast Asia…and then, on route from
New Guinea to Howland Island they vanished, and for the next 80-plus years people have
been arguing about how and why they vanished.
Did they run out of fuel, ditch in the ocean and drown?
Were they captured by the Japanese after straying too far north and being accused of spying?
Did they land on a deserted island, only to starve and then get eaten by coconut crabs?
Who knows, but that’s a topic beyond the scope of today’s video.
Despite the black mark on its history for being Earhart’s chariot of doom, the Model
10 Electra proved itself to be a fast, reliable, and capable transport, if a little bit on
the small side.
It had already been on the way out of major service by the time the US found itself at
war, and after 1945 it found itself being used by small so-called feeder airlines or
private operators.
The type did continue to see service for some considerable time in Central and South America,
being used by Brazil, Costa Rica, Ecuador, and Panama, to name a few, all the way up
to the 1960s.
Though not produced in massive numbers, quite a few Model 10s survive today, partly thanks
to several being in private hands for a considerable amount of time.
Most are on display, or under restoration in the United States, including the XC-35
which is currently in storage/preservation, and there are a couple kicking about in Canada
and New Zealand as well.
Though not perfect as a transport, the Electra was a very good aircraft, and the first twin-engine
design to be built by Lockheed.
But it would not be the last, and the Model 10 quickly evolved into such designs as the
Electra Junior, the Super Electra, and the militarised Lockheed Hudson.
But those are aircraft we’ll cover another day.
As always thank you all so much for watching, and a big thank you of course to the Patreon
supporters.
Now this is the last video that will go live before I am away in the UK for the next four
weeks, so I won’t be able to update the patreon list until I return as I’ve pre-recorded
the next few videos, obviously.
FYI I will be attending RIAT on the 15th, more details to follow soon.
A big thank you of course to our wing commander tier patrons, our highest tier supporters,
and a warm welcome to David Rabinowitz who is the newest member of this special group.
Right, I’m off to furiously begin packing preparations, But as always, thank you all
for your continued support, and I’ll catch you all next time.
Goodbye.