When it was introduced, the Boeing 377 Stratocruiser was the largest aircraft of its time. It was an engineering marvel that captured the hearts and minds of thousands, but never truly took off. Why was that?
The Boeing 377 was the first true long range airliner. It had the ability to cross both the Atlantic and the Pacific without needing to land, refuel or change aircraft. Arguably, it made the airline industry what it is today…
Pre-Boeing 377
Before the Stratocruiser was introduced, most airliners were small and only had a single deck. The most common aircraft of the era were the Douglas DC-2, Boeing 247 and Lockheed Model 10 Electra.
At the time, it took over 19 hours to cross the Atlantic, usually with the need to land and act similarly to a boat. Perhaps the most famous long range aircraft of the era was the Boeing 314 Clipper, a flying boat airliner.
In 1944, them-Boeing president, Philip G. Johnson died. This led to Bill Allen taking up his mantle as president. Allen, unlike Johnson was convinced that the future of the airline industry was bigger and faster.
He saw the success of the Boeing 314 Clipper, and other flying boat airliners of the era to prove that. Allen believed that if Boeing could invent a long range airliner that could fly without needed to land, it would be a cash cow.
Allen also saw a period of unrest, following the end of WWII. The US Government was no longer supplying contracts for military aircraft, and the US as a whole saw a mini recession in 1945 following the end of the war.
With that Allen saw that the future of the aviation industry, at least in the short term, would be in commercial airliners rather than military aircraft. As such, he began working on the future of air travel…
Development
Throughout WWII, Boeing had been developing new aircraft for the US military. One of these aircraft had been the C-97 Stratofreighter, a cargo variant of their famous B-29 bomber.
In early 1945, test flights of the C-97 Stratofreighter had seen it cross the US, from Seattle, Washington to Washington, DC. in a record six hours and four minutes. This naturally interested both the military and civilian buyers.
The C-97 entered service with the newly formed US Air Force, staying there until 1952. The record also interested Pan Am president Juan Trippe, who had previously bought the Boeing 314 Clipper.
Trippe approached Boeing and asked for them to develop the C-97 into a commercial airliner that could carrying more than either the Lockheed Constellation and the DC-4.
Trippe wasn’t worried about the price, believing that buying an expensive aircraft would be beneficial to Pan Am. In many ways, Trippe was correct, with much marketing material being focused around the Stratocruiser.
After much tinkering, Boeing unveiled the aircraft to Trippe and his team. Boeing called it the Boeing Model 377, but would soon enter service as the Boeing 377 Stratocruiser, in homage to the C-97’s Stratofreighter name.
Service
The 377 had a long and documented service life, both in military and commercial service, mostly being in the latter.
Military
Despite being a civilian variant of the military C-97 Stratofreighter, several converted military 377s do exist. All of them were former passenger airliners that were purchased by the Israeli Air Force in the early 1960’s.
In the early 1960’s, the Israeli Air Force wanted a cargo aircraft that was larger than anything they had at the time. The aircraft that fit the bill perfectly was the Lockheed C-130 Hercules.
However, the US, pressured by its Arab allies and not wanting hostile nations to get a hold of the C-130, embargoed the sale of C-130s to Israel. This left the Israeli Air Force with no other reliable alternative.
Learning about this, Israel’s largest aircraft manufacturer, Israel Aircraft Industries (IAI), offered to convert retired Boeing 377s. The Israeli Air Force liked that idea, and gave IAI the contract.
By 1964, the first of these aircraft entered service with the Israeli Air Force. Due to their immense size, the Israeli Air Force dubbed them Anak, after the figure in the Torah.
These 377s were designated as the 377M. These aircraft left Israeli Air Force service in 1977, replaced by C-130s for cargo missions. Currently, one 377M is on display at the Israeli Air Force Museum.
Commercial
The Stratocruiser is mostly remembered for its time in commercial service, some of which it is actually still doing!
Passenger
The 377 was first introduced in April 1949, with Pan Am, who soon became the largest operator of the type. Pan Am was one of only 10 airlines to ever operate the type.
Initially, the original orders were only from US-based airlines, with only US-based airlines operating the airliner for a while. Seeing the amazing opportunity of the 377, BOAC ordered several 377s.
Eventually, several US airlines decided to sell their 377s to other airlines. The most notable of these was United’s sale of all of their 377s to Venezuela’s Rutas Aéreas Nacionales and Ecuador’s LÃnea Internacional Aérea.
For the most part, the Stratocruiser operated long haul routes, usually transcontinental, transatlantic and later transpacific routes. The most common route the Stratocruiser flew on was London-New York.
The Stratocruiser was one of the first airliners that could carry a large amount of people and cross the Atlantic Ocean without the need to stop, or become a boat (such as the Boeing 314 Clipper).
Typically, the Stratocruiser had two different types of seating. the first was regular seating, as you’d find on any modern airliner. The second was berths- compartments above where people sat, equivalent to beds.
Cargo
The Stratocruiser first saw service as a cargo aircraft during the Korean War. Following their introduction to airline service, the US military was in need of cargo aircraft, so pressed several 377s into cargo service.
At the end of the war, the airliners wee returned, and the airlines who owned them were compensated. Whilst they went back to airliner service, some didn’t forget their cargo service…
Once the 377 had become obsolete, airlines abandoned the Stratocruiser like never before. Many early cargo airlines took advantage of that, and operated fleets of them on long haul cargo routes.
Several of these aircraft served in this role for over a decade, before becoming obsolete once again. Being retired from cargo service in 1963, due to high fuel costs and no longer being that large.
After this, the Boeing 377 was all but abandoned. Many of them were famously bought out by Aero Spacelines, who modified and re-engineered them heavily to produce the Guppy line of outsize cargo aircraft.
First came the Aero Spacelines Pregnant Guppy, then the Super Guppy and later the Mini Guppy. Both the Pregnant Guppy and Mini Guppy have since been retired. However, the Super Guppy, once even used by Airbus, is still in service.
Becoming Obsolete
In 1952, de Havilland released the de Havilland Comet, the world’s first jet-powered aircraft. Following this, several other aircraft manufacturers began releasing their own jet-powered aircraft.
In September 1956, Tupolev released the Tu-104. In October 1958, Boeing released the Boeing 707. In April 1959 Sud Aviation released the Sud Aviation Caravelle. In October 1959, Douglas released the DC-8.
All of these aircraft threatened the 377’s superiority. They were quicker, they carried more people, they were much cheaper and were more luxurious, being everything airlines of the era wanted.
The result was that the airlines that operated the 377 now had the opportunity to purchase an completely superior aircraft, for much less. Naturally, many of these airlines did so.
Many of these airlines soon took possession of fleets of these aircraft. Soon after, the 377 was retired from most airlines’ fleets, replaced by the DC-8, 707, Comet and/or Caravelle.
The remaining 377s were soon scrapped or stored. Several of them were reconfigured for cargo flights, with all interior being removed. Later on, many of these were converted into the Guppy line of outsize cargo aircraft.
Specifications
The Stratocruiser was itself developed from the Boeing C-97 Stratofreighter. Following its passenger service, the Stratocruiser was developed into several other cargo aircraft.
With that being said, we will look at the most common variant of the Stratocruiser, the standard Boeing 377.
| Specifications | Boeing 377 |
|---|---|
| Height | 38 ft 3 in (11.66 m) |
| Wingspan | 141 ft 3 in (43.05 m) |
| Length | 110 ft 4 in (33.63 m) |
| Crew | 5 |
| Seats | 114 |
| Cruise Speed | 301 mph (484 km/h, 262 kn) |
| Range | 4,200 mi (6,800 km, 3,600 nmi) |
| Service Ceiling | 32,000 ft (9,800 m) |
| MTOW | 148,000 lb (67,132 kg) |
How Safe Was The Boeing 377 Stratocruiser?
To date, there are no Stratocruisers operating in any capacity, not even in heritage flights. However, it is still important to understand how safe or dangerous the 377 was, both then and now.
During its time, the 377 was one of the safest aircraft of its time. And Boeing prided itself on this, marketing it as such. However, when compared with today’s modern jet airliners, the 377 is arguably one of the most dangerous aircraft.
Across all of the 377’s variants, only 13 have ever been involved in accidents, over a period of 19 years (1951-1970). This has resulted in a total of 139 fatalities, making it quite safe for the time period.
However, these do include the 377-derived Guppy line of cargo aircraft. When the aircraft was first introduced, it was considered fairly dangerous, having a well documented issue with the propeller pitch.
Although, following the FAA issuing an airworthiness directive, the issue was fixed. Most 377 pilots developed a technique to counter the pitch issue which soon became widespread.
Ground crews were also taught how often they needed to replace the propellers, and how to restore them after each flight. Despite this, the problem still persisted, although less than it would’ve been otherwise.
How Successful Was The Boeing 377 Stratocruiser?
This depends on how you look at it. Some would say that the Stratocruiser was arguably Boeing’s most successful piston-powered airliner ever. Whilst others would argue it was a waste of time and money for Boeing.
From Boeing’s perspective, the Stratocruiser was incredibly successful. Although it didn’t sell in great quantities, Boeing understood that and priced the Stratocruiser to reflect that, as well as its massive size.
Each 377 cost $1.225 million in 1945, roughly $17.6 million today. The Boeing 377 sold 56 times, netting Boeing roughly $68.6 million (today roughly $987.5 million).
With that being said, from an avgeek’s point of view, it was a massive failure. Aircraft from a similar era, such as the Lockheed Constellation and the Douglas DC-6 were much cheaper and are more common today.
Today, most major air museums around the world, have either a DC-6 or a Constellation. But most don’t have a Boeing 377, and if they do, its usually from the Guppy line of 377s, not an actual 377.
In fact, there is only one non-Guppy 377 on display in any museum around the world. So, unless you specifically travel to that one museum, you will likely never see an airliner- 377!
Legacy
The Stratocruiser operated between 1949 and 1963, before being developed into other aircraft. This left an impact on the Boeing and the industry as a whole.
Boeing
Despite being somewhat of a failure, the 377 was actually quite a profitable venture for Boeing. Whilst it was nowhere near its most profitable venture, it did provide a steady stream of income during the time it was produced.
The Model 377 provided Boeing with a large pool of capital to finance further ventures. This money helped to finance the research for the Boeing 707, the first American jet airliner.
Many of the engineers who worked on the 707 took what they’d learned on the Model 377 and adapted it for the 707. Of those engineers who were the youngest, many of them also worked on iconic airliners such as the 737 and 747.
Following such, many of the engineers who worked under the youngest Boeing 377 engineers, when they were working on the 737 or 747, learned a lot.
These engineers were taught principles of aircraft design that they weren’t at university. All due to the 377!
Boeing 377
Technically speaking, the Stratocruiser was retired in 1963. Many Stratocruisers were stored in the various aircraft graveyards around the world, whilst many others were scrapped.
A few of these Stratocruisers have since become museum exhibits, most notably the Erickson Museum and Israeli Air Force Museums. However, none of these still fly, and are static displays.
After they became obsolete, many Stratocruisers were pulled out of storage and converted by private companies into outsize cargo aircraft. Most notably, Aero Spacelines, with the Guppy line of aircraft.
Whilst the vast majority of these aircraft have since been retired, in favor of larger, faster and more fuel efficient aircraft. NASA still operates a series of Super Guppys for various different roles.
Future Airliners
During its time, the 377 was the largest airliner of its time. It was the first successful passenger aircraft with more than one deck, and remained as such until the A380 was released in 2007.
Although it was somewhat of a failure, Boeing never forgot that both BOAC and Pan Am, the two largest airlines of their time, were both very interested in the 377. Both airlines were the two largest operators of the 377.
The jet aircraft that replaced the 377 were longer than the 377, and carried many more people. However, Boeing never forgot the 377, and its design helped influence the original designs of the 747.
Many of the original designs had some form of double deck, whether a full double deck or a partial double deck as is present today. It was also instrumental in making the low wing configuration a standard for most future airliners.
Have you ever flown on a Boeing 377? What was it like? Tell me in the comments!