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The classic piston engine airliner – what an era for the airline growth, and why the jet airplane took over so quickly

Airplane Business 3 Comments

I had purchased a book by Bill Yenne titled “Classic American Airliners” for a friend as a present for the Christmas Holiday season.  When the book arrived, it was in rough shape from the trip, so I set the book aside and ordered another book that would replace this one, and kept the Bill Yenne book to read for myself.  After Christmas, I set down and started to look through the pages, and was romanced by this era of airline travel, when piston engines were it! I enjoyed reading about the Martin 4-0-4, the Convair 240, the development of the DC-4 from the military C-54, etc.  It was about an era when airline flight was being developed, and a time when less than 50% of the population of the United States had ever flown on an airlane.  The 50’s era airplanes represented the continued development of the piston engine airline, and how the booming economy of the 1950’s, drove the technology for bigger and better airplanes. Sure, the jet airline with a faster cruise, higher altitude operation, and double the passenger loads meant convenience and reliability.  However, the classic piston engine airplane used by the airline industry still has a unique place in history.  We will discover how technology AND the economic factors drove the piston engine airliner to extinction in less than 15 years.

The development of the piston airliner was with the Douglas manufacturer and the DC-3, improvements were in the pipeline, but World War II put the industry on hold.  During the war, several developments in piston technology, aircraft design, and the overall size of the airplane had grown proportionally. At the same time the airline industry was being developed, it was being heavily regulated by the Civil Aeronautics Board for all domestic and interstate air transport routes, with regulations that pertained to setting fares, the requested airline routes, and their schedules. While the CAB  regulated the routes/fares/competition, they also had as an obligation to maintain the profitability of the airline, therefore they also set the ticket fee for all of the domestic air travel.

Douglas DC-4 Airliner in flight

The Douglas DC-4 four engine piston airliner

With the CAB given this authority to regulate the commercial airlines, this growing industry would need some guidance. I believe the CAB was tasked to ensure that the airline would put safety above risk taking, and to ensure that any competition that would enter the market, would have a fair chance of succeeding.  If you have one or two dominant players in the market, what you have is a high capital investment for an aircraft the size needed to carry large numbers of passengers, it is easy to force out the smaller competitors.  Just like the FAA is designed to regulate AND promote general aviation, this type of justification for total regulatory type air service made sense.  However, I think it probably should have opened up to the free market sooner, as when, in 1978, airline deregulation was put in effect, air service expanded exponentially, fares dropped, and more convenience with more flights was the final result…and all of this with a GREAT safety record to boot!

The airline industry that was regulated by the CAB therefore, was setting up the competition based on the accommodations, as well as the quality of service as the total means of building their brand.  Since the “profitability” was guaranteed to some extent, service was king and this is what the industry catered to.  Flying by airline was elegant, expensive, and not the most convenient with limited choices for the airlines and the routes they flew.  There were very few direct flights, often with stops along the way, which took time and with the cantankerous operation of the engines, delays were very common. The safety record wasn’t the best either, most likely because of the limited performance and perhaps to a certain aspect, the non-standard procedures that many pilots adhered to at this time in commercial aviation.  This was a time before simulators could demonstrate catastrophic events, and with these piston airliners, there was just more things that could go wrong.

Convair 240 loading ramp

An oldie but a goodie…the Convair 240 with North Central Airlines colors.

The twin engine airliners began development before WWII, and went into production shortly after the end of the war.  The Convair 240 was a replacement for the twin engine Douglas DC-3 airplane, and was the first pressurized twin engine airline to be put into service.  The Martin 404 was in development and started to be delivered a few years after the Convair 240 was being flown by the airlines.  These twin engine airplanes were mostly used on the shorter routes to feed the longer range four engine airplanes, and offered reasonable performance with a cruise speed of up to 280 miles per hour, and a range of around 1,000 miles plus reserves.  Seating capacity was approximately 40 people, with the twin engine piston airplanes providing the feeder to the larger four engine airplanes. The Convair 240 series were eventually converted to turbo-propeller driven aircraft and renamed the Convair 580, with a few of these airplanes still in service serving the freight hauling role.

Twin engine airliner Martin 404

The twin engine piston airliner, the Martin 4-0-4.

The production of the FOUR engine piston airliner started after WWII, with the Douglas DC-4 that had actually been designed before the war.  With the development of the aircraft during the war, the first four engine transports became the military aircraft designated the C-54 Skymaster and delivered to the Air Force in 1942. Many of the C-54’s were converted to civil airline use following the war, although something like 79 official DC-4’s were built after most available C-54’s were converted.  It wasn’t long when more performance, comfort, and capability was what the airlines were demanding, and the competition started to develop the next generation of airplanes.  The DC-6 was the next logical airplane for the McDonald Douglas replacement of the DC-4.  It featured pressurization and can be distinguished from the DC-4 because the DC-6 had square windows Vs. the round ones on the -4. Of course, engine power was continuing to be increased from 1,300 horsepower, to the twin-wasp Pratt and Whitney 18 cylinder R-2800 series Pratt & Whitney engines.  One of the earliest developments of future passenger airliners was in 1938 with the Boeing 307 Stratoliner.  It was the first pressurized airplane designed for commercial passenger flight.  The cabin pressurization was a low 2.5 psi differential, yielding an 8,000 foot cabin while flying around 15,000 feet. This airplane was a huge leap for the industry that up to this point, the Douglas DC-3 was the mainstay airliner.

Boeing 307 in-flight

The pudgy 307 Boeing Stratoliner was the first pressurized airline flying passengers.

The development of the four engine airplanes continued, as the Douglas corporation was sort of leading the pack with the refinements of the Douglas DC-6 over the non-pressurized DC-4.  These larger airplanes weighed between 100,000 to 120,000 lbs at gross take-off weight, with service ceilings somewhere between 29,000 feet and 31,000 feet.  Anyone who has flown a high performance single that is turbocharged, or a light turbocharged twin engine piston airplanes, know that once you get above 20,000 the engines need a lot of attention.  Most of the piston engine airliners that were pressurized were probably not flown in the flight levels very much, it seems from my reading that most were happy to be at 16,000 to 25,000 feet. The fuel burn was as high as 600 gallons per hour on take-off, 400 gallons per hour in the climb, and slightly over 200 gallons of 100/130 octane fuel at cruise. This was for the later development models like the DC-7’s and Super Constellations, which each engine was producing something close to 3,500 horsepower on take-off.  With cruising speeds of around 300 miles per hour for the four engine airliners, it took a good day of flying to get from one coast to the other.

Lockheed Super Constellation

One of the most beautiful airplanes in flight – the Lockheed L-1049

They say that the old four engine airliners made a lot of noise in the cabin, which I am sure on take off at full song, they did probably make a good racket.  The old piston engines were also known for having a certain vibration, while anytime you have large propellers rotating, you are going to have more airframe vibration going through the airplane, no matter how well you have them statically balanced.  Of course, due to the limited performance of these piston airplanes, most were flown at lower altitudes where you would encounter more weather, resulting in perhaps flying through more ice, but certainly more time would be spent in the turbulent summer air. The wing loading of these older piston powered airliners were much lower when compared to the modern jet airliner, so it was two fold in how most airline trips were perceived. With the piston airliner, you spent more time riding in turbulence, while the jetliner climbed at stratospheric rates, and with a heavier wing loading, shrugged off turbulence more easily.

And in some ways…this was part of the romance in aviation that seems to be missing in today’s modern world of sterilized comfort.  I still love the smell of 100/130 octane burning from an air cooled engine, with the smoke or burned oil smell that gives you that feel something mechanical and fun is going on!  The way those old radial engines would slow turn the propeller and come to life, with smoke belching from each engine until it settled into a rhythmic hum at idle while warming up.  The flight itself was flown at a lower altitude, while the climb and decent gave more time to take a great view out the windows at the earth below…something we only take a glance at while on a jet airliner.

Douglas DC-6

A great view of a Dutch Airliner DC-6 in flight.

These large four engine transports would carry around fifty  to seventy  passengers, and a crew of five, with that expanding to one hundred passengers for the shorter haul routes.  The name of the game was LUXURY, and this was the method or theme for most of the air carriers at the time.  Sleeping births were common on the longer routes, which took cabin space and allowed fewer fares, and actual food preparation IE cooking of the meals was common place aboard the airplane with large ovens to cook the food.  Since the airlines were competing on service as the first order of business, they would petition the CAB for a route schedule, along with the operating cost, etc., and the fare would be set whereby the competition would be taken into consideration, which meant if the route was approved, it would be profitable IF they had enough customers to fly the route/schedule.  Of course, this was occurring at a time the economy was really booming, the 50’s was a time of great prosperity, with GDP growth amazing over this decade.  This meant more and more people could afford to take the airline instead of the train or bus, and the airline industry was on it’s way in America.

For the four engines powered airplanes, the take-off performance required 4,000 + feet over a 50′ obstacle, and a landing distance of between 3,500 feet and 4,500 feet of runway, with climb performance not much over 1,200 feet per minute on ALL FOUR ENGINES!  For landing, the Vref speeds were around 110 to 115 knots, with comfortable landing distances between 3,500 feet and 4,000 feet over a 50′ obstacle. The engines for these airplanes continued to develop more horsepower…at the expense of some reliability.  At the time these piston airliners were the mainstay for the airline industry, the engine overhaul shop was quite busy with most engines torn down between 800 and 1,200 hours for in house overhauls.  The photo below shows the leaking oil that was quite normal for the large radial engines, as they all seemed to have some type of an oil leak and would leave drops around the engine anytime it was shut down.

Aerial view of airport with piston airliners.

A view on the ramp back when the piston airliner was king.

Each airline had preferred relationships with the manufacturers, such as TWA’s association with Lockheed which explains the Constellation series with TWA…and it’s relationship tie in with Howard Hughes. United Airlines seemed to be a long time Douglas client, while Pan American Airlines was a Boeing customer who liked the Boeing Stratocruiser. This wasn’t a hard and fast rule to the market, but that is a breakdown of how the airlines would choose which type of airplane they were going to fly, as I can’t find any information that shows United Airlines took any deliveries of a Super Constellation. The Boeing 337 Stratocruiser was an interesting airplane in that it was  development from the B-29 Superfortress airframe.  It included a lower deck lounge that was sort of small, but was a novelty that set it apart, as well as the Boeing 337 Stratocruiser being a long range airplane. The airplanes continued development, with longer range, more seating capacity, more range and performance.

Boeing four engine piston airliner

The odd looking Boeing 337 Stratocruiser.

The last iteration of the four engine piston airline type aircraft were at a point they couldn’t push the performance envelope much more. The last versions of the twin row 18 cylinder turbo-charged AND  supercharged aircraft engine, just didn’t have the reliability that would make the airlines happy.  The airlines continued to operate and buy the four engine piston airplanes, but something new was on the horizon, and that was the jetliner that not only almost doubled the cruise speed of the piston airliner, it also carried almost twice the passenger load. These four engine piston airplanes kept a crew busy, considering the all weather flying they were doing, and with engines that needed constant attention. For the most part, once a turbine engine is started, you only need to monitor the limitations for N1 speed, turbine outlet temperature, and other parameters, other than that, they don’t require constant tweaking like the piston aircraft engines.

Douglas DC-6 flight deck

Look at all the dials – this would keep the crew busy on take-off…hence a flight engineer was required.

When Boeing first introduced the Boeing 707 to the airline industry, most thought that due to the high fuel burn of the four engine jet powerplants, that there was no way they were going to make a profit.  However, the industry learned very quickly that the capability AND the fact most people were intrigued with this new fast commercial airplane, it pretty much ran the piston airline business out of business quickly!  Why putt when you can zoom, so the jet set made it clear they were all in on paying more to ride the swept wing airline JET, as this was the modern era and it wise time to step up the game. Believe it or not, the Boeing 707 was the “hip” thing and it changed the culture for the modern age society.  Frank Sinatra sang the lyrics “Come fly with me, let’s fly, let’s fly away”, which was released a month after the first Boeing 707 went into service.

The Boeing 707 was first delivered in 1958 to Pan American Airlines, while the Douglas DC-8 came shortly thereafter.  Although there were a few jet powered airliners, they had a few problems including the de Havilland DH 106 Comet which first went into service in 1952, which with well publicized accidents in the first year of operation, sort of slowed the development of jetliner service.  But Boeing got it right, and the popularity of the 707 represented the new age and from everything going forward, commercial air travel became – either you were in a jet or you were out of business! There was no turning back, the jetliner continued it’s development and immediately was used for all overseas routes, as the savings in time and the reliability made the jetliner the only airplane to be considered, while domestic flights were taking notice that the jet was going to quickly replace the piston airliner.

Tex Johnson flying first 707

First Boeing 707 in flight…swept wings and the modern age of airline travel

The airlines quickly realized that all you had to do is feed those engines kerosene, and they would run almost forever, with very little maintenance in between.  Due to having the performance to get above the bad weather, and the capability and range to have alternatives, the airline industry safety record improved significantly.  The jet had much fewer in-flight engine shut downs, while performance with an engine shut down on a four engine transport still guaranteed a good climb rate, and without having a high workload such as shutting an engine down while feathering a propeller, things just got better and the safety record proved that. The days of the piston airliner were soon to be over, with the economics of the jetliner making more and more sense, the speed and utility value of the modern jetliner, made any further development of the piston airliner something the manufacturers understood would never pay off with down the road. The last upgrades to the piston airliners, the Lockheed Super Constellation 1049G, and the Douglas DC-7 were a tough sell…and these were the last to be produced before shutting production down in 1958 for both of these models.

What we have here is simple economics, that utilized technology developments to drive the industry to where it is today.  You have to look at consumer demand and preferences, which you can see by the market driven to the jet age, people wanted faster travel, more comfortable travel, and the market brought pricing that was very affordable.  As I look at Allegiant Airlines or Southwest Airlines, many fares are so cheap there is no way I could drive a car for that price, so the business model works, as well as the competition to offer many choices of flights.  This is what capitalism is all about, and why we need to stress this economic system as the best in the world, because it works so well.  We can complain about the customer service with the airlines, sometimes the layovers seem to be too long, etc., but you can’t argue with the fact that ticket prices and schedules have many choices for the consumer.

 

3 Responses to “The classic piston engine airliner – what an era for the airline growth, and why the jet airplane took over so quickly”

  1. Rod Beck Says:

    Hello loyal readers!

    Ones again, another fine article by my good friend and colleague, Mr. Mike Dempsey!

    Well, I’ll go back to 1951/52,when our 3rd grade class had the opportunity to “tour” Newark (now Newark- Liberty Airport-EWR)New Jersey. I recall clearly sitting in the cockpit of ether a Martin 202 or Convair 240, probably operated by Mohawk or Allegheny Airlines, not sure which; being nearly 65years ago, “headset” and all!

    Boy; was that really SOMETHING!

    The following summer, July 15th,on my 9th birthday, my father treated me to a “ride” in a Cessna 120. The pilot plus the TWO of us – looking back, I don’t know how that little bird ever got off the ground from Blairstown’s (1N7)short(2,000 ft then)grass runway on the humid day!

    But, by the time I was 15 or so, I’d flown, (as a student or dual)a J-3, Clipper, Super Cub, and Tri-Pacer – But that’s ANOTHER story for another time!

  2. Scott Says:

    Excellent post and love the historical survey! I love turboprops and jets! If I ever win the Powerball the L39 would be my dream toy jet to have fun with or an F5 Phantom!

  3. admin Says:

    Scott,

    Yeah…those old classic airliners were cool, I think that was a time when one of these airplanes flew overhead, you stopped and watched it as it was climbing out, cruising over, or on the descent for a landing. Now, a quick glance is more than anyone ever pays attention to a commercial airliner. I enjoyed reading about the development of the airplanes themselves, the market had continued to grow and the airlines themselves wanted more and more market share as they grew. The powerplant was where they just couldn’t get anything out of the radial engine anymore, as the Super Constellations 1049G and the Douglas DC-7 were pushing the engines at something like 3,500 horsepower for take-off. If you go to Youtube and check out the “classic airliners”, there is some great video of some of these great old airplanes that people have shared on-line.

    Regarding a Powerball winner, I think a fun little personal airplane would be the Sonex Aircraft SubSonex singe engine jet. Aerobatic, low operating cost, good performance at a price that even if you only won $250,000 on the Powerball, you could own and fly one of these. There is also a lot of Youtube video on the SubSonex…I especially like the video of the airplane doing a demonstration at Airventure, it looks like a very fun airplane.

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