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2022-07 #8 The Sporty Game

It's no secret that military aviation funds a lot of technology in the aviation business and that technology is applied to the commercial world. But the real driver of aircraft development was largely a guy named Juan Trippe, the founder of Pan American Airlines. In the 1930's commercial aviation in America was largely funded and subsidized by the US post office. Different airlines would be awarded a mail contract between certain cities and hauling people around really wasn't thought of much. Mail flying, and aviation was very dangerous in the 1930's as there were rarely any navigation aids, weather could be terrible and the planes were still being built from fabric and wood. Metal aircraft such as the Ford Tri-motor and later the DC3 the DC6 and the Boeing 314 would start to change all that.


But it was inevitable that people would be flying around in planes pretty soon. At a time when the great Zeppelins of Germany were landing in New York, America was still giving barnstorm rides and delivering the mail in surplus Jennies. America was pretty far behind the world.


Juan Trippe saw an opportunity to fly mail from Miami to Havana Cuba, which in 1934 was still a big deal and the fledgling PanAm was born. Trippe expanded his routes over time and eventually had about 2400 miles of routes around Central and the Northern part of South America and like all airlines the mail was subsidizing the carrying of passengers. European airlines were predominantly national airlines, fully funded by their governments to project influence around the world. By this time Air France, British Airways and especially Lufthansa were also starting to project power around the world and in Latin America. Trippe was able to convince the government that this was legal but largely in conflict with the Monroe Doctrine that held the Western hemisphere belonged to the US. We were also in the shadow of WWI where the Germans were not looked upon kindly and we were pretty isolationist. But he does convince the US govenment to raise postal rates for international deliveries making air expansion viable.


So fast forward. The US funds PanAm to do a lot of development and Tripp's next big thing is to go trans Atlantic with mail and passenger service. At the 11th hour the British, Germans and French - who held the intermediate lands on the 3 viable routes to Europe all put a kibosh on PanAm's Atlantic dreams. Trippe then had the Martin M-130 or China Clipper built and opened the air route across the Pacific through Hawaii, Midway, Wake and Guam to the Philippines at a time when no one thought it possible. The distance to Hawaii was about 2,400 miles and there wasn't a plane built that could fly that far until the China Clipper. The M-130 had a range of 3,000 miles but you still had to hit a tiny spec of land in the middle of an ocean for this to work. Concurrently radio navigation was developed and with land stations on the islands the age of the flying boat was born.





By the late 60's Pratt was well entrenched in commercial aviation. The B707 and the Douglas DC8 were powered by the P&W JT3 and the B737 and Douglas 727 were powered by the more powerful JT8. Both of these engines were successful military engines before going commercial. HOwever, none of these aircraft had the carrying capacity nor range that PanAm wanted. PanAm wanted a transpacific airplane. The other big players like American Airlines and Delta Airlines wanted something that would do the US coast to coast, US north to south and trans-Atlantic.


In those days the airplane maker contracted with an engine supplier and the engine maker was just like any other parts supplier on the airplane. Boeing selected P&W' s JT9 for the engine on the B747, Lockheed was developing the L1011 with the Rolls Royce RB211 engine and having lost the B747 bid, GE was contracted to the Douglas DC10 with the GE CF6 engine.


The B747 was immediately successful and still flies today. The "Queen of the Sky" is an icon in Aviation. But the airplane was big and the DC10 and L1011 were the right airplane domestically. The problem was there were 2 airplanes that were basically identical competing for the same business. The L1011 eventually disappeared along with Lockheed's presence in the commercial aviation field. Airbus eventually was formed as a 3rd airplane maker, again heavily subsidized by the governments involved, as Douglas started to wane due to the competition having financially gutted them. The DC10-10, DC10-30 and eventually the MD11 (a modern computerized airplane) were all successful but Douglas never could regain their place in American aviation, retreated back into military jets and eventually sold the commercial business to Boeing.


The math on jet engines is relatively straight forward. How much does it cost to build a new design engine, times how many airplanes do you think will be built, plus the spare parts you will sell over 20 years. Today the cost of designing and build a new centerline engine is about $1 billion dollars. When a new engine is proposed most companies are betting the farm on it.


It helps if you can adapt a current engine to cover multiple airplanes. GE proposed the 41,000 pound thrust CF6-6, the -6 suggesting a 6:1 bypass ratio, for the DC10-10. Later as the airplane got heavier the newer, more efficient and more powerful CF6-50 was fitted, the -50 suggesting 50,000 pounds of thrust. This engine was built for the fledging Airbus corporation who wanted to build a smaller twin engine jet called the A300, for high capacity and shorter European routes. Then GE had a brainstorm, went to Boeing and proposed fitting the GE engine on the B747. Like all airplanes of the time it was growing fast and needed more thrust. GE proposed that the customers would also like to have a choice on which engine they could have. GE's engines were performing well on the DC10 and the Rolls engine doing well on the L1011. Europe especially liked that Rolls Royce could get on the B747. Boeing agreed and it is reported that GE had to pay Boeing for the engineering costs to adapt the CF6 engine to the B747.


So it was done. GE was powering the the DC10-30, the B747 and the Airbus A300 with basically the same engine. Boeing also made a short version of the B747 called the SP or Special Purpose although a lot of us called it Fluf for "Fat Little Ugly Fucker." Other nicknames included Stupid Purchase, Short Plane and SFP or Short Fat Penis.


Qantas used this aircraft on the transpac route also called the Southern Cross route via SFO, Hawaii, Fiji. The B707 had been doing this route but the 707 only carried about 190 passengers while the SP carried over 300. The standard B747-200 carried about 480 passengers. With fewer passengers and weight, more fuel could be carried making these routes viable for the B747 while allowing Qantas, PanAm and United Airlines to carry more passengers per trip compared to the B707 and DC8.


Lufthansa also bought some SPs but JAL and ANA bought a bunch of them. Japan needed to move a lot of people around in a very small country. They didn't need so much the fuel range but the passenger capacity. The 747-SP for ANA had a special variant of the CF6-50 engine called the CF6-45. It was basically the exact same engine with a 10% detuning that would make it burn less fuel and last longer in service. Japan also used high density seating allowing up to 550 passengers to be crammed in like sardines on flights only lasting an hour or so.


Commercially, P&W was still the big dog with the B727 and B737 aircraft. In terms of engines sold and spare parts revenue the JT8D was a cash maker but GE had a good foothold in the business by the mid1970s and when I started working at GE the big deal at Ontario was the CF6-6, CF6-50 and the TF39 for the C5, all of which were being overhauled at GE's facility in Ontario.


If one is interested in the evolution of the engine competition I can highly recommend the book, "The Sporty Game." Not only does it explain how GE got on the B747 it goes into more depth on the people and the inevitable evolution where the engine became a separate competition from the airplane with different pricing and features. So that by the 90's an airline made a choice between say an Airbus A300 and a Boeing B767, largely similar airplanes, and then decides which of 3 engine makers they wanted on the airplane. The 80s became the heyday of air travel expansion and there was lots of money to be made. Freddy Laker, the DC10 and low cost flights to Europe allowed thousands and thousands of kids to backpack through Europe and basically invented the low cost/no frills airline. Additionally, overnight package delivery by FedEx founder Fred Smith along with UPS, DHL Airborne Express and others opened huge cargo airplane markets.


Here's a snapshot of the growth of the industry:





The CF6-50 - A single stage Fan provides core flow and bypass flow from one blade. A 14 stage compressor, 2 stage HP Turbine and a 5 stage LPT. The gearbox which houses fuel, oil and hydraulic pumps as well as the generators and engine control is moved to the bottom of the Fan case. This was the engine I learned my chops on.




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Keep em coming, I LOVE this shit !


Your comment about CF6-50 being "de-rated" to make the CF6-45 reminded me of the engines on the F-4 Phantom (another GE product - the J-79s) being "de-rated" after the Vietnam War so that they stopped spewing out tons of black smoke.


One big jet question for you - in the absence of a whole new fuel or engine geometry, do you think that there is much more room for big improvements in jet engine design ? It seems that all the amazing stuff, such as axial flow to centrifugal flow, afterburners, high bypass engines, massive material improvements in turbine blade design etc, have been done.


I'd love to know if any true…

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Dan Deutsch
Dan Deutsch
20 jul 2022
Contestando a

You have to wait for 40 years of career stories for that - LOL...


Spoiler alert(s) - The smoky F4s are a result of incomplete combustion. Fuel isn't a lot different today but engines are. The other thing you'll notice is the TF39 and CF6 are long engines. Engines bow and flex and heat and contract. This leads to blade tips rubbing against stationary seals and so on. The engine can also get what's called "bowed rotor" - When shut down the heat rises to the top. After a couple hours the top is more expanded then the bottom. When you start the engine you get vibration that takes a while to go away.


So the idea is to make…


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