In my trip back home from work in the bus, I thought about the 737 and the speculation about its future. Coincidently, my acquaintance and fellow blogger Saj Ahmad stated boldly today, “BOEING 737 WILL BE REPLACED – NOT RE-ENGINED” It’s a valid opinion. Why not?
However, the replacement might well be based on the 737.
Around the 737 there are several interesting concepts and question to consider.
- What is meant by “re-engining”?
- What is a “new aircraft”?
- When will the new product, be it “new” or “derivative”, will enter the market?
A friend of mine even asked a deeper question, “what is a “replacement”?” In his mind, a replacement is when a product is replaced by something very similar. He added that we often mix up “replacement” with “market change”. To illustrate his opinion he ask the question, “Is the 777-300ER the replacement for the 747-400?”. This friend, who works at Airbus asked further, “Is the A380 a replacement for the 747-400?”
He made a good point and I do not know the answer.
Now, back to the 737. Will the 737 replacement be a true replacement of the 737NG? Well, I do not know the answer although I have the feeling Boeing would like to focus on a slightly bigger capacity short-range aircraft. If my feeling is right then they will propose a short-range (transcontinental) product in the 160-210 seat category or the equivalent capacity of the 737-800 and 737-900. For the sake of simplicity we will call these “new” products as 737-8 and 737-9, after the 787-8 and 787-9 or 747-8.
Several months ago I wrote an entry related to a speculation about Boeing-Bombardier cooperation. In that blog entry there is a link to a press article in which Mr Jim McNerney reportedly said, “The CSeries and the other regional jets that are getting a little bigger, that’s not necessarily a market segment we want to be in.” The most interesting word here is “necessarily“. I like big guys’ discourse, they always have the right word to introduce some kind of fuzzyness. I did ask the question whether Boeing would focus on the bigger short-haul aircraft to a fellow blogger with whom I had a chat this summer in Montréal (by the way, if you go to his page, please click on the “$700 billion”). His answer didn’t give me a hint whether it was a positive one or a negative one.
If you ask me, I would say that the smaller short-haul narrowbody market is a crowded one and will be even more crowded in the coming years. Therefore, I do not think Boeing would focus on a product and fight in a market where the margins will be too thin. That will leave enough place for CSeries to grab a major share in the 100-130 seat narrowbody market permanently.
The 737 fuselage is well proven. The 737 fuselage production at Spirit Aerosystems facilities is awfully efficient. The transport infrastructure from Spirit’s plants to the 737 final assembly is also quite efficient. So, I do not see any reason to change this situation. Some clever people out there speculate about composite fuselage for a narrowbody. Frankly, I just don’t see any valid reason to switch to composite fuselage.
I once had a discussion with a very experienced weight engineer who worked at Airbus and who retired a couple years ago. He told me that there is not really a need, from the strength of material point of view, to use composite for a fuselage as small as 737’s. He added that 737’s skin can be as thin as 1.1 milimeter. In proportion it is the thickness of a coke can. Using a material as strong as carbon fiber would not give any benefit.
My conclusion is that if Boeing’s future short-haul aircraft is a narrowbody then they may want to keep a similar metallic fuselage as the current 737. Perhaps they will bring some alloy updates, but there is nothing revolutionary here.
I beg Boeing engineers to change the cockpit windows. I hope they read this blog.
If the fuselage remains metallic the question is whether they will do something about the wings. My humble opinion is that a Carbon Fiber Reinforced Plastic (“CFRP”) could well be a very good solution, including the wing ribs.
Metallic body and CFRP wings sound familiar, dont they? Yes, I think this combination is an excellent choice.
In order to achieve the right ecological and economic efficiency, the new product will need new engines. Well, can’t we call this a “re-engining”?
As far as the 737-8 and 737-9 are concerned and considering Boeing past solutions, I honestly think they would adopt an engine with “moderate” fan diameter which will keep the weight down. Since they already put the CFM engines on the 737, I do not see any valid reason to put an engine other than the LEAPX. The Specific Fuel Consumption (“SFC”) of those engines won’t be as good as other solutions. But at overall aircraft level, the benefit of smaller nacelles, lighter structure and lighter engines will give an excellent efficiency.
The changes described above are quite significant. Designing more appropriate and optimized landing gear would make sense. So yes, the landing gear will be a new one.
How Does It Look?
Should you call them new aircraft? Can it be considered as “re-engining”. I don’t know. Perhaps it should be considered as a new aircraft, especially when you know that the guts (“systems”) will be largely new.
Last but not least, the 737-8 and the 737-9 will have a “partial fly-by-wire” concept. I don’t think Boeing engineers want to put a full fly-by-wire on the narrowbody.
So, how will 737-8 and 737-9 look like? Considering the above mentioned aspects, the 737-8 and 737-9 will look very similar to the current 737-800 and the 737-900ER.
Window of Opportunity
The 737NG entered into service about ten long years after the A320 entry into service. In my very humble opinion, the 737-8 and 737-9 can enter into service well after A320 NEO. I believe Boeing will target LEAPX’ maturity for its 737-8 and 737-9 entry into service.
The year 2020 sounds very well, “twenty-twenty“.