I was reading, today, a bit about "Payload vs. Range" optimizations, and I've (occasionally) mentioned, before, how the a/c manufacturers, at the request of operators (or of their own accord for market needs) often bring out newer (stretched or shrunk) variants of their already deployed aircraft. This is because it's (likely) easier (speaking, here, naively, of course...), for the manufacturer, to build from a proven (and field-hardened) model rather than start with a clean-sheet design e.g., a stretch will be achieved by adding extra plugs to the existing fuselage, but much of the design (systems and flight controls) etc. can be carried over. For example, compared with the A320, the A321 has a stretched fuselage, with forward and rear fuselage plugs totaling ~23ft (front plug immediately forward of wing 14ft, and rear plug directly behind the wing ~9ft). Likewise, for the stretch from B737-700 to B737-800, the fuselage plugs are ~10ft (forward) and ~9ft (aft), for a total stretch of (approx.) ~19ft. 

Here are few other, well-known, examples:

1. A310 and A330/A340 are derived by shrink and stretch from A300, respectively.
2. A318/A319 and A321 are derived by shrink and stretch from A320, respectively.
3. A340-500/600 are stretches from A340-300 (The A340-600 is one of the longest and thinnest planes, I've ever flown on).
4. B747SP is derived by shrink from B747-100. (It was a joint request between Pan American World Airways and Iran Air, who were looking for a high-capacity airliner with enough range to cover Pan Am's New York–Middle Eastern routes and Iran Air's planned Tehran–New York route. The Tehran–New York route, when launched, was the longest non-stop commercial flight in the world. The 747SP is ~48 feet shorter than the 747-100.)
5. The (longest) DC-8-60s were stretches from the earlier DC-8s (e.g., DC-8-50).
6. MD-87 is derived by a shrink from other MD-80s (e.g., 81/82 etc.).
7. Derived from B737-300, B737-400 was a stretch whereas B737-500 (an afterthought) was a shrink.
8. The (ever popular) B737-800 was a stretched version of the B737-700.
9. B737-900/900ER are (equal) stretches of B737-800 (-900ER proved popular, but -900 not so much...)
10. The 737 MAX 9 has a longer (stretched) fuselage based on the 737 MAX 8. 

So, all such stretch or shrink considerations, from the base model, are driven by "Payload vs. Range" optimization requirements. For a given a/c variant, the aircraft is able to carry a maximum Payload over a specified Range, as shown on image #1, below, until a certain point (X), beyond which the Range can only be increased further if the operator is willing to reduce its Payload in exchange for fuel....

737 being such a historical example of a/c evolution, out of curiosity, focusing on it a bit, here, I've shown pictures below, one each, of the (-600/-700/-800/-900/MAX-8/MAX-9) variants. As you visualize, in these figures, the (successive) stretches of these models, please also find, here, below, the respective (Payload, Range, and Length) data (approximate values), for each model. 

737-600 (15,400 kg, 4,500 nm, 102 ft)
737-700 (17,600 kg, 4,400 nm, 110 ft)
737-800 (21,300 kg, 4,000 nm, 129 ft)
737-900 (21,100 kg, 3,200 nm, 138 ft)
737-MAX 8 (20,830 kg, 3,500 nm, 130 ft)
737-MAX 9 (20,000 kg, 3,500 nm, 138 ft)

As seen, in the above data, for these successive (737) models, as the supportable Payload of the model increases, its Range (typically) decreases.

Thanks for your interest...! Good flying...!!

Edited October 2, 20223 yr by P_7878

Excellent post my friend . 🙂

Interesting. Your last few posts have really been getting into the long and short of it. 😀

John

Thanks, johnb, and John F.....rhymes a bit....🙂....!!

[John F: Can never get enough of these 737s....🙂.... such a long history (and generations) of evolution......!]

Very nice set of shots and post! 😉 

Excellent post and shots.  As a real world aircraft A&P technician I have to agree completely.  It's also easier for the manufacturer to use the existing jigs and cheaper than creating an entirely new plane which takes a long time for certification.

3 hours ago, Alaska738 said:

Very nice set of shots and post! 😉 

Thanks much, Will. Cheers...!!

 

57 minutes ago, Jack_Sawyer said:

Excellent post and shots.  As a real world aircraft A&P technician I have to agree completely.  It's also easier for the manufacturer to use the existing jigs and cheaper than creating an entirely new plane which takes a long time for certification.

Glad to have your feedback, Jack...! Appreciated...!

Excvellent info and shots, P_7878 !!

Info and shots 👍

cheers 😉

bernd, pmplayer: Thank you both...for the comments...Cheers...!