DC-9: Short-medium range, small capacity airliner, designed to carry 60 (-10 series) to 140 (-50 series) passengers. Typical model seats 100-115. Generally flies routes 300-1200 miles
-80: Originally the DC-9-80, renamed in 1983. Designed as un up-rated, re-engined version of the DC-9 with new avionics and other technologies. The original model, the MD
-81, was launched in 1979. It carried up to 172 passengers (all coach) to a range of approximately 1500 miles. The MD
-82 had a higher MTOW and uprated engines. It's higher payload allowed a range of up to 1800 miles. The MD
-83 was developed as a response requests by airlines for a longer-range version of the MD
-82. With additional fuel cells (and reduced cargo capacity), the MD
-83 extended its range to 2200 miles.
-87 was developed to meet the needs of airlines for an aircraft that could carry the same number of passengers as a DC-9-50 but would have increased commonality with the new MD
-80s. Few were built but most still fly with various airlines today.
-88 brought the MD
-80 into the digital age with digital avionics and other improvements. Basically, it was an improved MD
-90 was the next step from the MD
-88. It lengthened the fuselage but MDD did not recommend additional passenger capacity. Designed with a similar EFIS cockpit to the MD
-88 and with the MD
-80s basic structure and flight characteristics, the pilots need only take a refresher course to re-certify for the MD
-90. Additionally, IAE V-2500 engines were installed and range increased again to over 2500 miles. However, the MD
-90 suffered intial performance and technical problems, and sales suffered as a result. Many airlines cancelled orders or options. There were two planed variants, the -30 and the -50, which had slightly higher performance capabilities, particularly its range of over 3000 miles.
Essentially, the MD
-90 was MDD's answer to the A320 and came out years before the 737NG. Unfortunately, MDD was unable to integrate their previous experience with mechincal/hydraulic aircraft with the new electrical systems and solve problems Airbus had already mastered.
The 717, originally called the MD
-95, was a "back to basics" program. Designed not from the MD
-90 or the MD
-80, the 717 goes back to the original DC-9, guts it, and puts in new avionics, new engines, and several other improvements to the original systems. Again, flight characteristics are similar enough to the DC-9 or MD
-80 that only short courses are needed for recertification. Range has been reduced to 1400 nm in the basic version, or 2000 nm in the High Gross Weight variant.
Originally, the MD
-95 was to have three variants: The -10, which was to seat 70-90 passengers and was a direct replacement to the DC-9-10; the -30 (now the 717-200), which was to seat 90-110 passengers and was designed as a direct replacement for the DC-9-30; and the -50, which was to seat 110-130 passengers and was designed as a direct replacement to the DC-9-50.
When Boeing and McDonnell Douglas merged, the entire MDD line was heavily scrutinized. The MD
-80 and MD
-90 were seen as direct competition to the 737, especially the Next Generation variants. These programs were cancelled as a result. The MD
-95 was not seen as a competitor to new 737s, except possibly to the -600 which was not designed for short-haul flights; however it was seen as a potential for Boeing to enter into the RJ
market, and besides there were fifty firm orders from ValuJet (now AirTran) and several more from other airlines.
The program was re-designated the 717 (which had been the product code for the KC
-135) and additional engineering was done in collaboration between Boeing and MDD engineers. Only the -30 series was built, and it was given the Boeing series number of -200. The -10, if built, would have been the -100, and the -50 would have become the -300.
Hope this helps.
It's what I know, but I don't waste time posting on threads when it comes to the obvious.
What a nice way to put it... You
had to learn from somewhere, didn't you?
[Edited 2004-12-09 17:21:35]
Those who fail to learn history are doomed to repeat it in summer school.