Update – McDonnell Douglas MD-91/92

Indeed, the emergence of the propfan, in whatever form it technically exists, has in recent years cast a shadow on the long-term viability of future-generation airliners wearing today’s family of turbofans. However, even the mighty Boeing has firmly placed its 7J7 propfan project on the back burner due to a degree of confusion in the marketplace as to precisely what is required and also due to a reluctance to invest almost four billion dollars (AUD) in a development programme that the airlines are presently only lukewarm about. In the interim, with only around $140m invested to date on the 7J7 programme, Boeing is quite happy to sit it out awaiting an eventual major hike in jet fuel prices that will undoubtedly become the fiscal driver for propfan aircraft.

Boeing is also presently saddled with not unsubstantial development costs on their 747-400 and 737-400 airliners and is hoping to sell many more 737s and 757s in a world without the 7J7. From Boeing’s perspective a delay of several years on the 7J7 is a very wise move.

A little over a thousand nautical miles south of Seattle lies Long Beach, the very home of Douglas. Now long merged with McDonnell, the people at Douglas still only speak ‘airliners’ and they are nowadays more than happy with the hand that fate has dealt them with their much admired DC-9 family of twinjets.

The future success of MDC is essentially secured on the back of the initial design of the first DC-9 way back in the early sixties. While Boeing at that time opted for its small domestic jet being of standard underwing engine design, Douglas went the road of BAC, Sud Aviation, Tupolev and Fokker and launched with a rear fuselage configuration that today magically allows the DC-9 airframe to be configured with propfan engines without a major redesign.

And this is the very reason the people at Long Beach are smiling. They always did well with the basic DC-9 twinjet. Indeed it beat the 737 into service by a full two years and due to the strong company heritage managed to not be unduly worried by its European competitors. In this environment, and aided substantially by the company’s willingness to entertain individual customer alterations to the basic design, the DC-9 flourished at a time when though a successful programme, the DC-8 long haul jet was definitely playing second fiddle to the hot selling Boeing 707.

MDC’s mistake though was to let production of the DC-9 lapse in the late seventies just at a time when deregulation was beginning to turn the vast US domestic market upside down with a massive, and unforeseen, requirement for small jets in the 100/ 120 seat class. Boeing scored all the goals on this one and as a result, its little 737 today has more than 2,000 sales to its credit. MDC didn’t entirely let the DC-9 lapse though (though a further development or upgrade of the basic Series 30 would at the time had proven a major seller) . as they looked ahead at tackling the 727 trijet head on with a similar sized development of the DC-9-50 which was duly designated the DC-9 Super 80.

History of course records that the Super 80 gave way to the MD-80 largely thanks to the corporate strain put upon the company at that time due to the ravaging that the DC-10 was (unjustly in technical terms) receiving almost daily in the lay media. This aircraft immediately attracted the interest of a large number of existing DC-9 operators who were also looking to replace early series 727s and augment their existing 727-200s in a rapidly expanding US airline environment.

The fact that the MD-81 burnt around 33% less fuel per air mile than the 727-200 was more than a major drawcard for the new and very stretched MDC twinjet. A measure of the success of this airliner derivative is that total MD-80 series sales are rapidly approaching those of the original DC-9 family with probably 2,000 total units being achieved before the end of this decade.

Enter the propfan concept and a tailor-made opportunity for MDC to have potentially the hottest selling airliners in their class in the decade to come. Why? Well the reasons are simple and neatly added together provide the Douglas division of MDC with a future airliner programme that almost cannot fail to be a success.

Firstly, MDC will be able to offer the marketplace the first commercially available propfans (burning around 40% less fuel per seat mile than the rival latest generation turbofans) in 1992/ 93. Even if the stalled Boeing 7J7 was given a relaunch now, it could not hope to be certificated and in airline livery before 1994 at the very earliest.

Secondly, as both the MD-91 and MD-92 are derivatives of an existing design, their individual development costs are far less than any new rival. MDC financial strategists estimate that while Boeing’s total development costs on the all new 7J7 will exceed $4bn, Douglas’ outgoings on both of the propfans will be around one third of this figure. Douglas have long ago amortised most of their ongoing R&D work on their twinjets with over 1,800 total orders written against the basic fuselage and systems and more than 700 against the newer MD-80 series wing. An all new design has to have this huge development sum written into the cost of each airliner delivered for x number of years and this could equate up to a saving of $5m an airframe for MDC. In short, the MDC propfans, seat for seat will be substantially cheaper to acquire than any competing all new propfan while still keeping them commercially competitive against the new turbofans such as the A320 and the 737-300/400 series. Thirdly, the MD-91 and 92 will still to all intents and purposes be essentially DC-9/MD-80 series aircraft and will as such attract some measure of commonality. Existing long time Douglas twinjet operators will be more attuned to listening to the MDC sales teams as they attempt to translate customer involvement from mere interest to contract status.

Finally, the ‘new’ MDC propfans will be the only real aircraft displaying this technology for many years to come. To add to this is the fact that the company is also offering not one but two aircraft that will be the essence of aircrew and maintenance commonality and will in terms of fuel burn outfly any conventional competitor either presently in production or envisaged for many years to come.

Another major benefit of the original DC-9 fuselage diameter is that it provides for a five abreast economy seating configuration as against six abreast for the Boeing family of single aisle airliners. Therefore an airline immediately eliminates by a factor of 50% one of the most disliked experiences in air transport – having to be seated in the centre seat in a crowded aircraft. This is okay if perhaps if you surrounded by the Swanettes though as fate would normally have it your two buddy companions are more likely to be of the oversized gorilla variety! With a DC-9/MD-80 your chances of having to endure this are 50% less to begin with than on the rival product. The other benefit is that MDC can offer slightly wider seats than can Boeing making the standard MD-80 seat fairly similar to the new wide seats now offered by Airbus on their A320. Again the cabin diameter also lends itself nicely to a four abreast first class configuration or conversely offering comparable seating standards to business class passengers as Canada’s Wardair do thereby offering a domestic business class that rivals many competing first class configurations. These points are rarely missed by the paying passenger.

So what essentially will these new propfans from Long Beach equate to in technical terms?

The MD-91 will be essentially a propfan version of the existing MD-87 (which is what the DC-9-30 should have been developed into more than a decade ago with Douglas pushing Pratt & Whitney to refan their JT8 many years earlier) and will feature the same, though derated, General Electric GE36 UDF engine as its larger brother. Accommodation will run between 115 and 130 passengers and the aircraft will have the same excellent field performance as the turbofan MD-87 with a max pax range of over 2,500nm.

The MD-92 meanwhile will actually be a stretched version (yes, there is still additional ‘stretch’ left in that long lived fusel age!) of the present MD-88 and will accommodate between 140 and 170 passengers. Field performance will be similar to existing MD-80s while range will be a little better than the MD-88. Certainly both variants will be able to fly comfortably against any headwind from Sydney to Perth at maximum passenger load and at a cruise speed that will be faster than that of the 737. Projected flyaway cost of the MD-92 will be, according to Douglas, similar to that of the A320. Douglas though are already a part of the way to being able to offer new generation propfans with their present MD-88. The 88 is essentially a glass cockpit version of the long-range MD-83. The MD-88 features a Sperry EFIS glass cockpit with four multi-display CRTs, an integrated Flight Management System (FMS), full Cat Ill all weather landing capability, inertial reference and increased use of composite materials providing additional strength and lighter weight. The beauty of the MD-88 is that Douglas are confident that it will be able to be later retrofitted with the GE36 replacing the existing P&W JT8-219s to literally become a present-day entry-level propfan. Delta endorsed this concept to the tune of a launch order for some 110 MD-88s in 1986 with the first having entered service late last year. Delta, an airline with an impeccable engineering record, will in time probably undertake the retrofit conversion themselves just as they did for their large DC-8 fleet a decade back with the substitution of P&W JT3s for CFM56 high bypass turbofans. In the MD-91/92, McDonnell Douglas have a worthy successor to one of the most respected short to medium range airliners ever built. That the offspring of the original DC-9-10 design will live on till the next century is a credit to the team that so many decades before also just happened to give us the mother of all commercially successful airliners – the DC-3.