Re: MD80 VS. MD90?

From:         kls@ohare.Chicago.COM (Karl Swartz)
Organization: Chicago Software Works
Date:         17 May 93 15:01:12 PDT
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>I know the MD90 has just been through its introductions barely two weeks ago.
>I (amd I am sure several other people) am interested in the updates to the MD80
>design? What are the differences between the MD80 and MD90?  Size, engine com-
>plement, crew and avionics package? 

There was some discussion in the group about this a while back, with
some answers to your questions, but the March 22, 1993 AW&ST has the
whole story.  Here's some info from that article:

    The MD-90 program, launched in 1989, currently has a total of 77
    firm orders, according to Douglas officials, Customers include
    Delta Air Lines, Alaska Airlines, Japan Air System, GATX, Scan-
    dinavian Airlines System and the Trunkliner program in China.

    Douglas plans to develop a series of MD-90 models as it had during
    the MD-80 program, and the first model of that planned series is
    the MD-90-30.  The Dash-30 has a fuselage 4.75 ft longer than the
    standard-length MD-80 and can carry 153 passengers in a typical
    two-class seating configuration.  Maximum seating capacity is 172
    passengers.

    ...

    The longest range MD-80 series aircraft is the MD-82, which is
    capable of carrying a typical load of 143 passengers over a
    distance of 2,080 naut. mi.  The MD-90-30 with 153 passengers is
    expected to be able to fly about 2,200 naut. mi.

    The MD-80 is in the $30-million price range, and the MD-90 will
    run about $5-7 million more, Douglas officials said.  Initial
    deliveries of MD-90s are scheduled for October, 1994.

A number of differences between the MD-80 and MD-90 are noted.  In
summary:

  * Engines: IAE V2500 instead of the P&W JT8D-200 family used on the
    MD-80, starting at 25,000 lbs. thrust vs. around 21,000 lbs. which
    allows both higher gross weights and a better thrust-to-weight
    ratio.  (These things are huge -- to me the aircraft almost looks
    like it's wearing Mickey Mouse ears when viewed from the front!)

  * APU: AlliedSignal's Garrett 131-9(D) is derived from the APU used
    on the B-2 bomber, and according to AW&ST provides 36% more horse-
    power with less weight and 23% lower fuel consumption as compared
    to the APU of the MD-80 family.  The main reason for the new APU
    was cited as the higher startup requirements for the larger V2500
    engines.

  * Cockpit: Similar in appearance to the MD-88, which unlike earlier
    MD-80 family members has a glass cockpit, with improvements.

  * Electrical Generating System: A new design intended to eliminate
    power surges.

  * Carbon Brakes: The new brakes proide an overall 400 lb. reduction
    in aircraft weight, and with a new digital anti-skid system should
    be more reliable.

  * Wing Icing: The MD-90 incorporates a number of design changes to
    eliminate the wing icing problems of the MD-80 family, which has
    resulted from cold fuel in the wing tanks cooling the upper wing
    surace.

  * Vacuum Lavatories: Along with the elimintion of the MD-80's
    forward service port, this system is supposed to eliminate the
    possibility of blue ice being ingested by the engines while also
    improving reliability.

  * New Interior: Based on the design from the stillborn UHB propfan
    project, this has the usual more light and bigger baggage bins
    features of every new design.  :-)

  * Cabin Airflow: A new environmental control system will increase
    airflow in the cabin, incidently reducing the time needed to cool
    a heat-soaked cabin.

MD-90 Technical Specifications (MD-90-30 from March 22, 1993 AW&ST
with MD-82 specs added from March 16, 1992 AW&ST)

					       MD-90-30      MD-82
    CAPACITY

    Pasengers
    Typical Mixed Class				    153
    Maximum					    172        155
    Cargo Holds (Cu. Ft.)			  1,300

    DIMENSIONS

    Span (Ft.)					  107.8      107.8
    Length Overall (Ft.)			  152.6      135.6
    Height Overall (Ft.)			   30.6       29.8
    Wing Area (Sq. Ft.)				  1,209      1,209
    Sweep Back at 25% Chord (Deg.)		   24.5

    WEIGHTS

    Max Ramp (Lb.)				157,000
    Max Takeoff (Lb.)				156,000    149,500
    Max Landing (Lb.)				142,000    130,000
    Max Zero Fuel (Lb.)				130,000
    OEW (Lb.)					 88,200     78,528

    Fuel Capacity (Gal. @ 6.7 Lb./Gal.)		  5,840
    Cruise Speed (35,000 Ft. ISA Standard Day)	 M 0.76    .76-.80
    Range (Naut. Mi./International Reserves)	  2,268      2,176 *
    FAA Takeoff Field (Ft. @ MTOGW SL Std Day)	  7,000      7,594
    FAA Landing Field (Ft. @ MLW SL Std Day)	  5,130      4,800

Note: I'm not sure than the MD-82 range figure is for the same
      conditions, though it seems about right.

The same AW&ST with the MD-82 specs lists several other MD-90 models:

    MD-90 model		-10	-30	-40
    Passengers		139	172	208
    Length		130.4	152.7	171.7
    MGTOW (1000 lbs.)	139	156	163.5

There's also the MD-95, otherwise known as the Trunkliner project for
the Chinese.  From everything I've seen it appears to be more closely
related to the MD-80 family (which remains in production) than to the
MD-90.

--
Karl Swartz	|INet	kls@ditka.chicago.com		
1-415/854-3409	|UUCP	uunet!decwrl!ditka!kls
		|Snail	2144 Sand Hill Rd., Menlo Park CA 94025, USA
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