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McDonnell Douglas YC-15

United States (1976)
Picture of McDonnell Douglas YC-15 Tactical Airlifter Transport Aircraft Prototype

While the USAF moved away from its AMST program which begat the YC-15, the design - in modified form - reemerged to become the C-17 Globemaster III transport.


Detailing the development and operational history of the McDonnell Douglas YC-15 Tactical Airlifter Transport Aircraft Prototype.  Entry last updated on 1/12/2018. Authored by Staff Writer. Content ©www.MilitaryFactory.com

During the early 1970s, the United States Air Force (USAF) actively sought a replacement for its excellent and highly-capable, yet-aging, Lockheed C-130 "Hercules" high-winged transports. These aircraft were introduced in the mid-1950s and went on to see extensive adoption and service across the globe. The USAF developed the "Advanced Medium STOL Transport" (AMST) program around the new requirement seeking an all-modern, medium-lift, tactically-minded form with better short-field / rough-field performance than what the in-service prop-driven C-130 could offer. The official requirement was drawn up in 1968 and the Request For Proposal (RFP) followed in 1972.

In the early stages, responses were had from industry players in Bell, Boeing, Lockheed (partnered with North American Rockwell) and McDonnell Douglas. Boeing and McDonnell Douglas ultimately advanced from this phase and each was granted a contract to cover two flyable prototypes for testing and head-to-head competition. They were designated as the Boeing "YC-14" (detailed elsewhere on this site) and the McDonnell Douglas "YC-15".

Unlike the Boeing submission, which relied on two engines overslung on the wing mainplanes, the YC-15 made use of a conventional four-engined layout with two nacelles paired under each wing element. Like the YC-14 (and the C-130 for that matter), the YC-15 too utilized a high-wing, straight-edged mainplane arrangement (of super-critical airfoil) for the needed lift, drag and short-field performance required by the USAF. Large double-slotted, externally-blown flaps made up a good length of the mainplane's span at the wing trailing edges and were intended to increase Short Take-Off and Landing (STOL) performance. The engines selected for the design were 4 x Pratt & Whitney JT8D-17 turbojets of 15,500lb thrust each which were already in production and service with civilian market airliners at the time.

The fuselage was large, relatively short and tubular in its general shape. The raised empennage would allow a cargo ramp to be lowered to accept cargo loads rather easily. The tail unit was configured in a typical "T-style" arrangement which saw the horizontal planes seated high atop the vertical fin. A tricycle undercarriage (retractable) was used for ground-running with the nosewheel being a revised version of the same steering leg used in the DC-8 narrow-body passenger airliner. Internally, the cockpit was taken from the proven McDonnell Douglas DC-10 wide-body passenger airliner with changes made to suit military service. The air-fueling receptacle came from the Fairchild A-10 "Thunderbolt II" attacker and other components were equally-borrowed from existing aircraft to speed development and keep costs at a minimum.
The two contracted-for YC-15 aircraft arrived in prototype form in 1975 with a first-flight recorded on August 26th, 1975 (the second prototype went into the air for the first time before year's end). Both aircraft were ahead of the competing Boeing design which did not make it airborne until the following year and the formal competition between the two began in late 1976.

Because of the changing requirements of the USAF, the AMST program suffered despite the progress being shown. Authorities eventually settled on continued support of the C-130 product for the foreseeable future and renewed a commitment to expanding the strategic transport capabilities of the USAF and this allowed the Hercules aircraft to see an extended service life that continues even today (2018).

The AMST program was ended in December of 1979 with no winner selected but the "C-X" program was drawn up in its place to now find a strategic-minded airlifter - this eventually led to a dimensionally larger version of the McDonnell Douglas YC-15 being built and flown - influencing what would become the swept-wing Boeing C-17 "Globemaster III" transport still to come. The C-17 entered service in 1995 and remains active today (2018) with nearly 300 units built. McDonnell Douglas eventually became a subsidiary of the Boeing Company brand, hence the C-17's official product name.

As built, the YC-15 utilized an operating crew of three. It held a capacity to ferry up to 150 combat-ready troops or up to 78,000lb of cargo. Dimensions included a length of 124.2 feet with a wingspan of 110.3 feet and a height of 43.2 feet. Empty weight was 105,000lb against an MTOW of 216,680lb. Performance specs included a maximum speed of 590 miles per hour with a cruising speed of 543mph, a range out to 3,000 miles and a service ceiling up to 30,000 feet.






Our Data Modules allow for quick visual reference when comparing a single entry against contemporary designs. Areas covered include general ratings, speed assessments, and relative ranges based on distances between major cities.

Image of collection of graph types

Relative Maximum Speed Rating
Hi: 750mph
Lo: 375mph
    This entry's maximum listed speed (590mph).

    Graph average of 562.5 miles-per-hour.
City-to-City Ranges
NYC
 
  LON
LON
 
  PAR
PAR
 
  BER
BER
 
  MOS
MOS
 
  TOK
TOK
 
  SYD
SYD
 
  LAX
LAX
 
  NYC
Graph showcases the McDonnell Douglas YC-15's operational range (on internal fuel) when compared to distances between major cities.
Aviation Era
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Unit Production Comparison
Comm. Market HI*: 44,000 units
Military Market HI**: 36,183 units
2
2


  * Commercial Market High belongs to Cessna 172.

  ** Military Market High belongs to Ilyushin Il-2.


Altitude Visualization
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National Flag Graphic
Origin: United States
Year: 1976
Type: Tactical Airlifter Transport Aircraft Prototype
Manufacturer(s): McDonnell Douglas - USA
Production: 2
Status: Cancelled
Global Operators:
United States (cancelled)
Historical Commitments / Honors:

Military lapel ribbon for Operation Allied Force
Military lapel ribbon for the Arab-Israeli War
Military lapel ribbon for the Battle of Britain
Military lapel ribbon for the Battle of Midway
Military lapel ribbon for the Berlin Airlift
Military lapel ribbon for the Chaco War
Military lapel ribbon for the Cold War
Military lapel ribbon for the Cuban Missile Crisis
Military lapel ribbon for the Falklands War
Military lapel ribbon for the French-Indochina War
Military lapel ribbon for the Golden Age of Flight
Military lapel ribbon for the 1991 Gulf War
Military lapel ribbon for the Indo-Pak Wars
Military lapel ribbon for the Iran-Iraq War
Military lapel ribbon for the Korean War
Military lapel ribbon for the 1982 Lebanon War
Military lapel ribbon for the Malayan Emergency
Military lapel ribbon for the attack on Pearl Harbor
Military lapel ribbon for the Six Day War
Military lapel ribbon for the Soviet-Afghan War
Military lapel ribbon for the Spanish Civil War
Military lapel ribbon for the Suez Crisis
Military lapel ribbon for the Vietnam War
Military lapel ribbon for Warsaw Pact of the Cold War-era
Military lapel ribbon for the WASP (WW2)
Military lapel ribbon for the World War 1
Military lapel ribbon for the World War 2
Military lapel ribbon for the Yom Kippur
* Ribbons not necessarily indicative of actual historical campaign ribbons. Ribbons are clickable to their respective campaigns/operations.
Measurements and Weights icon
Structural - Crew, Dimensions, and Weights:
Unless otherwise noted the presented statistics below pertain to the McDonnell Douglas YC-15 model. Common measurements, and their respective conversions, are shown when possible.

Operational
CREW


Personnel
3


Dimension
LENGTH


Feet
124.34 ft


Meters
37.9 m


Dimension
WIDTH


Feet
132.55 ft


Meters
40.4 m


Dimension
HEIGHT


Feet
43.31 ft


Meters
13.2 m


Weight
EMPTY


Pounds
104,940 lb


Kilograms
47,600 kg


Weight
LOADED


Pounds
216,681 lb


Kilograms
98,285 kg

Engine icon
Installed Power - Standard Day Performance:
4 x Pratt & Whitney JT8D-17 turbofan engines developing 16,000lb of thrust each.

Performance
SPEED


Miles-per-Hour
590 mph


Kilometers-per-Hour
950 kph


Knots
513 kts


Performance
RANGE


Miles
2,989 mi


Kilometers
4,810 km


Nautical Miles
2,597 nm


Performance
CEILING


Feet
30,003 ft


Meters
9,145 m


Miles
5.68 mi

Armament - Hardpoints (0):

None.
Variants: Series Model Variants
• YC-15 - Base Prototype Designation; two examples completed.
• C-15 - Assumed in-service designation.