McDonnell Douglas YC-15 (part 1)

YC-15

The McDonnell Douglas YC-15 was a prototype developed of the USAF ‘s AMST program in 1972. The competition was the Boeing YC-14.

McDonnell Douglas developed the YC-15 from the Breguet 941s, using extensive wind tunnel testing (for optimum configuration testing) and using Cornell Aeronautical Labs B-26B In-Flight Simulator (for flight control testing).

yc-15-line

The aircraft itself is 124.25 feet long, wingspan is 110.36ft, height is 43.30. Max gross weight is 216,680lbs. The interior cargo-box is 47 x 11.8 x 11.4.

Thrust for the YC-15 was provided by the JT8D turbofan (also the DC-9 powerplant) and produced a total thrust of 16,000lbs. The engines were mounted on shallow pylons mounted ahead of the wings leading edge. Thrust reversal was accomplished using so-called “daisy nozzles.” During final approach, with flaps fully extended and facing the engine, the engines provided 54% of the YC-15 lift.

The straight wings consisted of ailerons, double-slotted flaps, leading edge high lift devices (Kruger flaps, etc), and spoilers. The trailing edge devices, flaps and ailerons spanned 75% of the wings trailing edge. The flaps could extend as much as 46 degrees into the downstream. The YC-15 was the first jet powered aircraft to use externally blown flaps (EBF).

YC-15's EBF

YC-15’s EBF

Flight controls consisted of the conventional hydraulic system and a stability and control augmentation system (SCAS). The SCAS was dual channel and 3 axis enabling hands off flight for high angle approaches (tactical approaches) and modes for attitude, altitude and heading.

The YC-15 saw the first use of a heads up display (HUD) system, specifically called the VAM (Visual Approach Monitor). Developed by Sundstrand, the VAM displayed the horizon, flight path scale, airspeed indexer and touchdown point.

Sundstrand's VAM display

Sundstrand’s VAM display

Being essentially a research airplane, the YC-15 did not need to fully conform to MILSPECS. As such it borrowed components from various aircraft, the DC-10 cockpit enclosure, the F-15 fuel pumps, the C-141 stabilizing struts, the A-10 UARRSI, the C-5 cargo handling equipment and other parts from 9 other types of airplanes. Cockpit instrumentation used components from 10 different airplanes.

Here’s a cutaway of the YC-14 and YC-15 for comparison:

YC-14-YC-15

Part 2 will detail the YC-15s flight test program.

Part 3 will detail the YC-15 technological contributions to the C-17.

Cross-posted at Bring The Heat, Bring The Stupid.

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13 Comments

Filed under Aeronautical Engineering, Air Force, Airplanes, Flight simulation, Flying, History, Plane Pr0n, USAF

13 responses to “McDonnell Douglas YC-15 (part 1)

  1. Can really see the C-17’s profile in the side view. Does the C-17 take advantage of the blown flaps?

    • themavf14d

      It certainly does and there are quite a few other things that McDonnel Douglas learned from the AMST/YC-15 program. I’ll be detailing that in part 3.

  2. Old AF Sarge

    Great post Mav! I love it when you talk airplanes.

  3. The JT8D engine was not only the DC-9 power plant, it was also the power plant for the 727, and was a civvie version of the J52-P8B, the heart of the A-6 Intruder. Trivia!

  4. Pingback: YC-15 (part 1) | Bring the heat, Bring the Stupid

  5. Pingback: McDonnell Douglas YC-15 (part 2) | The Lexicans

  6. Pingback: Bring the heat, Bring the Stupid

  7. Jim

    Stationed NWC China Lake ’77 – 79, worked in control tower. Either this
    aircraft or a YC-14 flew low approach and departed, time has faded memory. With EDW not far away, saw unusual aircraft from time to time.

  8. Pingback: Mc Donnell Douglas YC-15 (part 3) | The Lexicans

  9. Pingback: Mc Donnell Douglas YC-15 (part 3) | Bring the heat, Bring the Stupid

  10. Pingback: Mc Donnell Douglas YC-15 (part 4) | The Lexicans

  11. Pingback: Mc Donnell Douglas YC-15 (part 4) | Bring the heat, Bring the Stupid

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