the President showed up wearing his favorite flight jacket, along with the entire White House press corps, the C-17 program was saved. The feeling around DoD was that if this bird was good enough for the Boss, it was okay to buy more.
Quickly, the NDAA program was allowed to die, and the USAF decided that the C-17 would be the only heavy airlifter the USAF would buy for the foreseeable future. It was therefore with more than a little pride that the C-17 team managers accepted personally from President Clinton the largest multi-year military procurement order in U.S. history, in mid-1996, for eighty additional Globemasters. Even better, there is talk of buying more. But first, let’s take you on a little tour of this incredible bird before we talk about the distant future.
For this we will take a quick trip down to Charleston AFB, to visit the 437th Airlift Wing. In late 1996 the C- 17A was operational with the 14th and 17th Airlift Squadrons (AS) of the 437th, with the 15th AS getting ready to transition from the C-141 to the new bird. For our tour, we’ll spend some time with aircraft 93-0600, which is also known as aircraft P-16 (the sixteenth production aircraft, which was funded in FY-93). It was delivered to the Air Force in November of 1994, fully a month early. This matter of early delivery is getting to be more and more common on the C-17 program, and is now the rule rather than the exception. Early deliveries mean cheaper planes for the taxpayers and higher profits for the stockholders of McDonnell Douglas, so it is a “win-win” situation for all involved. Despite being heavily flown since delivery, P-16 is a clean and neat aircraft, without so much as a scratch or smear to mar the finish, inside or out. At something like $175 million a copy for the early-production C-17s, you’d better believe that the USAF crew chiefs take
One thing to keep in mind, though. The whole idea of an aircraft like the Globemaster is absurd unless, of course, you have the kind of overseas commitments that the United States has. In that case, the heavy airlifter fleet is more precious than its weight in diamonds, and that is the point. When you need to establish an “aluminum bridge” to someplace like the Persian Gulf, there is no value you can place on such a capability.
Much of the C-17’s advanced technology is found in its wing, so let’s begin our examination of this remarkable aircraft there. The wing is mounted well forward, and very high; in fact it actually humps up above the top of the fuselage, to increase the headroom in the cargo compartment. The wings droop downward from root to tip, something engineers call an “anhedral.” The pointed wing tips bend up sharply to form “Whitcomb winglets,” named for the NASA aerodynamicist who invented them. These cute little bits of aerodynamic design improve the flow of air at the wing tips, where drag-increasing vortexes arise at certain speeds. The net effect of the winglets is to reduce drag by 4 to 6 percent (and therefore raise fuel efficiency), which more than compensates for the added weight. The engine pylons thrust aggressively forward, so much so that each engine extends right beyond the leading edge of the wing. But from below, the most striking features of the wing are four pods that extend past the trailing edge. These are called flap support fairings, and they contain the complex hydraulic actuators, levers, and linkages that give the C-17 control of its externally blown flaps. The wing is “wet,” with most of the aircraft’s 27, 108 gallons/102,614 liters stowed in self-sealing fuel tanks built into the thick wing structure. There are extensive fire detection and suppression provisions in the wing, including an onboard inert gas-generating system, which extracts nitrogen from engine bleed air and uses it to pressurize the empty space in the fuel tanks as fuel is consumed, to prevent the formation of potentially explosive vapors.
The engines on the production C-17s are Pratt and Whitney F-117 two-shaft, high-bypass turbofans rated at 40,700 lb/18,500 kg of thrust. The engine is based on the mature and reliable PW2000 series flying since 1984 on the Boeing 757. On the C-17, however, the engine core and the large fan section are both fitted with exceptionally powerful thrust reversers, which can be operated either in flight or on the ground. On the ground, thrust reversers work together with the wheel brakes and the spoilers on the upper surface of the wing, making it possible to land safely on short runways that previously would only have been used by a C-130. In fact, the C-17 is the
Along each side of the fuselage is a large canoe-shaped fairing, which is where the main landing gear is located. Given the troubles that Lockheed had with the C-5 landing gear, you’d better believe that Douglas made sure that they got the C-17’s landing gear system right. The shock absorbers are able to handle a sink rate upon landing of up to 15 feet/4.57 meters per second at full load. The steerable twin-wheel nose gear retracts aft, but the main gear on each side consists of two tandem three-wheel units, with big low-pressure tires for landing on soft ground. When raised, the main landing gear struts are rotated through 90 degrees by a clever arrangement of levers, pivots, and actuators before retracting into streamlined fairings. If hydraulic power is lost, the landing gear can still be deployed by gravity, free-falling and locking into place.
Like the C-130, the C-17 has an auxiliary power unit (APU) located in the landing gear fairing on the port one side. The Garrett GTCP331 is a compact gas turbine that can drive the aircraft’s electrical generators and hydraulic pumps on the ground without having to start the main engines. The APU can also provide power to start the engines, even under the worst arctic conditions, and there are powerful NiCad batteries to start the APU or provide emergency DC power to the aircraft’s systems.
The fuselage is 159 feet/48.5 meters long, measured from the nose to the tip of the tail cone, but the swept-back vertical stabilizer overhangs another 15 feet/4.57 meters. The tail of the C-17 incorporates a powerful two-section rudder. The top of the tail fin is just over 55 feet/16.8 meters above the ground, and there is a narrow internal passageway with a ladder so that maintenance crews can easily reach the hydraulic actuators and antennas, and even change the bulbs on the navigation lights. Empty weight of the C-17 is about 269,000 lb/122,000 kg. Overall, about 70 percent of the C-17’s structure, by weight, is aluminum alloy, 12 percent steel, 10 percent titanium, and 8 percent composites. There are two entry doors, the one on the left side with fold-down stairs, jump doors just aft of the wing on both sides, and the large loading ramp aft. Heading up one of the nose doors takes you directly into the cargo compartment. If you head forward, past the small galley and lavatory, and up a small staircase, you find yourself on the flight deck.
The flight deck provides side-by-side seating for the pilot and copilot, seats for two observers or a spare crew, two rear-facing courier seats, and two comfortable rest bunks. The seats are extremely comfortable (I love the sheepskin covers!), and the cockpit has the best layout I have ever seen. The flight controls are more like that of a fighter plane than a commercial airliner. The pilots control the C-17 with a stick-mounted handgrip (as opposed to a control wheel), heads-up display, and a console full of color multi-function display (MFD) panels, much like the new C-130J. The flight controls are based on a quad-redundant fly-by-wire system, with the same kind of FADEC engine controls that will soon appear on the C-130J. Between the two crew seats is a pedestal loaded with the flight management systems, as well as the controls for the radio systems. Further controls for the various flight systems are contained in a strip that runs across the top of the main instrument panel. There even is an electronic warfare suite, which includes a radar warning receiver, as well as controls for the onboard ALE- 40/47 decoy/flare/chaff launchers. Though all of this gives the C-17 cockpit a look like that of the Starship
The nose radome holds an AN/APS-133 weather and ground-mapping radar, which displays the data on one of the MFD panels. Also like the C-130, the C-17 is equipped with “Station Keeping Equipment” (SKE) that allows a group of aircraft to maintain a precise formation in zero-visibility conditions. The C-17 is also equipped with two independent mission computers, and virtually all of the electronic systems are tied together by a redundant MIL- STD 1553 digital data bus. This includes everything from the radio systems to the electronic warfare self-protection suite. Technology has moved on since the first C-17 was first delivered, though, and new-model mission computers will be part of a near-term upgrade. Just above the flight deck is a standard aerial refueling receptacle. Around this are the array of large “picture window” transparencies, which make the view from the cockpit so breathtaking. Without question, it is the finest cockpit design I have ever seen.
Just down the ladder from the cockpit is the loadmaster’s station. While it may just look like a little cubbyhole, it is a special place for the loadmasters in the USAF. For the first time in any aircraft design, somebody finally cared about the enlisted personnel that make up the crews of a transport plane, and took their needs and desires into account. From here, with a single well-designed master panel, the loadmaster can control the cargo
