Saturday, January 30, 2016

Three types of C-17s That Never Took Off

When the last C-17A was built, it ended a storied history at the Long Beach plant where thousands of  Douglas aircraft were manufactured. While the Southern California plant produced only the C-17A and the C-17A-ER (extended range), at least three other variants were offered. We’ll explore three other C-17 models that never made it off the drawing board.

A tough start but a smooth finish

The C-17 program had a rocky start. The jet was almost cancelled in the early 1990s as delays mounted and performance targets fell well short of expectations. However, the program eventually recovered with a total of 279 deliveries made to the United States and its allies. Even more impressive is the fact that 277 are still in service today over 20 years after the first flight back in 1993.

Today, the C-17 has met and exceeded most expectations. The jet can carry outsize cargo up to 170,000 lbs, fly halfway around the world with an air refueling or two and land on as little as 3,500 feet of runway. It was the backbone of heavy airlift during the wars in Iraq and Afghanistan. The C-17 has participated in nearly every major humanitarian relief effort throughout the world.  With such unique capabilities, Boeing made three major efforts to expand the product line.

The BC-17X Commercial Derivative. 
(Boeing Image)

While the capabilities of the C-17 are impressive, the efficiency of the aircraft has never been its strong point. With a blunt nose and a high lift wing, the operating costs of the jet are extremely high for a jet roughly the size of a Boeing 767. A C-17 burns about ¾ as much fuel per hour as a 747-400 but can carry only about half the pallets of its larger cargo carrying cousin.
McDonnell Douglas first pitched a commercial derivative in 1997. When Boeing acquired McDonnell Douglas, they renamed the project the BC-17. The BC-17 had a couple of false starts with Boeing sending out press releases that they were close to launching the commercial version. Unfortunately, demand never materialized. A creative plan to provide the jets to commercial operators under a CRAF-like contract where they could be recalled during times of war never gained traction either.

Boeing C-17B model as seen at airshows and conferences.

Another potential derivative was the Boeing C-17B. If you ever attended an airlift convention or airshow, you might have even seen a model of the upgraded Globemaster III. The C-17B was pitched as a way to allow landings at truly austere fields in locations where the “A” model couldn’t go. The C-17B  featured a center-truck gear, self-deflating tires and double-slotted flaps to allow landing on even shorter distances. 

This variant was proposed a few times by Boeing in an attempt to extend the production line, the last time publicly in 2008. The “B” model never caught on though. The C-17 was already an expensive plane to operate and by 2008, congress started to reign in the massive defense budget that would have been necessary to fund this new variant.

The War on Terror showed off the capabilities of the C-17 but it also exemplified that performance beyond its current capabilities were not required. Most missions did not require landing on a short or unimproved field. Even in poor nations like Afghanistan, most of the cargo could be delivered to a few established fields and transloaded to smaller aircraft like C-130s and/or convoyed to the final destination.

A C-17FE featuring modified flaps, winglets, lighter gear, and narrower fuselage.

Boeing’s final attempt to grow the Globemaster family came in the form of a shrunken version of the airlifter. The C-17FE was like a Globemaster on a SlimFast diet.  Instead of carrying 18 pallets, the “FE” version could only carry 13 in a single row.

The C-17FE was said to be large enough to carry two Stryker vehicles. Strangely, the C-17FE looked similar in size and carrying capacity to the C-141B.

The paper-jet was said to maintain 80% commonality with its larger brother. Boeing offered upgraded engines, improved economics, and added aerodynamic efficiencies.

The aerodynamic efficiencies were mainly derived from a narrower profile and blended winglets similar to the 737NG and 757. A revised wing was also reportedly under consideration.  The C-17FE was first discussed publicly in 2010. No serious interest ever materialized.


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