Aircraft Factfile and Recognition Guide - Boeing WC-135 Family

 

Background

General Dwight D. Eisenhower commissioned the Constant Phoenix program on Sept. 16, 1947, when he charged the Army Air Forces with the overall responsibility for detecting atomic explosions anywhere in the world. In September 1949, a WB-29 flying between Alaska and Japan detected nuclear debris from Russia's first atomic test--an event thought not possible until mid-1950.

Beginning in August 1950, WB-50 aircraft were converted for the air-sampling mission over a two-year period. WC-135 aircraft began replacing the WB-50s in December 1965 and became the workhorse of the atmospheric collection program.

Air sampling missions were routinely conducted over the Far East, Indian Ocean, Bay of Bengal, Mediterranean Sea, the Polar regions, and off the coasts of South America and Africa. The WC-135W played a major role in tracking radioactive debris from the Soviet Union's Chernobyl nuclear plant disaster. 

Currently the air-sampling mission supports the Limited Nuclear Test Ban Treaty of 1963, which prohibits any nation from above ground nuclear weapons testing.  WC-135s are currently the only aircraft in the inventory conducting air-sampling operations.

The WC-135W Constant Phoenix atmospheric collection aircraft supports national level consumers by collecting particulate and gaseous effluents and debris from accessible regions of the atmosphere in support of the Limited Nuclear Test Ban Treaty of 1963.

The aircraft is a modified C-135B or EC-135C platform. The Constant Phoenix's modifications are primarily related to its on-board atmospheric collection suite, which allows the mission crew to detect radioactive "clouds" in real time. The aircraft is equipped with external flow-through devices to collect particulates on filter paper and a compressor system for whole air samples collected in holding spheres.

The cockpit crew is from the 45th Reconnaissance Squadron at Offutt Air Force Base, Neb., and special equipment operators are assigned to Det. 1, Air Force Technical Applications Center at Offutt AFB.

Recognizing the KC-135 Series

The KC-135 series of aircraft are rather easy to identify. However, they can very easily be confused with any other aircraft that shares a similar silhouette. If you THINK you see a KC-135, but aren't sure if it really is one, keep in mind the following:

Wings: Low-mounted, swept-back, and tapered with a positive slant.
Engines: Four turbofans mounted on pylons under the wings. Engines extend well forward of the wings' leading edges.
Fuselage: Round, cigar-shaped, tapers to the rear. Rounded nose, stepped-up cockpit.
Tail: Swept-back, tapered fin with a square tip. Horizontal stabilizers are swept-back, tapered, and mid-mounted on the fuselage.
Boom: Aft of the fuselage is a little set of "ruddervators" that belong to the refueling boom. Found on all KC-135s and most EC-135s.

If there is NO BOOM on the aircraft and it shares the same characteristics, you're looking at the following:

NKC-135A: Air Force testbed for laser lab projects. The NKC-135A at the USAF Museum in Dayton, OH has a giant laser turret on the top of its forward fuselage.

(O)C-135: Basic KC-135 airframe WITHOUT the boom. Some C-135s may have some unusual bumps from the top and the bottom of the fuselage while the OC-135s are easily identified by the "Open Skies" stripe on the tail.

KC-135 "Vomit Comet": Operated by NASA, the aircraft is recognized by its NASA markings. It is used to train astronauts in weightless environments (like in space) by flying parabolas.

WC-135: Easily identified with the "Weather" stripe on the tail.

If the aircraft has an extended-length nose, it could be either of the following:

EC-135N/E ARIA/ALOTS: Monstrous "Snoopy" nose housing a seven-foot diameter parabolic radar. The ALOTS pod is located on the left-side of the fuselage and it is an external fairing. E-model ARIAs are identifiable with their TF-33 turbofans (similar to those on the KC-135E) while N-model ARIAs are powered by J57 turbojets (same powerplant as the KC-135A/Q).

RC-135S Cobra Ball: In addition to "thimble" noses, electronic receivers mounted in cheek fairings and a teardrop-shaped fairing on the aft fuselage, these also have large circular windows in the fuselage for the photography of foreign ballistic-missile tests at long range.

RC-135U Combat Sent: Cheek fairings and additional fairings in the chin, boomer, wingtip, tailcone and fin-top positions.

RC-135V/W Rivet Joint: Extended "thimble" noses and large plate aerials under the center-section. External differences between the two variants are restricted to a lengthened cheek fairing on the W-model, which also lacks auxiliary air intakes on its engine pods.

If the aircraft does NOT have a boom or an extended-length nose, it is NOT a C-135 series aircraft. Examples below include:

E-3 Sentry: Slightly larger, but most notable feature is a giant rotating radome on the rear fuselage.

E-6B Mercury: Flown by the US Navy and is powered by CFM turbofan engines (similar to the KC-135R)

E-8 Joint STARS: Giant section of electronics hanging off the bottom right side of the forward fuselage.

The E-3, E-6, and E-8 are all based off the Boeing 707-320 airliner while the C-135 series is based off the 367-80 Prototype.

The Dash 80 is smaller than the Boeing 707s that were in commercial service.

Specifications

Primary function: Air sampling and collection operations
Contractor: Boeing Aerospace Co.
Power Plant: WC-135C, Four Pratt & Whitney TF33-P9 turbofans without thrust reversers;
                    WC-135W, Four Pratt & Whitney TF33-P-5 turbofans with thrust reversers
Thrust: 16,050 pounds each engine
Wingspan: 130 feet, 10 inches  (39.8 meters)
Length: 139 feet, 11 inches  (42.5 meter)
Height: 42 feet (12.8 meters)
Weight: 120,170 pounds (54,508 kilograms)
Maximum Takeoff Weight: 300,500 pounds (136,304 kilograms)
Fuel Capacity: 130,000 pounds (58,967 kilograms)
Speed: 403 miles per hour (350 knots)
Ceiling: 40,000 feet  (12,192 feet)
Range: 4,000 nautical miles 
Crew: Varies with mission
Unit Cost: unavailable
Initial operating capability: December 1965

Sources: USAF WC-135 factfile, Fact Index - OC-135 Open Skies

© 2010 Steven Holzinger