Airborne: A Guided Tour of an Airborne Task Force by Tom Clancy
A Lockheed Martin C-130H Hercules of the 314th Airlift Wing flies resupply for a Brigade of the 82nd Airborne during an exercise at Fort Polk, Louisiana.
JOHN D. GRESHAM
The engines were, at the time, the most radical feature of the new Hercules design. For the first time on an American transport they were “turboprops.” This British invention coupled a gas turbine engine to a constant-speed gearbox driving a variable-pitch propeller. This hybrid design seems, at first, to be needlessly complex, but in practice, the Allison T56 turboprops proved to be highly fuel-efficient, reliable, and easier to maintain than a piston engine or jet of equivalent power. They were also relatively compact, with a lower forward cross-sectional area, providing reduced drag. This is not to say the new turboprops were perfect. The original electrically operated three-bladed propellers never worked properly, and were quickly replaced by hydraulically powered Hamilton-Standard units. Later, the three-bladed propellers were replaced by four-bladed models, similar to those used on the Navy’s Lockheed P-3 maritime patrol aircraft.
Like most engines, the Allison turboprop family has evolved through a series of modifications with increasing power. The chart below shows how the engines for the Hercules have developed:
C-130 Engine Development
As you can see, the trend has been a gradual but upward growth in power for the engines on the -130. From the flight crew’s point of view, though, the real improvement has been the ability to deliver all that power more efficiently through the transmission, and to do so in the conditions that are always tough on turbine powerplants: high and hot. High temperatures and high altitude (i.e., low pressure) are the bugaboos for turbine engine designers. These sap engine power and directly effect the flight characteristics of an aircraft. The Hercules has always done well when upgraded. The longevity of the C-130H production line (over thirty years to date) is a testimony to just how well.
If there is truth in the statement that beauty is in the eye of the be-holder, then the C-130 must be gorgeous to everyone it comes into contact with. For example, consider the perspective of an aircraft crew chief or loadmaster. These are normally senior enlisted personnel who manage the aircraft systems and payload on a USAF transport aircraft. Anything that can make their job easier or shorter is “good” from their perspective, as well as anything that makes “their” airplane more capable or less dependent on other people and organizations.39 One of these “good” features is a gas turbine auxiliary power unit (APU), located in the port-side landing gear fairing, that provides power to start the engine and operate the electrical and hydraulic systems on the aircraft, with no requirement for external support equipment to get under way. Another thing that keeps loadmasters and crew chiefs happy is how well things go into an aircraft. The C-130 designer gave a lot of thought to cargo handling, and this paid huge dividends over the next four decades. Previous airlifter designs had relied on large side-loading doors (which weaken the fuselage structure) or on an inefficient twin-boom tail, which allowed the entire aft end of the fuselage to hinge upward, or split into a pair of clamshell doors. The C-130 used an elegantly simple loading arrangement. The cargo deck was the same height as a truck bed. The lower surface of the upswept tail section was split, with the lightweight aft section retracting upward, and the strongly built forward section hinged downward to provide a cargo ramp. By lowering the ramp completely, a pair of 5-ton trucks could be driven right into the cargo compartment. So perfect was the concept behind the C-130’s rear ramp that it has become the standard method of designing aircraft cargo-loading ramps all over the world. These are some of the many things that Lockheed did to make the Hercules a “field” airplane, rather than one that needs a big base to keep going.
The cargo compartment itself is 10 feet 3 inches/3.12 meters wide, 9 feet/2.74 meters high, and 41 feet 5 inches/12.62 meters long, roughly the dimensions of a standard North American railroad boxcar. Some later models of the -130 added fuselage “plugs” (a structure that is dropped into a basic aircraft’s design) to extend the cargo compartment by some 15 feet/4.57 meters. In addition to the cargo door, there is a crew entry door forward on the port side that opens down to become a stairway. Aft, the paratrooper jump doors are located on either side, just in back of the trailing edge of the wing. These doors pull inward and then slide up and out of the way. When conducting paratrooper drop operations, the Hercules has an air deflector fitted to each door that protects jumpers from the sudden blast of air as they exit the aircraft. Along the top of each side of the cargo compartment runs a steel cable that can be reeled up and stowed out of the way, which is used by paratroops to hook their static lines prior to drop. There are also emergency exit hatches for the flight deck and the cargo compartment in the top of the fuselage. Along the sides and center of the cargo compartment are a series of fold-up, woven cloth seats which are surprisingly comfortable, in spite of their decidedly uncomfortable looks. The rated capacity of the C-130 is ninety-two soldiers or sixty-four paratroops with their equipment.
When the seats are folded up and the cargo compartment is clear, being inside gives one the impression of being inside a large aluminum shoebox. In the floor are various tie-down points, which allows almost every conceivable kind of cargo to be carried. Creature comforts in the Hercules are few and far between; this bird is built for function, not luxury. Still, life in the back of the C-130 is relatively comfortable. This is mainly due to a significant innovation in cargo aircraft design, being able to pressurize the entire cargo compartment. The whole compartment could be pressurized to maintain an equivalent cabin altitude of 8,000 feet/2,438 meters even at the aircraft’s operational ceiling of 33,000 feet/10,060 meters above sea level.
If the C-130 does have a vice, it is noise. C-130 crews like to joke that the pressurized cargo compartment was designed to keep the sound in, and ear protectors are essential equipment. Even this problem can be solved, though, if money is no object. The Royal Saudi Air Force operates a luxurious customized VC-130 VIP transport, with a barrier of thick sound insulation surrounding the passenger compartment. All this interior noise comes from the Herky’s four turboprop engines, which have a loud and distinctive roar. This means that planning a surprise assault landing, like the Israeli rescue mission at Entebbe, requires a keen awareness of the noise footprint at various speeds and descent angles. This is a minor tactical disadvantage, though, given all the other great features of the Hercules.
For all the noise in the cargo compartment, the crew chiefs love the fact that their standard equipment kit (carried on top of the rear ramp) includes virtually everything needed to configure the cargo compartment for almost any kind of load. This is vital, considering that a crew may be called upon in the middle of one trip to rapidly reconfigure their aircraft to go on another kind of mission. This is one of the reasons why the marriage of the Hercules and USAF Reserve/ANG has been such a resounding success. One of the best-kept secrets in the Air Force is that the majority of Hercules units belong to ANG and USAF Reserve units, being flown and operated by “Weekend Warriors.” Given the nature of the airlift mission, whether it is supporting a crisis combat situation like Desert Shield or Haiti, or a disaster relief scenario like Hurricane Hugo or the Los Angeles riots, the “total force” concept (Active, Reserve, and ANG working together) has proven to be tailor-made for the -130 force. More than one Army commander that I have talked to refers to the Hercules as “the packing crate for the American military”!
Over the years, the Hercules has carried probably every object that could possibly fit inside the cargo compartment. However, one of the most dramatic airdrop cargoes C-130 has ever delivered was the Army’s M-551 Sheridan light tank, which (until recently) was found in the lone armored battalion of the 82nd Airborne Division, the 3rd of the 73rd Armored (3/73). The 36,300-1b/16,500-kg vehicle is strapped to a pallet, equipped with a huge “drogue” extraction parachute. In the Low Altitude Precision Extraction System (LAPES) mode, the C-130 skims slowly only a f
Another of the C-130’s many virtues is the ability to operate off extremely short and rough airfields. The high wings and turboprop engines provide much of this capability, but the land gear is vital to this as well. The C-130’s landing gear retracts only a short distance, keeping the center of gravity low, allowing the plane to hug the ground. The main landing gear consists of two pairs of large-diameter tires arranged in tandem, giving it an extremely low ground pressure for such a large aircraft. The main gear has a relatively narrow track, only about fourteen feet between the port and starboard wheels, which facilitates operations on narrow taxiways. In fact, the aircraft can turn in a radius of only 85 feet/25.9 meters (measured from the wing tip). Also, with reverse thrust on the propellers (actually the pitch of the props is reversed), the C-130 can actually taxi backwards. Even the brakes have antiskid features similar to those on new-model automobiles. So good are the rough field characteristics of the Hercules that C-130s have safely landed on sand or mud so deep that the wheels sank over 20 inches/50 centimeters into the ground, and the planes were still able to take off!
Up front, the cockpit of the Hercules might best be described as “mature.” Very little of the computer age is evident on the flight deck of the C-130H, the standard model currently in service. The typical C-130 crew includes a pilot and copilot, navigator, and flight engineer (or “systems manager”) on the flight deck, and an enlisted loadmaster/crew chief in the cargo compartment. The avionics fit of the Hercules is limited, but functional, and has always been that way. Early C-130As had a distinctive “Roman” nose that dropped steeply away from the cockpit, but this was soon replaced by a roomy bulbous radome that has accommodated several successive generations of weather and ground-navigation radars. The standard electronics fit on USAF C-130Hs includes the AN/APN-218 doppler navigation radar, an AN/APN-232 radar altimeter, and a Westinghouse LPCR-130-1 weather radar with color display. A variety of HF, VHF, and UHF radio communications systems is fitted, and most C-130s are equipped so that they can have a satellite communications terminal added if mission requirements dictate such special gear. Of particular importance for airdrop missions is the AN/APN-169C “Station Keeping Equipment” (pronounced “ski”), which allows a group of transport aircraft to maintain precise formation even in the worst conditions of visibility and weather. Even mixed formations of different aircraft like C-130s, C-141s, and C-17s can be accommodated with the SKE gear. A radar-warning receiver is standard equipment, and there are provisions for fitting ALE-40 chaff and flare dispensers to counteract enemy missiles. Many C-130s operating into Sarajevo during the Bosnian Civil War (1992-96) were fitted with protective steel and Kevlar ballistic armor around the flight deck, and this proved so effective that it will be standard on the new-model C-130J.
For the C-130H, the maximum cruising speed is 386 kn/715 kph. Typical cruising altitude is about 35,000 feet/10,668 meters, but the aircraft can reach over 40,000 feet/12,192 meters. The top speed ever recorded for the type, with a stiff tail wind, was 541 kn/1,003 kph, by an RC-130A. A more important performance characteristic for an airlifter is the minimum flight, or stall, speed. The lower the stall speed, the shorter the takeoff and landing roll needs to be for a particular aircraft. For the Hercules, this is approximately 80 kn/148 kph, which is about the same as a Cessna 150! The airframe is designed to safely withstand a stress of +3 Gs in the positive direction, or -1 G in the negative direction. Also, the huge rudder gives the pilot tremendous control authority in yaw (turning horizontally). The aircraft can actually make a flat turn, without banking. All in all, the Hercules is quite easy to fly, with lots of power and lift, and all the control authority that a pilot could want of an aircraft this size. The fine qualities were evident from the early flights of the prototype, and have only gotten better with the years.
That first flight of the YC-130A prototype was a sixty-one-minute hop from Burbank, California, to Edwards AFB on August 23rd, 1954. After the initial prototypes, all the production C-130s were built at Marietta, Georgia, about twenty miles northwest of Atlanta. The first flight of a production model came on April 7th, 1955, and nearly ended in disaster when a quick-disconnect fuel line on the No. 2 engine broke loose and started a fire that caused the wing to break off after landing. Soon repaired, the aircraft had a long, adventurous career tracking missiles and spacecraft, and later as a gunship in Vietnam, remaining in service until the early 1990s! Deliveries to the Air Force began in 1955, and by 1958 the C-130A was found in six Troop Carrier Squadrons (later designated Tactical Airlift Squadrons [TASs]).
A “chalk” of 82nd Airborne Paratroops loaded aboard a C- 130H Hercules, preparing for a training jump under the watchful eye of an Air Force Loadmaster. A force of several hundred C-130s provide the bulk of America’s Medium Airlift muscle.
JOHN D. GRESHAM
From the start, the Hercules had an unusual career within the U.S. military. The first operational employment of the C-130 came in 1957, when President Eisenhower dispatched troops of the 101st Airborne Division to Little Rock, Arkansas. This federal effort to enforce court-ordered school desegregation against the opposition of a defiant state governor started the tradition of the C-130 being used in non-combatant/civil/relief efforts. The Hercules’ major overseas deployment came in 1958 during the Lebanon Crisis, delivering supplies to Marines who landed at Beirut to support a friendly government threatened by civil war. The first combat airborne assault for USAF C-130s came in 1960 in the Congo (now known as Zaire), where they delivered a battalion of French paratroops. The French were headed to the remote town of Stanleyville (now Kisangani) to rescue civilians and diplomats threatened by a local uprising. Following this, when Chinese troops invaded disputed regions on the northern borders of India in 1962, President Kennedy quietly dispatched a squadron of C-130s to help the Indian Army reinforce its remote Himalayan outposts. The Herks flew thousands of troops and tons of supplies into Leh, where a mountain-ringed 5,000-foot /1,524-meter runway of pierced steel plate (PSP) at an altitude of 10,500 feet/3,200 meters was the only link to the outside world. Even more astounding feats were ahead for the C-130, though.
In 1963, the U.S. Navy actually conducted C-130 carrier landing and takeoff trials onboard USS Forrestal (CV-59). The Chief of Naval Operations wanted to know if the big transport could be used to deliver supplies to carriers operating far from friendly bases. The aircraft was a KC-130F tanker on loan from the U.S. Marine Corps, and the Naval aviator in command was Lieutenant (later Admiral) James H. Flatley III, with the assistance of a Lockheed engineering test pilot, Ted Limmer, Jr. At a weight of 85,000 lb/38,555 kg, the aircraft came to a complete stop in a mere 270 feet/82.3 meters, about twice the wing span of the Hercules! This required some fancy flying—the aircraft reversed thrust on the propellers 3 feet/1 meter above the deck. At maximum load, the plane required a takeoff roll of only 745 feet/227 meters of the carrier’s 1,039-foot/316.7-meter flight deck. On one occasion, the plane stopped just opposite the captain’s bridge with “LOOK MA, NO HOOK” painted in big letters on the side of the fuselage. The Navy never followed up on this promising experiment (they bought the Northrop Grumman C-2 Greyhound instead), but the Herk’s unique ability to take off and land on a carrier remains to challenge the imagination of Joint Special Operations planners down in Tampa.
The war in Southeast Asia tested the Hercules under the most difficult combat conditions imaginable. All told C-130s transported about two thirds of all the troops and cargo tonnage moved by air inside South Vietnam. Frequently, the Herks flew through mortar and rocket fire into narrow 2,500-foot strips carved out in t
For the Hercules, Vietnam was a chance to prove how versatile it was. So it is only natural that the C-130 had a part in one of the most significant innovations of the Vietnam War: the development of the gunship. The idea was to load up a large transport aircraft with heavy machine guns and even cannons, and use the weapons as an airborne firebase for supporting ground operations. Originally (from 1965 to 1967) the first gunships were vintage C-47s (known as “Puff the Magic Dragon,” after the popular song of the day), with a battery of side-firing machine guns. The concept was to fly a “pylon turn” around a fixed point on the ground, with the aircraft in a 30° bank circling the target. Operated by the 4th Air Commando Squadron, these first gunships proved highly effective in breaking up night attacks on remote outposts while using parachute flares to illuminate the battlefield. The sight of a great sheet of tracer fire pouring down from the sky had a dramatic psychological impact on friend and foe alike. So successful were the AC-47s that it was decided to build an even bigger gunship. The obvious choice for the airframes were elderly C-130As. A prototype AC-130 gunship arrived in South Vietnam on September 21st, 1967, and it was flown in combat until it practically fell apart. The prototype AC-130 had an improvised analog fire control computer, four 20mm M61 Vulcan cannon (similar to those fitted in modern fighter planes) firing through ports cut in the side of the fuselage, and four 7.62mm “miniguns” (a six-barrel rotary machine gun that fired up to six thousand rounds per minute). It also carried an early Texas Instruments Forward-Looking Infrared (FLIR) sensor, a night-image intensifier (“starlight scope”), and a side-looking radar that unfortunately proved to be ineffective against guerrilla bands in the jungle.