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Lockheed C-130 Hercules

The Lockheed C-130 Hercules is an American four-engine turboprop military transport aircraft designed and built by Lockheed (now Lockheed Martin). Capable of using unprepared runways for takeoffs and landings, the C-130 was originally designed as a troop, medevac, and cargo transport aircraft. The versatile airframe has found uses in other roles, including as a gunship (AC-130), for airborne assault, search and rescue, scientific research support, weather reconnaissance, aerial refueling, maritime patrol, and aerial firefighting. It is now the main tactical airlifter for many military forces worldwide. More than 40 variants of the Hercules, including civilian versions marketed as the Lockheed L-100, operate in more than 60 nations.

The C-130 entered service with the U.S. in 1956, followed by Australia and many other nations. During its years of service, the Hercules has participated in numerous military, civilian and humanitarian aid operations. In 2007, the transport became the fifth aircraft to mark 50 years of continuous service with its original primary customer, which for the C-130 is the United States Air Force (USAF). The C-130 is the longest continuously produced military aircraft at more than 60 years, with the updated Lockheed Martin C-130J Super Hercules being produced.

Background and requirements
The Korean War showed that World War II-era piston-engine transports—Fairchild C-119 Flying Boxcars, Douglas C-47 Skytrains and Curtiss C-46 Commandos—were no longer adequate. On 2 February 1951, the United States Air Force issued a General Operating Requirement (GOR) for a new transport to Boeing, Douglas, Fairchild, Lockheed, Martin, Chase Aircraft, North American, Northrop, and Airlifts Inc.

The new transport would have a capacity of 92 passengers, 72 combat troops or 64 paratroopers in a cargo compartment that was approximately 41 ft long, 9 ft high, and 10 ft wide. Unlike transports derived from passenger airliners, it was to be designed specifically as a combat transport with loading from a hinged loading ramp at the rear of the fuselage. A notable advance for large aircraft was the introduction of a turboprop powerplant, the Allison T56 which was developed for the C-130. It gave the aircraft greater range than a turbojet engine as it used less fuel. Turboprop engines also produced much more power for their weight than piston engines. However, the turboprop configuration chosen for the T56, with the propeller connected to the compressor, had the potential to cause structural failure of the aircraft if an engine failed. Safety devices had to be incorporated to reduce the excessive drag from a windmilling propeller.

Design phase
The Hercules resembles a larger, four-engine version of the Fairchild C-123 Provider with a similar wing and cargo ramp layout. The C-123 had evolved from the Chase XCG-20 Avitruc first flown in 1950. The Boeing C-97 Stratofreighter had rear ramps, which made it possible to drive vehicles onto the airplane (also possible with the forward ramp on a C-124). The ramp on the Hercules was also used to airdrop cargo, which included a low-altitude parachute-extraction system for Sheridan tanks and even dropping large improvised "daisy cutter" bombs. The new Lockheed cargo plane had a range of 1100 nmi and it could operate from short and unprepared strips.

Fairchild, North American, Martin, and Northrop declined to participate. The remaining five companies tendered a total of ten designs: Lockheed two, Boeing one, Chase three, Douglas three, and Airlifts Inc. one. The contest was a close affair between the lighter of the two Lockheed (preliminary project designation L-206) proposals and a four-turboprop Douglas design.

The Lockheed design team was led by Willis Hawkins, starting with a 130-page proposal for the Lockheed L-206. Hall Hibbard, Lockheed vice president and chief engineer, saw the proposal and directed it to Kelly Johnson, who did not care for the low-speed, unarmed aircraft, and remarked, "If you sign that letter, you will destroy the Lockheed Company." Both Hibbard and Johnson signed the proposal and the company won the contract for the now-designated Model 82 on 2 July 1951.

The first flight of the YC-130 prototype was made on 23 August 1954 from the Lockheed plant in Burbank, California. The aircraft, serial number 53-3397, was the second prototype, but the first of the two to fly. The YC-130 was piloted by Stanley Beltz and Roy Wimmer on its 61-minute flight to Edwards Air Force Base; Jack Real and Dick Stanton served as flight engineers. Kelly Johnson flew chase in a Lockheed P2V Neptune.

After the two prototypes were completed, production began in Marietta, Georgia, where over 2,300 C-130s have been built through 2009.

The initial production model, the C-130A, was powered by Allison T56-A-9 turboprops with three-blade propellers and originally equipped with the blunt nose of the prototypes. Deliveries began in December 1956, continuing until the introduction of the C-130B model in 1959. Some A-models were equipped with skis and re-designated C-130D. As the C-130A became operational with Tactical Air Command (TAC), the C-130's lack of range became apparent and additional fuel capacity was added with wing pylon-mounted tanks outboard of the engines; this added 6,000 lb of fuel capacity for a total capacity of 40,000 lb.

Improved versions

The C-130B model was developed to complement the A-models that had previously been delivered, and incorporated new features, particularly increased fuel capacity in the form of auxiliary tanks built into the center wing section and an AC electrical system. Four-bladed Hamilton Standard propellers replaced the Aero Products' three-blade propellers that distinguished the earlier A-models. The C-130B had ailerons operated by hydraulic pressure that was increased from 2050 to 3000 psi, as well as uprated engines and four-blade propellers that were standard until the J-model.

The B model was originally intended to have "blown controls", a system that blows high-pressure air over the control surfaces to improve their effectiveness during slow flight. It was tested on an NC-130B prototype aircraft with a pair of T-56 turbines providing high-pressure air through a duct system to the control surfaces and flaps during landing. This greatly reduced landing speed to just 63 knots and cut landing distance in half. The system never entered service because it did not improve takeoff performance by the same margin, making the landing performance pointless if the aircraft could not also take off from where it had landed.

An electronic reconnaissance variant of the C-130B was designated C-130B-II. A total of 13 aircraft were converted. The C-130B-II was distinguished by its false external wing fuel tanks, which were disguised signals intelligence (SIGINT) receiver antennas. These pods were slightly larger than the standard wing tanks found on other C-130Bs. Most aircraft featured a swept blade antenna on the upper fuselage, as well as extra wire antennas between the vertical fin and upper fuselage not found on other C-130s. Radio call numbers on the tail of these aircraft were regularly changed to confuse observers and disguise their true mission.

The extended-range C-130E model entered service in 1962 after it was developed as an interim long-range transport for the Military Air Transport Service. Essentially a B-model, the new designation was the result of the installation of 1,360 USgal Sargent Fletcher external fuel tanks under each wing's midsection and more powerful Allison T56-A-7A turboprops. The hydraulic boost pressure to the ailerons was reduced back to 2050 psi as a consequence of the external tanks' weight in the middle of the wingspan. The E model also featured structural improvements, avionics upgrades, and a higher gross weight. Australia took delivery of 12 C130E Hercules during 1966–67 to supplement the 12 C-130A models already in service with the RAAF. Sweden and Spain fly the TP-84T version of the C-130E fitted for aerial refueling capability.

The KC-130 tankers, originally C-130F procured for the US Marine Corps (USMC) in 1958 (under the designation GV-1) are equipped with a removable 3,600 USgal stainless steel fuel tank carried inside the cargo compartment. The two wing-mounted hose and drogue aerial refueling pods each transfer up to 300 USgal/min to two aircraft simultaneously, allowing for rapid cycle times of multiple-receiver aircraft formations, (a typical tanker formation of four aircraft in less than 30 minutes). The US Navy's C-130G has increased structural strength allowing higher gross weight operation.

Further developments

The C-130H model has updated Allison T56-A-15 turboprops, a redesigned outer wing, updated avionics, and other minor improvements. Later H models had a new, fatigue-life-improved, center wing that was retrofitted to many earlier H-models. For structural reasons, some models are required to land with reduced amounts of fuel when carrying heavy cargo, reducing usable range.

The H model remains in widespread use with the United States Air Force (USAF) and many foreign air forces. Initial deliveries began in 1964 (to the RNZAF), remaining in production until 1996. An improved C-130H was introduced in 1974, with Australia purchasing 12 of the type in 1978 to replace the original 12 C-130A models, which had first entered Royal Australian Air Force (RAAF) service in 1958. The U.S. Coast Guard employs the HC-130H for long-range search and rescue, drug interdiction, illegal migrant patrols, homeland security, and logistics.

C-130H models produced from 1992 to 1996 were designated as C-130H3 by the USAF, with the "3" denoting the third variation in design for the H series. Improvements included ring laser gyros for the INUs, GPS receivers, a partial glass cockpit (ADI and HSI instruments), a more capable APN-241 color radar, night vision device compatible instrument lighting, and an integrated radar and missile warning system. The electrical system upgrade included Generator Control Units (GCU) and Bus Switching units (BSU) to provide stable power to the more sensitive upgraded components.

The equivalent model for export to the UK is the C-130K, known by the Royal Air Force (RAF) as the Hercules C.1. The C-130H-30 (Hercules C.3 in RAF service) is a stretched version of the original Hercules, achieved by inserting a 100 in plug aft of the cockpit and an 80 in plug at the rear of the fuselage. A single C-130K was purchased by the Met Office for use by its Meteorological Research Flight, where it was classified as the Hercules W.2. This aircraft was heavily modified, with its most prominent feature being the long red and white striped atmospheric probe on the nose and the move of the weather radar into a pod above the forward fuselage. This aircraft, named Snoopy, was withdrawn in 2001 and was then modified by Marshall of Cambridge Aerospace as a flight testbed for the A400M turbine engine, the TP400. The C-130K is used by the RAF Falcons for parachute drops. Three C-130Ks (Hercules C Mk.1P) were upgraded and sold to the Austrian Air Force in 2002.

Enhanced models

The MC-130E Combat Talon was developed for the USAF during the Vietnam War to support special operations missions in Southeast Asia, and led to both the MC-130H Combat Talon II as well as a family of other special missions aircraft. 37 of the earliest models currently operating with the Air Force Special Operations Command (AFSOC) are scheduled to be replaced by new-production MC-130J versions. The EC-130 Commando Solo is another special missions variant within AFSOC, albeit operated solely by an AFSOC-gained wing in the Pennsylvania Air National Guard, and is a psychological operations/information operations (PSYOP/IO) platform equipped as an aerial radio station and television stations able to transmit messaging over commercial frequencies. Other versions of the EC-130, most notably the EC-130H Compass Call, are also special variants, but are assigned to the Air Combat Command (ACC). The AC-130 gunship was first developed during the Vietnam War to provide close air support and other ground-attack duties.

The HC-130 is a family of long-range search and rescue variants used by the USAF and the U.S. Coast Guard. Equipped for the deep deployment of Pararescuemen (PJs), survival equipment, and (in the case of USAF versions) aerial refueling of combat rescue helicopters, HC-130s are usually the on-scene command aircraft for combat SAR missions (USAF only) and non-combat SAR (USAF and USCG). Early USAF versions were also equipped with the Fulton surface-to-air recovery system, designed to pull a person off the ground using a wire strung from a helium balloon. The John Wayne movie The Green Berets features its use. The Fulton system was later removed when aerial refueling of helicopters proved safer and more versatile. The movie The Perfect Storm depicts a real-life SAR mission involving aerial refueling of a New York Air National Guard HH-60G by a New York Air National Guard HC-130P.

The C-130R and C-130T are U.S. Navy and USMC models, both equipped with underwing external fuel tanks. The USN C-130T is similar but has additional avionics improvements. In both models, aircraft are equipped with Allison T56-A-16 engines. The USMC versions are designated KC-130R or KC-130T when equipped with underwing refueling pods and pylons and are fully night vision system compatible.

The RC-130 is a reconnaissance version developed during the Cold War. Sometimes called "ferret" aircraft, these planes were initially retrofitted standard C-130s.

The Lockheed L-100 (L-382) is a civilian variant, equivalent to a C-130E model without military equipment. The L-100 also has two stretched versions.

Next generation
In the 1970s, Lockheed proposed a C-130 variant with turbofan engines rather than turboprops, but the U.S. Air Force preferred the takeoff performance of the existing aircraft. In the 1980s, the C-130 was intended to be replaced by the Advanced Medium STOL Transport project. The project was canceled and the C-130 has remained in production.

Building on lessons learned, Lockheed Martin modified a commercial variant of the C-130 into a High Technology Test Bed (HTTB). This test aircraft set numerous short takeoff and landing performance records and significantly expanded the database for future derivatives of the C-130. Modifications made to the HTTB included extended chord ailerons, a long chord rudder, fast-acting double-slotted trailing edge flaps, a high-camber wing leading edge extension, a larger dorsal fin and dorsal fins, the addition of three spoiler panels to each wing upper surface, a long-stroke main and nose landing gear system, and changes to the flight controls and a change from direct mechanical linkages assisted by hydraulic boost, to fully powered controls, in which the mechanical linkages from the flight station controls operated only the hydraulic control valves of the appropriate boost unit.

The HTTB first flew on 19 June 1984, with civil registration of N130X. After demonstrating many new technologies, some of which were applied to the C-130J, the HTTB was lost in a fatal accident on 3 February 1993, at Dobbins Air Reserve Base, in Marietta, Georgia. The crash was attributed to disengagement of the rudder fly-by-wire flight control system, resulting in a total loss of rudder control capability while conducting ground minimum control speed tests (Vmcg). The disengagement was a result of the inadequate design of the rudder's integrated actuator package by its manufacturer; the operator's insufficient system safety review failed to consider the consequences of the inadequate design to all operating regimes. A factor that contributed to the accident was the flight crew's lack of engineering flight test training.

In the 1990s, the improved C-130J Super Hercules was developed by Lockheed (later Lockheed Martin). This model is the newest version and the only model in production. Externally similar to the classic Hercules in general appearance, the J model has new turboprop engines, six-bladed propellers, digital avionics, and other new systems.

Upgrades and changes
In 2000, Boeing was awarded a US$1.4 billion contract to develop an Avionics Modernization Program kit for the C-130. The program was beset with delays and cost overruns until project restructuring in 2007. In September 2009, it was reported that the planned Avionics Modernization Program (AMP) upgrade to the older C-130s would be dropped to provide more funds for the F-35, CV-22 and airborne tanker replacement programs. However, in June 2010, Department of Defense approved funding for the initial production of the AMP upgrade kits. Under the terms of this agreement, the USAF has cleared Boeing to begin low-rate initial production (LRIP) for the C-130 AMP. A total of 198 aircraft are expected to feature the AMP upgrade. The current cost per aircraft is US$14 million, although Boeing expects that this price will drop to US$7 million for the 69th aircraft.

In the 2000s, Lockheed Martin and the U.S. Air Force began outfitting and retrofitting C-130s with the eight-blade UTC Aerospace Systems NP2000 propellers. An engine enhancement program saving fuel and providing lower temperatures in the T56 engine has been approved, and the US Air Force expects to save $2 billion (~$ in ) and extend the fleet life.

In 2021, the Air Force Research Laboratory demonstrated the Rapid Dragon system which transforms the C-130 into a lethal strike platform capable of launching 12 JASSM-ER with 500 kg warheads from a standoff distance of 925 km. Future anticipated improvements support includes support for JDAM-ER, mine laying, drone dispersal as well as improved standoff range when 1900 km JASSM-XR become available in 2024.

Replacement
In October 2010, the U.S. Air Force released a capability request for information (CRFI) for the development of a new airlifter to replace the C-130. The new aircraft was to carry a 190% greater payload and assume the mission of mounted vertical maneuver (MVM). The greater payload and mission would enable it to carry medium-weight armored vehicles and unload them at locations without long runways. Various options were under consideration, including new or upgraded fixed-wing designs, rotorcraft, tiltrotors, or even an airship. The C-130 fleet of around 450 planes would be replaced by only 250 aircraft. The Air Force had attempted to replace the C-130 in the 1970s through the Advanced Medium STOL Transport project, which resulted in the C-17 Globemaster III that instead replaced the C-141 Starlifter.

The Air Force Research Laboratory funded Lockheed Martin and Boeing demonstrators for the Speed Agile concept, which had the goal of making a STOL aircraft that could take off and land at speeds as low as 70 kn on airfields less than 2,000 ft long and cruise at Mach 0.8-plus. Boeing's design used upper-surface blowing from embedded engines on the inboard wing and blown flaps for circulation control on the outboard wing. Lockheed's design also used blown flaps outboard, but inboard used patented reversing ejector nozzles.

Boeing's design completed over 2,000 hours of wind tunnel tests in late 2009. It was a 5 percent-scale model of a narrow body design with a 55000 lb payload. When the AFRL increased the payload requirement to 65000 lb, they tested a 5 percent-scale model of a widebody design with a 303000 lb take-off gross weight and an "A400M-size" 158 in wide cargo box. It would be powered by four IAE V2533 turbofans.

In August 2011, the AFRL released pictures of the Lockheed Speed Agile concept demonstrator. A 23% scale model went through wind tunnel tests to demonstrate its hybrid powered lift, which combined a low drag airframe with simple mechanical assembly to reduce weight and improve aerodynamics. The model had four engines, including two Williams FJ44 turbofans. On 26 March 2013, Boeing was granted a patent for its swept-wing powered lift aircraft.

In January 2014, Air Mobility Command, Air Force Materiel Command and the Air Force Research Lab were in the early stages of defining requirements for the C-X next generation airlifter program to replace both the C-130 and C-17. The aircraft would be produced from the early 2030s to the 2040s.

Military

The first production batch of C-130A aircraft were delivered beginning in 1956 to the 463d Troop Carrier Wing at Ardmore AFB, Oklahoma, and the 314th Troop Carrier Wing at Sewart AFB, Tennessee. Six additional squadrons were assigned to the 322d Air Division in Europe and the 315th Air Division in the Far East. Additional aircraft were modified for electronics intelligence work and assigned to Rhein-Main Air Base, Germany while modified RC-130As were assigned to the Military Air Transport Service (MATS) photo-mapping division. The C-130A entered service with the U.S. Air Force in December 1956.

In 1958, a U.S. reconnaissance C-130A-II of the 7406th Support Squadron was shot down over Armenia by four Soviet MiG-17s along the Turkish-Armenian border during a routine mission.

Australia became the first non-American operator of the Hercules with 12 examples being delivered from late 1958. The Royal Canadian Air Force became another early user with the delivery of four B-models (Canadian designation CC-130 Mk I) in October / November 1960.

In 1963, a Hercules achieved and still holds the record for the largest and heaviest aircraft to land on an aircraft carrier. During October and November that year, a USMC KC-130F (BuNo 149798), loaned to the U.S. Naval Air Test Center, made 29 touch-and-go landings, 21 unarrested full-stop landings and 21 unassisted take-offs on USS Forrestal (CVA-59) at a number of different weights. The pilot, Lieutenant (later Rear Admiral) James H. Flatley III, USN, was awarded the Distinguished Flying Cross for his role in this test series. The tests were highly successful, but the aircraft was not deployed this way. Flatley denied that C-130 was tested for carrier onboard delivery (COD) operations, or for delivering nuclear weapons. He said that the intention was to support the Lockheed U-2, also being tested on carriers. The Hercules used in the test, most recently in service with Marine Aerial Refueler Squadron 352 (VMGR-352) until 2005, is now part of the collection of the National Museum of Naval Aviation at NAS Pensacola, Florida.

In 1964, C-130 crews from the 6315th Operations Group at Naha Air Base, Okinawa commenced forward air control (FAC; "Flare") missions over the Ho Chi Minh Trail in Laos supporting USAF strike aircraft. In April 1965 the mission was expanded to North Vietnam where C-130 crews led formations of Martin B-57 Canberra bombers on night reconnaissance/strike missions against communist supply routes leading to South Vietnam. In early 1966 Project Blind Bat/Lamplighter was established at Ubon Royal Thai Air Force Base, Thailand. After the move to Ubon, the mission became a four-engine FAC mission with the C-130 crew searching for targets and then calling in strike aircraft. Another little-known C-130 mission flown by Naha-based crews was Operation Commando Scarf (or Operation Commando Lava), which involved the delivery of chemicals onto sections of the Ho Chi Minh Trail in Laos that were designed to produce mud and landslides in hopes of making the truck routes impassable.

In November 1964, on the other side of the globe, C-130Es from the 464th Troop Carrier Wing but loaned to 322d Air Division in France, took part in Operation Dragon Rouge, one of the most dramatic missions in history in the former Belgian Congo. After communist Simba rebels took white residents of the city of Stanleyville hostage, the U.S. and Belgium developed a joint rescue mission that used the C-130s to drop, air-land, and air-lift a force of Belgian paratroopers to rescue the hostages. Two missions were flown, one over Stanleyville and another over Paulis during Thanksgiving week. The headline-making mission resulted in the first award of the prestigious MacKay Trophy to C-130 crews.

In the Indo-Pakistani War of 1965, the No. 6 Transport Squadron of the Pakistan Air Force modified its C-130Bs for use as bombers to carry up to 20,000 lb of bombs on pallets. These improvised bombers were used to hit Indian targets such as bridges, heavy artillery positions, tank formations, and troop concentrations, though weren't that successful.

In October 1968, a C-130Bs from the 463rd Tactical Airlift Wing dropped a pair of M-121 10,000 lb bombs that had been developed for the massive Convair B-36 Peacemaker bomber but had never been used. The U.S. Army and U.S. Air Force resurrected the huge weapons as a means of clearing landing zones for helicopters and in early 1969 the 463rd commenced Commando Vault missions. Although the stated purpose of Commando Vault was to clear LZs, they were also used on enemy base camps and other targets.

During the late 1960s, the U.S. was eager to get information on Chinese nuclear capabilities. After the failure of the Black Cat Squadron to plant operating sensor pods near the Lop Nur Nuclear Weapons Test Base using a U-2, the CIA developed a plan, named Heavy Tea, to deploy two battery-powered sensor pallets near the base. To deploy the pallets, a Black Bat Squadron crew was trained in the U.S. to fly the C-130 Hercules. The crew of 12, led by Col Sun Pei Zhen, took off from Takhli Royal Thai Air Force Base in an unmarked U.S. Air Force C-130E on 17 May 1969. Flying for six and a half hours at low altitude in the dark, they arrived over the target and the sensor pallets were dropped by parachute near Anxi in Gansu province. After another six and a half hours of low-altitude flight, they arrived back at Takhli. The sensors worked and uploaded data to a U.S. intelligence satellite for six months before their batteries failed. The Chinese conducted two nuclear tests, on 22 September 1969 and 29 September 1969, during the operating life of the sensor pallets. Another mission to the area was planned as Operation Golden Whip, but it was called off in 1970. It is most likely that the aircraft used on this mission was either C-130E serial number 64-0506 or 64-0507 (cn 382-3990 and 382–3991). These two aircraft were delivered to Air America in 1964. After being returned to the U.S. Air Force sometime between 1966 and 1970, they were assigned the serial numbers of C-130s that had been destroyed in accidents. 64-0506 is now flying as 62–1843, a C-130E that crashed in Vietnam on 20 December 1965, and 64-0507 is now flying as 63–7785, a C-130E that had crashed in Vietnam on 17 June 1966.

The A-model continued in service through the Vietnam War, where the aircraft assigned to the four squadrons at Naha AB, Okinawa, and one at Tachikawa Air Base, Japan performed yeoman's service, including operating highly classified special operations missions such as the BLIND BAT FAC/Flare mission and Fact Sheet leaflet mission over Laos and North Vietnam. The A-model was also provided to the Republic of Vietnam Air Force as part of the Vietnamization program at the end of the war, and equipped three squadrons based at Tan Son Nhut Air Base. The last operator in the world is the Honduran Air Force, which is still flying one of five A model Hercules (FAH 558, c/n 3042) as of October 2009. As the Vietnam War wound down, the 463rd Troop Carrier/Tactical Airlift Wing B-models and A-models of the 374th Tactical Airlift Wing were transferred back to the United States where most were assigned to Air Force Reserve and Air National Guard units.

Another prominent role for the B model was with the United States Marine Corps, where Hercules initially designated as GV-1s replaced C-119s. After Air Force C-130Ds proved the type's usefulness in Antarctica, the U.S. Navy purchased several B-models equipped with skis that were designated as LC-130s. C-130B-II electronic reconnaissance aircraft were operated under the SUN VALLEY program name primarily from Yokota Air Base, Japan. All reverted to standard C-130B cargo aircraft after their replacement in the reconnaissance role by other aircraft.

The C-130 was also used in the 1976 Entebbe raid in which Israeli commando forces performed a surprise operation to rescue 103 passengers of an airliner hijacked by Palestinian and German terrorists at Entebbe Airport, Uganda. The rescue force—200 soldiers, jeeps, and a black Mercedes-Benz (intended to resemble Ugandan Dictator Idi Amin's vehicle of state)—was flown over 2200 nmi almost entirely at an altitude of less than 100 ft from Israel to Entebbe by four Israeli Air Force (IAF) Hercules aircraft without mid-air refueling (on the way back, the aircraft refueled in Nairobi, Kenya).

During the Falklands War (Guerra de las Malvinas) of 1982, Argentine Air Force C-130s undertook dangerous re-supply night flights as blockade runners to the Argentine garrison on the Falkland Islands. They also performed daylight maritime survey flights. One was shot down by a Royal Navy Sea Harrier using AIM-9 Sidewinders and cannon. The crew of seven were killed. Argentina also operated two KC-130 tankers during the war, and these refueled both the Douglas A-4 Skyhawks and Navy Dassault-Breguet Super Étendards; some C-130s were modified to operate as bombers with bomb-racks under their wings. The British also used RAF C-130s to support their logistical operations.

During the Gulf War of 1991 (Operation Desert Storm), the C-130 Hercules was used operationally by the U.S. Air Force, U.S. Navy, and U.S. Marine Corps, along with the air forces of Australia, New Zealand, Saudi Arabia, South Korea, and the UK. The MC-130 Combat Talon variant also made the first attacks using the largest conventional bombs in the world, the BLU-82 "Daisy Cutter" and GBU-43/B "Massive Ordnance Air Blast" (MOAB) bomb. Daisy Cutters were used to primarily clear landing zones and to eliminate mine fields. The weight and size of the weapons make it impossible or impractical to load them on conventional bombers. The GBU-43/B MOAB is a successor to the BLU-82 and can perform the same function, as well as perform strike functions against hardened targets in a low air threat environment.

Since 1992, two successive C-130 aircraft named Fat Albert have served as the support aircraft for the U.S. Navy Blue Angels flight demonstration team. Fat Albert I was a TC-130G (151891) a former U.S. Navy TACAMO aircraft serving with Fleet Air Reconnaissance Squadron Three (VQ-3) before being transferred to the BLUES, while Fat Albert II is a C-130T (164763). Although Fat Albert supports a Navy squadron, it is operated by the U.S. Marine Corps (USMC) and its crew consists solely of USMC personnel. At some air shows featuring the team, Fat Albert takes part, performing flyovers. Until 2009, it also demonstrated its rocket-assisted takeoff (RATO) capabilities; these ended due to dwindling supplies of rockets.

The AC-130 also holds the record for the longest sustained flight by a C-130. From 22 to 24 October 1997, two AC-130U gunships flew 36 hours nonstop from Hurlburt Field, Florida to Daegu International Airport, South Korea, being refueled seven times by KC-135 tanker aircraft. This record flight beat the previous record longest flight by over 10 hours and the two gunships took on 410000 lb of fuel. The gunship has been used in every major U.S. combat operation since Vietnam, except for Operation El Dorado Canyon, the 1986 attack on Libya.

During the invasion of Afghanistan in 2001 and the ongoing support of the International Security Assistance Force (Operation Enduring Freedom), the C-130 Hercules has been used operationally by Australia, Belgium, Canada, Denmark, France, Italy, the Netherlands, New Zealand, Norway, Portugal, Romania, South Korea, Spain, the UK, and the United States.

During the 2003 invasion of Iraq (Operation Iraqi Freedom), the C-130 Hercules was used operationally by Australia, the UK, and the United States. After the initial invasion, C-130 operators as part of the Multinational force in Iraq used their C-130s to support their forces in Iraq.

Since 2004, the Pakistan Air Force has employed C-130s in the War in North-West Pakistan. Some variants had forward looking infrared (FLIR Systems Star Safire III EO/IR) sensor balls, to enable close tracking of militants.

In 2017, France and Germany announced that they are to build up a joint air transport squadron at Evreux Air Base, France, comprising ten C-130J aircraft. Six of these will be operated by Germany. Initial operational capability is expected for 2021 while full operational capability is scheduled for 2024.

The Argentine Air Force has five C-130H aircraft that are part of a US-funded security assistance donation. The US has been leasing the aircraft to the Argentine Air Force through the Georgia Air National Guard since June 2023.

Deepwater Horizon Oil Spill

For almost two decades, the USAF 910th Airlift Wing's 757th Airlift Squadron and the U.S. Coast Guard have participated in oil spill cleanup exercises to ensure the U.S. military has a capable response in the event of a national emergency. The 757th Airlift Squadron operates the DOD's only fixed-wing Aerial Spray System which was certified by the EPA to disperse pesticides on DOD property to spread oil dispersants onto the Deepwater Horizon oil spill in the Gulf Coast in 2010.

During the 5-week mission, the aircrews flew 92 sorties and sprayed approximately 30,000 acres with nearly 149,000 gallons of oil dispersant to break up the oil. The Deepwater Horizon mission was the first time the US used the oil dispersing capability of the 910th Airlift Wing—its only large area, fixed-wing aerial spray program—in an actual spill of national significance. The Air Force Reserve Command announced the 910th Airlift Wing has been selected as a recipient of the Air Force Outstanding Unit Award for its outstanding achievement from 28 April 2010 through 4 June 2010.

Hurricane Harvey (2017)

C-130s temporarily based at Kelly Field conducted mosquito control aerial spray applications over areas of eastern Texas devastated by Hurricane Harvey. This special mission treated more than 2.3 million acres at the direction of Federal Emergency Management Agency (FEMA) and the Texas Department of State Health Services (DSHS) to assist in recovery efforts by helping contain the significant increase in pest insects caused by large amounts of standing, stagnant water. The 910th Airlift Wing operates the Department of Defense's only aerial spray capability to control pest insect populations, eliminate undesired and invasive vegetation, and disperse oil spills in large bodies of water.

The aerial spray flight also is now able to operate during the night with NVGs, which increases the flight's best case spray capacity from approximately 60 thousand acres per day to approximately 190 thousand acres per day. Spray missions are normally conducted at dusk and nighttime hours when pest insects are most active, the U.S. Air Force Reserve reports.

Aerial firefighting

In the early 1970s, Congress authorized the Modular Airborne Firefighting System (MAFFS), a joint operation between the U.S. Forest Service and the Department of Defense. MAFFS is roll-on/roll-off device that allows C-130s to be temporarily converted into a 3,000-gallon airtanker for fighting wildfires when demand exceeds the supply of privately contracted and publicly available airtankers.

In the late 1980s, 22 retired USAF C-130As were removed from storage and transferred to the U.S. Forest Service, which then transferred them to six private companies to be converted into airtankers. One of these C-130s crashed in June 2002 while operating near Walker, California. The crash was attributed to wing separation caused by fatigue stress cracking and contributed to the grounding of the entire large aircraft fleet. After an extensive review, US Forest Service and the Bureau of Land Management declined to renew the leases on nine C-130A over concerns about the age of the aircraft, which had been in service since the 1950s, and their ability to handle the forces generated by aerial firefighting.

More recently, an updated Retardant Aerial Delivery System known as RADS XL was developed by Coulson Aviation USA. That system consists of a C-130H/Q retrofitted with an in-floor discharge system, combined with a removable 3,500- or 4,000-gallon water tank. The combined system is FAA certified. On 23 January 2020, Coulson's Tanker 134, an EC-130Q registered N134CG, crashed during aerial firefighting operations in New South Wales, Australia, killing all three crew members. The aircraft had taken off out of RAAF Base Richmond and was supporting firefighting operations during Australia's 2019–20 fire season.

Variants

Significant military variants of the C-130 include:
 * C-130A
 * Initial production model with four Allison T56-A-11/9 turboprop engines. 219 were ordered and deliveries to the USAF began in Dec. 1956.

 * C-130B
 * Variant with four Allison T56-A-7 engines. 134 were ordered and entered USAF service in May 1959.

 * C-130E
 * Same engines as the C-130B but with two 1,290 U.S.gal external fuel tanks, and an increased maximum takeoff weight capability. Introduced in Aug. 1962 with 389 were ordered.

 * C-130F/G
 * Variants procured by the U.S. Navy for Marine Corps refueling missions, and other support/transport operations.

 * C-130H
 * Identical to the C-130E but with more powerful Allison T56-A-15 turboprop engines. Introduced in Jun. 1974 with 308 ordered.

 * C-130K
 * Designation for RAF Hercules C1/W2/C3 aircraft (C-130Js in RAF service are the Hercules C.4 and Hercules C.5)

 * C-130T
 * Improved variants procured by the U.S. Navy for Marine Corps refueling, and other support/transport operations.

 * C-130A-II Dreamboat
 * Early version Electronic Intelligence/Signals Intelligence (ELINT/SIGINT) aircraft

 * C-130J Super Hercules
 * Tactical airlifter, with new engines, avionics, and updated systems

 * C-130B BLC: A one-off conversion of C-130B 58–0712, modified with a double Allison YT56 gas generator pod under each outer wing, to provide bleed air for all the control surfaces and flaps.
 * AC-130A/E/H/J/U/W
 * Gunship variants

 * C-130D/D-6
 * Ski-equipped version for snow and ice operations United States Air Force / Air National Guard

 * CC-130E/H/J Hercules
 * Designation for Canadian Armed Forces / Royal Canadian Air Force Hercules aircraft. U.S. Air Force used the CC-130J designation to differentiate the standard C-130J variant from the "stretched" C-130J (company designation C-130J-30). CC-130H(T) is the Canadian tanker variant of the KC-130H.

 * C-130M: Designation used by the Brazilian Air Force for locally modified C-130H aircraft.
 * DC-130A/E/H
 * USAF and USN Drone control

 * EC-130
 * EC-130E/J Commando Solo – USAF / Air National Guard psychological operations version
 * EC-130E Airborne Battlefield Command and Control Center (ABCCC) – USAF procedural air-to-ground attack control, also provided NRT threat updates
 * EC-130E Rivet Rider – Airborne psychological warfare aircraft
 * EC-130H Compass Call – Electronic warfare and electronic attack.
 * EC-130V – Airborne early warning and control (AEW&C) variant used by USCG for counter-narcotics missions

 * GC-130
 * Permanently grounded instructional airframes

 * HC-130
 * HC-130B/E/H – Early model combat search and rescue
 * HC-130P/N Combat King – USAF aerial refueling tanker and combat search and rescue
 * HC-130J Combat King II – Next generation combat search and rescue tanker
 * HC-130H/J – USCG long-range surveillance and search and rescue, USAFR Aerial Spray & Airlift

 * JC-130
 * Temporary conversion for flight test operations; used to recover drones and spy satellite film capsules.

 * KC-130F/R/T/J
 * United States Marine Corps aerial refueling tanker and tactical airlifter

 * LC-130F/H/R
 * USAF / Air National Guard – Ski-equipped version for Arctic and Antarctic support operations; LC-130F and R previously operated by USN

 * MC-130
 * MC-130E/H Combat Talon I/II – Special operations infiltration/extraction variant
 * MC-130W Combat Spear/Dragon Spear – Special operations tanker/gunship
 * MC-130P Combat Shadow – Special operations tanker – all operational aircraft converted to HC-130P standard
 * MC-130J Commando II (formerly Combat Shadow II) – Special operations tanker Air Force Special Operations Command
 * YMC-130H – Modified aircraft under Operation Credible Sport for second Iran hostage crisis rescue attempt

 * NC-130
 * Permanent conversion for flight test operations

 * PC-130/C-130-MP
 * Maritime patrol

 * RC-130A/S
 * Surveillance aircraft for reconnaissance

 * SC-130J Sea Herc
 * Proposed maritime patrol version of the C-130J, designed for coastal surveillance and anti-submarine warfare.

 * TC-130
 * Aircrew training

 * VC-130H
 * VIP transport

 * WC-130A/B/E/H/J
 * Weather reconnaissance ("Hurricane Hunter") version for USAF / Air Force Reserve Command's 53d Weather Reconnaissance Squadron in support of the National Weather Service's National Hurricane Center

 * C-130(EM/BM) Erciyes
 * Turkey's Erciyes modernization program covers modernization of the avionics of C-130B/E variants of the aircraft. In scope of modernization the aircraft is equipped with Digital Cockpit (four-color Multifunctional Display with moving map capability-MFD), two Central Display Units (CDU) and two multifunction Central Control Computers compatible with international navigational requirements, as well as with a multifunction Mission Computer with high operational capability, Flight Management System (FMS), Link-16, Ground Mission Planning Unit compatible with the Air Force Information System, and display and lighting systems compatible with Night Vision Goggles. Other components such as GPS, indicator, anti-collision system, air radar, advanced military and civilian navigation systems, night-time invisible lighting for military missions, black box voice recorder, communication systems, advanced automated flight systems (military and civilian), systems enabling operation in the military network, digital moving map and ground mission planning systems are also included.

Operators

Former operators
 * North Yemen
 * Pahlavi Iran
 * South Vietnam
 * Zaire
 * Pahlavi Iran
 * South Vietnam
 * Zaire

Accidents
The C-130 Hercules has had a low accident rate in general. The Royal Air Force recorded an accident rate of about one aircraft loss per 250,000 flying hours over the last 40 years, placing it behind Vickers VC10s and Lockheed TriStars with no flying losses. USAF C-130A/B/E-models had an overall attrition rate of 5% as of 1989 as compared to 1–2% for commercial airliners in the U.S., according to the NTSB, 10% for B-52 bombers, and 20% for fighters (F-4, F-111), trainers (T-37, T-38), and helicopters (H-3).

Argentina

 * C-130B FAA TC-60. ex USAF 61-0964 received in February 1992 now at Museo Nacional de Aeronáutica since September 2011.

Australia

 * C-130A RAAF A97-214 used by 36 Squadron from early 1959, withdrawn from use late 1978; now at RAAF Museum, RAAF Base Williams, Point Cook.
 * C-130E RAAF A97-160 used by 37 Squadron from August 1966, withdrawn from use November 2000; to RAAF Museum, 14 November 2000, cocooned as of September 2005.

Belgium

 * C-130H Belgian Airforce tailnumber CH13 in service from 2009 until May 2021 is on display at the Beauvechain Air Base at the First Wing Historical Center.

Brazil

 * C-130H Brazilian Air Force FAB-2453 is on display at the Museu Aeroespacial in Rio de Janeiro since 2014.

Canada

 * CC-130E RCAF 10313 (later 130313) is on display at the National Air Force Museum of Canada, CFB Trenton
 * CC-130E RCAF 10307 (later 130307) is on display in the Reserve Hangar at the Canada Aviation and Space Museum, Ottawa, Ontario
 * CC-130E RCAF 130328 is on display at the Greenwood Aviation Museum, CFB Greenwood

Colombia

 * C-130B FAC 1010 (serial number 3521) moved on 14 January 2016 to the Colombian Aerospace Museum in Tocancipá, Cundinamarca, for static display.
 * C-130B FAC1011 (serial number 3585, ex 59–1535) preserved at the Colombian Air and Space Museum within CATAM AFB, Bogotá.

Indonesia

 * C-130B Indonesian Air Force A-1301 preserved at Sulaeman Airstrip, Bandung. Also occasionally used for Paskhas Training. The airplane is relocated to Air Force Museum in Yogyakarta in 2017.

Norway

 * C-130H Royal Norwegian Air Force 953 was retired on 10 June 2007 and moved to the Air Force museum at Oslo Gardermoen in May 2008.

Philippines

 * C-130B 4512 Philippine Air Force on display at Mactan Air Base aircraft park.

Saudi Arabia

 * C-130H RSAF 460 was operated by 4 Squadron Royal Saudi Air Force from December 1974 until January 1987. It was damaged in a fire at Jeddah in December 1989. Restored for ground training by August 1993. At Royal Saudi Air Force Museum, November 2002, restored for ground display by using a tail from another C-130H.

United Kingdom

 * Hercules C3 XV202 that served with the Royal Air Force from 1967 to 2011, is on display at the Royal Air Force Museum Cosford.

United States

 * GC-130A, AF Ser. No. 55-037 used by the 773 TCS, 483 TCW, 315 AD, 374 TCW, 815 TAS, 35 TAS, 109 TAS, belly-landed at Duluth, Minnesota, April 1973, repaired; 167 TAS, 180 TAS, to Chanute Technical Training Center as GC-130A, May 1984; now displayed at Museum of Missouri Military History, Missouri National Guard Ike Skelton Training Center, Jefferson City, Missouri. Previously displayed at Octave Chanute Aerospace Museum, (former) Chanute AFB, Rantoul, Illinois until museum closed.
 * C-130A, AF Ser. No. 56-0518 used by the 314 TCW, 315 AD, 41 ATS, 328 TAS; to Republic of Vietnam Air Force 435 Transport Squadron, November 1972; holds the C-130 record for taking off with the most personnel on board, during the evacuation of SVN, 29 April 1975, with 452. Returned to USAF, 185 TAS, 105 TAS; Flown to Little Rock AFB on 28 June 1989. It was converted to a static display at the LRAFB Visitor Center, Arkansas by Sept. 1989.
 * C-130A, AF Ser. No. 57-0453 was operated from 1958 to 1991, last duty with 155th TAS, 164th TAG, Tennessee Air National Guard, Memphis International Airport/ANGB, Tennessee, 1976–1991, named "Nite Train to Memphis"; to AMARC in December 1991, then sent to Texas for modification into a replica of C-130A-II Dreamboat aircraft, AF Ser. No. 56-0528, shot down by Soviet fighters in Soviet airspace near Yerevan, Armenia on 2 September 1958, while on ELINT mission with loss of all crew, displayed in National Vigilance Park, National Security Agency grounds, Fort George Meade, Maryland.
 * C-130B, AF Ser. No. 59-0528 was operated by 145th Airlift Wing, North Carolina Air National Guard; placed on static display at Charlotte Air National Guard Base, North Carolina in 2010.
 * C-130D, AF Ser. No. 57-0490 used by the 61st TCS, 17th TCS, 139th TAS with skis, July 1975 – April 1983; to MASDC, 1984–1985, GC-130D ground trainer, Chanute AFB, Illinois, 1986–1990; When Chanute AFB closed in September 1993, it moved to the Octave Chanute Aerospace Museum (former Chanute AFB), Rantoul, Illinois. In July 1994, it moved to the Empire State Air Museum, Schenectady County Airport, New York, until placed on the gate at Stratton Air National Guard Base in October 1994.
 * NC-130B, AF Ser. No. 57-0526 was the second B model manufactured, initially delivered as JC-130B; assigned to 6515th Organizational Maintenance Squadron for flight testing at Edwards AFB, California on 29 November 1960; turned over to 6593rd Test Squadron's Operating Location No. 1 at Edwards AFB and spent next seven years supporting Corona Program; "J" status and prefix removed from aircraft in October 1967; transferred to 6593rd Test Squadron at Hickam AFB, Hawaii and modified for mid-air retrieval of satellites; acquired by 6514th Test Squadron at Hill AFB, Utah in Jan. 1987 and used as electronic testbed and cargo transport; aircraft retired January 1994 with 11,000+ flight hours and moved to Hill Aerospace Museum at Hill AFB by January 1994.
 * C-130E, AF Ser. No. 62-1787, on display at the National Museum of the United States Air Force, Wright-Patterson AFB, Ohio, was flown to the museum on 18 August 2011. One of the greatest feats of heroism during the Vietnam War involved the C-130E, call sign "Spare 617". The C-130E attempted to airdrop ammunition to surround South Vietnamese forces at An Loc, Vietnam. Approaching the drop zone, Spare 617 received heavy enemy ground fire that damaged two engines, ruptured a bleed air duct in the cargo compartment, and set the ammunition on fire. Flight engineer TSgt Sanders was killed, and navigator 1st Lt Lenz and co-pilot 1st Lt Hering were both wounded. Despite receiving severe burns from hot air escaping from the damaged air bleed duct, loadmaster TSgt Shaub extinguished a fire in the cargo compartment, and successfully jettisoned the cargo pallets, which exploded in mid-air. Despite losing a third engine on the final approach, pilot Capt Caldwell landed Spare 617 safely. For their actions, Caldwell and Shaub received the Air Force Cross, the U.S. Air Force's second highest award for valor. TSgt Shaub also received the William H. Pitsenbarger Award for Heroism from the Air Force Sergeants Association.
 * KC-130F, USN/USMC BuNo 149798 used in tests in October–November 1963 by the U.S. Navy for unarrested landings and unassisted take-offs from the carrier USS Forrestal (CV-59), it remains the record holder for largest aircraft to operate from a carrier flight deck, and carried the name "Look Ma, No Hook" during the tests. Retired to the National Museum of Naval Aviation, NAS Pensacola, Florida in May 2003.
 * C-130G, USN/USMC BuNo 151891; modified to EC-130G, 1966, then testbed for EC-130Q TACAMO in 1981, then changed to TC-130G and used by Fleet Air Reconnaissance Squadron Three (VQ-3) for flight proficiency (bounce bird). In early 1991 it was transferred to AMMARG Davis-Monthan AFB Tucson, AZ. In May 1991 it was assigned as the U.S. Navy's Blue Angels USMC support aircraft, serving as "Fat Albert Airlines" from 1991 to 2002. Retired to the National Museum of Naval Aviation at NAS Pensacola, Florida in November 2002 where it remains on outside static display reflecting the BLUES colors.
 * C-130E, AF Ser. No. 64-0525 was on display at the 82nd Airborne Division War Memorial Museum at Fort Liberty, North Carolina. The aircraft was the last assigned to the 43rd AW at Pope AFB, North Carolina before retirement from the USAF.
 * C-130E-LM, AF Ser. No. 64-0533 – Taken in December 1964 by 314th Troop Carrier Wing, Sewart AFB, TN. Last assigned to 37th Airlift Squadron, Rhein-Main AB, Germany. Transferred to Elmendorf AFB for display, May 2004. Marked as 53-2453
 * C-130E, AF Ser. No. 69-6579 operated by the 61st TAS, 314th TAW, 50th AS, 61st AS; at Dyess AFB as maintenance trainer as GC-130E, March 1998; to Dyess AFB Linear Air Park, January 2004.
 * MC-130E Combat Talon I, AF Ser. No. 64-0567, unofficially known as "Wild Thing". It transported captured Panamanian dictator Manuel Noriega in 1989 during Operation Just Cause and participated in Operation Eagle Claw, the unsuccessful attempt to rescue U.S. hostages from Iran in 1980. Wild Thing was also the first fixed-wing aircraft to employ night-vision goggles. On display at Hurlburt Field, in Florida.
 * C-130E, AF Ser. No. 69-6580 operated by the 61st TAS, 314th TAW, 317th TAW, 314th TAW, 317th TAW, 40th AS, 41st AS, 43rd AW, retired after center wing cracks were detected in April 2002; to the Air Mobility Command Museum, Dover AFB, Delaware on 2 February 2004.
 * C-130E, AF Ser. No. 70-1269 was used by the 43rd AW and is on display at the Pope Air Park, Pope AFB, North Carolina as of 2006.
 * C-130H, AF Ser. No. 74-1686 used by the 463rd TAW; one of three C-130H airframes modified to YMC-130H for an aborted rescue attempt of Iranian hostages, Operation Credible Sport, with rocket packages blistered onto fuselage in 1980, but these were removed after the mission was canceled. Subsequent duty with the 4950th Test Wing, then donated to the Museum of Aviation at Robins AFB, Georgia, in March 1988.
 * C-130H, AF Ser. No. 88-4401 operated by the Ohio 179th Airlift Wing has been retired and is on display at the MAPS Air Museum in Canton, Ohio

title: Lockheed C-130 Hercules


text:
Commodore 1570

The Commodore 1570 is a 5¼" floppy disk drive for the Commodore 128 home/personal computer. It is a single-sided, 170 kB version of the Commodore 1571, released as a stopgap measure when Commodore International was unable to provide sufficient quantities of 1571s due to a shortage of double-sided drive mechanisms (which were supplied by an outside manufacturer). Like the 1571, it can read and write both GCR and MFM disk formats. The 1570 utilizes a 1571 logic board in a cream-colored original-1541-like case with a drive mechanism similar to the 1541's except that it was equipped with track-zero detection. Like the 1571, its built-in DOS provides a data burst mode for transferring data to the C128 computer at a faster speed than a 1541 can. Its ROM also contains some DOS bug fixes that didn't appear in the 1571 until much later. The 1570 can read and write all single-sided CP/M-format disks that the 1571 can access.

Although the 1570 is compatible with the Commodore 64, the C64 isn't capable of taking advantage of the drive's higher-speed operation, and when used with the C64 it's little more than a pricier 1541. Also, many early buyers of the C128 chose to temporarily make do with a 1541 drive, perhaps owned as part of a previous C64 setup, until the 1571 became more widely available.

The drive uses the CPU MOS 6502, floppy controller WD1770 or WD1772, I/O controllers 2x MOS Technology 6522 and 1x MOS Technology 6526.

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Commodore 1570


text:
Commodore 1571

The Commodore 1571 is Commodore's high-end 5¼" floppy disk drive, announced in the summer of 1985. With its double-sided drive mechanism, it has the ability to use double-sided, double-density (DS/DD) floppy disks, storing a total of 360 kB per floppy. It also implemented a "burst mode" that improved transfer speeds, helping address the very slow performance of previous Commodore drives.

Earlier Commodore drives used a custom group coded recording format that stored 170 kB per side of a disk. This made it fairly competitive in terms of storage, but limited it to only reading and writing disks from other Commodore machines. The 1571 was designed to partner with the new Commodore 128 (C128), which introduced support for CP/M. Adding double-density MFM encoding allowed the drive to read and write contemporary CP/M disks (and many others).

In contrast to its single-sided predecessors, the 1541 and the briefly-available 1570, the 1571 can use both sides of the disk at the same time. Previously, users could only use the second side by manually flipping them over. Because flipping the disk also reverses the direction of rotation, the two methods are not interchangeable; disks which had their back side created in a 1541 by flipping them over would have to be flipped in the 1571 too, and the back side of disks written in a 1571 using the native support for two-sided operation could not be read in a 1541.

Release and features
The 1571 was released to match the Commodore 128, both design-wise and feature-wise. It was announced in the summer of 1985, at the same time as the C128, and became available in quantity later that year. The later C128D had a 1571 drive built into the system unit. A double-sided disk on the 1571 would have a capacity of 340 kB (70 tracks, 1,360 disk blocks of 256 bytes each); as 8 kB are reserved for system use (directory and block availability information) and, under CBM DOS, 2 bytes of each block serve as pointers to the next logical block, 254 x 1,328 = 337,312 B or about 329.4 kB were available for user data. (However, with a program organizing disk storage on its own, all space could be used, e.g. for data disks.)

The 1571 was designed to accommodate the C128's "burst" mode for faster disk access, however the drive cannot use it if connected to older Commodore machines. This mode replaced the slow bit-banging serial routines of the 1541 with a true serial shift register implemented in hardware, thus dramatically increasing the drive speed. Although this originally had been planned when Commodore first switched from the parallel IEEE-488 interface to the CBM-488 custom serial interface, hardware bugs in the VIC-20's 6522 VIA shift register prevented it from working properly.

When connected to a C128, the 1571 would default to double-sided mode, which allowed the drive to read its own 340k disks as well as single-sided 170 kB 1541 disks. If the C128 was switched into C64 mode by typing GO 64 from BASIC, the 1571 will stay in double-sided mode. If C64 mode was activated by holding down the C= key on power-up, the drive would automatically switch to single-sided mode, in which case it is unable to read 340 kB disks (also the default if a 1571 is used with a C64, Plus/4, VIC-20, or PET). A manual command can also be issued from BASIC to switch the 1571 between single and double sided mode. There is also an undocumented command which allows the user to independently control either of the read/write heads of the 1571, making it possible to format both sides of a diskette separate from each other, however the resultant disk cannot be read in a 1541 as it would be spinning in reverse direction when flipped upside down. In the same vein, "flippy" disks created with a 1541 cannot be read on a 1571 with this feature; they must be inserted upside down.

The 1571 is not 100% low-level compatible with the 1541, however this isn't a problem except in some software that uses advanced copy protections such as the RapidLok system found on MicroProse and Accolade games.

The 1571 was noticeably quieter than its predecessor and tended to run cooler as well, even though, like the 1541, it had an internal power supply (later Commodore drives, like the 1541-II and the 3½" 1581, came with external power supplies). The 1541-II/1581 power supply makes mention of a 1571-II, hinting that Commodore may have intended to release a version of the 1571 with an external power supply. However, no 1571-IIs are known to exist. The embedded OS in the 1571 was CBM DOS V3.0 1571, an improvement over the 1541's V2.6.

Early 1571s had a bug in the ROM-based disk operating system that caused relative files to corrupt if they occupied both sides of the disk. A version 2 ROM was released, but though it cured the initial bug, it introduced some minor quirks of its own - particularly with the 1541 emulation. Curiously, it was also identified as V3.0.

As with the 1541, Commodore initially could not meet demand for the 1571, and that lack of availability and the drive's relatively high price (about US$300) presented an opportunity for cloners. Two 1571 clones appeared, one from Oceanic and one from Blue Chip, but legal action from Commodore quickly drove them from the market.

Commodore announced at the 1985 Consumer Electronics Show a dual-drive version of the 1571, to be called the Commodore 1572, but quickly canceled it, reportedly due to technical difficulties with the 1572 DOS. It would have had four times as much RAM as the 1571 (8 kB), and twice as much ROM (64 kB). The 1572 would have allowed for fast disk backups of non-copy-protected media, much like the old 4040, 8050, and 8250 dual drives.

The 1571 built into the European plastic-case C128 D computer is electronically identical to the stand-alone version, but 1571 version integrated into the later metal-case C128 D (often called C128 DCR, for D Cost-Reduced) differs a lot from the stand-alone 1571. It includes a newer DOS, version 3.1, replaces the MOS Technology CIA interface chip, of which only a few features were used by the 1571 DOS, with a very much simplified chip called 5710, and has some compatibility issues with the stand-alone drive. Because this internal 1571 does not have an unused 8-bit input/output port on any chip, unlike most other Commodore drives, it is not possible to install a parallel cable in this drive, such as that used by SpeedDOS, DolphinDOS and some other fast third-party Commodore DOS replacements.

Technical design
The drive detects the motor speed and generates an internal data sampling clock signal that matches with the motor speed.

The 1571 uses a saddle canceler when reading the data stream. A correction signal is generated when the raw data pattern on the disk consists of two consecutive zeros. With the GCR recording format a problem occurs in the read signal waveform. The worst case pattern 1001 may cause a saddle condition where a false data bit may occur. The original 1541 drives uses a one-shot to correct the condition. The 1571 uses a gate array to correct this digitally.

The drive uses the MOS 6502 CPU, WD1770 or WD1772 floppy controller, 2x MOS Technology 6522 I/O controllers and 1x MOS Technology 6526.

Disk format
Unlike the 1541, which was limited to GCR formatting, the 1571 could read both GCR and MFM disk formats. The version of CP/M included with the C128 supported the following formats:

 * IBM PC CP/M-86
 * Osborne 1 (double density upgrade)
 * Epson QX10
 * Kaypro II, IV
 * CBM CP/M FORMAT SS
 * CBM CP/M FORMAT DS

The 1571 can read any of the many CP/M $5 1/4$-disk formats. If the CP/M BIOS is modified, it is possible to read any soft sector 40-track MFM format. Single density (FM) formats are not supported because the density selector pin on the MFM controller chip in the drive is disabled (wired to ground).

A 1571 cannot boot from MFM disks; the user must boot CP/M from a GCR disk and then switch to MFM disks.

With additional software, it was possible to read and write to MS-DOS-formatted floppies as well. Numerous commercial and public-domain programs for this purpose became available, the best-known being SOGWAP's "Big Blue Reader". Although the C128 could not run any MS-DOS-based software, this capability allowed data files to be exchanged with PC users. Reading Atari 8-bit 130 kB or 180 kB disks was possible as well with special software, but the standard Atari 8-bit 90 kB format, which used FM rather than MFM encoding, could not be handled by the 1571 hardware without modifying the drive circuitry as the control line that determines if FM or MFM encoding is used by the disc controller chip was permanently wired to ground (MFM mode) rather than being under software control.

In the 1541 format, while 40 tracks are possible for a 5.25" DD drive like the 154x/157x, only 35 tracks are used. Commodore chose not to use the upper five tracks by default (or at least to use more than 35) due to the bad quality of some of the drive mechanisms, which did not always work reliably on those tracks.

For compatibility and ease of implementation, the 1571's double-sided format of one logical disk side with 70 tracks was created by putting together the lower 35 physical tracks on each of the physical sides of the disk rather than using two times 40 tracks, even though there were no more quality problems with the mechanisms of the 1571 drives.

title: Commodore 1571