The F-101A was not well-suited for low-altitude tactical strike operations because its structure was stressed only for maneuvers that did not exceed 6.33 G. The F-101C was a follow-on version of the single seat F-101A which had a strengthened structure designed to allow maneuvers at up to 7.33 G. The F-101C was externally identical to the F-101A and had similar internal equipment and armament. The F-101C was, however, 500 pounds heavier than the A because of its stronger structure. The F-101C had different fuel pumps and fuel feed and control systems, increasing its maximum available afterburner time from six minutes to 15. There were minor changes in the pressurization system. Generally, F-101As and Cs could be distinguished from each other only by their serial numbers, and usually a pilot did not even notice whether he was flying an A or a C.
The first F-101C flew on August 21, 1957, and the last of 47 examples was delivered in June of 1958. Ninety-six aircraft (56-049/56-135) originally ordered as F-101Cs were completed as RF-101Cs after the Air Force decided not to acquire any more Voodoo single-seat strike fighters.
The F-101C first served with the 27th Fighter Bomber Wing based at Bergstrom AFB. Fighter-bomber wings were redesignated as tactical fighter wings on July 7, 1958, and the 27th became the 27th TFW.
In service, one of the four 20-mm cannon of the F-101C was frequently removed in order to make room for TACAN navigation equipment.
On May 22, 1958, two air-refuelled F-101Cs flew a 5600-mile closed-circuit course beginning and terminating at Bergstrom AFB in Texas in 11 hours 35 minutes. A flight of F-101Cs flew from Andrews AFB in Maryland to Liege, Belgium in 6 hours 12 minutes on June 28, 1958.
In 1958, the F-101A/C Voodoos of the 27th TFW briefly deployed to Taiwan during a period of heightened tensions with the Mainland.
In a move partly based on economy considerations but also to bring the Voodoo closer to its proposed targets in the Soviet Union, before the last F-101C could be delivered, it was decided that TAC would transfer all of its single-seat Voodoo fighters to the 81st Tactical Fighter Wing based at RAF Bentwaters in Suffolk. Here, the F-101Cs replaced the Republic F-84F Thunderstreak. A flight of seven F-101Cs were ferried nonstop from Bergstrom AFB to RAF Bentwaters in Suffolk in 11 hours 2 minutes on August 10, 1958.
The 81st TFW operated three squadrons, the 78th, 91st, and 92nd TFS. The mission of each of the 81st TFW Voodoos was to deliver a single tactical nuclear weapon onto a Soviet or Eastern European target in the event of war. It was generally understood that such an attack would probably be a one-way mission, and pilots were given extensive training in escape and evasion techniques which would be used once they had ejected behind enemy lines.
The F-101A/C featured the MA-7 fire-control system with a nose radar that had originally been intended for the air-to-air role. After a few changes, this system became fairly adept at ground mapping and was very useful in the air-to-ground role. An MA-2 Low-Altitude Bombing System (LABS) was installed. In addition to the mapping radar, the F-101 used the ASN-6 dead-reckoning navigation system and was fitted with an ARN-14 navigational radio. An MB-1 autopilot was fitted. Defense was handled by an ASP-54 radar warning system. In the field, refinements were made to the all-weather low-altitude nuclear delivery system, which used the Voodoo's gun-ranging radar in a ground-mapping mode. The Low Altitude Bombing System (LABS) was later augmented by the Low Angle Drogued Delivery (LADD) system which permitted the aircraft to drop a parachute-retarded atomic bomb after making a low-altitude run-in to the target. The LABS system employed a Mergenthaler Linotype M-1 Toss Bombing System (TBS-1) which enabled the pilot to deliver his weapon by lining up the target on the crosshairs of his K-19 gunsight and pushing a button which computed an automatic weapons release.
A total of 47 F-101C tactical fighters were built. The F-101C fighters served with the 81st Tactical Fighter Wing until replaced by McDonnell F-4C Phantoms in 1965-66. Following their removal from active USAF service in 1965, ex-USAF F-101Cs were modified by Lockheed Aircraft Service Company of Ontario, California to serve with the Air National Guard as unarmed reconnaissance aircraft. A total of 31 F-101Cs were converted (serial numbers were 54-1486/1488, 1491, and 1493, plus 56-1/4, 6, 10/12/ 14, 16, 18-20, 22/23, 25/27, 29, 30, 32/36, and 39), accidents by this time having accounted for most of the remainder of the 47 F-101Cs originally built. In these converted F-101Cs, the armament was completely removed and new nose cones housing reconnaissance cameras were installed. These aircraft were then redesignated RF-101H. As compared to the RF-101C dedicated photo-reconnaissance version of the F-101C, the RF-101H had a shorter and broader nose. Along with the RF-101G (an equivalent conversion of the F-101A), they served with the 154th Tactical Reconnaissance Squadron of the Arkansas ANG, with the 165th TRS of the Kentucky ANG, and the 192nd TRS of the Nevada ANG. Beginning in 1970, these aircraft were supplemented by RF-101Cs that had been retired from active USAF stocks following the withdrawal from Vietnam. The last reconnaissance Voodoos were finally withdrawn from ANG service in 1979.
54-1486/1493 McDonnell F-101C-40-MC Voodoo 1486/1488 converted to RF-101H 1491 converted to RF-101H 1493 converted to RF-101H 56-0001/0005 McDonnell F-101C-40-MC Voodoo 0001/0004 converted to RF-101H. 56-0006/0019 McDonnell F-101C-45-MC Voodoo 0006 converted to RF-101H. 0010/0012 converted to RF-101H. 0011 at Pima Air Museum, Tucson, AZ. 0014 converted to RF-101H. 0016 converted to RF-101H. 0018,0019 converted to RF-101H. 56-0020/0032 McDonnell F-101C-50-MC Voodoo 0020 converted to RF-101H. 0022,0023 converted to RF-101H. 0025/0027 converted to RF-101H. 0029/0032 converted to RF-101H 56-0033/0039 McDonnell F-101C-55-MC Voodoo 0033/0036 converted to RF-101H 0039 converted to RF-101H
Engines: Two Pratt & Whitney J57-P-13 turbojets, 10,200 lb.s.t. dry and 15,000 lb.s.t. with afterburner. Dimensions: wingspan 39 feet 8 inches, length 67 feet 6 inches, height 18 feet 0 inches, wing area 368 square feet. Performance: Maximum speed 1012 mph at 35,000 feet. Initial climb rate 45,000 feet/min. Service ceiling 55,100 feet, combat ceiling 51,540 feet. Normal range 1315 miles, maximum range 2125 miles. Weights: 26,277 pounds empty, 48,908 pounds gross, 39,495 pounds combat weight, 51,000 pounds maximum takeoff. Fuel: Maximum internal fuel load was 2250 US gallons. A total of three under-fuselage drop tanks could be carried, bringing maximum fuel load to 3150 US gallons. Internal armament consisted of four 20-mm Colt-Browning M38 cannon. A single "special store" (i.e. a nuclear weapon) could be carried on a centerline station. This weapon was generally a Mk 7, weighing 3271 pounds and having an explosive yield of 1 megaton. The F-101C could not carry or deliver conventional bombs, but a baggage pod or a training shape could be carried on the centerline station in place of the nuclear weapon.