The XH-20 “Little Henry” was developed by a team led by Marvin Marks in close co-operation between the Helicopter and Propulsion Division of McDonnell and the AAF/USAF Rotor Wing Branch, Propeller Laboratory and Rotary Wing Unit, Aircraft Projects Section, Wright-Patterson AFB. At the time of its inception, the XH-20 was unique in being powered by two McDonnell-developed 18.42cm ramjet units weighing only 4.5kg each, mounted at the tips of the two-blade rotor and fed from tanks beside the pilot. The fuel, originally propane but later gasoline (motor car petrol), was boosted through a feed line to a delivery valve on the rotor head. From there centrifugal force took over to convey the fuel through the blades to the tip-mounted ramjets.
Having undertaken privately-funded studies of ramjets as powerplants for helicopters, McDonnell submitted an unsolicited proposal to the Air Materiel Command at Wright Field in the spring of 1946 and in July was awarded a contract for the development and testing of two experimental machines. It was then hoped that the powerplant would make it feasible to build small, lightweight helicopters by reducing or eliminating complex and heavy engine parts, gear systems, and transmissions. It was claimed that this powerplant installation would result in increased efficiency and would completely eliminate the need for a conventional anti-torque rotor. Accordingly, the two XH-20s were ordered as flying test-beds and were not intended as production prototypes. Their airframe was kept as simple as possible and consisted of welded tubes carried on three vertical legs ending with free-castoring wheels. Conventional helicopter controls were fitted, and the pitch lever incorporated a motorcycle-type throttle to regulate the fuel flow.
Fitted as a single-seater, the first of two prototypes (46-689 and 46-690) made both its first tethered flight on 5 May, 1947, and its first free flight on 29 August in St Louis with Charles R. Wood Jr. at the controls. With the project team then benefitting from the experience of Friedrich von Dobhloff, the Austrian engineer who had pioneered the application of jet principles to helicopters during the war, tests continued for four years. During that time, one of the two XH-20s was modified as a two-seater and, like the single-seater, proved generally satisfactory. However, the ramjet units had excessive fuel consumption, which drastically limited range and endurance when compared to conventionally-powered helicopters, and rate of descent in autorotation was excessive. Accordingly, the Air Force terminated the programme in 1951. The first XH-20 was preserved and is now part of the collection of the Air Force Museum at Wright-Patterson AFB, Ohio.
Main rotor diameter: 5.49m Length: 3.81m Height: 2.13m Max take-off weight: 254kg Empty weight: 129kg Cruising speed: 80km/h Endurance: 50min
Though the 1950 penetration fighter competition among XF-88, XF-90 and YF-93A resulted in no production contract, the Strategic Air Command still wanted an escort fighter, its F-84F being seen as only an interim solution. McDonnell’s design team under Herman Barkey responded with the heaviest single-seat fighter ever built. Powered by two 5307kg Pratt & Whitney J57-P-13 turbojets, the F-101 would carry four 20mm cannon plus three Hughes GAR-ID or GAR-2A Falcon missiles or 127mm high-velocity aircraft rockets (HVAR) mounted on rotary bomb doors. A single-seater, with the two engines side-by-side, the wing has a 35 degree sweepback on the leading edge and distinctive ‘W’-shape trailing edge.
The F-101 has mid-set wings with 35 degree sweepback, and swept-back tail surfaces with a one piece all-moving tailplane mounted near the tip of the fin. Conventional ailerons, rudder and trailing edge flaps are fitted, with an airbrake on each side of the tail-boom. A tricycle undercarriage has single wheels on each main unit and twin wheels on the nose unit. The mains retract inward into the wings and the nose wheels retract forward. A fire-control radar is in the nose.
The first F-101A flew on 29 September 1954 at St Louis, and exceeded Mach 1 on its maiden flight. This was a production craft, there being no service-test machine. SAC dropped its requirement and the 77 F-101As built went to the Tactical Air Command. The first delivery was made 2 May 1957 to the 27th Tactical Fighter Wing. Seven of these airframes were later designated JF-101A while being used for temporary tests.
F-101A Voodoo
The first of two YRF-101A service-test reconnaissance Voodoos flew on 10 May 1956, followed by 35 RF-101A airframes delivered to TAC’s 363rd Tactical Reconnaissance Wing at Shaw AFB, South Carolina. The reconnaissance Voodoo had a lengthened nose with space for downward or oblique cameras and other sensors.
On 12 December 1957, Major Adrian E. Drew, USAF, established a World Air Speed Record of 1207.6 mph, in an F-101 Voodoo.
An RF-101A was shot down during the Cuban missile crisis of October 1962.
The F-101B Voodoo was developed by modifying the single seat F-101 fighter involved extending the fuselage forward to house a new weapons system and a second crewman to operate it. The bigger F-101B Voodoo was fitted with 5438kg Pratt & Whitney J-57-P-55 engines, with their characteristic large afterburners.
The first F-101B flew on 27 March 1957 at St Louis. For long-range intercept, it could carry two Douglas MB-1 Genie nuclear unguided rockets as well as three Falcons. Deliveries began on 18 March 1959 to the 60th Fighter Interceptor Squadron.
Eventually, the F-101B equipped 16 ADC squadrons, guarding against the Soviet bomber threat to North America. ANG units operated the F-101B between 1970 and 1982.
The JF-101B designation was applied to two machines used for temporary tests. One NF-101B was structurally modified for development work. Very late in their careers, with reconnaissance Voodoos still needed long after the interceptor variant was retired, 22 of the two-seat airframes were converted to RF-101B. The TF-101B was a version of the interceptor with full dual controls.
The F-101C single-seat tactical fighter differed from the F-101A primarily in having the capability to carry a US tactical nuclear weapon, and 47 were delivered to TAC.
The RF-101C, the first of which was flown 12 July 1957, was an improved development of the RF-101A; 166 went to TAC squadrons. The USAF began operating the RF-101C in South East Asia in 1964 and suffered its first combat loss on 21 November 1964 when an RF-101C of the 15th Tactical Reconnaissance Squadron was shot down over Laos.
Though not as much publicised as other combat types, the RF-101C remained in combat until 1970. No less than 31 airframes were lost in battle, plus another six to operational causes. In the mid-1960s, a few RF-101Cs served with the Nationalist Chinese air force, flying clandestine missions over the mainland.
Other Voodoo variants were the F-101F, the USAF designation for the CF-101F interceptor operated by Canadian forces; the RF-101G, a conversion of high-hour RF-101A airframes for reconnaissance duties with the Air National Guard; and the RF-101H, another reconnaissance conversion.
After the cancellation of the Avro Arrow in February 1959, Canada urgently needed a fast interceptor to meet the continued threat from manned Soviet bombers. By late 1959, the RCAF picked the Voodoo as the aircraft that best met Canada’s requirements. In June 1961, the RCAF agreed to purchase sixty six nearly new CF-101B Voodoos from existing USAF stocks. The deal transferred the aircraft to five front line squadrons and an OTU, to replace obsolete CF-100s.
In 1961 and 1962, 410 Cougar and 425 Alouette Squadrons of Bagotville, 409 Night Hawk Squadron of Comox, and 416 Lyns Squadron of Chatham were equipped with 66 Voodoos in total (55 CF-101B and 10 CF-101F), all built by McDonnell-Douglas.
At the beginning of the 1970’s, the aging CAF Voodoo fleet was exchanged for sixty six lower timed USAF Voodoos. These replacement aircraft were equipped with a superior missile control system. Even with the Voodoo fleet restored to its original size, serviceability began to be a problem. In 1977, the CAF launched a program to find a new fighter to replace the Voodoo and by April 1980, the search eventually narrowed down to the CF-18 Hornet.
Since the Summer of 1983 each of the four Voodoo Squadrons has been stood down. First 410 Squadron converted to the CF-18 OTU. 409 Squadron became the first operational CF-18 Sqn. 425 and 416 Squadrons received CF-18s in December 1984.
EF-101B 101067 “Electric” Voodoo
One aircraft remained in service. The CAF received Voodoo 191067 in the early 1980s and modified it to an EF-101B for ECM duties. The aircraft ws operated by 414 ‘Electronic Warfare’ Sqn and known as the “Electric” Voodoo. The EF-101B was retired by the end of 1986.
Most of the Voodoo fleet was phased-out by the end of 1984 and the last Voodoo flight anywhere was made in April 1987, when #101006 was delivered to CFB Chatham for display at CFB Cornwallis.
One F-101B appeared briefly on the US civil register, as N8234, used for thunderstorm research by Colorado State University.
Altogether 807 Voodoos were built for the USAF. The McDonnell Aircraft Co. manufactured 479 F-101B Voodoos in the United States, between 1957 and 1961.
F-101 Engines: 2 x P&W J-57-P-13, 52.0kN Max take-off weight: 18000-22250 kg / 39683 – 49053 lb Empty weight: 12700 kg / 27999 lb Wingspan: 12.1 m / 39 ft 8 in Length: 20.6 m / 67 ft 7 in Height: 5.5 m / 18 ft 1 in Wing area: 43.2 sq.m / 465.00 sq ft Max. speed: 1940 km/h / 1205 mph Cruise speed: 950 km/h / 590 mph Ceiling: 15800 m / 51850 ft Range w/max.fuel: 4800 km / 2983 miles Crew: 1 Armament: 4 x 20mm machine-guns, 15 missiles
F-101A Voodoo Long-range escort fighter Engines: 2x Pratt and Whitney J57 turbojets 10,000 lb. thrust with afterburners. Crew: 1 Wingspan: 39 ft. 8 in Length: 67 ft. 5 in Armament: 4×20 mm. cannon
F-101B Voodoo Engines: 2 x Pratt&Whitney J57-P-55, 53347 N / 16,900 lb Length: 67ft 5in / 20.54 m Height: 18.012 ft / 5.49 m Wingspan: 39ft 8in / 12.09 m Max take off weight: 46679.9 lb / 21170.0 kg Max. speed: 1060 kts / 1963 km/h / 1,134 mph at 35,000 feet Service ceiling: 52001 ft / 15850 m Max ROC: 14,000 fpm Range: 1350 nm / 2500 km Crew: 2 Armament: 3x Missile AIM-4E Super Falcon, 2x AIR-2A Genie
On 29 July 1941 the McDonnell Aircraft Corporation received a contract for two prototype of a long-range single-seat fighter designated XP-67. The design embodied several innovatory features, not least was an attempt to maintain true aerofoil sections throughout the entire fighter, the centre fuselage and thc rear portions of the engine nacelles merging to give the aircraft a unique appearance. The two 1,350 hp Continental XI-1430 12-cylinder inverted-vee engines were fitted with General Electric D-23 turbo-superchargers and featured exhaust thrust augmentation. The cabin was pressurised and proposed armament comprised six 37-mm M-4 cannon. The first XP-67 was flown on 6 January 1944, and flight trials continued until 6 September 1944, when the prototype suffered irreparable fire damage. This accident and the unsatisfactory nature of certain aspects of the fighter’s performance led to the decision to abandon the second prototype and terminate the development contract.
Engines: 2 x Continental XI-1430 12-cylinder inverted-vee engines with General Electric D-23 turbo-superchargers and exhaust thrust augmenta¬tion, 1,350 hp. Max speed, 405 mph (652 km/h) at 25,000 ft (7 620 m) Max climb, 2,600 ft/min (13,20 m/sec) Max range, 2,385 sm (3 838 km) Service ceiling: 11400 m / 37400 ft Empty weight. 17,745 lb (8 049 kg) Normal loaded weight, 22,11l4 lb (10 031 kg) Span, 55 ft 0in (16,76m) Length, 44 ft 9.25 in (13,65) Height, 15 ft 9 in (4,80 m) Wing area, 414 sq ft (38,46 sq.m)
Designed to meet a requirement for a single-seat long-range escort fighter, the XF-88 was recipient of a contract for two prototypes on 14 February 1947. Powered by two 3,000 lb st (1361 kgp) Westinghouse XJ34-WE-13 turbojets, the first XF-88 was flown on 20 October 1948, but proved seriously underpowered. The second XF-88 was therefore fitted with two XJ34-WE-22 engines fitted with short afterburners which boosted thrust to 3,600 lb st (1 633 kgp), a change in designation to XF-88A accompanying this modification.
Performance was still insufficient, but the XF-88 was considered by the USAF to possess development potential and a Letter of Intent was issued covering further evolution of the basic design into what was eventually to become the F-101 Voodoo.
The first prototype was then recast as the XF-88B testbed for the Allison XT38 turboprop, with which it undertook many flights from April 1953 with 27 different propellers featuring varying numbers of blades in diameters between 4 and 10 ft (1.2 and 3.05 m). The XF-88s airframe then went forward to provide the structural and aerodynamic basis for the F-101 interceptor and reconnaissance fighter.
Engines: 2 x Westinghouse J34-WE-13 turbojets, 3000-lb (1361-kg) thrust Max speed, 641 mph (1 032 km/h) at sea level Time to 35,000 ft (10 670 m), 14.5 min Range, 1,737 mls (2 795 km) Empty weight, 12,140 lb (5 507 kg) Normal loaded weight, 18,500 lb (8 391 kg) Span, 39 ft 8 in (12,09 m) Length, 54 ft 1.5 in (16,50 m) Height, 17 ft 3 in (5,26 m) Wing area, 350 sq ft (32,52 sq.m)
McDonnell proposed a ‘parasite’ (‘symbiote’) fighter had to be small enough to be carried aloft by a bomber and released as required. As early as 1942 McDonnell had proposed such a type as the MX-472 for semi-external carriage by the B-29, and further evolution of the concept resulted during 1945 in four variants of the Model 27 design for internal carriage by the Northrop B-35 and Convair B-36 heavy bombers. Under the spur of early ‘Cold War’ events, McDonnell reworked the Model 27 into the XF-85 Goblin. Designed under the leadership of Herman D Barkley, the XF-85 the subject of a Letter of Intent for two prototypes on 9 October 1945. The XF-85 was to be stowed in the number one or four bomb bay of the B-36 intercontinental bomber. Over target, it would be dropped free to protect the B-36 from enemy interceptors.
The fuselage was virtually filled by the 3000-lb (1361-kg) thrust Westinghouse J34-WE-7 turbojet and its fuel plus the four 0.5-in (12.7-mm) machine-guns and their ammunition, the pilot being seated astride the engine under a bubble canopy immediately aft of the hook that permitted aerial release and recovery of this tiny fighter. The wings were swept at 37 degrees and arranged to unfold from their vertically stowed position, which gave the fighter a ‘hangared’ width of only 5 ft 4.75 in (1.64 m), for an extended span of 21 ft 1.5 in (6.54 m) after being lowered from the parent aircraft. The fighter was intended to be launched from and recovered by a retractable trapeze which was to be extended beneath the parent bomber, no undercarriage being fitted.
In 1947, indoor tests were begun to evaluate the mating arrangement between the Goblin and a mock-up of a B-36 fuselage. On 9 November 1947 the first of two XF-85s was disassembled at the manufacturer’s St Louis plant and flown aboard a C-97 transport to Moffett Field, California, for wind-tunnel tests. While being positioned in the tunnel, the aircraft fell 12.2 m, was badly damaged, and had to be returned to St Louis, being replaced at Moffett by the second machine.
On 5 June 1948, this second XF-85 was transported to Muroc AFB, California, and, with no B-36 airframe available for evaluation of the parasite fighter concept, experiments began using an EB-29B Superfortress. Ed Schoch, a former US Navy F6F Hellcat pilot with four air combat kills in the Pacific war, was the only man ever to fly the XF-85.
Flight trials were initiated by the second prototype which was powered by a 3,000 lb st (1361 kgp) Westinghouse J34-WE-37 turbojet. After five captive flights on the trapeze of a specially modified Superfortress (EB-29B), the XF-85 was launched at 20,000 ft (6 095 m) on 23 August 1948, this first free flight terminating in an emergency landing. On his first attempt on 23 August 1948, Schoch was attempting to re-engage the bomber’s trapeze when he slammed into it, shattering his canopy, ripping his helmet off, and knocking him unconscious. Schoch recovered in time to make a shaky landing on the XF-85’s underside skid in the Muroc desert, damaging the plane.
The second flight on 14 October 1948, resulted in a normal mid-air drop and subsequent hook-up. Three more times, however, struggling to manoeuvre the tricky Goblin, Schoch was forced to make belly landings in the desert rather than regain his link-up with the Superfortress.
On 8 April 1949, the original XF-85 made its first and only flight. In budget-lean 1949, the XF-85 programme was quietly terminated after 2 hr 19 min of test flying, although the Strategic Air Command eventually became interested in the parasite fighter concept when it became possible to carry an RF-84K aboard a B-36. The first XF-85 is on display at the Air Force Museum in Dayton, Ohio, while the second is at the Strategic Air Command Museum in Omaha, Nebraska, displayed in inaccurate markings with a spurious tail number.
Max speed (calculated), 664 mph (1 068 km/h) Combat endurance, 30 min Empty weight, 3,740 lb (1 696 kg) Loaded weight, 4,550 lb (2 064 kg) Span, 21 ft 1½ in (6,44 m) Length, 14 ft 10.5 in (4,53 m) Height, 8 ft 3.25 in (2,56 m) Wing area, 90 sq ft (8,36 sq.m)
