iscover
This shot of a US Air Force two-seat F-101B Voodoo over the desert shows to good effect the Voodoo's wing profile, and how the F-101's wing area was comparatively small compared with later fighters of the same size. This aircraft wears dayglo orange high-visibility colours for trials work.
Profile — McDonnell F-101 Voodoo
0 comment
Voodoo: First of the Big Twin Engined Jets
We truly underestimate the Voodoo.
Aviation enthusiasts, distracted by the 1950s rapid progress to Mach 2 fighters and the gee-whizzery that followed, generally overlook the tremendous place occupied by the McDonnell F-101 Voodoo in the history of the combat aircraft. Fighter development is very much about increasing engine power, and in this respect the Voodoo represented probably the biggest advance in history. A monstrous aircraft in its time, the Voodoo had almost twice as much power as any previous fighter. No other operational fighter has stood out so conspicuously among its peers, not head and shoulders above them, but head, shoulders and chest. The Voodoo was like nothing before it. But on the other hand – and this is the F-101s other great claim to fame – we have seen a great deal like it since. Although rapidly overtaken by refined successors, the Voodoo established a pattern for a class of fighter design that still evolves today. This lasting formula was: a voluminous airframe with an empty weight of around 12 tonnes (roughly 26,000lb), extravagantly fitted with not one but two of the largest engines practical and containing generous internal fuel tankage. The thrust will see to it that much more fuel can be carried externally, along with a great deal else. The same formula was applied to McDonnell’s next design, the Phantom, which became what the Voodoo nearly was: a multimission fighter that could perform all air-to-air functions plus most ground attack requirements. Then the concept evolved, with many important improvements, into the Phantom’s descendant, the F-15 Eagle, then the Sukhoi Su-27 Flanker and, 40 years after the Voodoo, the Lockheed F-22. Yet that formula has now existed for most of the history of air combat. The Voodoo first flew over 40 years ago in September 1954, at a point in time roughly halfway between the beginning of WWI and now. We should look at how the McDonnell Aircraft Company came to create the Voodoo, the first of the big twin engine jet fighters.
Origins
The F-101s direct ancestor was another Voodoo, the F-88. This was an amazingly futuristic aircraft that flew just three years after World War II ended, in October 1948. The single seat F-88 was McDonnell’s attempt to provide the USAF with a so called penetration fighter, a fighter that would penetrate enemy territory to protect vulnerable Convair B-36s. This original requirement, first expressed in 1945, is important because it meant the air force wanted a jet with both long range and an ability to fight other fighters. “Penetration fighter” was really just a grand title for the mission. Today we would call an aeroplane that could do that job a long range air superiority fighter. Lockheed also came up with a competing long range design, the equally hot looking F-90, while North American put up the F-93, a radically enlarged Sabre derivative. Now these were all flops. The airframes were fine – at least the McDonnell and Lockheed ones – but the engines had no hope of giving them adequate performance. Engines of the day could offer little power and therefore not much takeoff weight and fuel. But they were good at consuming what little fuel they could lift, so range and endurance were marginal, even in these “penetration” fighters. The proposed fighters also had only moderate thrust/weight ratios, even with their new fangled afterburners. The F-88, with a takeoff thrust/weight ratio of 0.39, was the best of the three designs. It owed this to its lightweight airframe, which came in at just 5.5 tonnes (12,100lb) empty and 8.4 tonnes (18,500lb) when laden with internal fuel and ammunition for a normal mission. Presumably, the F-88’s weights would have grown 10 or 15% in a fully equipped service model, bringing thrust/weight down to about 0.34. This was still respectable for the day, about the same as contemporary marks of the Sabre, but only using afterburner and still well below the MiG-15s dry thrust/weight of 0.47. Noted aviation writer Bill Gunston has suggested that McDonnell could have built a better F-88 if it had used the biggest engine available, the Sabre’s GE J47, which produced about 22kN (5000lb) dry thrust. Why McDonnell chose the Westinghouse J34, producing only 16kN (3600lb) even with reheat, is unknown. The F-90 also used J34s but had a heavier airframe – 8.3 tonnes (18,000lb) empty, 12.3 tonnes (27,000lb) normal loaded – so its thrust/weight was only 0.30 for even the prototypes. At 6.4 tonnes (14,000lb) empty, the F-93 was a little heavier than the F-88 but had a better powerplant, a single 36kN (8090lb) Rolls-Royce Tay, which was a developed Nene built under licence by Pratts and designated J48 in US service. The prototype F-93’s afterburning thrust/weight was 0.36. Dissatisfied, the air force told the makers in 1950 that it didn’t want any of their penetration fighters, and consequently the programme lapsed. Significantly, though, McDonnell’s F-88 was judged the best of the inadequate bunch. It had generally superior performance, which it must have owed largely to its higher thrust/weight ratio. But it was still going nowhere. Then the Korean War intervened and led to a revival. Just as the need for all-out performance against zippy MiGs led to the F-104 Starfighter and, with it, the modern breed of lightweight fighter, the difficulty in escorting B-29s over North Korea led to the F-101 and its heavyweight descendants. In Korea the air force found, or was reminded, that the F-86 Sabre did not have the range to be a satisfactory bomber escort. Early, straight wing models of the F-84 Thunderjet had good range but no performance. So the USAF Strategic Air Command looked for something that would have both, and in January 1951 revived the programme by issuing a new outline for a penetration fighter. SAC must have also known that engineers at Pratt & Whitney were developing something that would make it all possible: the JT3 turbojet. Designated J57 in military service and producing 46kN (10,200lb) of dry thrust and 67kN (15,000lb) with afterburning, this two spool engine was roughly twice as powerful as the J47s that were powering F-86s and B-47s of the day. It should be noted that this very important engine also made possible the B-52 and, perhaps most significantly, the first successful jetliner, the 707. The J57 also propelled the F-100 Super Sabre, the first supersonic fighter, and the slightly later F-102 Delta Dagger interceptor. With such a large engine, the F-100 and F-102 were as powerful as any rival when they first flew in 1953 and 1954. But a new Voodoo, mounting two J57s, would belittle both.
This content is available exclusively to Australian Aviation members.
A monthly membership is only $5.99 or save with our annual plans.
- Australian Aviation quarterly print & digital magazines
- Access to In Focus reports every month on our website
- Unlimited access to all Australian Aviation digital content
- Access to the Australian Aviation app
- Australian Aviation quarterly print & digital magazines
- Access to In Focus reports every month on our website
- Access to our Behind the Lens photo galleries and other exclusive content
- Daily news updates via our email bulletin
- Unlimited access to all Australian Aviation digital content
- Access to the Australian Aviation app
- Australian Aviation quarterly print & digital magazines
- Access to In Focus reports every month on our website
- Access to our Behind the Lens photo galleries and other exclusive content
- Daily news updates via our email bulletin
Want to see more stories from trusted news sources?
Make Australian Aviation a preferred news source on Google.
Click here to add Australian Aviation as a preferred news source.
