Bitter disappointment: The F-101 in SAC war plans

Yesterday's news reports of the publication of a declassified 1956 Strategic Air Command study of proposed targets has for many reasons already garnered worldwide notoriety.  The report may be viewed here at the National Security Archive: http://nsarchive.gwu.edu/nukevault/ebb538-Cold-War-Nuclear-Target-List-Declassified-First-Ever/

What has not been mentioned is that along with the B-47s, B-52s, and missile systems was SAC's strategic fighter of the future, the F-101A Voodoo.  By the time the study was commissioned in February 1956, the entire F-101 program was suffering multiple problems that would nearly lead to its cancellation.  While the pitch-up problem was garnering most of the headlines, its still-secret armament concept, the McDonnell Model 96 weapon-fuel pod, was causing tremendous problems of its own.  To this day, it remains virtually unknown even among those who otherwise know the Voodoo pretty well.  But this study illustrates what the F-101A weapon system was intended to accomplish in the event of a general nuclear war, a supersonic intruder using unimaginably powerful weapons to blow gaping breaches in Soviet defenses in front of streams of B-47 and B-52 bombers with the intent of utterly destroying the Soviet Union.  The scale of these SAC war plans for the late 1950s is mind-boggling, and it should give pause to both historians as well as those who today would propose the same mode of warfare against a different enemy.  This history serves as both a lesson and a warning.  It must never be revisited.  The following is a re-edited section from my recent book on the F-101, incorporating new information based on SAC Report SM 129-56: Atomic Weapons Requirements Study for 1959: 


Bitter disappointment: The F-101 in SAC war plans and the end of the Model 96

Still far above the fray as all hell began to break loose with the Voodoo and the strategic fighter concept in general, the Joint Chiefs of Staff commissioned a study of atomic weapons requirements for 1959 as SM 129-56 on 15 February 1956, published four months later on 15 June 1956.  Anticipating both new bomber and missile capabilities available to Strategic Air Command by that time, the study assessed and prioritized a burgeoning list of strategic targets within the Soviet Union and allied states.  Target categories for Strategic Air Command were: 1.) Soviet nuclear bomber, air defense, and tactical aircraft; 2.) air bases, launch sites and depots; 3.) atomic stockpile sites; 4.) military and government control centers; air industry and resources directly supporting enemy air capability.  Further strikes would be directed against Soviet population centers.  SAC medium and heavy bomber forces  in 1959 were projected to consist of 1,267 B-47, 225 RB-47, 495 B-52 aircraft, along with strategic missile forces consisting of 64 Snark ICCMs, 60 Rascal air-launched cruise missiles, 72 Crossbow missiles, and 180 IRBMs.  Aircraft payloads would consist of MK 6 B and MK 6 C fission weapons, MK 15 boosted fission and MK 27 thermonuclear weapons, forming the primary armament for the B-47 force.  High-yield MK 36 weapons would primarily be reserved for the B-52 force.  RB-47s were programmed for the MK 28 as primary armament, with the MK 27 as alternate.  

Also among the SAC assets directed against 3,400 projected targets, or Designated Ground Zeroes (DGZs) were a projected 150 F-101A Voodoo strategic fighters by 1959, enough to equip two combat wings.  Given the relatively short range and earliest arrival of forward-based F-101A strategic fighters, their primary targets would have consisted of Soviet fighter and interceptor bases and air defense sites, although a handful of forward bomber bases would also be within range.  As listed in SM 129-56, the primary weapon for the F-101A was to be the MK 28 bomb, with the MK 27 as an alternate weapon.  Unlike the lower-yield MK 28-Y2 versions slated for other nuclear-capable fighters like the F-100D and F-105, as a SAC aircraft the F-101A would carry the more powerful MK 28-Y1 producing 1.1 megatons yield, ten times the destructive power of the W-5 weapon that the Voodoo had been redesigned to carry a few short years previously.  The MK 27, slated as a primary weapon for both the B-47 and the Rascal air-launched cruise missile, had a yield of 2 megatons.  Against airfield targets, ground burst was specified to maximize blast radius, ensure the collapse and destruction of any underground facilities, crater runways, and produce enough heavy local fallout to prohibit repair or use of the target.  Under visual delivery conditions, the expected accuracy for the F-101A was a Circular Error Probable (CEP) of 600 feet.  The unparalleled combination of fighter speed and megaton-level punch of the F-101A constituted an extremely formidable weapon in the hands of SAC planners.  But as the report was being written, it was all becoming for naught.

Model 96 LABS and “Over-the-shoulder” delivery flight paths.  When this study was published on 22 June 1954, the 100-kiloton W-5 fission weapon was the planned payload for the Model 96 store, along with 849 gallons of fuel.  With the rapid development of lightweight, small-diameter hydrogen bombs, by early 1956 the 1.1 megaton MK 28 was slated as the primary weapon for the F-101A by 1959, with the larger and more powerful W-27 warhead earmarked for carriage in a modified Model 96 pod.  This would have made the Voodoo by far the most heavily armed fighter aircraft ever conceived.   Department of Energy.

By the beginning of 1956, McDonnell had more pod concepts on the drawing boards, but flight test of the F-101/Model 96 combination was continuing to reveal serious problems.  By this time, F-101As had arrived at Kirtland AFB, NM and were undergoing flight testing with the 4925^th Test Group (Atomic), including 53-2441.   McDonnell had developed two new electronic warfare versions of the Model 102 store, with formal design work beginning in November 1955, both retaining the original shape of the Model 96 store.  The Model 102H contained both fuel and electronic countermeasures equipment.  Interchangeable nose and tail assemblies were available, containing AN/ALT-6, AN/ALT-7, and/or AN/ALT-8 “noise” jammers, and an 11-carton capacity AN/ALE-1 chaff dispenser.  The Model 102J store was not provided with jamming equipment, instead carrying 943 gallons of fuel along with an ALE-1 chaff dispenser with 20 cartons capacity.  These were followed in March of 1956 when work began on a new design, the Model 117A store.  Intended for both the F-101 and RF-101, the newer pod could contain various combinations of ALT-6B and ALT-8B dispensers along with an ALE-1 unit with a 20-carton capacity.  Unlike the previous designs, the Model 117A apparently did not contain fuel.  The equipment in these pods were standard for SAC B-47B-II and B-47E-II Stratojet aircraft that were upgraded with Phase III ECM equipment beginning in late 1954.  By the beginning of 1956, SAC had made the decision to get out of the fighter business and would begin to deactivate its existing strategic fighter units.  Given the change in mission and the forthcoming “Blue Cradle” EB-47E aircraft with Phase IV ECM to provide escort jamming support for the bombers, and the fact that the equipment was not standard for TAC (which in any case considered electronic countermeasures of little importance) work on these new ECM stores for the F-101 would eventually be cancelled.

JF-101A 53-2427 with the Model 96.  The final warhead considered was the XW-27 hydrogen weapon, much improved over the earlier and heavier TX-15 boosted-fission design.  With a yield of two megatons, the XW-27 / Model 96 would have made the F-101A by far the most heavily-armed fighter ever to enter service.  Instead, the development of this vital component of the WS-105A strategic weapon system stalled and it was never deployed.  Gerald Balzer Collection, Greater St. Louis Air & Space Museum.

Unfortunately, it was becoming clear that the problems of the Model 96 store on the F-101 were nowhere near being solved.  In addition to the continuing deficiencies in both directional and lateral stability, another serious problem cropped up during testing.  The Model 96 shape added a great deal of cross-sectional area to the forward and middle of the aircraft, with a sharp drop-off in cross sectional area aft of the wing.  Under the recently discovered “Area Rule”, this sharp discontinuity in the area distribution would have led to higher than anticipated transonic drag.  Given that the F-101 cruised and fought in the transonic region, this increased drag resulted in a reduction in mission radius and increased buffeting and associated control problems at altitude. 

JF-101A 53-2428, the second “special weapon” test aircraft, at Lambert Field with a T-63 training “shape” for the MK 7 fission weapon.  Both the T-63 shape and lower and aft fuselage of the Voodoo are tufted for flow studies. Gerald Balzer Collection, Greater St. Louis Air & Space Museum.

In January 1955, the Air Force Special Weapons Center (AFSWC) stated that application of the thermonuclear XW-27 warhead to the Model 96 appeared feasible. With regard to the payload of the Model 96 store, word came down that major structural changes would be necessary for the Model 96 to accommodate the XW-27 warhead.  Meanwhile, the W-5 warhead that the Model 96 was built to carry was already obsolete as smaller, lighter, and higher-yield weapons such as the MK 28 were on the horizon.  These smaller weapons would offer at least as much yield as the Model 96 with negligible aerodynamic effects on the F-101 and, due to decreased weight and drag penalty, a similar combat radius when carrying one centerline weapon with two 450-gallon fuel tanks.  Seeing rapidly diminishing returns ahead for continued development of the F-101/Model 96 combination, the XW-5/F-101 and XW-27/F-101 programs were canceled in March 1956 in favor of future integration with the MK 28.  In the interim, the F-101 would make do with the relatively puny MK 7 weapons used by the F-84 once the Voodoo became operational with SAC strategic fighter wings.  The upshot was that, while the F-101A remained useful for the nuclear delivery mission, it lacked the needed range and strategic-level “punch” that had been expected of the high-yield warheads to be accommodated in the Model 96 store.  As with the air superiority mission, the F-101 was now unable to fulfill the anticipated vision of the “strategic fighter”.  This meant that even before SM 129-56 was published in June 1956, the targeteers of Strategic Air Command had to go back to the drawing board to account for a strategic fighter that now appeared completely useless for its apocalyptic mission.