The interceptor its engine nearly killed

What makes it special

Full specifications

Figures are for the production F3H-2 (redesignated F-3B in 1962) with the Allison J71 engine. Sources differ slightly on a few values — these are the most commonly cited; contested figures are flagged.

Baseline note: the figures below describe the F3H-2 — redesignated F-3B in September 1962 — with the Allison J71-A-2E turbojet. That is the mark McDonnell built in the largest number, 239 of 519 production airframes, and the one that carried the type’s full weapons fit. It is also dimensionally identical to the F3H-2N all-weather fighter and the F3H-2M Sparrow carrier, so a single set of numbers covers the whole J71 family; what separated the three marks was fire control and stores, not structure. Sources are Angelucci and Bowers, The American Fighter, René Francillon’s McDonnell Douglas Aircraft since 1920, Tommy Thomason’s U.S. Naval Air Superiority, Bert Kinzey’s F3H Demon in Detail & Scale, and the National Museum of Naval Aviation’s own file on its airframe. Deltas for the F3H-2N (F-3C), the F3H-2M (MF-3B) and the J40-powered F3H-1N are in grey. Five cautions before the numbers. First, the engine ratings. The J71-A-2E is quoted at 9,700 lbf dry and 14,750 lbf in afterburner by Angelucci; the variant tables in the same literature give 9,500 and 14,250 for the J71-A-2; flugzeuginfo gives 9,700 and 14,000; and Norman Polmar, writing in Naval History, gives 9,500 and 14,400. The spread reflects sub-model and rating condition rather than any real disagreement about the aeroplane, and every one of those numbers is a long way short of what the Demon was designed to have. Second, the ceiling. Angelucci gives 35,050 ft, which the English Wikipedia carries as the service ceiling; a large family of other tables gives 42,650 ft. Both are probably right about different things — the lower figure a combat ceiling at gross weight, the higher a service ceiling at combat weight — and 35,050 ft alone would describe an all-weather interceptor that could not reach the bombers it existed to meet. Third, empty weight. Angelucci gives 21,133 lb; flugzeuginfo and militaryfactory give 22,132 and 22,134 lb. The digits are suspiciously similar and one of the two is very likely a transposition that has since been copied everywhere. Fourth, the production breakdown. The English Wikipedia variant list credits 239 aircraft to the F3H-2N and 239 to the F3H-2, which cannot be true: with 58 F3H-1Ns and 80 F3H-2Ms that comes to 616 against a stated total of 519. The bureau number blocks settle it — 58 F3H-1N, 142 F3H-2N, 80 F3H-2M, 239 F3H-2, which is exactly 519, plus two XF3H-1 prototypes for 521 airframes altogether. The 142 is used here. Fifth, and most important for reading the rest of this page: the Demon looks supersonic and was not. Its best published figures are 716 mph at sea level and 647 mph at 30,000 ft, which work out at about Mach 0.94 and Mach 0.95. No Demon exceeded Mach 1 in level flight, at any weight, on any day.

Armament & payload

The Demon was the first US Navy fighter designed around missiles rather than guns, and it went to sea with half its cannon taken out to save weight

The F3H-2’s fit is quickly stated: four 20 mm Colt Mk 12 cannon in the lower forward fuselage with 150 rounds a gun, four missile stations carrying Sparrow inboard and Sidewinder outboard, and underwing pylons rated at 6,000 lb (2,720 kg) of bombs, rockets or fuel on the strike-configured F3H-2. What makes it interesting is the order in which those things were treated. The Demon was conceived when the US Navy was deciding that the fleet air defence problem was a radar-and-missile problem rather than a gunnery problem, and it was among the first American fighters designed on that assumption. In squadron service the upper pair of cannon was frequently removed altogether to claw back weight from an aeroplane that had none to spare.

The result is an armament fit that reads as more modern than the airframe carrying it. An F3H-2 on barrier patrol in 1959 was flying a mission — radar search, radar lock, semi-active missile shot against a target it might never see — that would have been recognisable to a Phantom crew a decade later, and unrecognisable to a Banshee pilot five years earlier. The weapons were ahead of the aircraft, and everybody involved knew it. VF-64 fired the first Sparrow III launched by a deployed fleet squadron from USS Midway in December 1958. Not one of those weapons was ever fired at an enemy aircraft. The Demon flew over Lebanon in the summer of 1958 and over the Taiwan Strait during the Quemoy crisis that autumn, and left the fleet in 1964, a year before the Phantoms that replaced it began shooting down MiGs with the developed version of the same missile. Fits varied sharply between the F3H-2N, the F3H-2M and the F3H-2, between what was cleared on paper and what squadrons carried, and over time as the Sparrow I gave way to the Sparrow III; no single published loading chart covers the type, and the guns were often not carried at full complement at all.

Sourcing caveat: no single published loading chart covers the F3H-2, the F3H-2N and the F3H-2M together. The secondary literature disagrees about which marks could carry which Sparrow, about whether the four-gun battery was standard or nominal in late service, and about the exact external stores capacity. Figures here follow Angelucci and Bowers, Thomason and Kinzey, cross-checked against the Boeing heritage data sheet for the type; where those disagree with the commoner web tables the disagreement is stated rather than smoothed over. The 6,000 lb figure is the manufacturer’s, not a squadron’s.

Variants

McDonnell built 521 Demons in five marks, and the first fifty-eight of them were a national scandal

The Demon’s variant history is really the history of one engine. The US Navy issued its requirement for a high-performance swept-wing carrier fighter on 21 May 1948 and picked McDonnell’s answer in January 1949; two XF3H-1 prototypes were ordered on 30 September 1949. The condition of the contract was that the aircraft be built around the Westinghouse J40, an engine the Navy was promoting as the single powerplant for its whole next generation, promising over 11,000 lbf — three times what the F2H Banshee had. On that promise the Navy also hung the F4D Skyray, the A3D Skywarrior and the XF10F Jaguar. The J40 delivered about half of what was advertised, with a restricted flight envelope and constant compressor stalls, and four experimental engines destroyed themselves on the test bed.

Meanwhile the aeroplane got heavier. The MiG-15’s appearance over Korea persuaded the Navy to turn the Demon from a short-range day interceptor into a medium-range all-weather fighter, adding roughly 7,000 lb to an aircraft that had weighed 22,000 lb. In March 1951 — before the mock-up review, which did not happen until July — 150 F3H-1Ns were ordered straight into production. James S. McDonnell personally wrote to Washington warning that the J40 would give a "disappointingly underpowered combination" and asking for a substitute. The Navy said no, and pressed on in the hope that the more powerful J40-WE-10 would arrive. It never did. Of the 35 F3H-1Ns that flew with the J40, eight suffered major accidents, at least three of them from engine failure. The National Museum of Naval Aviation records eleven Demon crashes between August 1952 and October 1955 and four pilots killed; the Boeing heritage account gives the trigger for the permanent grounding as the loss of six aircraft and four pilots. In July 1955 the entire F3H-1N fleet was grounded for good.

What happened next is the detail worth remembering. The grounded airframes were not repaired and not flown out. They were loaded onto barges at McDonnell’s St Louis plant, floated down the Mississippi and delivered to Navy technical training establishments as ground instructional hulls; the aircraft at Patuxent River went by barge to Norfolk and then by flatcar. Time magazine, on 7 November 1955, called the grounding a "fiasco" and counted 21 unflyable aeroplanes fit only for ground training against a loss of $200 million. Norman Polmar puts the number of never-flown airframes shipped this way at about 25. Either way, a brand-new front-line fighter went down a river on a barge to be taken apart by apprentices, and the J40 programme was killed the same year. Westinghouse was out of the aircraft engine business altogether by 1965.

The rescue was the Allison J71, which required both the wings and the fuselage to be redesigned and enlarged, and cost enough in money and delay that the Navy seriously considered cancelling the Demon outright. The first J71-powered Demon flew in October 1954, the first production F3H-2N in the spring of 1955, and the type finally entered service with VF-14 "Tophatters" on 7 March 1956, nearly five years after the prototype’s first flight. From there the Demon was a serviceable if underpowered fleet interceptor: 23 Navy fighter squadrons flew it — some accounts say 22 — between 1956 and 1964, and the aeroplane pilots had every reason to distrust turned out to be stable at altitude, easy to bring aboard, and well liked for its visibility, which earned it the nickname "the Chair". The power-to-weight ratio earned it the other one: "lead sled".

And then there is the part of the story that outlived the aircraft entirely. From 1953 McDonnell had been drawing bigger, more powerful Demons under the company designations F3H-G and F3H-H — the "Super Demon" — a modular machine that could take one- or two-seat noses and interchangeable nose cones for radar or cameras. The Navy ordered a full-scale mock-up in 1954, decided it already had enough fighters, and instead authorised two prototypes of an attack aircraft, the AH-1. On 26 May 1955 four Navy officers arrived at St Louis and rewrote the requirement inside an hour into an all-weather fleet-defence interceptor. That aircraft became the XF4H-1, and then the F-4 Phantom II. The family resemblance is not a coincidence and not a stylistic echo: the Phantom is what the Demon turned into when McDonnell was finally given engines that worked.

XF3H-1 (ordered 1949, first flight 1951 / 2)

Company Model 58. Prototype single-seat clear-weather interceptor, Westinghouse XJ40-WE-6 at 6,500 lbf dry and 9,200 lbf in afterburner — Polmar gives 7,200 and 10,900 for the same engine, one of many small unresolved disagreements in this programme’s literature. First flew 7 August 1951 from Lambert Field with McDonnell test pilot Robert Edholm. Easy to fly, manoeuvrable, responsive — and severely underpowered, especially high up. The first prototype was lost about four months later; both were grounded on engine trouble; the first was destroyed outright when its engine exploded on 18 March 1954.

F3H-1N (1953–55 / 58; nominally F-3A in 1962)

Company Model 58Q. The first production mark and the disaster. Single-seat all-weather fighter on the J40-WE-22 at 7,200 lbf dry and 10,900 lbf reheated, in an airframe sized for an engine of 13,700 lbf. Ordered before the mock-up was reviewed. Thirty-five flew; eight had major accidents; the fleet was permanently grounded in July 1955 and about 21 to 25 airframes went to Navy technical schools as ground instructional hulls. A handful of the bureau numbers in the F3H-1N block — 133520 and 133522 among them — reappear in the F3H-2N block, which is where the surviving airframes went.

F3H-1P (proposed / 0)

Reconnaissance version of the F3H-1. Never built, and given what happened to the F3H-1N, never likely to have been.

F3H-2N (1955–56 / 142; F-3C from 1962)

Company Model 58W. The re-engined aircraft and the mark that saved the programme: Allison J71-A-2, enlarged and strengthened wings and fuselage, four 20 mm cannon, APG-51A radar, Sidewinder capability. Entered service with VF-14 "Tophatters" on 7 March 1956. Wikipedia’s variant table credits this mark with 239 aircraft, which is arithmetically impossible; the bureau number blocks give 142.

F3H-2M (1955–57 / 80; MF-3B from 1962)

Company Model 58Y. The Sparrow carrier: four AAM-N-2 Sparrow I beam-riding missiles, the weapon that made the Demon one of the first American fighters armed primarily with guided missiles rather than guns. The beam-riding guidance was a dead end and was superseded within a few years by the semi-active Sparrow III, but the mark established the doctrine the Phantom would inherit.

F3H-2 (1957–60 / 239; F-3B from 1962)

Company Model 58AA and the most-built Demon of all. A strike fighter: it kept the Sidewinder and Sparrow capability of the -2N and -2M and added 6,000 lb of bombs or rockets on underwing pylons. This is the aircraft the baseline figures describe. Wikipedia gives production as ending in November 1959; Tom Cleaver’s account has the last airframe delivered on 8 April 1960.

F3H-2P (proposed / 0)

Company Model 58T. Photo-reconnaissance version of the F3H-2, drawn and never built. The Demon therefore served its whole career without a reconnaissance variant, unusual for a 1950s carrier fighter.

F3H-3 (proposed / 0)

Proposed re-engining with the General Electric J73. Unbuilt. Had it happened it would have been the third engine in five years for one airframe, which is a fair summary of the programme.

F3H-G / F3H-H "Super Demon" (1953–54 / 0 built, one full-scale mock-up)

The most consequential Demon variant of all, and none was built. A larger, heavier, twin-engined development with interchangeable one- and two-seat noses and swappable nose cones for radar or cameras, presented to the Navy on 19 September 1953. The Navy built the mock-up, decided it had enough fighters, ordered two AH-1 attack prototypes instead in October 1954, then rewrote the requirement again in May 1955. The result was the XF4H-1 — the F-4 Phantom II. Every Phantom that ever flew is a lineal descendant of this study.

Export and licence production (none)

There was none. No foreign navy or air force ever ordered, evaluated or operated the Demon, and no licence was granted. It was a US Navy aircraft exclusively, from first flight to last, and its reputation travelled far enough that nobody asked.

Closing note on survivors and on the record. Three Demons survive, out of 521 airframes built. All three are original aircraft; not one is a reproduction, and no reproduction Demon has ever been constructed. They are BuNo 137078, an F3H-2M accepted by the Navy on 24 May 1957 and flown for roughly two years, now at the National Museum of Naval Aviation at NAS Pensacola in VF-193 markings; BuNo 133566, an F3H-2N at the Intrepid Sea, Air & Space Museum in New York, displayed in VF-41 markings; and BuNo 145221, an F3H-2 delivered in July 1958 which served aboard USS Franklin D. Roosevelt and USS Shangri-La and has been at the Pima Air & Space Museum in Tucson since 1978 on loan from Pensacola. None is airworthy, none is in private hands, and there is no Demon gate guardian anywhere. That is a survival rate of about one airframe in 174, which is poor even by the standards of 1950s naval jets, and it reflects both a short service life and the fact that a substantial part of the production run had already been cut up by trainee mechanics before the type entered squadron service. Set against the record, the Demon deserves a more careful verdict than its nickname suggests. It was a genuinely good airframe: a large, well-behaved swept wing, excellent high-altitude handling, an honest and maintainable radar, and a cockpit view good enough that pilots named the aeroplane after a chair. It was also McDonnell’s first swept-wing aircraft, the only single-engined carrier fighter the company ever built, one of the first American fighters designed around missiles, and the machine from which the F-4 Phantom II directly descends. What it never had was an engine. The Navy tied it to the Westinghouse J40, overrode the manufacturer when he told them the engine would not do, and the bill came in at 11 crashes, four dead pilots, 21 to 25 new fighters barged to trade schools, $200 million and five years. The Allison J71 made the Demon serviceable from 1956 to 1964 and never made it good. It left the fleet in September 1964 when VF-161 "Chargers" traded its F-3s for F-4Bs, having never fired a shot in combat — and its replacement, built by the same firm from the same drawings with two engines that worked, went on to become the most important Western fighter of the Cold War.

From great hope to Phantom’s father

Twelve Demon stories

The Demon in pictures

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The Demon in motion

A curated video feature for the McDonnell F3H Demon is coming soon. In the meantime, explore the photo gallery above and the operator map below.

Where the Demon flew

Where the record stands

The Demon has no confirmed air-to-air combat record. It was built to intercept high-altitude bombers and stood carrier air-defence alert through the tense late 1950s and early 1960s, but the war it was designed for never came, and it was retired before Vietnam. Its legacy is not written in kills but in doctrine — the missile-armed, all-weather interception it pioneered — and in the aircraft it fathered, the F-4 Phantom II.

Compare the combat record of every military aircraft. Figures as of July 2026.

Everything people ask about the F3H Demon

Continue the tour

Every fact, checked

• National Naval Aviation Museum — F3H DemonOfficial Navy museum page: role, engine problems, production and the F-4 Phantom lineage.
• Vintage Aviation News — The Forgotten Ancestor of the PhantomDetailed account of the J40 losses, the J71 rescue, armament and Phantom connection.
• Pima Air & Space Museum — McDonnell F3H-2Museum specification sheet and service summary for the production Demon.
• The Armory Life — F3H DemonNarrative on the J40 fiasco, the 35-degree wing, the J71 switch and Sparrow armament.
• War History Online — Doomed Before It Entered ServiceFeature on the Demon’s troubled development and the engine that nearly killed it.
• Joe Baugher — McDonnell F3H DemonDetailed reference for variants, specifications, engine types and service dates.
• Military Factory — McDonnell F3H DemonCross-checked specification tables and production breakdown.
• Historical Marker Database — F3H-2N DemonConcise service and armament summary from a museum historical marker.