The evolutionary Demon

The McDonnell Aircraft Company expressed a fondness for paranormal or spooky aircraft names.

This may date back to the company’s ambitious XP-67 fighter design during World War II occasionally referred to as the Bat or Moonbat, although the official nature of such a moniker is unclear.

Nonetheless, McDonnell — later McDonnell-Douglas and now part of the mega Boeing holdings — ran through a list of names with its ensuing jet fighters, including Phantom, Banshee, Goblin, and the F3H Demon.

McDonnell’s first foray into swept wings for fighters, the XF3H Demon was designed to use one Westinghouse J40 turbojet engine. The J40 failed to develop into the high-performance powerplant that was envisioned, and early F3Hs with lower-rated J40s were considered overweight as a result.

McDonnell’s reliance on a single J40 instead of a pair of jet engines as was its practice earlier would not be repeated with the company’s later production jet fighters, all of which used two engines.  

First flight of the XF3H-1 was Aug. 7, 1951. The original 56 production F3H-1s used J40 engines producing 7,200 pounds of static thrust (variously reported as 7,250 or up to 7,500 pounds).

The higher-rated J40 did not materialize before a switch was made to the Allison J71 engine rated at 9,700 pounds of static thrust used in the F3H-2.

It can be frustrating chasing airplane specifications. The Navy’s own official Standard Aircraft Characteristics description of the F3H-2M says its J71 engine has a normal thrust rating of 8,800 pounds and a military rating of 10,200. A number of F3H-1s had already been re-engined with the higher-rated Allison before the F3H-2 made its first flight in the summer of 1955.

What resulted was a reasonably viable swept wing jet fighter for the Navy, carrying four 20-mm cannons in the nose and later Sparrow and Sidewinder air-to-air missiles.

The primary mission for the F3H-1 was listed in an official description as “the destruction of enemy aircraft.”

The 239 F3H-2s could be configured as strike fighters, with air-to-ground ordnance. It was the F3H-2M that was Sparrow-equipped, capable of carrying four of the supersonic missiles, and the F3H-2N included Sidewinders in a limited all-weather fighter role.

The F3H pilot was enclosed in a pressurized cockpit with ample glazing. An ejection seat and automatic pilot were furnished. To increase lift during crucial slow airspeed landings and takeoffs, the Demon’s swept wing incorporated power-actuated leading edge slats and trailing edge plain flaps. 

The F3H was designed with a simple 90° outboard upward wing folding mechanism that increased the number of Demons that could be stowed on an aircraft carrier.

“A total of 64 airplanes can be accommodated in a landing spot on the hangar decks of a CVA-19 class angled deck carrier,” Navy officials noted.

This referenced the World-War II Essex-class carriers, a number of which were upgraded with angled flight decks in the 1950s. 

The angled flight decks were especially useful for early jet fighters, allowing them to land on the angled portion while others could simultaneously take off from the forward catapults. The angle of the deck, skewed to the left of center, gave landing jets a clear exit path in the event of a go-around.

The F3H-2N’s wingspan was 35′, 4″ in flight. That was reduced to 25′, 4″, for hangar deck stowage. The wing fold was placed at a point that made the folded wings no higher than the tail, which stood a bit more than 14.5′ above the ground. The Demon was 58′, 11.5″ in length.

Maximum speed listed for the F3H-2N by the Navy was 628 knots at sea level. Other tables vary slightly, but the F3H was a subsonic performer.

In 1962, nomenclature for Navy aircraft was revised, and the F3H became the F-3. More than 500 Demons issued from the McDonnell assembly line in St. Louis.

In service well into 1964, Demons complemented faster fighters like the F-8 Crusader and F-4 Phantom II, McDonnell’s successor to the Demon. The family resemblance is evident between the Demon and the Phantom II. 

Three Demons are displayed at this time. A single F3H-2M (MF-3B) is in the National Naval Aviation Museum at Pensacola, Florida. Two F3H-2Ns (F-3C) are at the Pima Air and Space Museum in Tucson, Arizona, and the USS Intrepid Museum in New York City.